WorldWideScience

Sample records for mode output power

  1. A dual mode charge pump with adaptive output used in a class G audio power amplifier*

    Institute of Scientific and Technical Information of China (English)

    Feng Yong; Peng Zhenfei; Yang Shanshan; Hong Zhiliang; Liu Yang

    2011-01-01

    A dual mode charge pump to produce an adaptive power supply for a class G audio power amplifier is presented. According to the amplitude of the input signals, the charge pump has two level output voltage rails available to save power. It operates both in current mode at high output load and in pulse frequency modulation (PFM) at light load to reduce the power dissipation. Also, dynamic adjustment of the power stage transistor size based on load current at the PFM mode is introduced to reduce the output voltage ripple and prevent the switching frequency from audio range. The prototype is implemented in 0.18μm 3.3 V CMOS technology. Experimental results show that the maximum power efficiency of the charge pump is 79.5% @ 0.5x mode and 83.6% @ lx mode. The output voltage ripple is less than 15 mV while providing 120 mA of the load current at PFM control and less than 18 mV while providing 300 mA of the load current at current mode control. An analytical model for ripple voltage and efficiency calculation of the proposed PFM control demonstrates reasonable agreement with measured results.

  2. A dual mode charge pump with adaptive output used in a class G audio power amplifier

    Energy Technology Data Exchange (ETDEWEB)

    Feng Yong; Peng Zhenfei; Yang Shanshan; Hong Zhiliang [State Key Laboratory of ASIC and System, Fudan University Shanghai 201203 (China); Liu Yang, E-mail: zlhong@fudan.edu.cn [Shanghai Design Center, Analog Devices, Shanghai 200021 (China)

    2011-04-15

    A dual mode charge pump to produce an adaptive power supply for a class G audio power amplifier is presented. According to the amplitude of the input signals, the charge pump has two level output voltage rails available to save power. It operates both in current mode at high output load and in pulse frequency modulation (PFM) at light load to reduce the power dissipation. Also, dynamic adjustment of the power stage transistor size based on load current at the PFM mode is introduced to reduce the output voltage ripple and prevent the switching frequency from audio range. The prototype is implemented in 0.18 {mu}m 3.3 V CMOS technology. Experimental results show that the maximum power efficiency of the charge pump is 79.5% - 0.5x mode and 83.6% - 1x mode. The output voltage ripple is less than 15 mV while providing 120 mA of the load current at PFM control and less than 18 mV while providing 300 mA of the load current at current mode control. An analytical model for ripple voltage and efficiency calculation of the proposed PFM control demonstrates reasonable agreement with measured results. (semiconductor integrated circuits)

  3. Techniques for increasing output power from mode-locked semiconductor lasers

    Energy Technology Data Exchange (ETDEWEB)

    Mar, A.; Vawter, G.A.

    1996-02-01

    Mode-locked semiconductor lasers have drawn considerable attention as compact, reliable, and relatively inexpensive sources of short optical pulses. Advances in the design of such lasers have resulted in vast improvements in pulsewidth and noise performance, at a very wide range of repetition rates. An attractive application for these lasers would be to serve as alternatives for large benchtop laser systems such as dye lasers and solid-state lasers. However, mode-locked semiconductor lasers have not yet approached the performance of such systems in terms of output power. Different techniques for overcoming the problem of low output power from mode-locked semiconductor lasers will be discussed. Flared and arrayed lasers have been used successfully to increase the pulse saturation energy limit by increasing the gain cross section. Further improvements have been achieved by use of the MOPA configuration, which utilizes a flared semiconductor amplifier s amplify pulses to energies of 120 pJ and peak powers of nearly 30W.

  4. Output power spectrum of a single-mode laser driven by coloured pump and quantum noises with coloured correlation

    Institute of Scientific and Technical Information of China (English)

    Han Li-Bo; Cao Li; Wu Da-Jin

    2004-01-01

    By using the linear approximation method, the output power spectrum is calculated for a single-mode laser driven by coloured pump and quantum noises with coloured correlation. We have observed that the configuration of the output power spectrum is complicated: that is, it can be of single peak, two peaks or three peaks. The configurations of the power spectrum can be transformed from one into another by changing the cross-correlation time, the cross-correlation coefficient between the two noises, and pump noise intensity.

  5. Single-transverse-mode near-IR superluminescent diodes with cw output power up to 100 mW

    Science.gov (United States)

    Andreeva, E. V.; Il'chenko, S. N.; Kostin, Yu O.; Yakubovich, S. D.

    2014-10-01

    A series of light-emitting modules based on single-mode quantum-well superluminescent diodes with centre emission wavelengths of about 790, 840, 960 and 1060 nm and a cw output power up to 100 mW in free space is developed. A sufficiently long service life of these devices is demonstrated.

  6. Low Power Very High Frequency Switch-Mode Power Supply with 50 V Input and 5 V Output

    DEFF Research Database (Denmark)

    Madsen, Mickey Pierre; Knott, Arnold; Andersen, Michael A. E.

    2014-01-01

    This paper presents the design of a resonant converter with a switching frequency in the very high frequencyrange (30-300 MHz), a large step down ratio (10 times) and low output power (1 W). Several different invertersand rectifiers are analyzed and compared. The class E inverter and rectifier ar...

  7. Nonlinear Fractional Sliding Mode Controller Based on Reduced Order FNPK Model for Output Power Control of Nuclear Research Reactors

    Science.gov (United States)

    Davijani, Nafiseh Zare; Jahanfarnia, Gholamreza; Abharian, Amir Esmaeili

    2017-01-01

    One of the most important issues with respect to nuclear reactors is power control. In this study, we designed a fractional-order sliding mode controller based on a nonlinear fractional-order model of the reactor system in order to track the reference power trajectory and overcome uncertainties and external disturbances. Since not all of the variables in an operating reactor are measurable or specified in the control law, we propose a reduced-order fractional neutron point kinetic (ROFNPK) model based on measurable variables. In the design, we assume the differences between the approximated model and the real system is limited. We use the obtained model in the controller design process and use the Lyapunov method to perform a stability analysis of the closed-loop system. We simulate the proposed reduced-order fractional-order sliding mode controller (ROFOSMC) using Matlab/Simulink, and its performance is compared with that of a reduced order integer-order sliding mode controller (ROIOSMC). Our simulation results indicate an acceptable performance of the proposed approach in tracking the reference power trajectory with respect to ROIOSMC because of faster response of control effort signal and the smaller tracking error. Moreover, the results illustrate the capability of the controller in rejection of the disturbance and the noise signals and the robustness of controller against uncertainty.

  8. 多路输出反激式开关电源的设计%Design of multiple-output flyback switching mode power supply

    Institute of Scientific and Technical Information of China (English)

    杜琰琪; 范鹏飞; 凌有铸

    2012-01-01

    设计了一种基于TOP246Y芯片的单端反激式多路输出开关电源,电源提供八路输出,为电机伺服系统中的功率板和控制板提供可靠的工作电压.实验表明,电源能够在输入电压波动较大的情况下提供稳定的直流输出,达到设计指标要求.%The paper designed a single-ended flyback multi-output switching mode power supply based on TOP246Y chip,which has eight outputs and provides a reliable voltage for the motor servo system in the power board and control board. This paper mainly introduced the high-frequency transformer and chip peripheral circuit design. According to the requirements of the design, the circuit diagram, the calculation step of main parameter of transformer as well as the main 5 V output t voltage waveform were presentecl. Experiments show that the power can provide a stable DC output to meet the design target requirements in the case of input voltage fluctuations.

  9. Output beam analysis of high power COIL

    Institute of Scientific and Technical Information of China (English)

    Deli Yu(于德利); Fengting Sang(桑凤亭); Yuqi Jin(金玉奇); Yizhu Sun(孙以珠)

    2003-01-01

    As the output power of a chemical oxygen iodine laser (COIL) increases, the output laser beam instabilityappears as the far-field beam spot drift and deformation for the large Fresnel number unstable resonator.In order to interpret this phenomenon, an output beam mode simulation code was developed with the fastFourier transform method. The calculation results show that the presence of the nonuniform gain in COILproduces a skewed output intensity distribution, which causes the mirror tilt and bulge due to the thermalexpansion. With the output power of COIL increases, the mirror surfaces, especially the back surface ofthe scraper mirror, absorb more and more heat, which causes the drift and deformation of far field beamspot seriously. The initial misalignment direction is an important factor for the far field beam spot driftingand deformation.

  10. A modified relativistic magnetron with TEM output mode

    Science.gov (United States)

    Shi, Di-Fu; Qian, Bao-Liang; Wang, Hong-Gang; Li, Wei; Ju, Jin-Chuan; Du, Guang-Xing

    2017-01-01

    A modified relativistic magnetron (RM) with TEM output mode is proposed. By setting the coupling slots at the bottom of the resonant cavities in the transmission region rather than in the interaction region, besides possessing the original RM's advantages of high power conversion efficiency and radiating the lowest order mode, the modified RM not only improves the compactness and miniaturization of the magnetic field system, which is beneficial to realize the RMs packed by a permanent magnet, but also improves the robustness of operating frequency to structural perturbations of the coupling slots, which contributes to optimize the RM performance by adjusting the coupling slot dimensions with a relatively stable operating frequency. In the three-dimensional particle-in-cell (PIC) simulation, the modified RM with a reduction of 27.2% in the weight of the coils, 35.8% in the occupied space of the coils, and 18.6% in the operating current, can output a relatively pure TEM mode, which has been demonstrated as the dominant output mode by simulation, corresponding to an output power of 495.0 MW and a power conversion efficiency of 56.4%, at the resonant frequency of 4.30 GHz. In addition, an output power of above 2 GW can also be obtained from the RM in simulations.

  11. REGULATION OF INSTANTANEOUS POWER OUTPUT VALUE IN MAGNETRON WITH CONTINUOUS GENERATION MODE (M-105-, M-112-TYPES BEING PART OF PLASMA TECHNOLOGICAL UNIT

    Directory of Open Access Journals (Sweden)

    S. V. Bordusov

    2010-01-01

    Full Text Available The paper presents results of investigations pertaining to the possibility of regulating instantaneous power output  in a magnetron of M-105 (M-112-type by changing the capacity value of a capacitor in structure diagram for doubling voltage of high-voltage power supply on the basis of a step-up transformer operating in the saturation regime.

  12. The Output Power Sistribution mode of PV System%光伏发电系统输出功率分布模型研究

    Institute of Scientific and Technical Information of China (English)

    葛业斌; 张步涵; 颜秋容

    2012-01-01

    Photovoltaic solar energy utilization as the main form, have been widely used as a platform to use solar energy in the world. However, PV system is significantly different from traditional energy at its randomness. The existing photovoltaic system can't be as traditional thermal power, hydro power, as the output stable, so the power output of photovoltaic power generation system is a problem worthy of study. In this paper, based on the study of multiple [actors on the output of PV system, a mathematical model suitable for the effect of certain factors and random factors was established. Then the executable program was designed to simulate the output power of the PV system. Finally, the simulation results were analyzed to obtain an output power distribution model suitable for distribution system reliability evaluation of PV system.%在研究多种因素对光伏发电系统输出功率影响的前提下,建立适合确定性影响因素和多种随机性影响因素共同作用下的光伏发电系统输出功率的数学模型.然后编写光伏发电系统的输出功率的可执行程序,进行仿真.最后,对仿真结果进行分析,从而得到适用于配电系统可靠性评估的光伏发电系统的输出功率分布模型.

  13. Exercise efficiency of low power output cycling.

    Science.gov (United States)

    Reger, M; Peterman, J E; Kram, R; Byrnes, W C

    2013-12-01

    Exercise efficiency at low power outputs, energetically comparable to daily living activities, can be influenced by homeostatic perturbations (e.g., weight gain/loss). However, an appropriate efficiency calculation for low power outputs used in these studies has not been determined. Fifteen active subjects (seven females, eight males) performed 14, 5-min cycling trials: two types of seated rest (cranks vertical and horizontal), passive (motor-driven) cycling, no-chain cycling, no-load cycling, cycling at low (10, 20, 30, 40 W), and moderate (50, 60, 80, 100, 120 W) power outputs. Mean delta efficiency was 57% for low power outputs compared to 41.3% for moderate power outputs. Means for gross (3.6%) and net (5.7%) efficiencies were low at the lowest power output. At low power outputs, delta and work efficiency values exceeded theoretical values. In conclusion, at low power outputs, none of the common exercise efficiency calculations gave values comparable to theoretical muscle efficiency. However, gross efficiency and the slope and intercept of the metabolic power vs mechanical power output regression provide insights that are still valuable when studying homeostatic perturbations.

  14. Proposal for the Award of a Contract for the Supply of Four-Quadrant Switched-Mode Power Converters with Variable Bipolar Output for the LHC

    CERN Document Server

    2003-01-01

    This document concerns the award of a contract for the supply of 444 four-quadrant switched-mode power converters rated at 600 A, ±10 V and 50 four-quadrant switched-mode power converters rated at 600 A, ± 40 V. Following a market survey carried out among 66 firms in fifteen Member States and a call for tenders for prototypes (IT-2847/SL/LHC) sent on 22 March 2001, a call for tenders (IT-2847/SL/LHC/Rev.) for the supply of switched-mode power converters rated at 600 A, ±10 V and 600 A, ± 40 V was sent to three firms on 1 August 2002. The Finance Committee is invited to agree to the negotiation of a contract with the consortium CIRTEM (FR)/ E.E.I. (IT) for the supply of 444 switched-mode power converters rated at 600 A, ± 10 V and 50 switched-mode power converters rated at 600 A, ± 40 V for a total amount of 8 048 835 euros (11 703 994 Swiss francs) not subject to revision. The rate of exchange used is that stipulated in the tender. The firm has indicated the following distribution by country of the cont...

  15. Solar Power Station Output Inverter Control Design

    Directory of Open Access Journals (Sweden)

    J. Bauer

    2011-04-01

    Full Text Available The photovoltaic applications spreads in these days fast, therefore they also undergo great development. Because the amount of the energy obtained from the panel depends on the surrounding conditions, as intensity of the sun exposure or the temperature of the solar array, the converter must be connected to the panel output. The Solar system equipped with inverter can supply small loads like notebooks, mobile chargers etc. in the places where the supplying network is not present. Or the system can be used as a generator and it shall deliver energy to the supply network. Each type of the application has different requirements on the converter and its control algorithm. But for all of them the one thing is common – the maximal efficiency. The paper focuses on design and simulation of the low power inverter that acts as output part of the whole converter. In the paper the design of the control algorithm of the inverter for both types of inverter application – for islanding mode and for operation on the supply grid – is discussed. Attention is also paid to the design of the output filter that should reduce negative side effects of the converter on the supply network.

  16. Silicon Integrated Dual-Mode Interferometer with Differential Outputs

    Directory of Open Access Journals (Sweden)

    Niklas Hoppe

    2017-09-01

    Full Text Available The dual-mode interferometer (DMI is an attractive alternative to Mach-Zehnder interferometers for sensor purposes, achieving sensitivities to refractive index changes close to state-of-the-art. Modern designs on silicon-on-insulator (SOI platforms offer thermally stable and compact devices with insertion losses of less than 1 dB and high extinction ratios. Compact arrays of multiple DMIs in parallel are easy to fabricate due to the simple structure of the DMI. In this work, the principle of operation of an integrated DMI with differential outputs is presented which allows the unambiguous phase shift detection with a single wavelength measurement, rather than using a wavelength sweep and evaluating the optical output power spectrum. Fluctuating optical input power or varying attenuation due to different analyte concentrations can be compensated by observing the sum of the optical powers at the differential outputs. DMIs with two differential single-mode outputs are fabricated in a 250 nm SOI platform, and corresponding measurements are shown to explain the principle of operation in detail. A comparison of DMIs with the conventional Mach-Zehnder interferometer using the same technology concludes this work.

  17. Proposal for the award of three contracts for the supply of qualifying prototypes for switch-mode power converters with variable bipolar output for the LHC

    CERN Document Server

    2001-01-01

    This document concerns the award of three contracts, each for the design, documentation, manufacture, factory testing and delivery of one qualifying prototype four-quadrant switch-mode power converter at ± 600 A, ± 10 V and one qualifying prototype four-quadrant switch-mode power converter at ± 600 A, ± 40 V. Following a market survey carried out among 66 firms in fifteen Member States, a call for tenders (IT-2847/SL/LHC) was sent on 22 March 2001 to six firms and one consortium, consisting of two firms, in six Member States. By the closing date, CERN had received four tenders from three firms and the consortium in five Member States. The Finance Committee is invited to agree to the negotiation of contracts with two firms and one consortium for the design, documentation, manufacture, factory testing and delivery of one four-quadrant switch-mode power converter at ± 600 A, ± 10 V and one four-quadrant switch-mode power converter at ± 600 A, ± 40 V: 1) JEMA (ES) for a total amount of 144 128 euros (220 ...

  18. Coupling output of multichannel high power microwaves

    Science.gov (United States)

    Li, Guolin; Shu, Ting; Yuan, Chengwei; Zhang, Jun; Yang, Jianhua; Jin, Zhenxing; Yin, Yi; Wu, Dapeng; Zhu, Jun; Ren, Heming; Yang, Jie

    2010-12-01

    The coupling output of multichannel high power microwaves is a promising technique for the development of high power microwave technologies, as it can enhance the output capacities of presently studied devices. According to the investigations on the spatial filtering method and waveguide filtering method, the hybrid filtering method is proposed for the coupling output of multichannel high power microwaves. As an example, a specific structure is designed for the coupling output of S/X/X band three-channel high power microwaves and investigated with the hybrid filtering method. In the experiments, a pulse of 4 GW X band beat waves and a pulse of 1.8 GW S band microwave are obtained.

  19. Auxetic piezoelectric energy harvesters for increased electric power output

    Science.gov (United States)

    Li, Qiang; Kuang, Yang; Zhu, Meiling

    2017-01-01

    This letter presents a piezoelectric bimorph with auxetic (negative Poisson's ratio) behaviors for increased power output in vibration energy harvesting. The piezoelectric bimorph comprises a 2D auxetic substrate sandwiched between two piezoelectric layers. The auxetic substrate is capable of introducing auxetic behaviors and thus increasing the transverse stress in the piezoelectric layers when the bimorph is subjected to a longitudinal stretching load. As a result, both 31- and 32-modes are simultaneously exploited to generate electric power, leading to an increased power output. The increasing power output principle was theoretically analyzed and verified by finite element (FE) modelling. The FE modelling results showed that the auxetic substrate can increase the transverse stress of a bimorph by 16.7 times. The average power generated by the auxetic bimorph is 2.76 times of that generated by a conventional bimorph.

  20. Capital Power:From Input to Output

    Institute of Scientific and Technical Information of China (English)

    You Wanlong; Alice

    2009-01-01

    @@ After thirty yeas "going out" of China overseas investment,we learn from our failed lessons and also successful experience.Chinese enterprises are now standing at a new starting point of "going out".China is transforming from "capital input power" to "capital output power".

  1. Corrugated waveguide mode purifier for TEM output in a dual-mode operation overmoded coaxial millimeter-wave generator

    Science.gov (United States)

    Bai, Zhen; Zhang, Jun; Zhong, Huihuang; Zhang, Dian

    2017-01-01

    A coaxial corrugated waveguide mode purifier is designed for a dual-mode operation overmoded coaxial millimeter-wave generator. With the purifier, the mixed TEM and TM01 modes output are purified into a pure TEM mode. Particle-in-cell (PIC) simulation shows that the purifier would not decrease the total output power of the generator, and plays an independent role to the upstream structure. Effects of mode composition ratio and phase difference on the purification ability of the purifier are also researched by both electromagnetism and PIC simulations, which show that the purifier has a certain tolerance for both the mode composition ratio and phase difference.

  2. Programmable Input Mode Instrumentation Amplifier Using Multiple Output Current Conveyors

    Directory of Open Access Journals (Sweden)

    Pankiewicz Bogdan

    2017-03-01

    Full Text Available In this paper a programmable input mode instrumentation amplifier (IA utilising second generation, multiple output current conveyors and transmission gates is presented. Its main advantage is the ability to choose a voltage or current mode of inputs by setting the voltage of two configuration nodes. The presented IA is prepared as an integrated circuit block to be used alone or as a sub-block in a microcontroller or in a field programmable gate array (FPGA, which shall condition analogue signals to be next converted by an analogue-to-digital converter (ADC. IA is designed in AMS 0.35 µm CMOS technology and the power supply is 3.3 V; the power consumption is approximately 9.1 mW. A linear input range in the voltage mode reaches ± 1.68 V or ± 250 µA in current mode. A passband of the IA is above 11 MHz. The amplifier works in class A, so its current supply is almost constant and does not cause noise disturbing nearby working precision analogue circuits.

  3. Discontinuous Mode Power Supply

    Science.gov (United States)

    Lagadinos, John; Poulos, Ethel

    2012-01-01

    A document discusses the changes made to a standard push-pull inverter circuit to avoid saturation effects in the main inverter power supply. Typically, in a standard push-pull arrangement, the unsymmetrical primary excitation causes variations in the volt second integral of each half of the excitation cycle that could lead to the establishment of DC flux density in the magnetic core, which could eventually cause saturation of the main inverter transformer. The relocation of the filter reactor normally placed across the output of the power supply solves this problem. The filter reactor was placed in series with the primary circuit of the main inverter transformer, and is presented as impedance against the sudden changes on the input current. The reactor averaged the input current in the primary circuit, avoiding saturation of the main inverter transformer. Since the implementation of the described change, the above problem has not reoccurred, and failures in the main power transistors have been avoided.

  4. Stability of the single-mode output of a laser diode array with phase conjugate feedback

    DEFF Research Database (Denmark)

    Juul Jensen, S.; Løbel, M.; Petersen, P.M.

    2000-01-01

    The stability of the output of a single-mode laser diode array with frequency selective phase conjugate feedback has been investigated experimentally. Both the long-term stability of the laser output and the sensitivity to feedback generated by external reflection of the output beam are examined....... The output power and the center wavelength are found to be extremely stable in a 100 h stability measurement. External feedback of the output beam into the laser is seen to decrease both the spatial and the temporal coherence of the output significantly. We outline an approach to obtain a stable single...

  5. Uncertainties in predicting solar panel power output

    Science.gov (United States)

    Anspaugh, B.

    1974-01-01

    The problem of calculating solar panel power output at launch and during a space mission is considered. The major sources of uncertainty and error in predicting the post launch electrical performance of the panel are considered. A general discussion of error analysis is given. Examples of uncertainty calculations are included. A general method of calculating the effect on the panel of various degrading environments is presented, with references supplied for specific methods. A technique for sizing a solar panel for a required mission power profile is developed.

  6. Battery Energy Storage System for PV Output Power Leveling

    Directory of Open Access Journals (Sweden)

    Rajkiran Singh

    2014-01-01

    Full Text Available Fluctuating photovoltaic (PV output power reduces the reliability in power system when there is a massive penetration of PV generators. Energy storage systems that are connected to the PV generators using bidirectional isolated dc-dc converter can be utilized for compensating the fluctuating PV power. This paper presents a grid connected energy storage system based on a 2 kW full-bridge bidirectional isolated dc-dc converter and a PWM converter for PV output power leveling. This paper proposes two controllers: a current controller using the d-q synchronous reference and a phase-shift controller. The main function of the current controller is to regulate the voltage at the high-side dc, so that the voltage ratio of the high-voltage side (HVS with low-voltage side (LVS is equal to the transformer turns ratio. The phase-shift controller is employed to manage the charging and discharging modes of the battery based on PV output power and battery voltage. With the proposed system, unity power factor and efficient active power injection are achieved. The feasibility of the proposed control system is investigated using PSCAD simulation.

  7. Switching-mode Audio Power Amplifiers with Direct Energy Conversion

    DEFF Research Database (Denmark)

    Ljusev, Petar; Andersen, Michael Andreas E.

    2005-01-01

    This paper presents a new class of switching-mode audio power amplifiers, which are capable of direct energy conversion from the AC mains to the audio output. They represent an ultimate integration of a switching-mode power supply and a Class D audio power amplifier, where the intermediate DC bus...

  8. Overmoded subterahertz surface wave oscillator with pure TM{sub 01} mode output

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Guangqiang; Zeng, Peng; Wang, Dongyang [Northwest Institute of Nuclear Technology, P. O. Box 69-1, Xi' an 710024 (China); Science and Technology on High Power Microwave Laboratory, Xi' an 710024 (China); Wang, Jianguo, E-mail: wanguiuc@mail.xjtu.edu.cn [Northwest Institute of Nuclear Technology, P. O. Box 69-1, Xi' an 710024 (China); School of Electronic and Information Engineering, Xi' an Jiaotong University, Xi' an 710049 (China); Li, Shuang [Northwest Institute of Nuclear Technology, P. O. Box 69-1, Xi' an 710024 (China); Science and Technology on High Power Microwave Laboratory, Xi' an 710024 (China); School of Electronic and Information Engineering, Xi' an Jiaotong University, Xi' an 710049 (China)

    2016-02-15

    Overmoded O-type Cerenkov generators using annular electron beams are facing the problem of multi-modes output due to the inevitable structural discontinuities. A simple but effective method to achieve the pure TM{sub 01} mode output is applied on the 0.14 THz overmoded surface wave oscillator (SWO) in this paper. In spite of still using an overmoded slow wave structure to ensure the easy fabrication, the followed smooth circular waveguide is shrinkingly tapered to the output waveguide with appropriate radius that it cuts off other higher modes except TM{sub 01} mode. Moreover, the modified device here has the same power capacity as the previous one according to the numerical analysis. By optimized lengths of the transition waveguide and tapered waveguide, particle-in-cell simulation results indicate that the subterahertz wave with output power increased 14.2% at the same frequency is obtained from the proposed SWO under the previous input conditions, and importantly, the output power is all carried by TM{sub 01} mode as expected. Further simulation results in the pulse regime confirm the feasibility of the optimized structure in the actual experiments. This simple and viable design is also applicable to overmoded devices in the lower frequency band of subterahertz wave.

  9. Call-related factors influencing output power from mobile phones.

    Science.gov (United States)

    Hillert, Lena; Ahlbom, Anders; Neasham, David; Feychting, Maria; Järup, Lars; Navin, Roshan; Elliott, Paul

    2006-11-01

    Mobile phone use is increasing but there is also concern for adverse health effects. Well-designed prospective studies to assess several health outcomes are required. In designing a study of mobile phone use, it is important to assess which factors need to be considered in classifying the exposure to radiofrequency fields (RF). A pilot study was performed in Sweden and in the UK 2002 to 2003 to test the feasibility of recruiting a cohort of mobile phone users from a random population sample and from mobile phone subscription lists for a prospective study. As one part of this pilot study, different factors were evaluated regarding possible influence on the output power of the phones. By local switch logging, information on calls made from predefined subscriptions or dedicated handsets were obtained and the output power of phones during calls made indoors and outdoors, in moving and stationary mode, and in rural as well in urban areas were compared. In this experiment, calls were either 1, 1.5 or 5 min long. The results showed that high mobile phone output power is more frequent in rural areas whereas the other factors (length of call, moving/stationary, indoor/outdoor) were of less importance. Urban and rural area should be considered in an exposure index for classification of the exposure to RF from mobile phones and may be assessed by first base station during mobile phone calls or, if this information is not available, possibly by using home address as a proxy.

  10. Experimental Investigation on Power Output in Aged Wind Turbines

    Directory of Open Access Journals (Sweden)

    N. Murugan

    2012-01-01

    Full Text Available An investigation on the power output on effect of tower height with same diameter of rotor was conducted in a wind turbine site. As the wind acceleration is varying with height, 3 levels were selected according to the availability of tower. The responses of power output with respect to variation of wind speed are changing for the tower heights of 30, 40, and 50 m. The study showed that the actual ideal power output and measured real power output follow the same trend within range of operating wind speed. The empirical model used for calculation of actual ideal power output was compared with real power output and the overall concepts in power output also had been analysed.

  11. Highly efficient high power single-mode fiber amplifier utilizing the distributed mode filtering bandgap rod fiber

    DEFF Research Database (Denmark)

    Laurila, Marko; Alkeskjold, Thomas T.; Jørgensen, Mette Marie

    2012-01-01

    We report on an ytterbium doped single mode distributed mode filtering rod fiber in an amplifier configuration delivering high average output power, up to 292 watts, using a mode-locked 30ps source at 1032nm with good power conversion efficiency. We study the modal stability of the output beam...

  12. Robust output LQ optimal control via integral sliding modes

    CERN Document Server

    Fridman, Leonid; Bejarano, Francisco Javier

    2014-01-01

    Featuring original research from well-known experts in the field of sliding mode control, this monograph presents new design schemes for implementing LQ control solutions in situations where the output system is the only information provided about the state of the plant. This new design works under the restrictions of matched disturbances without losing its desirable features. On the cutting-edge of optimal control research, Robust Output LQ Optimal Control via Integral Sliding Modes is an excellent resource for both graduate students and professionals involved in linear systems, optimal control, observation of systems with unknown inputs, and automatization. In the theory of optimal control, the linear quadratic (LQ) optimal problem plays an important role due to its physical meaning, and its solution is easily given by an algebraic Riccati equation. This solution turns out to be restrictive, however, because of two assumptions: the system must be free from disturbances and the entire state vector must be kn...

  13. Adaptive output feedback control of aircraft flexible modes

    OpenAIRE

    Ponnusamy, Sangeeth Saagar; Bordeneuve-Guibé, Joël

    2012-01-01

    The application of adaptive output feedback augmentative control to the flexible aircraft problem is presented. Experimental validation of control scheme was carried out using a three disk torsional pendulum. In the reference model adaptive control scheme, the rigid aircraft reference model and neural network adaptation is used to control structural flexible modes and compensate for the effects unmodeled dynamics and parametric variations of a classical high order large passenger aircraft. Th...

  14. Output power control for large wind power penetration in small power system

    Energy Technology Data Exchange (ETDEWEB)

    Senjyu, Tomonobu; Kaneko, Toshiaki; Uehara, Akie; Yona, Atsushi; Sekine, Hideomi [University of the Ryukyus, 1 Senbaru, Nishihara-cho, Nakagami, Okinawa 903-0213 (Japan); Kim, Chul-Hwan [Sungkyunkwan University, Suwon 440-746 (Korea)

    2009-11-15

    Nowadays, wind turbine generator (WTG) is increasingly required to provide control capabilities regarding output power. Under this scenario, this paper proposes an output power control of WTG using pitch angle control connected to small power systems. By means of the proposed method, output power control of WTG considering states of power system becomes possible, and in general both conflicting objectives of output power leveling and acquisition power increase are achieved. In this control approach, WTG is given output power command by fuzzy reasoning which has three inputs for average wind speed, variance of wind speed, and absolute average of frequency deviation. Since fuzzy reasoning is used, it is possible to define output power command corresponding to wind speed condition and changing capacity of power system momentarily. Moreover, high performance pitch angle control based on output power command is achieved by generalized predictive control (GPC). The simulation results by using actual detailed model for wind power system show the effectiveness of the proposed method. (author)

  15. Multi Carrier Modulator for Switch-Mode Audio Power Amplifiers

    DEFF Research Database (Denmark)

    Knott, Arnold; Pfaffinger, Gerhard; Andersen, Michael Andreas E.

    2008-01-01

    While switch-mode audio power amplifiers allow compact implementations and high output power levels due to their high power efficiency, they are very well known for creating electromagnetic interference (EMI) with other electronic equipment, in particular radio receivers. Lowering the EMI of swit...

  16. Design study of the KAGRA output mode cleaner

    Science.gov (United States)

    Kumeta, Ayaka; Bond, Charlotte; Somiya, Kentaro

    2015-02-01

    Most second-generation gravitational-wave detectors employ an optical resonator called an output mode cleaner (OMC), which filters out junk light from the signal and the reference light, before it reaches the detection photodiode located at the asymmetric port of the large-scale interferometer. The optical parameters of the OMC should be carefully chosen to satisfy the requirements to filter out unwanted light whilst transmitting the gravitational-wave signal. We use the simulation program FINESSE and realistic mirror phase maps that have the same surface quality as the KAGRA test masses to find out a proper design of the KAGRA OMC.

  17. Solar Power Station Output Inverter Control Design

    OpenAIRE

    Bauer, J.; Lettl, J.

    2011-01-01

    The photovoltaic applications spreads in these days fast, therefore they also undergo great development. Because the amount of the energy obtained from the panel depends on the surrounding conditions, as intensity of the sun exposure or the temperature of the solar array, the converter must be connected to the panel output. The Solar system equipped with inverter can supply small loads like notebooks, mobile chargers etc. in the places where the supplying network is not present. Or the system...

  18. Verification of hourly forecasts of wind turbine power output

    Energy Technology Data Exchange (ETDEWEB)

    Wegley, H.L.

    1984-08-01

    A verification of hourly average wind speed forecasts in terms of hourly average power output of a MOD-2 was performed for four sites. Site-specific probabilistic transformation models were developed to transform the forecast and observed hourly average speeds to the percent probability of exceedance of an hourly average power output. (This transformation model also appears to have value in predicting annual energy production for use in wind energy feasibility studies.) The transformed forecasts were verified in a deterministic sense (i.e., as continuous values) and in a probabilistic sense (based upon the probability of power output falling in a specified category). Since the smoothing effects of time averaging are very pronounced, the 90% probability of exceedance was built into the transformation models. Semiobjective and objective (model output statistics) forecasts were made compared for the four sites. The verification results indicate that the correct category can be forecast an average of 75% of the time over a 24-hour period. Accuracy generally decreases with projection time out to approx. 18 hours and then may increase due to the fairly regular diurnal wind patterns that occur at many sites. The ability to forecast the correct power output category increases with increasing power output because occurrences of high hourly average power output (near rated) are relatively rare and are generally not forecast. The semiobjective forecasts proved superior to model output statistics in forecasting high values of power output and in the shorter time frames (1 to 6 hours). However, model output statistics were slightly more accurate at other power output levels and times. Noticeable differences were observed between deterministic and probabilistic (categorical) forecast verification results.

  19. High-power single-mode trench-assisted EDFA

    Science.gov (United States)

    Gaur, Ankita; Rastogi, Vipul

    2015-06-01

    A trench assisted, 0.15-NA, effective single mode leaky Erbium Doped Fiber Amplifier is proposed for high power applications. The segmented-core of the fiber enables to achieve 783 μm2 mode area which reduces nonlinearity and increases power handling capacity of the fiber. The leakage loss of the modes is controlled by annular core segments and low index trench in the cladding. The leakage loss of the LP11 mode is 10.49 dB/m and that of the fundamental mode is 0.017 dB/m at 1530 nm wavelength. We have injected 20 mW power into each mode and have calculated the gain for 26 m length of the fiber using 250 W pump at 980 nm wavelength. The signal power in the LP01 mode is amplified to 122 W and that in the LP11 mode drops down to 5.78×10-27 W. The low output signal power in LP11 mode ensures selective single mode amplification of fundamental mode. Selective single mode amplification confirms good beam quality at the output end.

  20. 固定导通时间控制的多路输出DC/DC电源的研制%Development of multi-channel output DC/DC power source on fixed on-time mode

    Institute of Scientific and Technical Information of China (English)

    王泽景; 徐怡; 龚春英

    2016-01-01

    For the cross-regulation problem in multiple-output flyback converters, this paper presents several ways to improve the multi-channel output voltage accuracy.Based on the control method of fixed on-time mode, this pa-per analyzes its principle and presents a wide input voltage range (200~900V) multiple-output dual switch fly-back, and the load is 50W, and output voltage has seven terminals.The problems encountered in the process of the development were described and analyzed, and several solutions are given.%针对多路输出反激变换器交叉调整率的问题,给出了提高多路输出电压精度的几种方法.采用了固定导通时间模式的控制方法,分析了其工作原理,研制了一款宽输入电压范围(200~900V)、50W七路输出双管反激变换电源,并针对研制过程中遇到的问题进行了介绍和分析,给出了解决方法.

  1. 3D simulations on output power fluctuation in a short bunch rf-linac FEL

    Science.gov (United States)

    Sentoku, Y.; Furukawa, H.; Mima, K.; Taguchi, T.; Kuruma, S.; Yasuda, H.; Yamanaka, C.; Nakai, S.

    1995-04-01

    A space-time dependent 3D simulation code has been developed in order to analyze the RF-linac FEL oscillator dynamics. Our simulation code employed both the transverse mode spectral method and the longitudinal finite difference method. The electron beam is modeled by a group of super particles which have a density profile in the time domain. In this model the electron beam is able to determine the energy spread and the finite emittance. This simulation code enables us to describe the transverse mode competition and the slippage effects in the resonator cavity. In this paper, a high power infrared FEL with a short bunch electron beam is investigated. The output power fluctuation with cavity desynchronism is simulated with this code. Especially, we investigated the effects of the transverse mode competition, energy spread, and the finite emittance of the electron beam on the output fluctuation. Using FELIX parameters, the FEL oscillator is simulated for 300 passes. The output power oscillates periodically in the case of single transverse mode and not in the case of multi-transverse modes. In a warm beam with multi-transverse modes, the emission is higher than that with a single mode, and the optical pulse shape is almost the after 100 passes. Furthermore, the phase space motion of the laser field is periodic and stable. As a result of the simulation, we recommend that high power infrared FEL operation should include multi-transverse modes in order to get higher emission and a more stable optical pulse.

  2. Power output during women's World Cup road cycle racing.

    Science.gov (United States)

    Ebert, Tammie R; Martin, David T; McDonald, Warren; Victor, James; Plummer, John; Withers, Robert T

    2005-12-01

    Little information exists on the power output demands of competitive women's road cycle racing. The purpose of our investigation was to document the power output generated by elite female road cyclists who achieved success in FLAT and HILLY World Cup races. Power output data were collected from 27 top-20 World Cup finishes (19 FLAT and 8 HILLY) achieved by 15 nationally ranked cyclists (mean +/- SD; age: 24.1+/-4.0 years; body mass: 57.9+/-3.6 kg; height: 168.7+/-5.6 cm; VO2max 63.6+/-2.4 mL kg(-1) min(-1); peak power during graded exercise test (GXT(peak power)): 310+/-25 W). The GXT determined GXT(peak power), VO2peak lactate threshold (LT) and anaerobic threshold (AT). Bicycles were fitted with SRM powermeters, which recorded power (W), cadence (rpm), distance (km) and speed (km h(-1)). Racing data were analysed to establish time in power output and metabolic threshold bands and maximal mean power (MMP) over different durations. When compared to HILLY, FLAT were raced at a similar cadence (75+/-8 vs. 75+/-4 rpm, P=0.93) but higher speed (37.6+/-2.6 vs. 33.9+/-2.7 km h(-1), P=0.008) and power output (192+/-21 vs. 169+/-17 W, P=0.04; 3.3+/-0.3 vs. 3.0+/-0.4 W kg(-1), P=0.04). During FLAT races, riders spent significantly more time above 500 W, while greater race time was spent between 100 and 300 W (LT-AT) for HILLY races, with higher MMPs for 180-300 s. Racing terrain influenced the power output profiles of our internationally competitive female road cyclists. These data are the first to define the unique power output requirements associated with placing well in both flat and hilly women's World Cup cycling events.

  3. Design study of the KAGRA output mode-cleaner

    CERN Document Server

    Kumeta, Ayaka; Somiya, Kentaro

    2014-01-01

    Most second-generation gravitational-wave detectors employ an optical resonator called an output mode-cleaner (OMC), which filters out junk light from the signal and the reference light, before it reaches the detection photodiode located at the asymmetric port of the large-scale interferometer. The optical parameters of the OMC should be carefully chosen to satisfy the requirements to filter out unwanted light whilst transmitting the gravitational wave signal and reference light. The Japanese gravitational-wave detector KAGRA plans to use a very small amount of reference light to minimize the influence of quantum noise for gravitational waves from binary neutron stars, and hence the requirements to the OMC are more challenging than for other advanced detectors. In this paper, we present the result of numerical simulations, which verify that the OMC requirements are satisfied with the current design. We use the simulation program FINESSE and realistic mirror phase maps that have the same surface quality as the...

  4. Impact of Altitude on Power Output during Cycling Stage Racing.

    Science.gov (United States)

    Garvican-Lewis, Laura A; Clark, Bradley; Martin, David T; Schumacher, Yorck Olaf; McDonald, Warren; Stephens, Brian; Ma, Fuhai; Thompson, Kevin G; Gore, Christopher J; Menaspà, Paolo

    2015-01-01

    The purpose of this study was to quantify the effects of moderate-high altitude on power output, cadence, speed and heart rate during a multi-day cycling tour. Power output, heart rate, speed and cadence were collected from elite male road cyclists during maximal efforts of 5, 15, 30, 60, 240 and 600 s. The efforts were completed in a laboratory power-profile assessment, and spontaneously during a cycling race simulation near sea-level and an international cycling race at moderate-high altitude. Matched data from the laboratory power-profile and the highest maximal mean power output (MMP) and corresponding speed and heart rate recorded during the cycling race simulation and cycling race at moderate-high altitude were compared using paired t-tests. Additionally, all MMP and corresponding speeds and heart rates were binned per 1000 m (3000 m) according to the average altitude of each ride. Mixed linear modelling was used to compare cycling performance data from each altitude bin. Power output was similar between the laboratory power-profile and the race simulation, however MMPs for 5-600 s and 15, 60, 240 and 600 s were lower (p ≤ 0.005) during the race at altitude compared with the laboratory power-profile and race simulation, respectively. Furthermore, peak power output and all MMPs were lower (≥ 11.7%, p ≤ 0.001) while racing >3000 m compared with rides completed near sea-level. However, speed associated with MMP 60 and 240 s was greater (p sea-level. A reduction in oxygen availability as altitude increases leads to attenuation of cycling power output during competition. Decrement in cycling power output at altitude does not seem to affect speed which tended to be greater at higher altitudes.

  5. Sliding mode control for efficiency optimization of wind energy systems with double output induction generator

    Energy Technology Data Exchange (ETDEWEB)

    Puleston, P.F.; Mantz, R.J.; Battaiotto, P.E.; Valenciaga, F. [La Plata Univ., Electrical Engineering Dept., La Plata (Argentina)

    2000-07-01

    This paper deals with generation efficiency maximization of wind energy conversion system (WECS) with double output induction generator (DOIG). In the first place, to design a sliding mode controller, an apropos model of the DOIG with electronic drive in the rotor is developed. Then, conditions of maximum power generation are obtained. Finally, a sliding mode control strategy for this type of WECS is presented. The proposed strategy varies the firing angle of the electronic drive in order to set the extreme control values equal to the maximum and minimum available control action of the system. Consequently, robustness to parametric uncertainties and external disturbances is maximised. (Author)

  6. Dual-cavity Nd:YAG laser with Laguerre-Gaussian (LG0n) mode output

    Science.gov (United States)

    Kim, D. J.; Kim, J. W.

    2017-01-01

    Direct excitation of an arbitrary Laguerre-Gaussian (LG0n) mode with helical wavefronts in a diode-end-pumped solid state laser employing a dual-cavity configuration is reported. Through simple adjustments of the intra-cavity apertures in the dual-cavity laser configuration, the spatial gain distribution and the cavity loss could be optimized for the targeted LG0 n mode. This approach has been applied to a diode-pumped Nd: YAG laser to achieve selective lasing of the LG01, LG02, and LG03 modes. Also, an optical vortex laser beam was produced directly from the laser resonator by determining the wavefront handedness of each LG mode output using an intra-cavity etalon. The prospects of further power scaling and laser performance improvements will be discussed.

  7. Tunable Single-Longitudinal-Mode High-Power Fiber Laser

    Directory of Open Access Journals (Sweden)

    Jonas K. Valiunas

    2012-01-01

    Full Text Available We report a novel CW tunable high-power single-longitudinal-mode fiber laser with a linewidth of ∼9 MHz. A tunable fiber Bragg grating provided wavelength selection over a 10 nm range. An all-fiber Fabry-Perot filter was used to increase the longitudinal mode spacing of the laser cavity. An unpumped polarization-maintaining erbium-doped fiber was used inside the cavity to eliminate mode hopping and increase stability. A maximum output power of 300 mW was produced while maintaining single-longitudinal-mode operation.

  8. High-Precision Half-Wave Rectifier Circuit In Dual Phase Output Mode

    Directory of Open Access Journals (Sweden)

    Theerayut Jamjaem

    2009-12-01

    Full Text Available This paper present high-precision half-wave rectifier circuit in dual phase output mode by 0.5 μm CMOS technology, +/- 1.5 V low voltage, it has received input signal and sent output current signal, respond in high frequency. The main structure compound with CMOS inverter circuit, common source circuit, and current mirror circuit. Simulation and confirmation quality of working by PSpice program, then it able to operating at maximum frequency about 100 MHz, maximum input current range about 400 μAp-p, high precision output signal, low power dissipation, and uses a little transistor.Keywords-component; half-wave; rectifier circuit; highprecession; dual phase;

  9. High-power Er:YAG laser with quasi-top-hat output beam.

    Science.gov (United States)

    Kim, J W; Mackenzie, J I; Hayes, J R; Clarkson, W A

    2012-05-01

    A simple method for simultaneously exciting the fundamental (TEM00) transverse mode and first order Laguerre-Gaussian (LG01) donut mode in an end-pumped solid-state laser to yield a quasi-top-hat output beam is reported. This approach has been applied to an Er:YAG laser, in-band pumped by an Er,Yb fiber laser, yielding 9.6 W of continuous-wave output at 1645 nm in a top-hat-like beam with beam propagation factor (M2)<2.1 for 24 W of incident pump power at 1532 nm. The corresponding slope efficiency with respect to incident pump power was 49%. The prospects of further scaling of output power and improved overall efficiency are considered.

  10. Sliding-mode control of single input multiple output DC-DC converter

    Science.gov (United States)

    Zhang, Libo; Sun, Yihan; Luo, Tiejian; Wan, Qiyang

    2016-10-01

    Various voltage levels are required in the vehicle mounted power system. A conventional solution is to utilize an independent multiple output DC-DC converter whose cost is high and control scheme is complicated. In this paper, we design a novel SIMO DC-DC converter with sliding mode controller. The proposed converter can boost the voltage of a low-voltage input power source to a controllable high-voltage DC bus and middle-voltage output terminals, which endow the converter with characteristics of simple structure, low cost, and convenient control. In addition, the sliding mode control (SMC) technique applied in our converter can enhance the performances of a certain SIMO DC-DC converter topology. The high-voltage DC bus can be regarded as the main power source to the high-voltage facility of the vehicle mounted power system, and the middle-voltage output terminals can supply power to the low-voltage equipment on an automobile. In the respect of control algorithm, it is the first time to propose the SMC-PID (Proportion Integration Differentiation) control algorithm, in which the SMC algorithm is utilized and the PID control is attended to the conventional SMC algorithm. The PID control increases the dynamic ability of the SMC algorithm by establishing the corresponding SMC surface and introducing the attached integral of voltage error, which endow the sliding-control system with excellent dynamic performance. At last, we established the MATLAB/SIMULINK simulation model, tested performance of the system, and built the hardware prototype based on Digital Signal Processor (DSP). Results show that the sliding mode control is able to track a required trajectory, which has robustness against the uncertainties and disturbances.

  11. Method for Prediction of the Power Output from Photovoltaic Power Plant under Actual Operating Conditions

    Science.gov (United States)

    Obukhov, S. G.; Plotnikov, I. A.; Surzhikova, O. A.; Savkin, K. D.

    2017-04-01

    Solar photovoltaic technology is one of the most rapidly growing renewable sources of electricity that has practical application in various fields of human activity due to its high availability, huge potential and environmental compatibility. The original simulation model of the photovoltaic power plant has been developed to simulate and investigate the plant operating modes under actual operating conditions. The proposed model considers the impact of the external climatic factors on the solar panel energy characteristics that improves accuracy in the power output prediction. The data obtained through the photovoltaic power plant operation simulation enable a well-reasoned choice of the required capacity for storage devices and determination of the rational algorithms to control the energy complex.

  12. LOAD THAT MAXIMIZES POWER OUTPUT IN COUNTERMOVEMENT JUMP

    Directory of Open Access Journals (Sweden)

    Pedro Jimenez-Reyes

    2016-02-01

    Full Text Available ABSTRACT Introduction: One of the main problems faced by strength and conditioning coaches is the issue of how to objectively quantify and monitor the actual training load undertaken by athletes in order to maximize performance. It is well known that performance of explosive sports activities is largely determined by mechanical power. Objective: This study analysed the height at which maximal power output is generated and the corresponding load with which is achieved in a group of male-trained track and field athletes in the test of countermovement jump (CMJ with extra loads (CMJEL. Methods: Fifty national level male athletes in sprinting and jumping performed a CMJ test with increasing loads up to a height of 16 cm. The relative load that maximized the mechanical power output (Pmax was determined using a force platform and lineal encoder synchronization and estimating the power by peak power, average power and flight time in CMJ. Results: The load at which the power output no longer existed was at a height of 19.9 ± 2.35, referring to a 99.1 ± 1% of the maximum power output. The load that maximizes power output in all cases has been the load with which an athlete jump a height of approximately 20 cm. Conclusion: These results highlight the importance of considering the height achieved in CMJ with extra load instead of power because maximum power is always attained with the same height. We advise for the preferential use of the height achieved in CMJEL test, since it seems to be a valid indicative of an individual's actual neuromuscular potential providing a valid information for coaches and trainers when assessing the performance status of our athletes and to quantify and monitor training loads, measuring only the height of the jump in the exercise of CMJEL.

  13. Switching-mode Audio Power Amplifiers with Direct Energy Conversion

    DEFF Research Database (Denmark)

    Ljusev, Petar; Andersen, Michael Andreas E.

    2005-01-01

    This paper presents a new class of switching-mode audio power amplifiers, which are capable of direct energy conversion from the AC mains to the audio output. They represent an ultimate integration of a switching-mode power supply and a Class D audio power amplifier, where the intermediate DC bus...... has been replaced with a high frequency AC link. When compared to the conventional Class D amplifiers with a separate DC power supply, the proposed single conversion stage amplifier provides simple and compact solution with better efficiency and higher level of integration, leading to reduced...

  14. Measurement of output power density from mobile phone as a function of input sound frequency.

    Science.gov (United States)

    Calabrò, Emanuele; Magazù, Salvatore

    2013-01-01

    Measurements of power density emitted by a mobile phone were carried out as a function of the sound frequency transmitted by a sound generator, ranging from 250 to 14000 Hz. Output power density was monitored by means of the selective radiation meter Narda SRM 3000 in spectrum analysis mode, and the octave frequency analysis of each tone used for the experimental design was acquired by the sound level meter Larson Davis LxT Wind. Vodafone providers were used for mobile phone calls with respect to various local base station in Southern-Italy. A relationship between the mobile phone microwaves power density and the sound frequencies transmitted by the sound generator was observed. In particular, microwaves power density level decreases significantly at sound frequency values larger than 4500 Hz. This result can be explained assuming that discontinuous transmission mode of global system for mobile communications is powered not only in silence-mode, but also at frequencies larger than 4500 Hz.

  15. 10-W cladding-pumped fiber laser with single transverse mode output

    Institute of Scientific and Technical Information of China (English)

    Ping Yan(闰平); Mali Gong(巩马理); Pan Ou(欧攀); Wenlou Wei(韦文楼); Ruizhen Cui(崔瑞贞); Qiang Liu(柳强); Weipu Jia(贾维溥)

    2003-01-01

    A Yb-doped double-clad fiber laser is demonstrated with a measured power output of 10.6 W and a fundamental spatial mode. The optical-to-optical conversion efficiency is 44% and the slope efficiency is 86% closed to quantum efficiency of optical conversion. In our laser system, a D-shape (340 μm/400 μm) inner cladding Yb-doped fiber is used as the gain material within the Fabry-Perot cavity. Multimode diode pump radiation is injected into the cladding through an end facet of the composite fiber.

  16. Fiber laser pumped high power mid-infrared laser with picosecond pulse bunch output.

    Science.gov (United States)

    Wei, Kaihua; Chen, Tao; Jiang, Peipei; Yang, Dingzhong; Wu, Bo; Shen, Yonghang

    2013-10-21

    We report a novel quasi-synchronously pumped PPMgLN-based high power mid-infrared (MIR) laser with picosecond pulse bunch output. The pump laser is a linearly polarized MOPA structured all fiberized Yb fiber laser with picosecond pulse bunch output. The output from a mode-locked seed fiber laser was directed to pass through a FBG reflector via a circulator to narrow the pulse duration from 800 ps to less than 50 ps and the spectral FWHM from 9 nm to 0.15 nm. The narrowed pulses were further directed to pass through a novel pulse multiplier through which each pulse was made to become a pulse bunch composing of 13 sub-pulses with pulse to pulse time interval of 1.26 ns. The pulses were then amplified via two stage Yb fiber amplifiers to obtain a linearly polarized high average power output up to 85 W, which were then directed to pass through an isolator and to pump a PPMgLN-based optical parametric oscillator via quasi-synchronization pump scheme for ps pulse bunch MIR output. High MIR output with average power up to 4 W was obtained at 3.45 micron showing the feasibility of such pump scheme for ps pulse bunch MIR output.

  17. Quantum dot amplifiers with high output power and low noise

    DEFF Research Database (Denmark)

    Berg, Tommy Winther; Mørk, Jesper

    2003-01-01

    Quantum dot semiconductor optical amplifiers have been theoretically investigated and are predicted to achieve high saturated output power, large gain, and low noise figure. We discuss the device dynamics and, in particular, show that the presence of highly inverted barrier states does not limit ...

  18. Failure mode and effects analysis outputs: are they valid?

    Directory of Open Access Journals (Sweden)

    Shebl Nada

    2012-06-01

    Full Text Available Abstract Background Failure Mode and Effects Analysis (FMEA is a prospective risk assessment tool that has been widely used within the aerospace and automotive industries and has been utilised within healthcare since the early 1990s. The aim of this study was to explore the validity of FMEA outputs within a hospital setting in the United Kingdom. Methods Two multidisciplinary teams each conducted an FMEA for the use of vancomycin and gentamicin. Four different validity tests were conducted: · Face validity: by comparing the FMEA participants’ mapped processes with observational work. · Content validity: by presenting the FMEA findings to other healthcare professionals. · Criterion validity: by comparing the FMEA findings with data reported on the trust’s incident report database. · Construct validity: by exploring the relevant mathematical theories involved in calculating the FMEA risk priority number. Results Face validity was positive as the researcher documented the same processes of care as mapped by the FMEA participants. However, other healthcare professionals identified potential failures missed by the FMEA teams. Furthermore, the FMEA groups failed to include failures related to omitted doses; yet these were the failures most commonly reported in the trust’s incident database. Calculating the RPN by multiplying severity, probability and detectability scores was deemed invalid because it is based on calculations that breach the mathematical properties of the scales used. Conclusion There are significant methodological challenges in validating FMEA. It is a useful tool to aid multidisciplinary groups in mapping and understanding a process of care; however, the results of our study cast doubt on its validity. FMEA teams are likely to need different sources of information, besides their personal experience and knowledge, to identify potential failures. As for FMEA’s methodology for scoring failures, there were discrepancies

  19. Modeling the power output of piezoelectric energy harvesters

    KAUST Repository

    Al Ahmad, Mahmoud

    2011-04-30

    Design of experiments and multiphysics analyses were used to develop a parametric model for a d 33-based cantilever. The analysis revealed that the most significant parameters influencing the resonant frequency are the supporting layer thickness, piezoelectric layer thickness, and cantilever length. On the other hand, the most important factors affecting the charge output arethe piezoelectric thickness and the interdigitated electrode dimensions. The accuracy of the developed model was confirmed and showed less than 1% estimation error compared with a commercial simulation package. To estimate the power delivered to a load, the electric current output from the piezoelectric generator was calculated. A circuit model was built and used to estimate the power delivered to a load, which compared favorably to experimentally published power data on actual cantilevers of similar dimensions. © 2011 TMS.

  20. Mechanical power output during running accelerations in wild turkeys.

    Science.gov (United States)

    Roberts, Thomas J; Scales, Jeffrey A

    2002-05-01

    We tested the hypothesis that the hindlimb muscles of wild turkeys (Meleagris gallopavo) can produce maximal power during running accelerations. The mechanical power developed during single running steps was calculated from force-plate and high-speed video measurements as turkeys accelerated over a trackway. Steady-speed running steps and accelerations were compared to determine how turkeys alter their running mechanics from a low-power to a high-power gait. During maximal accelerations, turkeys eliminated two features of running mechanics that are characteristic of steady-speed running: (i) they produced purely propulsive horizontal ground reaction forces, with no braking forces, and (ii) they produced purely positive work during stance, with no decrease in the mechanical energy of the body during the step. The braking and propulsive forces ordinarily developed during steady-speed running are important for balance because they align the ground reaction force vector with the center of mass. Increases in acceleration in turkeys correlated with decreases in the angle of limb protraction at toe-down and increases in the angle of limb retraction at toe-off. These kinematic changes allow turkeys to maintain the alignment of the center of mass and ground reaction force vector during accelerations when large propulsive forces result in a forward-directed ground reaction force. During the highest accelerations, turkeys produced exclusively positive mechanical power. The measured power output during acceleration divided by the total hindlimb muscle mass yielded estimates of peak instantaneous power output in excess of 400 W kg(-1) hindlimb muscle mass. This value exceeds estimates of peak instantaneous power output of turkey muscle fibers. The mean power developed during the entire stance phase increased from approximately zero during steady-speed runs to more than 150 W kg(-1) muscle during the highest accelerations. The high power outputs observed during accelerations

  1. Research of the Power Plant Operational Modes

    Directory of Open Access Journals (Sweden)

    Koismynina Nina M.

    2017-01-01

    Full Text Available In this article the algorithm of the power plant operational modes research is offered. According to this algorithm the program for the modes analysis and connection power transformers choice is developed. The program can be used as educational means for studying of the power plant electric part, at the same time basic data are provided. Also the program can be used for the analysis of the working power plants modes. Checks of the entered data completeness and a choice correctness of the operational modes are provided in the program; in all cases of a deviation from the correct decisions to the user the relevant information is given.

  2. High output power electric motors with bulk HTS elements

    Science.gov (United States)

    Kovalev, L. K.; Ilushin, K. V.; Kovalev, K. L.; Penkin, V. T.; Poltavets, V. N.; Koneev, S. M.-A.; Akimov, I. I.; Gawalek, W.; Oswald, B.; Krabbes, G.

    2003-04-01

    New types of electric machines with the rotors containing bulk HTS (YBCO and Bi-Ag) elements are presented. Different schematics of hysteresis, reluctance, “trapped field” and composed synchronous HTS machines are discussed. The two-dimensional mathematical models describing the processes in such types of HTS machines were developed on the basis of the theoretical analysis of the electrodynamic and hysteresis processes in the single-domain and polycrystal YBCO ceramic samples and plate shape Bi-Ag elements. The test results of the series of hysteresis, reluctance, “trapped field” and composed with permanent magnets HTS motors with output power rating 0.1-18 kW and current frequency 50 and 400 Hz are given. These results show that in the media of liquid nitrogen the specific output power per one weight unit of HTS motors is 4-7 times better than for conventional electric machines. Comparison of the theoretical and experimental characteristics of the developed HTS motors show that they are in good agreement. The test results for liquid nitrogen cryogenic pump system with hysteresis 500 W HTS motor are discussed. The designs and first test results of HTS motor operating in the media of liquid nitrogen with output power 100 kW and power factor more than 0.8 are given. Future development and applications of new types of HTS motors for aerospace technology, on-land industry and transport systems are discussed.

  3. Emergency Linkage Mode of Power Enterprise

    Directory of Open Access Journals (Sweden)

    Feng Jie

    2016-01-01

    Full Text Available Power emergency disposal needs take full advantage of the power enterprise within the external emergency power and resources. Based on analyzing and summarizing the relevant experience of domestic and foreign emergency linkage, this paper draws the Emergency Linkage subjects, Emergency Linkage contents, Emergency Linkage level, which are three key elements if power enterprise Emergency Linkage. Emergency Linkage subjects are divided into the two types of inner subjects and the external body; Emergency Linkage contents are in accordance with four phases of prevention, preparedness, response and recovery; Emergency Linkage level is divided into three levels of enterprise headquarter, provincial enterprise and incident unite. Binding power enterprise emergency management practice, this paper studies the internal Emergency Linkage modes (including horizontal mode and vertical mode, external Emergency Linkage mode and comprehensive Emergency Linkage Mode of power enterprise based on Fishbone Diagram and Process Management Technology.

  4. Maximum Power Output of Quantum Heat Engine with Energy Bath

    CERN Document Server

    Liu, Shengnan

    2016-01-01

    The difference between quantum isoenergetic process and quantum isothermal process comes from the violation of the law of equipartition of energy in the quantum regime. To reveal an important physical meaning of this fact, here we study a special type of quantum heat engine consisting of three processes: isoenergetic, isothermal and adiabatic processes. Therefore, this engine works between the energy and heat baths. Combining two engines of this kind, it is possible to realize the quantum Carnot engine. Furthermore, considering finite velocity of change of the potential shape, here an infinite square well with moving walls, the power output of the engine is discussed. It is found that the efficiency and power output are both closely dependent on the initial and final states of the quantum isothermal process. The performance of the engine cycle is shown to be optimized by control of the occupation probability of the ground state, which is determined by the temperature and the potential width. The relation betw...

  5. Supercontinuum Generation with Output Power of 1.7 W Pumped by a Picosecond Laser Pulse

    Science.gov (United States)

    Pan, Er-Ming; Ruan, Shuang-Chen; Guo, Chun-Yu; Wang, Yun-Cai; Wei, Hui-Feng

    2010-10-01

    By using a photonic crystal fiber, a supercontinuum source with output power up to 1.7W, pumped by a passively mode-locked diode-pumped Nd:YVO4 picosecond laser is obtained. A spectral width of the supercontinuum is 1700 nm (500-2200 nm) with the 5 dB spectral width approximately 1000 nm (1200-2200 nm). This high power wide band supercontinuum source meets the demand of many applications such as optical coherence tomography, frequency metrology and wavelength-division-multiplexing systems. The evolution of the supercontinuum with the increasing pump power is presented and analyzed.

  6. Blue Superluminescent Light-Emitting Diodes with Output Power above 100 mW for Picoprojection

    Science.gov (United States)

    Kopp, Fabian; Eichler, Christoph; Lell, Alfred; Tautz, Sönke; Ristić, Jelena; Stojetz, Bernhard; Höß, Christine; Weig, Thomas; Schwarz, Ulrich T.; Strauss, Uwe

    2013-08-01

    We present a blue InGaN research and development superluminescent light-emitting diode (SLED) that is suitable for picoprojection. The SLED reaches an output power of >100 mW with a peak wavelength of 443 nm and a spectral bandwidth of >2.6 nm as well as a single-mode far-field driven in cw mode at 25 °C. In order to figure out an optimized waveguide design, which enables such a high output power at lowest operation current, we compare the performance of diodes with curved and tilted shaped ridges in detail, using the lasing threshold current as a criterion for lasing or superluminescence, respectively.

  7. Power-output regularization in global sound equalization

    DEFF Research Database (Denmark)

    Stefanakis, Nick; Sarris, J.; Cambourakis, G.

    2008-01-01

    The purpose of equalization in room acoustics is to compensate for the undesired modification that an enclosure introduces to signals such as audio or speech. In this work, equalization in a large part of the volume of a room is addressed. The multiple point method is employed with an acoustic...... power-output penalty term instead of the traditional quadratic source effort penalty term. Simulation results demonstrate that this technique gives a smoother decline of the reproduction performance away from the control points....

  8. Maximum Power Output of Quantum Heat Engine with Energy Bath

    Directory of Open Access Journals (Sweden)

    Shengnan Liu

    2016-05-01

    Full Text Available The difference between quantum isoenergetic process and quantum isothermal process comes from the violation of the law of equipartition of energy in the quantum regime. To reveal an important physical meaning of this fact, here we study a special type of quantum heat engine consisting of three processes: isoenergetic, isothermal and adiabatic processes. Therefore, this engine works between the energy and heat baths. Combining two engines of this kind, it is possible to realize the quantum Carnot engine. Furthermore, considering finite velocity of change of the potential shape, here an infinite square well with moving walls, the power output of the engine is discussed. It is found that the efficiency and power output are both closely dependent on the initial and final states of the quantum isothermal process. The performance of the engine cycle is shown to be optimized by control of the occupation probability of the ground state, which is determined by the temperature and the potential width. The relation between the efficiency and power output is also discussed.

  9. Distribution of power output when establishing a breakaway in cycling.

    Science.gov (United States)

    Abbiss, Chris R; Menaspà, Paolo; Villerius, Vincent; Martin, David T

    2013-07-01

    A number of laboratory-based performance tests have been designed to mimic the dynamic and stochastic nature of road cycling. However, the distribution of power output and thus physical demands of high-intensity surges performed to establish a breakaway during actual competitive road cycling are unclear. Review of data from professional road-cycling events has indicated that numerous short-duration (5-15 s), high-intensity (~9.5-14 W/kg) surges are typically observed in the 5-10 min before athletes' establishing a breakaway (ie, riding away from a group of cyclists). After this initial high-intensity effort, power output declined but remained high (~450-500 W) for a further 30 s to 5 min, depending on race dynamics (ie, the response of the chase group). Due to the significant influence competitors have on pacing strategies, it is difficult for laboratory-based performance tests to precisely replicate this aspect of mass-start competitive road cycling. Further research examining the distribution of power output during competitive road racing is needed to refine laboratory-based simulated stochastic performance trials and better understand the factors important to the success of a breakaway.

  10. Multi-decadal Variability of the Wind Power Output

    Science.gov (United States)

    Kirchner Bossi, Nicolas; García-Herrera, Ricardo; Prieto, Luis; Trigo, Ricardo M.

    2014-05-01

    The knowledge of the long-term wind power variability is essential to provide a realistic outlook on the power output during the lifetime of a planned wind power project. In this work, the Power Output (Po) of a market wind turbine is simulated with a daily resolution for the period 1871-2009 at two different locations in Spain, one at the Central Iberian Plateau and another at the Gibraltar Strait Area. This is attained through a statistical downscaling of the daily wind conditions. It implements a Greedy Algorithm as classificator of a geostrophic-based wind predictor, which is derived by considering the SLP daily field from the 56 ensemble members of the longest homogeneous reanalysis available (20CR, 1871-2009). For calibration and validation purposes we use 10 years of wind observations (the predictand) at both sites. As a result, a series of 139 annual wind speed Probability Density Functions (PDF) are obtained, with a good performance in terms of wind speed uncertainty reduction (average daily wind speed MAE=1.48 m/s). The obtained centennial series allow to investigate the multi-decadal variability of wind power from different points of view. Significant periodicities around the 25-yr frequency band, as well as long-term linear trends are detected at both locations. In addition, a negative correlation is found between annual Po at both locations, evidencing the differences in the dynamical mechanisms ruling them (and possible complementary behavior). Furthermore, the impact that the three leading large-scale circulation patterns over Iberia (NAO, EA and SCAND) exert over wind power output is evaluated. Results show distinct (and non-stationary) couplings to these forcings depending on the geographical position and season or month. Moreover, significant non-stationary correlations are observed with the slow varying Atlantic Multidecadal Oscillation (AMO) index for both case studies. Finally, an empirical relationship is explored between the annual Po and the

  11. Using machine learning to predict wind turbine power output

    Science.gov (United States)

    Clifton, A.; Kilcher, L.; Lundquist, J. K.; Fleming, P.

    2013-06-01

    Wind turbine power output is known to be a strong function of wind speed, but is also affected by turbulence and shear. In this work, new aerostructural simulations of a generic 1.5 MW turbine are used to rank atmospheric influences on power output. Most significant is the hub height wind speed, followed by hub height turbulence intensity and then wind speed shear across the rotor disk. These simulation data are used to train regression trees that predict the turbine response for any combination of wind speed, turbulence intensity, and wind shear that might be expected at a turbine site. For a randomly selected atmospheric condition, the accuracy of the regression tree power predictions is three times higher than that from the traditional power curve methodology. The regression tree method can also be applied to turbine test data and used to predict turbine performance at a new site. No new data are required in comparison to the data that are usually collected for a wind resource assessment. Implementing the method requires turbine manufacturers to create a turbine regression tree model from test site data. Such an approach could significantly reduce bias in power predictions that arise because of the different turbulence and shear at the new site, compared to the test site.

  12. 磁耦和谐振式电能传输系统的功率输出特性分析及其最大功率点追踪%Analysis of output property and MPPT of magnetically-coupled resonant mode power transfer system

    Institute of Scientific and Technical Information of China (English)

    李森涛; 樊绍胜; 李富林; 蒋大玉

    2015-01-01

    Abstruct:In order to analyzes and optimize output power of magnetically⁃coupled resonant mode wireless power transfer sys⁃tem,the power output property of this system is analyzed and a simplified model of this system is given in this paper,which is of benefit to the designer to analyze or determine the parameters of the magnetically⁃coupled resonant wireless power transfer sys⁃tem. Moreover,to solve the problem that the output power of magnetically⁃coupled resonant wireless power transfer system varies drastically with the change of relative distance and position of two resonant coils,based on the output property discussed above, a practical maximum power point tracking(MPPT)method is proposed in this paper to stabilize and maximize the power of the system in relatively wide range.%为分析与优化磁耦合谐振式无线电能传输系统的输出功率,对磁耦合谐振式无线电能传输系统的功率输出特性进行分析与试验,并提出一种简化的系统模型,以方便设计者分析或确定磁共振式无线电能传输系统的参数。另外为解决原始系统输出功率随线圈相对位置而急剧变化,在此根据磁耦合谐振式无线电能传输系统的功率输出特性提出了一种可行的最大功率点追踪(MPPT)方法以稳定系统的输出功率,使得负载能够在宽距离范围内实现功率最大化。

  13. Reliability of power output during eccentric sprint cycling.

    Science.gov (United States)

    Brughelli, Matt; Van Leemputte, Marc

    2013-01-01

    The purpose of this study was to determine the reliability of power outputs during maximal intensity eccentric cycling over short durations (i.e., eccentric sprint cycling) on a "motor-driven" isokinetic ergometer. Fourteen physically active male subjects performed isokinetic eccentric cycling sprints at 40, 60, 80, 100, and 120 revolutions per minute (rpm) on 4 separate occasions (T1-T4). Each sprint lasted for 6 seconds, and absolute measures of mean power (MP) and peak power (PP) per revolution were recorded. Significant increases in MP and PP were observed between T1 and subsequent trials, but no significant differences were identified between T2, T3, and T4. The coefficient of variation (CV) and intraclass correlation coefficient (ICC) were calculated to reflect within-subject and between-session reliability of MP and PP at each cadence. The CV improved to below 10% for cadences of 60, 80, 100, and 120 rpm between T3 and T4, and the majority of ICC values improved to above 0.90. The remaining ICC values remained in the moderate range between T3 and T4 (i.e., 0.82-0.89). Coefficient of variation and ICC values for the 40 rpm cadence remained at unacceptable levels throughout the 4 trials and thus should be avoided in future investigations. The results of this study indicate that reliable power outputs may be obtained after 2 familiarization sessions during eccentric sprint cycling at cadences ranging from 60 to 120 rpm.

  14. Power output uniformity and power output capabilities of a guidewire-compatible cylindrical light-diffusing catheter

    Science.gov (United States)

    Anderson, Steven C.; Narciso, Hugh L., Jr.; Mai, David; Doiron, Daniel R.

    1994-07-01

    Cardiovascular Photodynamic Therapy requires the uniform application of laser energy over the length of an atherosclerotic lesion, thus ensuring equal treatment to all parts of the lesion. The total amount of laser energy delivered to the lesion also affects the results of the treatment. Uniform light distribution both radially and axially of a cylindrical diffuser during Photodynamic Therapy prevents miscalculated dosimetry and uneven treatment. Maximizing the amount of laser power delivered to the cylindrical diffuser tip (without inducing temperature elevation) minimizes the exposure time thus reducing the overall treatment time. Power output uniformity and power output capabilities are thus crucial factors in the design of a cardiovascular cylindrical diffuser. This paper will discuss the output characteristics and performance of six guidewire compatible cylindrical diffusers. Each diffuser consists of an array of fiber optics surrounding an inner guidewire lumen. This assembly is covered by an outer sheath. The fibers launch into an elastomer which contains a scattering medium. In this way a light diffusing tip is created. The total length of the fiber system is 3.0 meters. The total length of the difffuser tip is 2.0 cm.

  15. Power quality improvement in switched mode power supplies using ...

    African Journals Online (AJOL)

    user

    A SEPIC stores the energy in an inductor, and transfers that energy to the output storage capacitor. ..... 2011–2017. ... His areas of interest include power electronics, electrical machines and drives, renewable energy systems, active filters, ...

  16. A high-power switch-mode dc power supply for dynamic loads

    Energy Technology Data Exchange (ETDEWEB)

    Shimer, D.W.; Lange, A.C. [Lawrence Livermore National Lab., CA (United States); Bombay, J.N. [Kaiser Engineers, Oakland, CA (United States)

    1994-06-23

    High-voltage dc power supplies are often required to operate with highly dynamic loads, such as arcs. A switch-mode dc power supply can offer significant advantages over conventional thyristor-based dc power supplies under such conditions. It can quickly turn off the supply to extinguish the arc, and it can quickly recover after the arc. It has a relatively small output filter capacitance, which results in small stored energy available to the arc. A 400-kW, 50-kV switch-mode dc power supply for an electron-beam gun that exploits these advantages was designed and tested. It uses four 100-kW, current-source-type dc-dc converters with inputs in parallel and outputs in series. The dc-dc converters operate at 20 kHz in the voltage regulator part and 10 kHz in the inverter, transformer, and output rectifier part of the circuit. Insulated gate bipolar transistors (IGBTs) are used as the power switches. Special techniques are used to protect the power supply and load against arcs and hard shorts. The power supply has an efficiency of 93%, an output voltage ripple of 1%, and fast dynamic response. In addition, it is nearly one-third the size of conventional power supplies.

  17. An Exploration into Power Market Mode

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ Power system has its industrial structure featuring both natural monopoly and competition, making deregulation and re-regulation become the main melody in the evolution of the regulatory system for power industry. Consequently, it is one of the main tasks for power reform to determine a new and rational regulatory mode.

  18. A Simple MPPT Algorithm for Novel PV Power Generation System by High Output Voltage DC-DC Boost Converter

    DEFF Research Database (Denmark)

    Sanjeevikumar, Padmanaban; Grandi, Gabriele; Wheeler, Patrick

    2015-01-01

    This paper presents the novel topology of Photo Voltaic (PV) power generation system with simple Maximum Power Point Tracking (MPPT) algorithm in voltage operating mode. Power circuit consists of high output voltage DC-DC boost converter which maximizes the output of PV panel. Usually traditional...... of DC-DC converters for PV integration. Hence, to overcome these difficulties this paper investigates a DC-DC boost converter together with the additional parasitic component within the circuit to provide high output voltages for maximizing the PV power generation. The proposed power system circuit...... substantially improves the high output-voltage by a simple MPPT closed loop proportional-integral (P-I) controller, and requires only two sensor for feedback needs. The complete numerical model of the converter circuit along with PV MPPT algorithm is developed in numerical simulation (Matlab/Simulink) software...

  19. Output tracking control of mobile manipulators based on dynamical sliding-mode control

    Institute of Scientific and Technical Information of China (English)

    WU Yuxiang; FENG Ying; HU Yueming

    2007-01-01

    A dynamical sliding-mode controller is devised to track the output of mobile manipulators. During the investi- gation, firstly a reduced dynamic model considering the dynamics of the driving motor is developed for mobile manipulators. Then, the system is decomposed into four lower-dimensional subsystems by means of diffeomorphism and nonlinear input transformation. Moreover, a design method of the dynamical sliding-mode controller that is applied to the output tracking of mobile manipulators is proposed. The simulation results indicate that the dynamical sliding-mode controller can not only track the given trajec- tory correctly but also reduce the chattering of sliding-mode control system considerably.

  20. A model to predict the power output from wind farms

    Energy Technology Data Exchange (ETDEWEB)

    Landberg, L. [Riso National Lab., Roskilde (Denmark)

    1997-12-31

    This paper will describe a model that can predict the power output from wind farms. To give examples of input the model is applied to a wind farm in Texas. The predictions are generated from forecasts from the NGM model of NCEP. These predictions are made valid at individual sites (wind farms) by applying a matrix calculated by the sub-models of WASP (Wind Atlas Application and Analysis Program). The actual wind farm production is calculated using the Riso PARK model. Because of the preliminary nature of the results, they will not be given. However, similar results from Europe will be given.

  1. Listening to music affects diurnal variation in muscle power output.

    Science.gov (United States)

    Chtourou, H; Chaouachi, A; Hammouda, O; Chamari, K; Souissi, N

    2012-01-01

    The purpose of this investigation was to assess the effects of listening to music while warming-up on the diurnal variations of power output during the Wingate test. 12 physical education students underwent four Wingate tests at 07:00 and 17:00 h, after 10 min of warm-up with and without listening to music. The warm-up consisted of 10 min of pedalling at a constant pace of 60 rpm against a light load of 1 kg. During the Wingate test, peak and mean power were measured. The main finding was that peak and mean power improved from morning to afternoon after no music warm-up (pmusic warm-up. Moreover, peak and mean power were significantly higher after music than no music warm-up during the two times of testing. Thus, as it is a legal method and an additional aid, music should be used during warm-up before performing activities requiring powerful lower limbs' muscles contractions, especially in the morning competitive events.

  2. Multi Carrier Modulator for Switch-Mode Audio Power Amplifiers

    DEFF Research Database (Denmark)

    Knott, Arnold; Pfaffinger, Gerhard; Andersen, Michael Andreas E.

    2008-01-01

    While switch-mode audio power amplifiers allow compact implementations and high output power levels due to their high power efficiency, they are very well known for creating electromagnetic interference (EMI) with other electronic equipment, in particular radio receivers. Lowering the EMI of switch......-mode audio power amplifiers while keeping the performance measures to excellent levels is therefore of high general interest. A modulator utilizing multiple carrier signals to generate a two level pulse train will be shown in this paper. The performance of the modulator will be compared in simulation...... to existing modulation topologies. The lower EMI as well as the preserved audio performance will be shown in simulation as well as in measurement results on a prototype....

  3. Model output statistics applied to wind power prediction

    Energy Technology Data Exchange (ETDEWEB)

    Joensen, A.; Giebel, G.; Landberg, L. [Risoe National Lab., Roskilde (Denmark); Madsen, H.; Nielsen, H.A. [The Technical Univ. of Denmark, Dept. of Mathematical Modelling, Lyngby (Denmark)

    1999-03-01

    Being able to predict the output of a wind farm online for a day or two in advance has significant advantages for utilities, such as better possibility to schedule fossil fuelled power plants and a better position on electricity spot markets. In this paper prediction methods based on Numerical Weather Prediction (NWP) models are considered. The spatial resolution used in NWP models implies that these predictions are not valid locally at a specific wind farm. Furthermore, due to the non-stationary nature and complexity of the processes in the atmosphere, and occasional changes of NWP models, the deviation between the predicted and the measured wind will be time dependent. If observational data is available, and if the deviation between the predictions and the observations exhibits systematic behavior, this should be corrected for; if statistical methods are used, this approaches is usually referred to as MOS (Model Output Statistics). The influence of atmospheric turbulence intensity, topography, prediction horizon length and auto-correlation of wind speed and power is considered, and to take the time-variations into account, adaptive estimation methods are applied. Three estimation techniques are considered and compared, Extended Kalman Filtering, recursive least squares and a new modified recursive least squares algorithm. (au) EU-JOULE-3. 11 refs.

  4. All-fiber 194 W single-frequency single-mode Yb-doped master-oscillator power-amplifier

    Science.gov (United States)

    Mermelstein, M. D.; Brar, K.; Andrejco, M. J.; Yablon, A. D.; Fishteyn, M.; Headley, C., III; DiGiovanni, D. J.

    2008-02-01

    A four-stage all-fiber single-frequency single-mode continuous-wave (cw) master-oscillator power-amplifier (MOPA) at 1083 nm is presented. Small mode area (SMA) and large mode area (LMA) amplifier stages are mode matched with a fiber mode converter (MC) and the signal and pumps are combined with tapered fiber bundles (TFBs). The final power stage uses a LMA Yb doped SBS-suppressing fiber. A single-frequency output power of 194 W is demonstrated with optical net and slope efficiencies of 73% and 80%, respectively. Numerical simulations for the signal output power and the SBS-induced Stokes backscattered power in the 4th stage amplifier agree with the experimental results. Pulse amplifier measurements showed a 400 W peak power output that was limited by the forward output ASE. The SBS reflectivity at 400 W output was only 2.75 x 10 -4.

  5. An Indicator for Separation of Structural and Harmonic Modes in Output-Only Modal Testing

    DEFF Research Database (Denmark)

    Brincker, Rune; Andersen, P.; Møller, N.

    2000-01-01

    In this paper a technique for separation of harmonic and structural modes in output-only modal testing and identification is presented. The indicator is based on the basic differences of the statistical properties of a harmonic response and narrow-band stochastic response of a structural mode. Th...

  6. Changes in muscle coordination and power output during sprint cycling.

    Science.gov (United States)

    O'Bryan, Steven J; Brown, Nicholas A T; Billaut, François; Rouffet, David M

    2014-07-25

    This study investigated the changes in muscle coordination associated to power output decrease during a 30-s isokinetic (120rpm) cycling sprint. Modifications in EMG amplitude and onset/offset were investigated from eight muscles [gluteus maximus (EMGGMAX), vastus lateralis and medialis obliquus (EMGVAS), medial and lateral gastrocnemius (EMGGAS), rectus femoris (EMGRF), biceps femoris and semitendinosus (EMGHAM)]. Changes in co-activation of four muscle pairs (CAIGMAX/GAS, CAIVAS/GAS, CAIVAS/HAM and CAIGMAX/RF) were also calculated. Substantial power reduction (60±6%) was accompanied by a decrease in EMG amplitude for all muscles other than HAM, with the greatest deficit identified for EMGRF (31±16%) and EMGGAS (20±14%). GASonset, HAMonset and GMAXonset shifted later in the pedalling cycle and the EMG offsets of all muscles (except GASoffset) shifted earlier as the sprint progressed (Ppower reduction during fatiguing sprint cycling is accompanied by marked reductions in the EMG activity of bi-articular GAS and RF and co-activation level between GAS and main power producer muscles (GMAX and VAS). The observed changes in RF and GAS EMG activity are likely to result in a redistribution of the joint powers and alterations in the orientation of the pedal forces. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  7. An Indicator for Separation of Structural and Harmonic Modes in Output-Only Modal Testing

    DEFF Research Database (Denmark)

    Brincker, Rune; Andersen, P.; Møller, N.

    2000-01-01

    In this paper a technique for separation of harmonic and structural modes in output-only modal testing and identification is presented. The indicator is based on the basic differences of the statistical properties of a harmonic response and narrow-band stochastic response of a structural mode....... The indicator is demonstrated on an example where a plate is loaded by an engine rotating with quasi-stationary speed. An output-only modal identification is performed using a technique based on Frequency Domain Decomposition (FDD), and what appears to be three harmonic components and five structural modes were...

  8. Adaptive Output Feedback Sliding Mode Control for Complex Interconnected Time-Delay Systems

    Directory of Open Access Journals (Sweden)

    Van Van Huynh

    2015-01-01

    Full Text Available We extend the decentralized output feedback sliding mode control (SMC scheme to stabilize a class of complex interconnected time-delay systems. First, sufficient conditions in terms of linear matrix inequalities are derived such that the equivalent reduced-order system in the sliding mode is asymptotically stable. Second, based on a new lemma, a decentralized adaptive sliding mode controller is designed to guarantee the finite time reachability of the system states by using output feedback only. The advantage of the proposed method is that two major assumptions, which are required in most existing SMC approaches, are both released. These assumptions are (1 disturbances are bounded by a known function of outputs and (2 the sliding matrix satisfies a matrix equation that guarantees the sliding mode. Finally, a numerical example is used to demonstrate the efficacy of the method.

  9. Prognostic health monitoring in switch-mode power supplies with voltage regulation

    Science.gov (United States)

    Hofmeister, James P (Inventor); Judkins, Justin B (Inventor)

    2009-01-01

    The system includes a current injection device in electrical communication with the switch mode power supply. The current injection device is positioned to alter the initial, non-zero load current when activated. A prognostic control is in communication with the current injection device, controlling activation of the current injection device. A frequency detector is positioned to receive an output signal from the switch mode power supply and is able to count cycles in a sinusoidal wave within the output signal. An output device is in communication with the frequency detector. The output device outputs a result of the counted cycles, which are indicative of damage to an a remaining useful life of the switch mode power supply.

  10. Current-Driven Switch-Mode Audio Power Amplifiers

    DEFF Research Database (Denmark)

    Knott, Arnold; Buhl, Niels Christian; Andersen, Michael A. E.

    2012-01-01

    The conversion of electrical energy into sound waves by electromechanical transducers is proportional to the current through the coil of the transducer. However virtually all audio power amplifiers provide a controlled voltage through the interface to the transducer. This paper is presenting...... a switch-mode audio power amplifier not only providing controlled current but also being supplied by current. This results in an output filter size reduction by a factor of 6. The implemented prototype shows decent audio performance with THD + N below 0.1 %....

  11. Increased Photovoltaic Power Output via Diffractive Spectrum Separation

    Science.gov (United States)

    Kim, Ganghun; Dominguez-Caballero, Jose A.; Lee, Howard; Friedman, Daniel J.; Menon, Rajesh

    2013-03-01

    In this Letter, we report the preliminary demonstration of a new paradigm for photovoltaic power generation that utilizes a broadband diffractive-optical element (BDOE) to efficiently separate sunlight into laterally spaced spectral bands. These bands are then absorbed by single-junction photovoltaic cells, whose band gaps correspond to the incident spectral bands. We designed such BDOEs by utilizing a modified version of the direct-binary-search algorithm. Gray scale lithography was used to fabricate these multilevel optics. They were experimentally characterized with an overall optical efficiency of 70% over a wavelength range of 350-1100 nm, which was in excellent agreement with simulation predictions. Finally, two prototype devices were assembled: one with a pair of copper indium gallium selenide based photovoltaic devices, and another with GaAs and c-Si photovoltaic devices. These devices demonstrated an increase in output peak electrical power of ˜42% and ˜22%, respectively, under white-light illumination. Because of the optical versatility and manufacturability of the proposed BDOEs, the reported spectrum-splitting approach provides a new approach toward low-cost solar power.

  12. Increased photovoltaic power output via diffractive spectrum separation.

    Science.gov (United States)

    Kim, Ganghun; Dominguez-Caballero, Jose A; Lee, Howard; Friedman, Daniel J; Menon, Rajesh

    2013-03-22

    In this Letter, we report the preliminary demonstration of a new paradigm for photovoltaic power generation that utilizes a broadband diffractive-optical element (BDOE) to efficiently separate sunlight into laterally spaced spectral bands. These bands are then absorbed by single-junction photovoltaic cells, whose band gaps correspond to the incident spectral bands. We designed such BDOEs by utilizing a modified version of the direct-binary-search algorithm. Gray scale lithography was used to fabricate these multilevel optics. They were experimentally characterized with an overall optical efficiency of 70% over a wavelength range of 350-1100 nm, which was in excellent agreement with simulation predictions. Finally, two prototype devices were assembled: one with a pair of copper indium gallium selenide based photovoltaic devices, and another with GaAs and c-Si photovoltaic devices. These devices demonstrated an increase in output peak electrical power of ∼ 42% and ∼ 22%, respectively, under white-light illumination. Because of the optical versatility and manufacturability of the proposed BDOEs, the reported spectrum-splitting approach provides a new approach toward low-cost solar power.

  13. Muscle coordination is key to the power output and mechanical efficiency of limb movements.

    Science.gov (United States)

    Wakeling, J M; Blake, O M; Chan, H K

    2010-02-01

    The purpose of this study was to determine which features of muscle mechanics and muscle coordination affect the power output from a limb during locomotion. Eight subjects were tested while cycling at maximum exertion for 25 min on a stationary dynamometer. Cadence and load were varied to span a range of power outputs and myoelectric activity was measured from 10 muscles in the leg. Cycle-by-cycle variations in muscle coordination, cadence and power output were observed and the EMG intensity across all muscles was used as an estimate of the metabolic cost for each cycle. Data for the cycles at greatest power output were separated into three groups: maximum power, 80% power but lower EMG intensity and 80% power and higher EMG intensity. Torque-angular velocity relations were determined for the ankle and knee joints. During cycling at maximum power output the ankle joint was not extending at the velocity necessary for maximum power output; thus, maximum limb power occurs when some of the individual muscles cannot be generating maximum power output. Increases in EMG intensity occurred with no increase in power output from the limb: these corresponded to decreases in the efficiency and changes in coordination. Increases in power were achieved that were not matched by equivalent increases in EMG intensity, but did occur with changes in coordination. It is proposed that the power output from the limb is limited by the coordination pattern of the muscles rather than the maximum power output from any one muscle itself.

  14. Basic study on dynamic reactive-power control method with PV output prediction for solar inverter

    Directory of Open Access Journals (Sweden)

    Ryunosuke Miyoshi

    2016-01-01

    Full Text Available To effectively utilize a photovoltaic (PV system, reactive-power control methods for solar inverters have been considered. Among the various methods, the constant-voltage control outputs less reactive power compared with the other methods. We have developed a constant-voltage control to reduce the reactive-power output. However, the developed constant-voltage control still outputs unnecessary reactive power because the control parameter is constant in every waveform of the PV output. To reduce the reactive-power output, we propose a dynamic reactive-power control method with a PV output prediction. In the proposed method, the control parameter is varied according to the properties of the predicted PV waveform. In this study, we performed numerical simulations using a distribution system model, and we confirmed that the proposed method reduces the reactive-power output within the voltage constraint.

  15. Analysis on Output Teaching Mode of College English Based on Implicit Learning Theory

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ling; LIN Wen-qin

    2014-01-01

    The application of language, to a great extant, requires learners to understand the inputted information quickly as well as automatically, and combine verbal fragments into meaningful outputted language. This type of spontaneous mechanism depends on the effective input of language and long-rang internalization of language structure, which helps to form the implicit knowl-edge in students’conceptual system, thus to realize the automatic use of language. Therefore, the article intends to combine im-plicit learning theory with the output teaching mode with a purpose of working out a practical teaching mode to enhance the teaching effect and college students’applied abilities to use English.

  16. Adaptive robust maximum power point tracking control for perturbed photovoltaic systems with output voltage estimation.

    Science.gov (United States)

    Koofigar, Hamid Reza

    2016-01-01

    The problem of maximum power point tracking (MPPT) in photovoltaic (PV) systems, despite the model uncertainties and the variations in environmental circumstances, is addressed. Introducing a mathematical description, an adaptive sliding mode control (ASMC) algorithm is first developed. Unlike many previous investigations, the output voltage is not required to be sensed and the upper bound of system uncertainties and the variations of irradiance and temperature are not required to be known. Estimating the output voltage by an update law, an adaptive-based H∞ tracking algorithm is then developed for the case the perturbations are energy-bounded. The stability analysis is presented for the proposed tracking control schemes, based on the Lyapunov stability theorem. From a comparison viewpoint, some numerical and experimental studies are also presented and discussed.

  17. Mode Adaptive Droop Control with Virtual Output Impedances for an Inverter-Based Flexible AC Microgrid

    DEFF Research Database (Denmark)

    Kim, Jaehong; Guerrero, Josep M.; Rodriguez, Pedro;

    2011-01-01

    in islanded and grid-connected mode. The proposed control scheme does not need any mode switching action. Thus, it is relatively simple in control for full mode of operation. Smooth transitions between the operation modes and the effectiveness of the proposed control scheme are evaluated through simulation...... control combined with a derivative controller is used in islanded mode. In grid-connected mode, to strictly control the power factor in the point of common coupling (PCC), a droop method combined with an integral controller is adopted. Small-signal analysis of the proposed control is shown both...

  18. Maximum Power Point Tracking Based on Sliding Mode Control

    Directory of Open Access Journals (Sweden)

    Nimrod Vázquez

    2015-01-01

    Full Text Available Solar panels, which have become a good choice, are used to generate and supply electricity in commercial and residential applications. This generated power starts with the solar cells, which have a complex relationship between solar irradiation, temperature, and output power. For this reason a tracking of the maximum power point is required. Traditionally, this has been made by considering just current and voltage conditions at the photovoltaic panel; however, temperature also influences the process. In this paper the voltage, current, and temperature in the PV system are considered to be a part of a sliding surface for the proposed maximum power point tracking; this means a sliding mode controller is applied. Obtained results gave a good dynamic response, as a difference from traditional schemes, which are only based on computational algorithms. A traditional algorithm based on MPPT was added in order to assure a low steady state error.

  19. Second Order Sliding Mode-Based Output Feedback Tracking Control for Uncertain Robot Manipulators

    OpenAIRE

    Van, Mien; Hee-Jun Kang; Young-Soo Suh

    2013-01-01

    In this paper, a robust output feedback tracking control scheme for motion control of uncertain robot manipulators without joint velocity measurement based on a second-order sliding mode (SOSM) observer is presented. Two second‐order sliding mode observers with finite time convergence are developed for velocity estimation and uncertainty identification, respectively. The first SOSM observer is used to estimate the state vector in finite time without filtration. However, for uncertainty identi...

  20. Peak power tunable mid-infrared oscillator pumped by a high power picosecond pulsed fiber amplifier with bunch output

    Science.gov (United States)

    Wei, Kaihua; Guo, Yan; Lai, Xiaomin; Fan, Shanhui

    2016-07-01

    A high power mid-infrared optical parametric oscillator (OPO) with picosecond pulse bunch output is experimentally demonstrated. The pump source was a high power master oscillation power amplifier (MOPA) picosecond pulsed fiber amplifier. The seed of the MOPA was a gain-switched distributed Bragg reflector (DBR) laser diode (LD) with picosecond pulse operation at a high repetition rate. The seed laser was amplified to 50 W by two-stage pre-amplifiers and a large mode area (LMA) Yb fiber based power-amplifier. A fiber-pigtailed acousto-optic modulator with the first order diffraction transmission was inserted into the second pre-amplifier to form a picosecond pulse bunch train and to change the peak power simultaneously. The power-amplified pulse bunches were focused to pump a wavelength-tunable OPO for emitting high power mid-infrared laser. By adjusting the OPO cavity length, the maximum average idler powers obtained at 3.1, 3.3 and 3.5 μm were 7, 6.6 and 6.4 W respectively.

  1. Maximizing Output Power of a Solar Panel via Combination of Sun Tracking and Maximum Power Point Tracking by Fuzzy Controllers

    OpenAIRE

    Mohsen Taherbaneh; A. H. Rezaie; H. Ghafoorifard; Rahimi, K; M. B. Menhaj

    2010-01-01

    In applications with low-energy conversion efficiency, maximizing the output power improves the efficiency. The maximum output power of a solar panel depends on the environmental conditions and load profile. In this paper, a method based on simultaneous use of two fuzzy controllers is developed in order to maximize the generated output power of a solar panel in a photovoltaic system: fuzzy-based sun tracking and maximum power point tracking. The sun tracking is performed by changing the solar...

  2. Beam quality of InGaAs ridge lasers at high output power.

    Science.gov (United States)

    Hunziker, G; Harder, C

    1995-09-20

    The nonlinear behavior of the light-current characteristic of single quantum well, graded-index-separateheterostructure ridge laser diodes emitting at 980 nm is investigated. We have measured the beam-quality factor |M|(2) as a function of the output power, under continuous-wave and transient conditions.The time constant associated with beam degradation under the transient condition suggests that the temperature profile in the cavity plays a significant role in the lateral guiding of the lasing modes. The two-dimensional heat equation is solved for the device, and the time-resolved thermally induced refractive-index profile is computed. There is excellent agreement between the time required to reach a steady index profile and that required to degrade the beam. The small beam astigmatism (typically 2 µm) measured under CW operating conditions in the linear regime indicates that the mode is essentially index guided, which permits simple quantitative modeling of the waveguide.

  3. Single-input Multiple-output Tunable Log-domain Current-mode Universal Filter

    Directory of Open Access Journals (Sweden)

    P. Prommee

    2013-06-01

    Full Text Available This paper describes the design of a current-mode single-input multiple-output (SIMO universal filter based on the log-domain filtering concept. The circuit is a direct realization of a first-order differential equation for obtaining the lossy integrator circuit. Lossless integrators are realized by log-domain lossy integrators. The proposed filter comprises only two grounded capacitors and twenty-four transistors. This filter suits to operate in very high frequency (VHF applications. The pole-frequency of the proposed filter can be controlled over five decade frequency range through bias currents. The pole-Q can be independently controlled with the pole-frequency. Non-ideal effects on the filter are studied in detail. A validated BJT model is used in the simulations operated by a single power supply, as low as 2.5 V. The simulation results using PSpice are included to confirm the good performances and are in agreement with the theory.

  4. 75 FR 3985 - Trade Regulation Rule Relating to Power Output Claims for Amplifiers Utilized in Home...

    Science.gov (United States)

    2010-01-26

    ... receive information useful to their purchasing decision, or, at worst, could be deceived by certain power... CFR Part 432 Trade Regulation Rule Relating to Power Output Claims for Amplifiers Utilized in Home... Rule Relating to Power Output Claims for Amplifiers Utilized in Home Entertainment Products...

  5. Abnormally High Power Output of Wind Turbine in Cold Weather: A Preliminary Study

    Directory of Open Access Journals (Sweden)

    Christophe Leclerc

    2003-01-01

    Full Text Available According to popular belief, air temperature effects on wind turbine power output are produced solely by air density variations, and power is proportional to air density. However, some cases have been reported, all involving stall-controlled wind turbines, in which unexpected high power output was observed at very low temperatures.

  6. Non-invasive prediction of blood lactate response to constant power outputs from incremental exercise tests.

    Science.gov (United States)

    Sullivan, C S; Casaburi, R; Storer, T W; Wasserman, K

    1995-01-01

    We determined the ability of gas exchange analyses during incremental exercise tests (IXT) to predict blood lactate levels associated with a range of constant power output cycle ergometer tests. Twenty-seven healthy young men performed duplicate IXT and four 15-min constant power output tests at intensities ranging from moderate to very severe, before and after a training program. End-exercise blood lactate levels were approximated from superficial venous samples obtained 60 s after each constant power output test. From IXT, the power outputs corresponding to peak oxygen uptake (Wmax) and lactic acidosis threshold (WLAT), were determined. We examined the ability of four measures of exercise intensity to predict blood lactate levels for power outputs above the LAT: (1) power output (W), (2) power difference (W-WLAT), (3) power fraction (W/Wmax) and (4) power difference to delta ratio [(W-WLAT)/(Wmax-WLAT)]. Correlation coefficients were r = 0.38, 0.69, 0.75, and 0.81, respectively. The best linear regression prediction equation was: lactate (mmol.l-1) = 12.2[(W-WLAT)/(Wmax-WLAT)] + 0.7 mmol.l-1. This relationship was not significantly affected by training, despite increased values of LAT and peak oxygen uptake. Normalizing exercise intensity to the range of power outputs between WLAT and Wmax provided an estimate of blood lactate response to constant power outputs with a standard error of the estimate of 1.66 mmol.l-1.

  7. Relationships between torque, velocity and power output during plantarflexion in healthy subjects.

    Science.gov (United States)

    Nadeau, S; Gravel, D; Arsenault, A B

    1997-03-01

    This study investigated the relationships existing between torque, velocity and power output during plantarflexion. Using a Biodex dynamometric system, 15 healthy subjects performed three maximal dynamic tests, ranging from -12 degrees (-0.209 rad) of dorsiflexion to +47 degrees (+0.818 rad) of plantarflexion and one static test (test 4) at an angle of +10 degrees (+0.174 rad). The dynamic assessment included a 30 degrees s-1 (0.52 rad s-1) concentric isokinetic test (test 1) preceded by a 2-sec maximal pre-loading contraction. The other two dynamic tests were performed using the isotonic mode of testing with a selected torque of 27 N m; one of these tests was executed with pre-loading (test 2) while the other was performed without pre-loading (test 3). The results indicated that the dynamic peak torque, the peak power and the peak velocity were obtained in test 1, test 2 and test 3, respectively. These peak values, as well as the values of torque (test 1 and test 4), power (test 2) and velocity (test 3) obtained at a constant angle +10 degrees (+0.174 rad), were selected for the correlation analyses. The results showed that the torque, velocity and power output during plantarflexion were linearly related to one another with significant correlations (0.71 < r < 0.92; p < 0.01). This finding suggests that a common factor of muscular performance is assessed. Furthermore, these results indicated that the maximal torque produced by a subject can be predictive of his or her maximal velocity and power. Consequently, a stronger subject can generate higher velocity and power than a weaker subject when tested with the same load during maximal effort.

  8. High power picosecond vortex laser based on a large-mode-area fiber amplifier.

    Science.gov (United States)

    Tanaka, Yuichi; Okida, Masahito; Miyamoto, Katsuhiko; Omatsu, Takashige

    2009-08-03

    We present the production of picosecond vortex pulses from a stressed large-mode-area fiber amplifier for the first time. 8.5 W picosecond output with a peak power of approximately 12.5 kW was obtained at a pump power of 29 W. 2009 Optical Society of America.

  9. Thermally induced mode distortion and its limit to power scaling of fiber lasers.

    Science.gov (United States)

    Ke, Wei-Wei; Wang, Xiao-Jun; Bao, Xian-Feng; Shu, Xiao-Jian

    2013-06-17

    A general model is proposed to describe thermal-induced mode distortion in the step-index fiber (SIF) high power lasers. Two normalized parameters in the model are able to determine the mode characteristic in the heated SIFs completely. Shrinking of the mode fields and excitation of the high-order modes by the thermal-optic effect are investigated. A simplified power amplification model is used to describe the output power redistribution under various guiding modes. The results suggest that fiber with large mode area is more sensitive on the thermally induced mode distortion and hence is disadvantaged in keeping the beam quality in high power operation. The model is further applied to improve the power scaling analysis of Yb-doped fiber lasers. Here the thermal effect is considered to couple with the optical damage and the stimulated Raman scattering dynamically, whereas direct constraint from the thermal lens is relaxed. The resulting maximal output power is from 67kW to 97kW, depending on power fraction of the fundamental mode.

  10. Numerical Calculation of the Output Power of a MHD Generator

    Directory of Open Access Journals (Sweden)

    Adrian CARABINEANU

    2014-12-01

    Full Text Available Using Lazăr Dragoş’s analytic solution for the electric potential we perform some numerical calculations in order to find the characteristics of a Faraday magnetohydrodymamics (MHD power generator (total power, useful power and Joule dissipation power.

  11. VDCC Based Dual-Mode Quadrature Sinusoidal Oscillator with Outputs at Appropriate Impedance Levels

    Directory of Open Access Journals (Sweden)

    Mayank Srivastava

    2016-01-01

    Full Text Available This article presents a new dual-mode (i.e. both current-mode and voltage-mode quadrature sinusoidal oscillator using two Voltage Differencing Current Conveyors (VDCCs, two resistors and two capacitors. The proposed configuration use only grounded passive elements and enjoys independent resistor/electronic tuning of both Condition of Oscillation (CO as well as Frequency of Oscillation (FO. The quadrature current and voltage mode outputs of this circuit are available at appropriate impedance terminals. The behavior of presented oscillator is also examined under non ideal/parasitic conditions. The validity of the proposed configuration has been confirmed by SPICE simulations with TSMC 0.18μm process parameters.

  12. The Improved Power of the Central Lobe in the Beam Combination and High Power Output

    Institute of Scientific and Technical Information of China (English)

    LIU Hou-Kang; WEI Yun-Rong; DONG Jing-Xing; LOU Qi-Hong; XUE Yu-Hao; LI Zhen; HE Bing; ZHOU Jun; DING Ya-Qian; JIAO Meng-Li; LIU Chi; QI Yun-Feng

    2012-01-01

    In order to increase the power fraction of the central lobe in the coherent beam combination of lasers in an array,the effects of the distance factor of near-field distribution on far-field interference patterns are calculated and demonstrated experimentally.An improved beam array of interwoven distribution is demonstrated to enable the power in the central lobe to reach 41%.An optimized mirror array is carefully designed to obtain a high duty ratio,which is up to 53.3% at a high power level.By using these optimized methods and designs,the passive phase locking of eight Yb-doped fiber amplifiers with ring cavities are obtained,and a pleasing interference pattern with 87% visibility is observed.The maximum coherent output power of the system is up to 1066 W.%In order to increase the power fraction of the central lobe in the coherent beam combination of lasers in an array, the effects of the distance factor of near-field distribution on far-field interference patterns are calculated and demonstrated experimentally. An improved beam array of interwoven distribution is demonstrated to enable the power in the central lobe to reach 41%. An optimized mirror array is carefully designed to obtain a high duty ratio, which is up to 53.3% at a high power level. By using these optimized methods and designs, the passive phase locking of eight Yb-doped fiber amplifiers with ring cavities are obtained, and a pleasing interference pattern with 87% visibility is observed. The maximum coherent output power of the system is up to 1066 W.

  13. Examining the Variability of Wind Power Output in the Regulation Time Frame: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Hodge, B. M.; Shedd, S.; Florita, A.

    2012-08-01

    This work examines the distribution of changes in wind power for different time scales in the regulation time frame as well as the correlation of changes in power output for individual wind turbines in a wind plant.

  14. Optimization of Output Properties for Bias Signal-Modulated in a Single-Mode Laser

    Institute of Scientific and Technical Information of China (English)

    LI Tai-Quan; DONG Ping; YANG Hong-Quan; HAN Li-Bo

    2005-01-01

    Defining the quantity K as the signal-to-noise ratio (SNR) and the normalized intensity fluctuation C(0) of a single-mode laser for bias signal modulation driven by color noises with colored correlation, the whole output properties of the laser system is described by K. It is found that there is a maximum in the curves of K versus D, Q, and io. The optimization parameters are gained.

  15. Output feedback fractional-order nonsingular terminal sliding mode control of underwater remotely operated vehicles.

    Science.gov (United States)

    Wang, Yaoyao; Chen, Jiawang; Gu, Linyi

    2014-01-01

    For the 4-DOF (degrees of freedom) trajectory tracking control problem of underwater remotely operated vehicles (ROVs) in the presence of model uncertainties and external disturbances, a novel output feedback fractional-order nonsingular terminal sliding mode control (FO-NTSMC) technique is introduced in light of the equivalent output injection sliding mode observer (SMO) and TSMC principle and fractional calculus technology. The equivalent output injection SMO is applied to reconstruct the full states in finite time. Meanwhile, the FO-NTSMC algorithm, based on a new proposed fractional-order switching manifold, is designed to stabilize the tracking error to equilibrium points in finite time. The corresponding stability analysis of the closed-loop system is presented using the fractional-order version of the Lyapunov stability theory. Comparative numerical simulation results are presented and analyzed to demonstrate the effectiveness of the proposed method. Finally, it is noteworthy that the proposed output feedback FO-NTSMC technique can be used to control a broad range of nonlinear second-order dynamical systems in finite time.

  16. Optimization of the output power of a pulsed gas laser by using magnetic pulse compression

    Science.gov (United States)

    Louhibi, D.; Ghobrini, Mourad; Bourai, K.

    1999-12-01

    In pulsed gas lasers, the excitation of the active medium is produced through the discharge of a storage capacitor. Performances of these lasers were essentially linked to the type of switch used and also to its mode of operation. Thyratrons are the most common switches. Nevertheless, their technological limitations do not allow a high repetition rate, necessary for optimization of the output power of this type of laser. These limitations can be surpassed by combining the thyratron to a one stage of a magnetic pulse compression circuit. The mpc driver can improve the laser excitation pulse rise time and increase the repetition rate, increasing the laser output power of pulsed gas laser such as; nitrogen, excimer and copper vapor lasers. We have proposed in this paper a new configuration of magnetic pulse compression, the magnetic switch is place in our case in the charge circuit, and while in the typical utilization of magnetic pulse compression, it is placed in the discharge circuit. In this paper, we are more particularly interested in the design and the modeling of a saturate inductance that represents the magnetic switch in the proposed configuration of a thyratron - mpc circuit combination.

  17. Variable power combiner for RF mode shimming in 7-T MR imaging.

    Science.gov (United States)

    Yazdanbakhsh, Pedram; Solbach, Klaus; Bitz, Andreas K

    2012-09-01

    This contribution discusses the utilization of RF power in an MRI system with RF mode shimming which enables the superposition of circularly polarized modes of a transmit RF coil array driven by a Butler matrix. Since the required power for the individual modes can vary widely, mode-shimming can result in a significant underutilization of the total available RF power. A variable power combiner (VPC) is proposed to improve the power utilization: it can be realized as a reconfiguration of the MRI transmit system by the inclusion of one additional matrix network which receives the power from all transmit amplifiers at its input ports and provides any desired (combined) power distribution at its output ports by controlling the phase and amplitude of the amplifiers' input signals. The power distribution at the output ports of the VPC is then fed into the "mode" ports of the coil array Butler matrix in order to superimpose the spatial modes at the highest achievable power utilization. The VPC configuration is compared to the standard configuration of the transmit chain of our MRI system with 8 transmit channels and 16 coils. In realistic scenarios, improved power utilization was achieved from 17% to 60% and from 14% to 55% for an elliptical phantom and a region of interest in the abdomen, respectively, and an increase of the power utilization of 1 dB for a region of interest in the upper leg. In general, it is found that the VPC allows significant improvement in power utilization when the shimming solution demands only a few modes to be energized, while the technique can yield loss in power utilization in cases with many modes required at high power level.

  18. Transmission Power Control using Small-Capacity UPFC under Output Voltage Saturation

    Science.gov (United States)

    Kuroda, Takeshi; Takeshita, Takaharu; Fujita, Hideki

    This paper presents a fast transmission power control scheme using a UPFC (Unified Power Flow Controller) under the output voltage saturation. For practical use of the UPFC, the fast and stable power response and the reduced power converter capacity are desired. The authors propose the fast and stable control scheme under the output voltage saturation of the reduced capacity UPFC. The effectiveness of the proposed control algorithm of the UPFC has been verified by experiments.

  19. Wide Output Range Power Processing Unit for Electric Propulsion Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A power supply concept capable of operation over 25:1 and 64:1 impedance ranges at full power has been successfully demonstrated in our Phase I effort at...

  20. Three-Input Single-Output Electronically Controllable Dual-Mode Universal Biquad Filter Using DO-CCCIIs

    Directory of Open Access Journals (Sweden)

    M. Siripruchyanun

    2007-01-01

    Full Text Available This article presents a dual-mode (voltage-mode and current-mode universal biquadratic filter performing completely standard functions: lowpass, highpass, bandpass, band-reject, and allpass functions, based on plus-type dual-output second-generation, current controlled, current conveyor (DO-CCCII+. The features of the circuit are that the bandwidth and natural frequency can be tuned electronically via the input bias currents: the circuit description is very simple, consisting of merely 2 DO-CCCIIs and 2 capacitors: the circuit can provide either the voltage-mode or current-mode filter without changing circuit topology. Additionally, each function response can be selected by suitably selecting input signals with digital method. Without any external resistors, the proposed circuit is very suitable to further develop into an integrated circuit. The PSPICE simulation results are depicted. The given results agree well with the theoretical anticipation. The maximum power consumption is approximately 1.81 mW at ±1.5 V supply voltages.

  1. High Power Tm3+-Doped Fiber Lasers Tuned by a Variable Reflective Output Coupler

    Directory of Open Access Journals (Sweden)

    Yulong Tang

    2008-01-01

    Full Text Available Wide wavelength tuning by a variable reflective output coupler is demonstrated in high-power double-clad Tm3+-doped silica fiber lasers diode-pumped at ∼790  nm. Varying the output coupling from 96% to 5%, the laser wavelength is tuned over a range of 106  nm from 1949 to 2055  nm. The output power exceeds 20  W over 90-nm range and the maximum output power is 32  W at 1949  nm for 51-W launched pump power, corresponding to a slope efficiency of ∼70%. Assisted with different fiber lengths, the tuning range is expanded to 240  nm from 1866 to 2107  nm with the output power larger than 10  W.

  2. Thermally induced nonlinear mode coupling in high power fiber amplifiers

    DEFF Research Database (Denmark)

    Johansen, Mette Marie; Hansen, Kristian Rymann; Alkeskjold, Thomas T.;

    2013-01-01

    Thermally induced nonlinear mode coupling leads to transverse mode instability (TMI) in high power fiber amplifiers. A numerical model including altering mode profiles from thermal effects and waveguide perturbations predicts a TMI threshold of ~200W.......Thermally induced nonlinear mode coupling leads to transverse mode instability (TMI) in high power fiber amplifiers. A numerical model including altering mode profiles from thermal effects and waveguide perturbations predicts a TMI threshold of ~200W....

  3. OTA a wide common mode low power

    Directory of Open Access Journals (Sweden)

    Héctor Iván Gómez-Ortiz

    2016-07-01

    Full Text Available This paper presents the design of an operational transconductance amplifier OTA operating in sub-threshold region for low power consumption. Simulations were performed in SYNOPSYS tools program for a 180nm technology. The differential amplifier is supplied with a VDD of 600mV, and has a load capacitance of 15pF. Amplifier gain is 60.08dB with unity-gain frequency of 21.7kHz, and a phase margin greater than 50degrees. Wide common mode operation is achieved by using complementary input differential pairs (NMOS and PMOS showing a range of operation of 500mV.

  4. Sliding mode output feedback control based on tracking error observer with disturbance estimator.

    Science.gov (United States)

    Xiao, Lingfei; Zhu, Yue

    2014-07-01

    For a class of systems who suffers from disturbances, an original output feedback sliding mode control method is presented based on a novel tracking error observer with disturbance estimator. The mathematical models of the systems are not required to be with high accuracy, and the disturbances can be vanishing or nonvanishing, while the bounds of disturbances are unknown. By constructing a differential sliding surface and employing reaching law approach, a sliding mode controller is obtained. On the basis of an extended disturbance estimator, a creative tracking error observer is produced. By using the observation of tracking error and the estimation of disturbance, the sliding mode controller is implementable. It is proved that the disturbance estimation error and tracking observation error are bounded, the sliding surface is reachable and the closed-loop system is robustly stable. The simulations on a servomotor positioning system and a five-degree-of-freedom active magnetic bearings system verify the effect of the proposed method.

  5. Magnetic Bearing Amplifier Output Power Filters for Flywheel Systems

    Science.gov (United States)

    Lebron-Velilla, Ramon C.; Jansen, Ralph H.; Palazzolo, Alan; Thomas, Erwin; Kascak, Peter E.; Birchenough, Arthur G.; Dever, Timothy P.

    2003-01-01

    Five power filters and two types of power amplifiers were tested for use with active magnetic bearings for flywheel applications. Filter topologies included low pass filters and low pass filters combined with trap filters at the PWM switching frequency. Two state and three state PWM amplifiers were compared. Each system was evaluated based on current magnitude at the switching frequency, voltage magnitude at 500 kHz, and power consumption. The base line system was a two state amplifier without a power filter. The recommended system is a three state power amplifier with a 50 kHz low pass filter and a 27 kHz trap filter. This system uses 5.57 W. It reduces the switching current by an order of magnitude and the 500 kHz voltage by two orders of magnitude. The relative power consumption varied depending on the test condition between 60 to 130 percent of the baseline.

  6. Modeling of Electric Power Consumption by Industrial Enterprises with Ambiguous Interrelation between Power Consumption and Report Output

    Directory of Open Access Journals (Sweden)

    D. R. Moroz

    2007-01-01

    Full Text Available The paper gives description of a method for modeling electric power consumption by industrial enterprises with a complicated technological process that differs in accounting parameters of power consumption distribution laws and volume of output. The proposed method permits reliably to evaluate specific technological consumption of electric power and a direct component of electric power consumption.

  7. Holmium-doped 2.1 μm waveguide chip laser with an output power > 1 W.

    Science.gov (United States)

    Lancaster, D G; Stevens, V J; Michaud-Belleau, V; Gross, S; Fuerbach, A; Monro, T M

    2015-12-14

    We demonstrate the increasing applicability of compact ultra-fast laser inscribed glass guided-wave lasers and report the highest-power glass waveguide laser with over 1.1 W of output power in monolithic operation in the short-infrared near 2070 nm achieved (51% incident slope efficiency). The holmium doped ZBLAN chip laser is in-band pumped by a 1945 nm thulium fiber laser. When operated in an extended-cavity configuration, over 1 W of output power is realized in a linearly polarized beam. Broad and continuous tunability of the extended-cavity laser is demonstrated from 2004 nm to 2099 nm. Considering its excellent beam quality of M² = 1.08, this laser shows potential as a flexible master oscillator for single frequency and mode-locking applications.

  8. Technique for enhancing the power output of an electrostatic generator employing parametric resonance

    Science.gov (United States)

    Post, Richard F.

    2016-02-23

    A circuit-based technique enhances the power output of electrostatic generators employing an array of axially oriented rods or tubes or azimuthal corrugated metal surfaces for their electrodes. During generator operation, the peak voltage across the electrodes occurs at an azimuthal position that is intermediate between the position of minimum gap and maximum gap. If this position is also close to the azimuthal angle where the rate of change of capacity is a maximum, then the highest rf power output possible for a given maximum allowable voltage at the minimum gap can be attained. This rf power output is then coupled to the generator load through a coupling condenser that prevents suppression of the dc charging potential by conduction through the load. Optimized circuit values produce phase shifts in the rf output voltage that allow higher power output to occur at the same voltage limit at the minimum gap position.

  9. Automation of Mode Locking in a Nonlinear Polarization Rotation Fiber Laser through Output Polarization Measurements.

    Science.gov (United States)

    Olivier, Michel; Gagnon, Marc-Daniel; Habel, Joé

    2016-02-28

    When a laser is mode-locked, it emits a train of ultra-short pulses at a repetition rate determined by the laser cavity length. This article outlines a new and inexpensive procedure to force mode locking in a pre-adjusted nonlinear polarization rotation fiber laser. This procedure is based on the detection of a sudden change in the output polarization state when mode locking occurs. This change is used to command the alignment of the intra-cavity polarization controller in order to find mode-locking conditions. More specifically, the value of the first Stokes parameter varies when the angle of the polarization controller is swept and, moreover, it undergoes an abrupt variation when the laser enters the mode-locked state. Monitoring this abrupt variation provides a practical easy-to-detect signal that can be used to command the alignment of the polarization controller and drive the laser towards mode locking. This monitoring is achieved by feeding a small portion of the signal to a polarization analyzer measuring the first Stokes parameter. A sudden change in the read out of this parameter from the analyzer will occur when the laser enters the mode-locked state. At this moment, the required angle of the polarization controller is kept fixed. The alignment is completed. This procedure provides an alternate way to existing automating procedures that use equipment such as an optical spectrum analyzer, an RF spectrum analyzer, a photodiode connected to an electronic pulse-counter or a nonlinear detecting scheme based on two-photon absorption or second harmonic generation. It is suitable for lasers mode locked by nonlinear polarization rotation. It is relatively easy to implement, it requires inexpensive means, especially at a wavelength of 1550 nm, and it lowers the production and operation costs incurred in comparison to the above-mentioned techniques.

  10. nLight Demonstrates World Record Output Power at 1470nm

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Diode Laser Bar Outputs 88W CW in Eyesafe Wavelength Range nLight, a leading manufacturer of high-power semiconductor lasers, today announced that it has achieved a new world record for output power from a single 1-cm InP diode laser bar. The 50 percent fill factor bar produced 88W continuous-wave (CW) power at1470 nm. The bar was mounted on the company's commercially available CascadesTM microchannel water-cooled package.

  11. Wide Output Range Power Processing Unit for Electric Propulsion Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Hall thrusters can be operated over a wide range of specific impulse while maintaining high efficiency. However S/C power system constraints on electric propulsion...

  12. A New Current Mode SIMO-Type Universal Biquad Employing Multi-Output Current Conveyors (MOCCIIs

    Directory of Open Access Journals (Sweden)

    S. Du

    2009-04-01

    Full Text Available This study presents a new current-mode singleinput and multi-output (SIMO type universal biquad circuit using second generation multi-output current conveyors (MOCCII as the active components. The proposed circuit employs three MOCCIIs, two grounded capacitors and four grounded resistors, therefore offers electroning tuning possibilities. It can simultaneously realize second order low-pass, band-pass, high-pass, notch and all-pass filters. The circuit is cascadable and has low sensitivities. It provides independent control of ω0 (natural angular frequency and Q (quality factor. The influences of MOCCII parasitic elements have been analyzed and simulated using PSPICE. Experimental results including frequency responses of low-pass, high-pass, band-pass and band-stop filters, as well as frequency responses of filters with different ω0 (keeping Q invariable and different Q (keeping ω0 invariable are shown to be in agreement with theory.

  13. A dual-mode phase-shift modulation control scheme for voltage multiplier based X-ray power supply

    Energy Technology Data Exchange (ETDEWEB)

    Iqbal, S [School of Electrical and Electronics Engineering, University Sains Malaysia, 14300 Nibong Tebal, Pulau Pinang (Malaysia); Besar, R; Venkataseshaiah, C, E-mail: shahidsidu@hotmail.co [Faculty of Engineering and Technology, Multimedia University, 75450 Melaka (Malaysia)

    2010-05-15

    This paper proposes a dual-mode phase-shift modulation control scheme for series resonant inverter fed voltage multiplier (VM) based X-ray power supply. In this control scheme the outputs voltage of two parallel connected series resonant inverters are mixed before supplying to VM circuit. The output voltage of the power supply is controlled by varying the phase-shift between the output voltages of two inverters. In order to achieve quick rise of output voltage, the power supply is started with zero phase-shift and as the output voltage reaches 90% of the target voltage, the phase-shift is increased to a value which corresponds to target output voltage to prevent overshoot. The proposed control scheme has been shown to have good performance. Experimental results based on the scaled-down laboratory prototype are presented to validate the effectiveness of proposed dual-mode phase shift modulation control scheme.

  14. A study on electric power management for power producer-suppliers utilizing output of megawatt-solar power plants

    Directory of Open Access Journals (Sweden)

    Hirotaka Takano

    2016-01-01

    Full Text Available The growth in penetration of photovoltaic generation units (PVs has brought new power management ideas, which achieve more profitable operation, to Power Producer-Suppliers (PPSs. The expected profit for the PPSs will improve if they appropriately operate their controllable generators and sell the generated electricity to contracted customers and Power Exchanges together with the output of Megawatt-Solar Power Plants (MSPPs. Moreover, we can expect that the profitable cooperation between the PPSs and the MSPPs decreases difficulties in the supply-demand balancing operation for the main power grids. However, it is necessary that the PPSs treat the uncertainty in output prediction of PVs carefully. This is because there is a risk for them to pay a heavy imbalance penalty. This paper presents a problem framework and its solution to make the optimal power management plan for the PPSs in consideration with the electricity procurement from the MSPPs. The validity of the authors’ proposal is verified through numerical simulations and discussions of their results.

  15. Performance of improved magnetostrictive vibrational power generator, simple and high power output for practical applications

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, Toshiyuki, E-mail: ueno@ec.t.kanazawa-u.ac.jp [Kanazawa University, Kakuma-machi, Kanazawa-city, Ishikawa 920-1192 (Japan)

    2015-05-07

    Vibration based power generation technology is utilized effectively in various fields. Author has invented novel vibrational power generation device using magnetostrictive material. The device is based on parallel beam structure consisting of a rod of iron-gallium alloy wound with coil and yoke accompanied with permanent magnet. When bending force is applied on the tip of the device, the magnetization inside the rod varies with induced stress due to the inverse magnetostrictive effect. In vibration, the time variation of the magnetization generates voltage on the wound coil. The magnetostrictive type is advantageous over conventional such using piezoelectric or moving magnet types in high efficiency and high robustness, and low electrical impedance. Here, author has established device configuration, simple, rigid, and high power output endurable for practical applications. In addition, the improved device is lower cost using less volume of Fe-Ga and permanent magnet compared to our conventional, and its assembly by soldering is easy and fast suitable for mass production. Average power of 3 mW/cm{sup 3} under resonant vibration of 212 Hz and 1.2 G was obtained in miniature prototype using Fe-Ga rod of 2 × 0.5× 7 mm{sup 3}. Furthermore, the damping effect was observed, which demonstrates high energy conversion of the generator.

  16. Voltage-Mode Multifunction Biquadratic Filter with One Input and Six Outputs Using Two ICCIIs

    Directory of Open Access Journals (Sweden)

    Hua-Pin Chen

    2014-01-01

    Full Text Available A novel voltage-mode multifunction biquadratic filter with one input and six outputs is presented. The proposed circuit can realize inverting and noninverting low-pass, bandpass, and high-pass filters, simultaneously, by using two inverting second-generation current conveyors (ICCIIs, two grounded capacitors, and four resistors. Moreover, the proposed circuit offers the following attractive advantages: no requirements for component matching conditions, the use of only grounded capacitors, and low active and passive sensitivities. HSPICE and MATLAB simulations results are provided to demonstrate the theoretical analysis.

  17. Voltage-mode multifunction biquadratic filter with one input and six outputs using two ICCIIs.

    Science.gov (United States)

    Chen, Hua-Pin

    2014-01-01

    A novel voltage-mode multifunction biquadratic filter with one input and six outputs is presented. The proposed circuit can realize inverting and noninverting low-pass, bandpass, and high-pass filters, simultaneously, by using two inverting second-generation current conveyors (ICCIIs), two grounded capacitors, and four resistors. Moreover, the proposed circuit offers the following attractive advantages: no requirements for component matching conditions, the use of only grounded capacitors, and low active and passive sensitivities. HSPICE and MATLAB simulations results are provided to demonstrate the theoretical analysis.

  18. New synthesis algorithm of static output feedback sliding mode control for a class of uncertain systems

    Institute of Scientific and Technical Information of China (English)

    Ji XIANG; Hongye SU; Jian CHU; Xiaoyu ZHANG

    2004-01-01

    Based on a kind of regular form,a Lyapunov matrix with special structure is presented to design the sliding surface matrix conveniently and then an effective algorithm is developed on it.A simple static output feedback sliding mode control law without extra dynamic equation is given,such that the predefined sliding surface is reached in finite time for the general matching uncertainties.In the reported result,this extra dynamic equation is used for evaluating the norm bound of the unmeasured state vector.Finally,some examples are studied to illustrate the proposed approach.

  19. High-power transverse-mode-switchable all-fiber picosecond MOPA.

    Science.gov (United States)

    Liu, Tong; Chen, Shengping; Qi, Xue; Hou, Jing

    2016-11-28

    A high-power transverse-mode-switchable all-fiber picosecond laser in a master-oscillator power-amplifier (MOPA) configuration is demonstrated. The master oscillator is a gain-switched laser diode delivering picosecond pulses with 25 MHz repetition rate at the wavelength of 1.06 μm. After multi-stage amplification in ytterbium-doped fibers, the average output power is scaled to 117 W. A mechanical long-period grating is employed as a fiber mode convertor to achieve controllable conversion from the fundamental (LP01) to the second-order (LP11) mode. Efficient mode conversion is demonstrated and the output characteristics for both modes are investigated. It is shown that LP01 and LP11 modes have nearly identical optical-to-optical conversion efficiency during amplification, but the nonlinear spectral degradation is significantly alleviated for LP11 mode operation. Owing to the compact all-fiber architecture, this high-power transverse-mode-switchable fiber laser is reliable during long-term operation and thus promising for many practical applications, e.g. high-resolution laser micro-processing.

  20. Extension Sliding Mode Controller for Maximum Power Point Tracking of Hydrogen Fuel Cells

    Directory of Open Access Journals (Sweden)

    Meng-Hui Wang

    2013-01-01

    Full Text Available Fuel cells (FCs are characterized by low pollution, low noise, and high efficiency. However, the voltage-current response of an FC is nonlinear, with the result that there exists just one operating point which maximizes the output power given a particular set of operating conditions. Accordingly, the present study proposes a maximum power point tracking (MPPT control scheme based on extension theory to stabilize the output of an FC at the point of maximum power. The simulation results confirm the ability of the controller to stabilize the output power at the maximum power point despite sudden changes in the temperature, hydrogen pressure, and membrane water content. Moreover, the transient response time of the proposed controller is shown to be faster than that of existing sliding mode (SM and extremum seeking (ES controllers.

  1. Interleaved Flyback DC-DC Converter Design with 350 W Power Output Using LT 3757 in LT Spice

    Science.gov (United States)

    Rahayu, S.; Firmansyah, E.; Isnaeni, M.

    2017-04-01

    DC-DC converter becomes one important part in micro-inverter used in solar panel application. Its function is to convert output voltage level of solar panel 42-48 Vdc to a voltage level of 350 Vdc before being converted into an AC voltage at the inverter. The proposed converter topology is a flyback because the number of components used is not too much which can suppress the production cost. In this paper, simulation of flyback converter on the interleaved operating mode with a maximum output power of 350 W using software Ltspicewas conducted. From the simulation results, obtained that by applying a switching frequency of 100 kHz, the obtained value of the components of the primary inductor (LP) 3.3 μH, the secondary inductor (LS) 27 μH, the output capacitor (Cout) 47μF and ripple voltage (Vr) 212.65 mV.

  2. SWITCH MODE PULSE WIDTH MODULATED DC-DC CONVERTER WITH MULTIPLE POWER TRANSFORMERS

    DEFF Research Database (Denmark)

    2009-01-01

    A switch mode pulse width modulated DC-DC power converter comprises at least one first electronic circuit on a input side (1) and a second electronic circuit on a output side (2). The input side (1) and the output side (2) are coupled via at least two power transformers (T1, T2). Each power...... transformer (T1, T2) comprises a first winding (T1a, T2a) arranged in a input side converter stage (3, 4) on the input side (1) and a second winding (T1 b, T2b) arranged in a output side converter stage (5) on the output side (2), and each of the windings (T1a, T1 b, T2a, T2b) has a first end and a second end...

  3. High-power single-transverse-mode ridge optical waveguide semiconductor lasers

    NARCIS (Netherlands)

    Popovichev, VV; Davydova, EI; Marmalyuk, AA; Simakov, A; Uspenskii, MB; Chel'nyi, AA; Bogatov, AP; Drakin, AE; Plisyuk, SA; Sratonnikov, AA

    2002-01-01

    More than 200 mW of a single-transverse-mode cw output power is obtained from a semiconductor heterolaser by optimising the waveguide properties of its ridge structure. e laser-beam divergence is close to the diffraction limit and its brightness exceeds 5 x 10(7) W cm(-2) sr(-1). The calculated and

  4. Low-jitter and high-power 40 GHz all-active mode-locked lasers

    DEFF Research Database (Denmark)

    Yvind, Kresten; Larsson, David; Christiansen, Lotte Jin

    2004-01-01

    A novel design strategy for the epitaxial structure of monolithic mode-locked semiconductor lasers is presented. Using an all-active design, we fabricate 40-GHz lasers generating 2.8-ps almost chirp-free pulses with record low high-frequency jitter and more than 7-mW fiber coupled output power....

  5. Power output of offshore wind farms in relation to atmospheric stability

    NARCIS (Netherlands)

    Alblas, L.; Bierbooms, W.; Veldkamp, D.

    2014-01-01

    Atmospheric stability is known to influence wind farm power output, by affecting power losses due to wakes. This research tries to answer what atmospheric stability does to the power production and how conventional simulations using the Jensen wake model compare and can be improved. Data is used fro

  6. Output Impedance Shaping for Frequency Compensation of MOS Audio Power Amplifiers

    NARCIS (Netherlands)

    van der Zee, Ronan A.R.; Mostert, Fred

    2009-01-01

    A frequency compensation technique for MOS audio power amplifiers is presented that allows the frequency compensation capacitors around the power transistors to be smaller than the circuit parasitics without power or stability penalty. Stability is analysed by inspecting the output impedance of the

  7. Power output of offshore wind farms in relation to atmospheric stability

    NARCIS (Netherlands)

    Alblas, L.; Bierbooms, W.A.A.M.; Veldkamp, D.

    2014-01-01

    Atmospheric stability is known to influence wind farm power output, by affecting power losses due to wakes. This research tries to answer what atmospheric stability does to the power production and how conventional simulations using the Jensen wake model compare and can be improved. Data is used

  8. Power Scaling Fiber Amplifiers Using Very-Large-Mode-Area Fibers

    Science.gov (United States)

    2016-02-23

    implied, of the Air Force Research Laboratory or the U. S. Government. OPS-16-11957; 19 July 2016. Government Purpose Rights. 14. ABSTRACT DEW -class...level, their use in directed-energy weapon ( DEW ) systems require narrow linewidth, which to date has restricted their output power to below 1kW...fiber. Provided the thermal changes are sufficiently slow compared to the mode formation length, any given mode of the fiber will adiabatically

  9. High-Order Current-Mode and Transimpedance-Mode Universal Filters with Multiple-Inputs and Two-Outputs Using MOCCIIs

    Directory of Open Access Journals (Sweden)

    J. Horng

    2009-12-01

    Full Text Available A high-order current-mode and transimpedance-mode universal filter with multiple-inputs and two-outputs based on multiple output second-generation current conveyors (MOCCIIs is introduced. By choosing the input current terminals appropriately, the current-mode and transimpedance-mode lowpass, bandpass, highpass, notch or allpass filters can be obtained without component matching conditions. The proposed nth order universal filter requires (n+1 MOCCIIs, (n+1 resistors and n grounded capacitors. As examples, the first-order, biquadratic and third-order universal filters are given and compared with previous published works.

  10. Intelligent coordinated control of power-plant main steam pressure and power output

    Institute of Scientific and Technical Information of China (English)

    刘红波; 李少远; 柴天佑

    2004-01-01

    An intelligent coordinated control strategy has been proposed and successfully applied to a 300MW boiler-turbine unit i.e. Unit 1 of Yuanbaoshan power plant in China. Load following operation of coal-fired boiler-turbine unit in the power plant leads to changes in operating points which result in nonlinear variations of the plant variables and parameters. For the variation of operating condition and slowly varying dynamics, an intelligent control scheme has been developed by combining fuzzy self-tuning with adaptive control and auto-tuning techniques. As there exist strong couplings between control loops of main steam pressure and power output in the unit, a new design for static decoupler aimed at decoupling for setpoints and unmeasured pulverized coal disturbance of the system at the same time is presented. Satisfactory industrial application results show that such a control system has enhanced adaptability and robustness to the complex process, and better control performance and high economic benefit have been obtained.

  11. Investigation on the integral output power model of a large-scale wind farm

    Institute of Scientific and Technical Information of China (English)

    BAO Nengsheng; MA Xiuqian; NI Weidou

    2007-01-01

    The integral output power model of a large-scale wind farm is needed when estimating the wind farm's output over a period of time in the future.The actual wind speed power model and calculation method of a wind farm made up of many wind turbine units are discussed.After analyzing the incoming wind flow characteristics and their energy distributions,and after considering the multi-effects among the wind turbine units and certain assumptions,the incoming wind flow model of multi-units is built.The calculation algorithms and steps of the integral output power model of a large-scale wind farm are provided.Finally,an actual power output of the wind farm is calculated and analyzed by using the practical measurement wind speed data.The characteristics of a large-scale wind farm are also discussed.

  12. Improving the Output Power Stability of a High Concentration Photovoltaic System with Supercapacitors: A Preliminary Evaluation

    Directory of Open Access Journals (Sweden)

    Yu-Pei Huang

    2015-01-01

    Full Text Available The output power of a high concentration photovoltaic (HCPV system is very sensitive to fluctuating tracking errors and weather patterns. To help compensate this shortcoming, supercapacitors have been successfully incorporated into photovoltaic systems to improve their output power stability. This study examined the output power stability improvement of an HCPV module with a supercapacitor integrated into its circuit. Furthermore, the equivalent model of the experimental circuit is presented and analyzed. Experimental results suggest that integrating a supercapacitor into an HCPV module could improve its output power stability and further extend its acceptance angle. This paper provides preliminary data of the improvement and its evaluation method, which could be utilized for further improvements to an HCPV system.

  13. Second Order Sliding Mode-Based Output Feedback Tracking Control for Uncertain Robot Manipulators

    Directory of Open Access Journals (Sweden)

    Mien Van

    2013-01-01

    Full Text Available In this paper, a robust output feedback tracking control scheme for motion control of uncertain robot manipulators without joint velocity measurement based on a second-order sliding mode (SOSM observer is presented. Two second‐order sliding mode observers with finite time convergence are developed for velocity estimation and uncertainty identification, respectively. The first SOSM observer is used to estimate the state vector in finite time without filtration. However, for uncertainty identification, the values are constructed from the high switching frequencies, necessitating the application of a filter. To estimate the uncertainties without filtration, a second SOSM‐based nonlinear observer is designed. By integrating two SOSM observers, the resulting observer can theoretically obtain exact estimations of both velocity and uncertainty. An output feedback tracking control scheme is then designed based on the observed values of the state variables and the direct compensation of matched modelling uncertainty using their identified values. Finally, results of a simulation for a PUMA560 robot are shown to verify the effectiveness of the proposed strategy.

  14. Water Power Calculator Temperature and Analog Input/Output Module Ambient Temperature Testing

    Energy Technology Data Exchange (ETDEWEB)

    Mark D. McKay

    2011-02-01

    Water Power Calculator Temperature and Analog input/output Module Ambient Temperature Testing A series of three ambient temperature tests were conducted for the Water Power Calculator development using the INL Calibration Laboratory’s Tenney Environmental Chamber. The ambient temperature test results demonstrate that the Moore Industries Temperature Input Modules, Analog Input Module and Analog Output Module, ambient temperature response meet or exceed the manufactures specifications

  15. Continuous-wave high specific output power Ar-He-Xe laser with transverse RF excitation

    NARCIS (Netherlands)

    Udalov, Yu.B.; Peters, P.J.M.; Heeman-Ilieva, M.B.; Witteman, W.J.; Ochkin, V.N.

    1994-01-01

    A transverse RF excited gas discharge has been successfully used to produce a CW Ar-He-Xe laser. A maximum output power of 330 mW has been obtained from an experimental device with 37 cm active length and a 2.25 (DOT) 2.25 cm2 cross-section. This corresponds to a specific output power of about 175 m

  16. Output Tracking Using a Discrete-Time Sliding Mode Controller with Reduced-Order State-Error Estimation

    NARCIS (Netherlands)

    Monsees, G.; Scherpen, J.M.A.

    2001-01-01

    This paper presents a novel output-based, discrete-time, sliding mode controller design methodology. In order to reproduce an output target profile, feed-forward controllers yield an excellent performance, however their robustness against disturbances and parameter variations is limited. In this pap

  17. Maximizing Output Power of a Solar Panel via Combination of Sun Tracking and Maximum Power Point Tracking by Fuzzy Controllers

    Directory of Open Access Journals (Sweden)

    Mohsen Taherbaneh

    2010-01-01

    Full Text Available In applications with low-energy conversion efficiency, maximizing the output power improves the efficiency. The maximum output power of a solar panel depends on the environmental conditions and load profile. In this paper, a method based on simultaneous use of two fuzzy controllers is developed in order to maximize the generated output power of a solar panel in a photovoltaic system: fuzzy-based sun tracking and maximum power point tracking. The sun tracking is performed by changing the solar panel orientation in horizontal and vertical directions by two DC motors properly designed. A DC-DC converter is employed to track the solar panel maximum power point. In addition, the proposed system has the capability of the extraction of solar panel I-V curves. Experimental results present that the proposed fuzzy techniques result in increasing of power delivery from the solar panel, causing a reduction in size, weight, and cost of solar panels in photovoltaic systems.

  18. Open-phase operating modes of power flow control topologies in a Smart Grid Distribution Network

    Science.gov (United States)

    Astashev, M. G.; Novikov, M. A.; Panfilov, D. I.; Rashitov, P. A.; Remizevich, T. V.; Fedorova, M. I.

    2015-12-01

    The power flow regulating circuit node in an alternating current system is reviewed. The circuit node is accomplished based on a thyristor controlled phase angle regulator (TCPAR) with controlled thyristor switch. Research results of the individual phase control of the output voltage for the TCPAR are presented. Analytical expressions for the overvoltage factor calculation in the thyristor switch circuit for open-phase operating modes are received. Based on evaluation of overvoltage in operational and emergency modes, the implementability conditions of the individual phase control of the output voltage are determined. Under these conditions, maximal performance and complete controllability are provided.

  19. Multi-Output Power Converter, Operated from a Regulated Input Bus, for the Sireus Rate Sensor

    Directory of Open Access Journals (Sweden)

    Torrecilla Marcos Compadre

    2017-01-01

    Full Text Available This paper describes a DC to DC converter designed to meet the power supply requirements of the SiREUS Coarse Rate Sensor (CRS which is a 3-axis MEMS Rate Sensor (MRS that uses a resonating ring gyro and will be used in different ESA missions. The converter supplies +5V, −5V, 3.3V, 1.8V and 40V and it has been designed and prototyped by Clyde Space Ltd with the EQM and FM units being manufactured by Selex ES. The first model was designed for a 28V un-regulated bus and the second model presented here has been designed for a 50V regulated bus. PWM voltage regulation was not used because of the noise requirements and the regulated input bus allowed an unregulated power stage approach. There are also stringent volume and interface constraints, which also affected the design. For such reasons, a fixed dutycycle, quasi-resonant single-ended topology with output linear regulators has been implemented; having the advantages of providing low switching losses, low radiated and conducted noise and no over-voltage failure mode. This paper highlights the techniques used to satisfy stringent noise and protection requirements of the load.

  20. Artificial Neural Networks to Predict the Power Output of a PV Panel

    Directory of Open Access Journals (Sweden)

    Valerio Lo Brano

    2014-01-01

    Full Text Available The paper illustrates an adaptive approach based on different topologies of artificial neural networks (ANNs for the power energy output forecasting of photovoltaic (PV modules. The analysis of the PV module’s power output needed detailed local climate data, which was collected by a dedicated weather monitoring system. The Department of Energy, Information Engineering, and Mathematical Models of the University of Palermo (Italy has built up a weather monitoring system that worked together with a data acquisition system. The power output forecast is obtained using three different types of ANNs: a one hidden layer Multilayer perceptron (MLP, a recursive neural network (RNN, and a gamma memory (GM trained with the back propagation. In order to investigate the influence of climate variability on the electricity production, the ANNs were trained using weather data (air temperature, solar irradiance, and wind speed along with historical power output data available for the two test modules. The model validation was performed by comparing model predictions with power output data that were not used for the network's training. The results obtained bear out the suitability of the adopted methodology for the short-term power output forecasting problem and identified the best topology.

  1. Distributed Bragg reflector ring oscillators: A large aperture source of high single-mode optical power

    Energy Technology Data Exchange (ETDEWEB)

    Dzurko, K.M.; Hardy, A.; Scifres, D.R.; Welch, D.F.; Waarts, R.G.; Lang, R.J. (Spectra Diode Labs., San Jose, CA (United States))

    1993-06-01

    Distributed Bragg reflector (DBR) ring oscillators are the first monolithic semiconductor lasers containing broad-area active regions which operate in a single mode to several times their threshold current. Orthogonally oriented diffraction gratings surrounding an unpatterned active region select a single spatial and temporal mode of oscillation. This paper presents both analytic and experimental verification of single mode operation for active dimensions up to 368 [times] 1000 [mu]m. Threshold current densities under 200 A/cm[sup 2] and total differential efficiencies greater than 60% have been measured. DBR ring oscillators have demonstrated over 1 W of single frequency output power, 460 mW of spatially coherent, single frequency output power, and nearly circular diffraction limited output to 4 [times] I[sub th]. The performance potential of these devices is enormous, considering that the output apertures are nearly two orders of magnitude wider than conventional single mode sources which generate up to 0.2 W of coherent output.

  2. Effects of loading and size on maximum power output and gait characteristics in geckos.

    Science.gov (United States)

    Irschick, Duncan J; Vanhooydonck, Bieke; Herrel, Anthony; Andronescu, Anemone

    2003-11-01

    Stride length, stride frequency and power output are all factors influencing locomotor performance. Here, we first test whether mass-specific power output limits climbing performance in two species of geckos (Hemidactylus garnoti and Gekko gecko) by adding external loads to their bodies. We then test whether body size has a negative effect on mass-specific power output. Finally, we test whether loading affects kinematics in both gecko species. Lizards were induced to run vertically on a smooth wooden surface with loads of 0-200% of body mass (BM) in H. garnoti and 0-100% BM in G. gecko. For each stride, we calculated angular and linear kinematics (e.g. trunk angle, stride length), performance (maximum speed) and mean mass-specific power output per stride. The addition of increasingly large loads caused an initial increase in maximum mass-specific power output in both species, but for H. garnoti, mass-specific power output remained constant at higher loads (150% and 200% BM), even though maximum velocity declined. This result, in combination with the fact that stride frequency showed no evidence of leveling off as speed increased in either species, suggests that power limits maximum speed. In addition, the large gecko (G. gecko) produced significantly less power than the smaller H. garnoti, despite the fact that both species ran at similar speeds. This difference disappeared, however, when we recalculated power output based on higher maximum speeds for unloaded G. gecko moving vertically obtained by other researchers. Finally, the addition of external loads did not affect speed modulation in either species: both G. gecko and H. garnoti increase speed primarily by increasing stride frequency, regardless of loading condition. For a given speed, both species take shorter but more strides with heavier loads, but for a given load, G. gecko attains similar speeds to H. garnoti by taking longer but fewer strides.

  3. Modelling and Prediction of Photovoltaic Power Output Using Artificial Neural Networks

    Directory of Open Access Journals (Sweden)

    Aminmohammad Saberian

    2014-01-01

    Full Text Available This paper presents a solar power modelling method using artificial neural networks (ANNs. Two neural network structures, namely, general regression neural network (GRNN feedforward back propagation (FFBP, have been used to model a photovoltaic panel output power and approximate the generated power. Both neural networks have four inputs and one output. The inputs are maximum temperature, minimum temperature, mean temperature, and irradiance; the output is the power. The data used in this paper started from January 1, 2006, until December 31, 2010. The five years of data were split into two parts: 2006–2008 and 2009-2010; the first part was used for training and the second part was used for testing the neural networks. A mathematical equation is used to estimate the generated power. At the end, both of these networks have shown good modelling performance; however, FFBP has shown a better performance comparing with GRNN.

  4. Evaluating the contribution of lower extremity kinetics to whole body power output during the power snatch.

    Science.gov (United States)

    Lee, Sangwoo; DeRosia, Kyle D; Lamie, Landon M

    2017-09-21

    This study evaluated the contribution of lower extremity (hip, knee and ankle) net joint torques (NJT) to whole body power (WBP) output during the power snatch (PS). Ten experienced weightlifters (five males and five females) performed five trials of the PS with 60% of one repetition maximum. Lower extremity NJT and WBP were extracted through a three-dimensional motion analyses and used for data analyses. Pearson correlation coefficients were obtained to observe the relationship between lower extremity NJT and WBP. Multiple-regression (stepwise) analyses was also conducted to evaluate the contribution of lower extremity NJT to WBP during the PS with the hip, knee and ankle NJT being the independent variables. Hip NJT was characterised as a significant positive correlation with WBP (r = 0.47, p < 0.01), while knee NJT showed a significant negative correlation with WBP (r = -0.34, p < 0.05). A significant inter-correlation was also observed between hip NJT and knee NJT (r = -0.66, p < 0.01). Hip NJT was identified as a significant contributor to WBP during the PS. Practically, this study suggested that training skills allowing weightlifters to utilise hip extensor muscle action would help to improve WBP during the PS.

  5. A stable, power scaling, graphene-mode-locked all-fiber oscillator

    Science.gov (United States)

    Popa, D.; Jiang, Z.; Bonacchini, G. E.; Zhao, Z.; Lombardi, L.; Torrisi, F.; Ott, A. K.; Lidorikis, E.; Ferrari, A. C.

    2017-06-01

    We report power tunability in a fiber laser mode-locked with a solution-processed filtered graphene film on a fiber connector. ˜370 fs pulses are generated with output power continuously tunable from ˜4 up to ˜52 mW. This is a simple, low-cost, compact, portable, all-fiber ultrafast source for applications requiring environmentally stable, portable sources, such as imaging.

  6. Stretch-induced enhancement of mechanical power output in human multijoint exercise with countermovement.

    Science.gov (United States)

    Takarada, Y; Hirano, Y; Ishige, Y; Ishii, N

    1997-11-01

    The relation between the eccentric force developed during a countermovement and the mechanical power output was studied in squatting exercises under nominally isotonic load (50% of 1-repetition maximum). The subjects (n = 5) performed squatting exercises with a countermovement at varied deceleration rates before lifting the load. The ground reaction force and video images were recorded to obtain the power output of the body. Net muscle moments acting at hip, knee, and ankle joints were calculated from video recordings by using inverse dynamics. When an intense deceleration was taken at the end of downward movement, large eccentric force was developed, and the mechanical power subsequently produced during the lifting movement was consistently larger than that produced without the countermovement. Both maximal and mean power outputs during concentric actions increased initially with the eccentric force, whereas they began to decline when the eccentric force exceeded approximately 1.4 times the sum of load and body weight. Video-image analysis showed that this characteristic relation was predominantly determined by the torque around the knee joint. Electromyographic analyses showed no consistent increase in time-averaged integrated electromyograph from vastus lateralis with the power output, suggesting that the enhancement of power output is primarily caused by the prestretch-induced improvement of an intrinsic force-generating capability of the agonist muscle.

  7. Optimal cycling time trial position models: aerodynamics versus power output and metabolic energy.

    Science.gov (United States)

    Fintelman, D M; Sterling, M; Hemida, H; Li, F-X

    2014-06-03

    The aerodynamic drag of a cyclist in time trial (TT) position is strongly influenced by the torso angle. While decreasing the torso angle reduces the drag, it limits the physiological functioning of the cyclist. Therefore the aims of this study were to predict the optimal TT cycling position as function of the cycling speed and to determine at which speed the aerodynamic power losses start to dominate. Two models were developed to determine the optimal torso angle: a 'Metabolic Energy Model' and a 'Power Output Model'. The Metabolic Energy Model minimised the required cycling energy expenditure, while the Power Output Model maximised the cyclists׳ power output. The input parameters were experimentally collected from 19 TT cyclists at different torso angle positions (0-24°). The results showed that for both models, the optimal torso angle depends strongly on the cycling speed, with decreasing torso angles at increasing speeds. The aerodynamic losses outweigh the power losses at cycling speeds above 46km/h. However, a fully horizontal torso is not optimal. For speeds below 30km/h, it is beneficial to ride in a more upright TT position. The two model outputs were not completely similar, due to the different model approaches. The Metabolic Energy Model could be applied for endurance events, while the Power Output Model is more suitable in sprinting or in variable conditions (wind, undulating course, etc.). It is suggested that despite some limitations, the models give valuable information about improving the cycling performance by optimising the TT cycling position.

  8. New Current-Mode Bandpass Filters Using Three Single-Output ICCIIs

    Directory of Open Access Journals (Sweden)

    Ahmed M. Soliman

    2007-11-01

    Full Text Available New current-mode bandpass filters using three single outputs inverting second generation current conveyors (ICCII are introduced. The first circuit uses two ICCII+ and one ICCII−, and realizes an inverting bandpass response. This circuit has one floating resistor and no independent gain control. The second circuit uses three ICCII− and realizes a noninverting bandpass response. The third circuit uses three ICCII+ and realizes also a noninverting bandpass response. The second and third circuits employ four grounded resistors and two grounded capacitors and have independent control on Q and on the center frequency gain by varying a single grounded resistor. Spice simulation results using 0.5 um CMOS transistors are included to support the theoretical analysis.

  9. Design study and prototype experiment of the KAGRA output mode-cleaner

    Science.gov (United States)

    Yano, Kazushiro; Kumeta, Ayaka; Somiya, Kentaro

    2016-05-01

    The sensitivity of the Japanese gravitational-wave detector KAGRA is limited mainly by quantum noise. In order to reduce the quantum noise level, KAGRA employs an output mode-cleaner (OMC), which filters out junk light to clean up the signal and the reference light at the signal extraction port. The proper design of the OMC is a key to achieve the target sensitivity of KAGRA. In this proceeding, we present two results. One is the final result of numerical simulations, from which we determined the optical parameters of the OMC. The other is the latest results of our prototype experiment, the goal of which is to establish the control scheme of the OMC.

  10. Systematic Observation of Time-Dependent Phenomena in the RF Output Spectrum of High Power Gyrotrons

    Directory of Open Access Journals (Sweden)

    Kern Stefan

    2012-09-01

    Full Text Available At IHM/KIT, high power gyrotrons with conventional cavity (e.g. 1 MW CW at 140 GHz for the stellarator Wendelstein 7-X and coaxial cavity (2 MW shortpulse at 170 GHz for ITER for fusion applications are being developed and verified experimentally. Especially with respect to the problem of parasitic RF oscillations in the beam tunnel of some W7-X tubes, investigations of the gyrotron RF output spectrum have proved to be a valuable source of diagnostic information. Signs of transient effects in millisecond pulses, like frequency switching or intermittent low-frequency modulation, have indicated that truly time-dependent measurements with high frequency resolution and dynamic range could give deeper insight into these phenomena. In this paper, an improved measurement system is presented, which employs a fast oscilloscope as receiver. Shorttime Fourier transform (STFT is applied to the time-domain signal, yielding time-variant spectra with frequency resolutions only limited by acquisition length and STFT segmentation choice. Typical reasonable resolutions are in the range of 100 kHz to 10 MHz with a currently memory-limited maximum acquisition length of 4 ms. A key feature of the system consists in the unambiguity of frequency measurement: The system receives through two parallel channels, each using a harmonic mixer (h = 9 – 12 to convert the signal from RF millimeter wave frequencies (full D-Band, 110 – 170 GHz to IF (0 – 3 GHz. For each IF output signal of each individual mixer, injection side and receiving harmonic are initially not known. Using accordingly determined LO frequencies, this information is retrieved from the redundancy of the channels, yielding unambiguously reconstructed RF spectra with a total span of twice the usable receiver IF bandwidth, up to ≈ 6 GHz in our case. Using the system, which is still being improved continuously, various transient effects like cavity mode switching, parasitic oscillation frequency variation

  11. Detecting, categorizing and forecasting large romps in wind farm power output using meteorological observations and WPPT

    DEFF Research Database (Denmark)

    Cutler, N.; Kay, M.; Jacka, K.

    2007-01-01

    (swings) in power output. In addition to this, detected large ramps are studied in detail and categorized. WPPT combines wind speed and direction forecasts from the Australian Bureau of Meteorology regional numerical weather prediction model, MesoLAPS, with real-time wind power observations to make hourly...

  12. Mid-infrared laser with 1.2 W output power based on PPLT

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The optical parametric oscillator (OPO) based on the periodically poled lithium tantalate (PPLT) crystal (40 mm×5 mm×1 mm) is fabricated. The OPO is pumped by a Q-switched Nd:YAG laser working at 1.064 μm. An average idler output power (around 3.8 μm) of 1.2 W and signal output power (around 1.48 μm) of 3 W are obtained when the pump power is 20 W.

  13. Improving power output of inertial energy harvesters by employing principal component analysis of input acceleration

    Science.gov (United States)

    Smilek, Jan; Hadas, Zdenek

    2017-02-01

    In this paper we propose the use of principal component analysis to process the measured acceleration data in order to determine the direction of acceleration with the highest variance on given frequency of interest. This method can be used for improving the power generated by inertial energy harvesters. Their power output is highly dependent on the excitation acceleration magnitude and frequency, but the axes of acceleration measurements might not always be perfectly aligned with the directions of movement, and therefore the generated power output might be severely underestimated in simulations, possibly leading to false conclusions about the feasibility of using the inertial energy harvester for the examined application.

  14. Optimizing high-power Yb-doped fiber amplifier systems in the presence of transverse mode instabilities.

    Science.gov (United States)

    Jauregui, Cesar; Otto, Hans-Jürgen; Breitkopf, Sven; Limpert, J; Tünnermann, A

    2016-04-18

    The average output power of Yb-doped fiber amplifier systems is currently limited by the onset of transverse mode instabilities. Besides, it has been recently shown that the transverse mode instability threshold can be significantly reduced by the presence of photodarkening in the fiber. Therefore, reducing the photodarkening level of the core material composition is the most straightforward way to increase the output average power of fiber amplifier systems but, unfortunately, this is not always easy or possible. In this paper we present guidelines to optimize the output average power of fiber amplifiers affected by transverse mode instabilities and photodarkening. The guidelines derived from the simulations do not involve changes in the composition of the active material (except for its doping concentration), but can still lead to a significant increase of the transverse mode instability threshold. The dependence of this parameter on the active ion concentration and the core conformation, among others, will be studied and discussed.

  15. Reproducibility of cardiac power output and other cardiopulmonary exercise indices in patients with chronic heart failure.

    Science.gov (United States)

    Jakovljevic, Djordje G; Seferovic, Petar M; Nunan, David; Donovan, Gay; Trenell, Michael I; Grocott-Mason, Richard; Brodie, David A

    2012-02-01

    Cardiac power output is a direct measure of overall cardiac function that integrates both flow- and pressure-generating capacities of the heart. The present study assessed the reproducibility of cardiac power output and other more commonly reported cardiopulmonary exercise variables in patients with chronic heart failure. Metabolic, ventilatory and non-invasive (inert gas re-breathing) central haemodynamic measurements were undertaken at rest and near-maximal exercise of the modified Bruce protocol in 19 patients with stable chronic heart failure. The same procedure was repeated 7 days later to assess reproducibility. Cardiac power output was calculated as the product of cardiac output and mean arterial pressure. Resting central haemodynamic variables demonstrate low CV (coefficient of variation) (ranging from 3.4% for cardiac output and 5.6% for heart rate). The CV for resting metabolic and ventilatory measurements ranged from 8.2% for respiratory exchange ratio and 14.2% for absolute values of oxygen consumption. The CV of anaerobic threshold, peak oxygen consumption, carbon dioxide production and respiratory exchange ratio ranged from 3.8% (for anaerobic threshold) to 6.4% (for relative peak oxygen consumption), with minute ventilation having a CV of 11.1%. Near-maximal exercise cardiac power output and cardiac output had CVs of 4.1 and 2.2%, respectively. Cardiac power output demonstrates good reproducibility suggesting that there is no need for performing more than one cardiopulmonary exercise test. As a direct measure of cardiac function (dysfunction) and an excellent prognostic marker, it is strongly advised in the assessment of patients with chronic heart failure undergoing cardiopulmonary exercise testing.

  16. Power output in vertical jumps: Does optimum loading depend on activity profiles?

    Science.gov (United States)

    Pazin, Nemanja; Berjan, Bobana; Nedeljkovic, Aleksandar; Markovic, Goran; Jaric, Slobodan

    2013-01-01

    The previously proposed Maximum Dynamic Output hypothesis (MDO; i.e. the optimum load for maximizing the power output during jumping is one's own body) was tested on individuals of various activity profiles. Forty males (10 strength-trained athletes, 10 speed-trained athletes, 10 physically active non-athletes, and 10 sedentary individuals) performed different vertical jumps on a force plate while a pulley system was used to either reduce or increase the subject's body weight by 10–30%. As expected, an increase in external loading resulted in a significant increase (p < 0.001) in force output and a concomitant decrease of peak jumping velocity in all groups of participants. The main finding, however, was that all groups revealed the maximum peak and mean power output at approximately the subjects’ own body weight although their weight represented prominently different percentage of their maximum dynamic strength. While a significant (p < 0.05), albeit moderate, 'group × load' interaction in one jump was observed for the peak power output, the individual optimum load for maximizing the power output number did not differ among the groups. Although apparently further research on various types of movements is needed, the present results provide, so far, the strongest support of the MDO hypothesis. PMID:22864398

  17. Investigation of a metallic photonic crystal high power microwave mode converter

    Directory of Open Access Journals (Sweden)

    Dong Wang

    2015-02-01

    Full Text Available It is demonstrated that an L band metallic photonic crystal TEM-TE11 mode converter is suitable for narrow band high power microwave application. The proposed mode converter is realized by partially filling metallic photonic crystals along azimuthal direction in a coaxial transmission line for phase-shifting. A three rows structure is designed and simulated by commercial software CST Microwave Studio. Simulation results show that its conversion efficiency is 99% at the center frequency 1.58 GHz. Over the frequency range of 1.56-1.625 GHz, the conversion efficiency exceeds 90 %, with a corresponding bandwidth of 4.1 %. This mode converter has a gigawatt level power handling capability which is suitable for narrow band high power microwave application. Using magnetically insulated transmission line oscillator(MILO as a high power microwave source, particle-in-cell simulation is carried out to test the performance of the mode converter. The expected TE11 mode microwave output is obtained and the MILO works well. Mode conversion performance of the converter is tested by far-field measurement method. And the experimental result confirms the validity of our design. Then, high power microwave experiment is carried out on a Marx-driven Blumlein water line pulsed power accelerator. Microwave frequency, radiated pattern and power are measured in the far-field region and the results agree well with simulation results. The experiment also reveals that no microwave breakdown or pulse shortening took place in the experimental setup.

  18. Determinants of mobile phone output power in a multinational study: implications for exposure assessment

    DEFF Research Database (Denmark)

    Vrijheid, M; Madsen, Stine Mann; di Vecchia, Paolo

    2009-01-01

    OBJECTIVES: The output power of a mobile phone is directly related to its radiofrequency (RF) electromagnetic field strength, and may theoretically vary substantially in different networks and phone use circumstances due to power control technologies. To improve indices of RF exposure for epidemi......OBJECTIVES: The output power of a mobile phone is directly related to its radiofrequency (RF) electromagnetic field strength, and may theoretically vary substantially in different networks and phone use circumstances due to power control technologies. To improve indices of RF exposure...... with urban use of the SMP were observed principally in Sweden where the study covered very sparsely populated areas. CONCLUSIONS: Average power levels are substantially higher than the minimum levels theoretically achievable in GSM networks. Exposure indices could be improved by accounting for average power...

  19. Low-timing-jitter high-power mode-locked 1063 nm Nd:GdVO₄ master oscillator power amplifier.

    Science.gov (United States)

    Wang, Zhi-min; Zhang, Feng-feng; Zuo, Jun-wei; Yang, Jing; Yuan, Lei; Peng, Qin-jun; Cui, Da-fu; Xu, Zu-yan

    2015-10-01

    A low-timing-jitter high-power semiconductor saturable absorber mirror mode-locked picosecond (ps) 1063 nm Nd:GdVO4 master oscillator power amplifier is presented. Using a single-pass Nd:GdVO4 amplifier, an amplified laser with 21.5 W output power and 8.3 ps pulsewidth was achieved at 250 MHz repetition rate. Employing a servo control, an average RMS timing jitter of ∼222  fs was realized. This laser can be used as a drive laser for photocathode injectors in free-electron lasers.

  20. Impact of heavy soiling on the power output of PV modules

    Science.gov (United States)

    Schill, Christian; Brachmann, Stefan; Heck, Markus; Weiss, Karl-Anders; Koehl, Michael

    2011-09-01

    Fraunhofer ISE is running a PV-module outdoor testing set-up on the Gran Canaria island, one of the Canary Island located west of Morroco in the Atlantic Ocean. The performance of the modules is assessed by IV-curve monitoring every 10 minutes. The electronic set-up of the monitoring system - consisting of individual electronic loads for each module which go into an MPP-tracking mode between the IV-measurements - will be described in detail. Soiling of the exposed modules happened because of building constructions nearby. We decided not to clean the modules, but the radiation sensors and recorded the decrease of the power output and the efficiency over time. The efficiency dropped to 20 % within 5 months before a heavy rain and subsequently the service personnel on site cleaned the modules. A smaller rain-fall in between washed the dust partly away and accumulated it at the lower part of the module, what could be concluded from the shape of the IV-curves, which were similar to partial shading by hot-spot-tests and by partial snow cover.

  1. A combined compensation method for the output voltage of an insulated core transformer power supply

    Science.gov (United States)

    Yang, L.; Yang, J.; Liu, K. F.; Qin, B.; Chen, D. Z.

    2014-06-01

    An insulated core transformer (ICT) power supply is an ideal high-voltage generator for irradiation accelerators with energy lower than 3 MeV. However, there is a significant problem that the structure of the segmented cores leads to an increase in the leakage flux and voltage differences between rectifier disks. A high level of consistency in the output of the disks helps to achieve a compact structure by improving the utilization of both the rectifier components and the insulation distances, and consequently increase the output voltage of the power supply. The output voltages of the disks which are far away from the primary coils need to be improved to reduce their inhomogeneity. In this study, by investigating and comparing the existing compensation methods, a new combined compensation method is proposed, which increases the turns on the secondary coils and employs parallel capacitors to improve the consistency of the disks, while covering the entire operating range of the power supply. This method turns out to be both feasible and effective during the development of an ICT power supply. The non-uniformity of the output voltages of the disks is less than 3.5% from no-load to full-load, and the power supply reaches an output specification of 350 kV/60 mA.

  2. Matching of Silicon Thin-Film Tandem Solar Cells for Maximum Power Output

    Directory of Open Access Journals (Sweden)

    C. Ulbrich

    2013-01-01

    Full Text Available We present a meaningful characterization method for tandem solar cells. The experimental method allows for optimizing the output power instead of the current. Furthermore, it enables the extraction of the approximate AM1.5g efficiency when working with noncalibrated spectra. Current matching of tandem solar cells under short-circuit condition maximizes the output current but is disadvantageous for the overall fill factor and as a consequence does not imply an optimization of the output power of the device. We apply the matching condition to the maximum power output; that is, a stack of solar cells is power matched if the power output of each subcell is maximal at equal subcell currents. The new measurement procedure uses additional light-emitting diodes as bias light in the JV characterization of tandem solar cells. Using a characterized reference tandem solar cell, such as a hydrogenated amorphous/microcrystalline silicon tandem, it is possible to extract the AM1.5g efficiency from tandems of the same technology also under noncalibrated spectra.

  3. Determinants of VO(2) kinetics at high power outputs during a ramp exercise protocol.

    Science.gov (United States)

    Lucía, Alejandro; Rivero, José-Luis L; Pérez, Margarita; Serrano, Antonio L; Calbet, José A L; Santalla, Alfredo; Chicharro, José L

    2002-02-01

    To determine the relationship between the additional, nonlinear increase in oxygen uptake (Delta VO(2)) that occurs at high power outputs during a ramp cycle ergometer test, on one hand; and possible explanatory mechanisms of the phenomenon, such as cardiorespiratory work, blood lactate, fitness level, or muscle fiber distribution, on the other. Ten healthy, sedentary young adults (age (mean +/- SEM), 22 +/- 1 yr) were chosen as subjects. A muscle biopsy specimen was taken from the vastus lateralis of the right leg to determine fiber type distribution by immunohistochemical identification of myosin heavy chain (MHC) isoforms. During the ramp tests (power output increases of 5 W every 15-s interval), the ventilatory threshold (VT) and lactate threshold (LT) were measured. We defined Delta VO(2) as the difference between "true" VO(2) values observed at the maximal power output (VO(2)obs) and those expected (VO(2)exp) from the previous linear VO2:power output relationship below the VT. A nonlinear increase was observed in VO2 (Delta VO(2) = 239 +/- 79 mL x min(-1), P < 0.05 for VO(2)obs vs VO(2)exp), which was significantly correlated with the percentage of type IIX fibers (r = 0.80, P < 0.05). No other correlations were found between Delta VO(2) and possible explanatory mechanisms. A greater percentage of type IIX fibers is associated with a higher excess VO(2) at high power outputs (above VT).

  4. Constant Power Control of a Proton Exchange Membrane Fuel Cell through Adaptive Fuzzy Sliding Mode

    Directory of Open Access Journals (Sweden)

    Minxiu Yan

    2013-05-01

    Full Text Available Fuel cell is a device that converts the chemical energy from a fuel into electricity through a chemical reaction with oxygen or another oxidizing agent. The paper describes a mathematical model of proton exchange membrane fuel cells by analyzing the working mechanism of the proton exchange membrane fuel cell. Furthermore, an adaptive fuzzy sliding mode controller is designed for the constant power output of PEMFC system. Simulation results prove that adaptive fuzzy sliding mode control has better control effect than conventional fuzzy sliding mode control.

  5. High-Power Er3+/Yb3+ Codoped Double-Cladding Fibre Amplifier with More Than 2 W Output Power

    Institute of Scientific and Technical Information of China (English)

    LIU Yan-Ge; FENG Xin-Huan; LI Li-Jun; LI Yao; YUAN Shu-Zhong; KAI Gui-Yun; LI Yi-Gang; DONG Xiao-Yi

    2005-01-01

    @@ A high-power Er3+/Yb3+-codoped double-cladding all-fibre amplifier was successfully demonstrated and experimentally investigated. The amplifier could be operated with a maximum output power of 2.18 W and 2.11 W at 1541nm and 1550nm wavelengths, respectively, when the maximum pump power was 6.07W. The power conversion efficiency was up to 35.6% and 34.4% at the two wavelengths, respectively. The output power and the gain were greater than 2.00 W and 20.0dB, respectively, in the wavelength range from 1539nm to 1565nm for 20.0mW input signal power. The gain fluctuation and the noise figure around 1550nm wavelength were less than 0.3 dB and 6.0 dB, respectively.

  6. Power Output Improvement of PV Module for Agricultural Use by Using Inexpensive Sunlight Concentrator

    Institute of Scientific and Technical Information of China (English)

    NISHIMURA Ryo

    2010-01-01

    PV modules are used as stand alone power sources for agricultural equipments such as lifting pumps in farms,where the power infrastructure is not yet improved.In order to expand the agricultural use of PV module,the cost of PV generation should be reduced.In this paper,the power output performance of a commercial PV module was improved by using a sunlight concentrator that could be assembled inexpensively and a simple sun-tracking method.

  7. Using a nonparametric PV model to forecast AC power output of PV plants

    OpenAIRE

    Almeida, Marcelo Pinho; Perpiñan Lamigueiro, Oscar; Narvarte Fernández, Luis

    2015-01-01

    In this paper, a methodology using a nonparametric model is used to forecast AC power output of PV plants using as inputs several forecasts of meteorological variables from a Numerical Weather Prediction (NWP) model and actual AC power measurements of PV plants. The methodology was built upon the R environment and uses Quantile Regression Forests as machine learning tool to forecast the AC power with a confidence interval. Real data from five PV plants was used to validate the methodology, an...

  8. Smoothing of Grid-connected Wind-Diesel Power Output Using Energy Capacitor System

    Directory of Open Access Journals (Sweden)

    Adel A. Elbaset

    2014-06-01

    Full Text Available This paper presents a small hybrid power system consists of two types of power generation; wind turbine and diesel generation, DG connected to power distribution system. The fluctuations like random nature of wind power, turbulent wind, and sudden changes in load demand create imbalances in power distribution that can affect the frequency and the voltage in the power system. So, addition of Energy capacitor System, ECS is useful for compensation of fluctuating power, since it is capable of controlling both active and reactive power simultaneously and can smooth the output power flow. Hence, this paper proposes herein a dynamic model and simulation of a grid connected wind/DG based-ECS with power flow controllers between load and generation. Moreover, the paper presents a study to analyze the leveling of output fluctuation of wind power with the installation of ECS. To control the power exchanged between the ECS system and the AC grid, a load Following Control, LFC based supervisor is proposed with the aim to minimize variations of the power generated by the diesel generator. The interesting performance of the proposed supervisor is shown with the help of simulations. The computer simulation program is confirmed on a realistic circuit model which implemented in the Simulink environment of Matlab and works as if on line.

  9. How large customer direct power transaction mode give consideration to power generation cleaning and power saving

    Science.gov (United States)

    Liu, Yu; Zeng, Ming; Liu, Wei; Li, Ran

    2017-05-01

    The so-called Large Customers' Direct Power Transaction, refers to the mode that the users on high voltage level, or being seized of hold the large power or independent power distribution, have the qualification of purchasing electricity directly from the generation companies and pay reasonable electricity transmission and distribution fee to the power network enterprises because the transaction is through its transmission channel. The Direct Purchase promotes the marketization level of electricity trading, but there are some problems in its developing process, especially whether promotes the green optimal allocation of power resources, this paper aims to explore the solution.

  10. A VCO with Harmonic Suppressed and Output Power Improved Using Defected Ground Structure

    Directory of Open Access Journals (Sweden)

    Haiwen Liu

    2003-01-01

    microstrip line with DGS has a wide low-pass band for the fundamental frequency and a stopband for the second harmonic with good performance. To evaluate the effects of DGS on microwave VCOs, two GaAs field-effect transistor (FET VCOs have been designed and fabricated. One of them has a 50Ω microstrip line with DGS at the output section, while the other has only a 50Ω straight line. Measured results show that DGS suppresses the second harmonic more than −20 dBm at the output and yields improved output power by 3−5%.

  11. Enhanced power output of an electrospun PVDF/MWCNTs-based nanogenerator by tuning its conductivity

    Science.gov (United States)

    Yu, Hao; Huang, Tao; Lu, Mingxia; Mao, Mengye; Zhang, Qinghong; Wang, Hongzhi

    2013-10-01

    PVDF nanofibre-based piezoelectric nanogenerators are directly prepared via electrospinning without any post-poling treatment. The effect of the addition of multi-walled carbon nanotubes (MWCNTs) on the fibre diameter, mechanical properties, β-phase composition, surface and volume conductivities, output voltage and output power are investigated. Increased surface conductivity of the poly-vinylidene fluoride (PVDF) nanofibre mats, which plays an important role in the enhancement of output power, is first found by the addition of an appropriate amount of MWCNTs. The maximum generated piezo-voltage exhibited by PVDF nanofibre mats in the presence of 5 wt% MWCNTs is as high as 6 V, while the average capacitor charging power is 81.8 nW, increases of 200% and 44.8%, respectively, compared with bare PVDF nanofibre mats.

  12. Anomalous TWTA output power spikes and their effect on a digital satellite communications system

    Science.gov (United States)

    May, Brian D.; Kerczewski, Robert J.; Svoboda, James S.

    1992-01-01

    Several 30 GHz, 60 W traveling wave tube amplifiers (TWTA) were manufactured for the NASA Lewis Research Center's High Burst Rate Link Evaluation Terminal Project. An unusual operating problem characterized by anomalous nonperiodic output power spikes, common to all of the TWTAs proved during testing to significantly affect the performance of a digitally-modulated data transmission test system. Modifications made to the TWTAs significantly curtailed the problem and allowed acceptable system performance to be obtained. This paper presents a discussion of the TWTA output power spike problem, possible causes of the problem, and the solutions implemented by the manufacturer which improved the TWTA performance to an acceptable level. The results of the testing done at NASA Lewis on the TWTAs both before and after the improvement made by Hughes are presented, and the effects of the output power spikes on the performance of the test system are discussed.

  13. Development of Compact Ozonizer with High Ozone Output by Pulsed Power

    Science.gov (United States)

    Tanaka, Fumiaki; Ueda, Satoru; Kouno, Kanako; Sakugawa, Takashi; Akiyama, Hidenori; Kinoshita, Youhei

    Conventional ozonizer with a high ozone output using silent or surface discharges needs a cooling system and a dielectric barrier, and therefore becomes a large machine. A compact ozonizer without the cooling system and the dielectric barrier has been developed by using a pulsed power generated discharge. The wire to plane electrodes made of metal have been used. However, the ozone output was low. Here, a compact and high repetition rate pulsed power generator is used as an electric source of a compact ozonizer. The ozone output of 6.1 g/h and the ozone yield of 86 g/kWh are achieved at 500 pulses per second, input average power of 280 W and an air flow rate of 20 L/min.

  14. Acute effect of static stretching on power output during concentric dynamic constant external resistance leg extension.

    Science.gov (United States)

    Yamaguchi, Taichi; Ishii, Kojiro; Yamanaka, Masanori; Yasuda, Kazunori

    2006-11-01

    The purpose of the present study was to clarify the effect of static stretching on muscular performance during concentric isotonic (dynamic constant external resistance [DCER]) muscle actions under various loads. Concentric DCER leg extension power outputs were assessed in 12 healthy male subjects after 2 types of pretreatment. The pretreatments included (a) static stretching treatment performing 6 types of static stretching on leg extensors (4 sets of 30 seconds each with 20-second rest periods; total duration 20 minutes) and (b) nonstretching treatment by resting for 20 minutes in a sitting position. Loads during assessment of the power output were set to 5, 30, and 60% of the maximum voluntary contractile (MVC) torque with isometric leg extension in each subject. The peak power output following the static stretching treatment was significantly (p extensive static stretching significantly reduces power output with concentric DCER muscle actions under various loads. Common power activities are carried out by DCER muscle actions under various loads. Therefore, the result of the present study suggests that relatively extensive static stretching decreases power performance.

  15. Validation of a six second cycle test for the determination of peak power output.

    Science.gov (United States)

    Herbert, Peter; Sculthorpe, Nick; Baker, Julien S; Grace, Fergal M

    2015-01-01

    The present study examined the agreement between peak power output during a standard Wingate anaerobic test (WAnT) and a six second 'all-out' test on a Wattbike Pro. Nine males (40.7 ± 19.4 yrs, 1.76 ± 0.03 cm, 82.11 ± 8.9 kg) underwent three testing protocols on separate days. The protocols consisted 30 second WAnT (WAnT30), a modified WAnT over 6 seconds (WAnT6) and a 6 second peak power test (PPT6). PPT6 was correlated with WAnT30 (r = 0.9; p power between any trial. PPT6 resulted in significantly greater power outputs than in WAnT30 and WAnT6 (p power output compared with WAnT30. This identifies that PPT6 and WAnT6 as short duration 'all-out' tests that have practical applications for researchers and coaches who wish to assess peak power output without the fatiguing effects associated with a standard WAnT.

  16. Sliding mode control of switching power converters techniques and implementation

    CERN Document Server

    Tan, Siew-Chong; Tse, Chi-Kong

    2011-01-01

    Sliding Mode Control of Switching Power Converters: Techniques and Implementation is perhaps the first in-depth account of how sliding mode controllers can be practically engineered to optimize control of power converters. A complete understanding of this process is timely and necessary, as the electronics industry moves toward the use of renewable energy sources and widely varying loads that can be adequately supported only by power converters using nonlinear controllers.Of the various advanced control methods used to handle the complex requirements of power conversion systems, sliding mode c

  17. The influence of tendon compliance on muscle power output and efficiency during cyclic contractions.

    Science.gov (United States)

    Lichtwark, G A; Barclay, C J

    2010-03-01

    Muscle power output and efficiency during cyclical contractions are influenced by the timing and duration of stimulation of the muscle and the interaction of the muscle with its mechanical environment. It has been suggested that tendon compliance may reduce the energy required for power production from the muscle by reducing the required shortening of the muscle fibres. Theoretically this may allow the muscle to maintain both high power output and efficiency during cyclical contraction; however, this has yet to be demonstrated experimentally. To investigate how tendon compliance might act to increase muscle power output and/or efficiency, we attached artificial tendons of varying compliance to muscle fibre bundles in vitro and measured power output and mechanical efficiency during stretch-shorten cycles (2 Hz) with a range of stretch amplitudes and stimulation patterns. The results showed that peak power, average power output and efficiency (none of which can have direct contributions from the compliant tendon) all increased with increasing tendon compliance, presumably due to the tendon acting to minimise muscle energy use by allowing the muscle fibres to shorten at optimal speeds. Matching highly compliant tendons with a sufficiently large amplitude length change and appropriate stimulation pattern significantly increased the net muscle efficiency compared with stiff tendons acting at the same frequency. The maximum efficiency for compliant tendons was also similar to the highest value measured under constant velocity and force conditions, which suggests that tendon compliance can maximise muscle efficiency in the conditions tested here. These results provide experimental evidence that during constrained cyclical contractions, muscle power and efficiency can be enhanced with compliant tendons.

  18. Optimal design parameters of the bicycle-rider system for maximal muscle power output.

    Science.gov (United States)

    Yoshihuku, Y; Herzog, W

    1990-01-01

    The purpose of this study was to find the optimal values of design parameters for a bicycle-rider system (crank length, pelvic inclination, seat height, and rate of crank rotation) which maximize the power output from muscles of the human lower limb during bicycling. The human lower limb was modelled as a planar system of five rigid bodies connected by four smooth pin joints and driven by seven functional muscle groups. The muscles were assumed to behave according to an adapted form of Hill's equation. The dependence of the average power on the design parameters was examined. The instantaneous power of each muscle group was studied and simultaneous activity of two seemingly antagonistic muscle groups was analyzed. Average peak power for one full pedal revolution was found to be around 1100 W. The upper body position corresponding to this peak power output was slightly reclined, and the pedalling rate was 155 rpm for a nominal crank length of 170 mm.

  19. Dual Mode Low Power Hall Thruster Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Sample and return missions desire and missions like Saturn Observer require a low power Hall thruster that can operate at high thrust to power as well as high...

  20. Mode transition coordinated control for a compound power-split hybrid car

    Science.gov (United States)

    Wang, Chen; Zhao, Zhiguo; Zhang, Tong; Li, Mengna

    2017-03-01

    With a compound power-split transmission directly connected to the engine in hybrid cars, dramatic fluctuations in engine output torque result in noticeable jerks when the car is in mode transition from electric drive mode to hybrid drive mode. This study designed a mode transition coordinated control strategy, and verified that strategy's effectiveness with both simulations and experiments. Firstly, the mode transition process was analyzed, and ride comfort issues during the mode transition process were demonstrated. Secondly, engine ripple torque was modeled using the measured cylinder pumping pressure when the engine was not in operation. The complete dynamic plant model of the power-split hybrid car was deduced, and its effectiveness was validated by a comparison of experimental and simulation results. Thirdly, a coordinated control strategy was designed to determine the desired engine torque, motor torque, and the moment of fuel injection. Active damping control with two degrees of freedom, based on reference output shaft speed estimation, was designed to mitigate driveline speed oscillations. Carrier torque estimation based on transmission kinematics and dynamics was used to suppress torque disturbance during engine cranking. The simulation and experimental results indicate that the proposed strategy effectively suppressed vehicle jerks and improved ride comfort during mode transition.

  1. Smoothing Control of Wind Farm Output by Using Kinetic Energy of Variable Speed Wind Power Generators

    Science.gov (United States)

    Sato, Daiki; Saitoh, Hiroumi

    This paper proposes a new control method for reducing fluctuation of power system frequency through smoothing active power output of wind farm. The proposal is based on the modulation of rotaional kinetic energy of variable speed wind power generators through power converters between permanent magnet synchronous generators (PMSG) and transmission lines. In this paper, the proposed control is called Fluctuation Absorption by Flywheel Characteristics control (FAFC). The FAFC can be easily implemented by adding wind farm output signal to Maximum Power Point Tracking control signal through a feedback control loop. In order to verify the effectiveness of the FAFC control, a simulation study was carried out. In the study, it was assumed that the wind farm consisting of PMSG type wind power generator and induction machine type wind power generaotors is connected with a power sysem. The results of the study show that the FAFC control is a useful method for reducing the impacts of wind farm output fluctuation on system frequency without additional devices such as secondary battery.

  2. SIMULATING MODEL OF SYSTEM FOR MAXIMUM OUTPUT POWER OF SOLAR BATTERY

    Directory of Open Access Journals (Sweden)

    Abdul Majid Al-Khatib

    2005-01-01

    Full Text Available Simulating model and algorithm for control of electric power converter of a solar battery are proposed in the paper. Control device of D.C. step-down converter with pulse-width modulation is designed on microprocessor basis. Simulating model permits to investigate various operational modes of a solar battery, demonstrates a process with maximum power mode and is characterized by convenient user’s interface.

  3. High-power single-mode vertical-cavity surface-emitting lasers

    Science.gov (United States)

    Samal, Nigamananda

    High-power single-mode vertical-cavity surface-emitting lasers (VCSEL) have a great potential to replace the distributed feedback (DFB) and Fabry-Perot (FP) edge emitting lasers that are currently used in optical communication. VCSELs also have tremendous potential in many niche applications such as "optical read and write," laser printing, bar code scanning and sensing. Despite many of their inherent advantages over its rivals, VCSELs still suffer from some outstanding issues. Most prominent are "limited power" and "multi-mode behavior" at higher injection. This work aims at a few solutions for these fundamental issues. Using strain-compensated GaAsSb as an active material and a standard single-aperture design, 1.3 mum VCSELs are demonstrated and characterized. These devices face basic issues such as "limited output power" and "multi-mode behavior." These VCSELs achieved room temperature CW operation with power outputs from 50--200 muW for wavelengths ranging from 1245 to 1290 nm. To resolve the issue of limited power, several on-wafer thermal-management schemes are proposed. One of the schemes is pursued in this work. To resolve the issue of multi-mode behavior, a novel device design using asymmetric double oxide-apertures is proposed, theoretically modeled, and implemented in this work. The optical mode behavior of this novel design is compared with a traditional single-aperture design using fabricated devices and theoretical modeling. A clear trend of spectral purity in the modal behavior of the devices, under both continuous wave (CW) and pulsed conditions, is demonstrated and is in good agreement with theoretical predictions. One of the novel designs tested on an InGaAs VCSEL has shown a multi-mode power more than 23 mW with maximum wall plug efficiency of 32%, threshold current of 2.5 mA, threshold voltage of 1.2 V, and a slope efficiency of 0.83 W/A. The best design demonstrated a room temperature CW single-mode output power of more than 7 mW with a side

  4. Design of eight-mode polarization-maintaining few-mode fiber for multiple-input multiple-output-free spatial division multiplexing.

    Science.gov (United States)

    Wang, Lixian; LaRochelle, Sophie

    2015-12-15

    We propose a polarization-maintaining few-mode fiber (FMF) that features an elliptical ring shaped core with a high refractive index contrast ∼0.03 between the core and the cladding. This fiber design alleviates the usual trade-off between the number of guided modes and the achievable birefringence that is usually observed in conventional elliptical-core FMFs. Through numerical simulations, we show that this fiber design can support up to 10 guided vector modes over the entire C band while providing large birefringence. Except for the two fundamental modes, the eight higher-order vector modes are all separated from their adjacent modes by effective index differences >10⁻⁴, which is the typical birefringence value of single-mode polarization maintaining fibers. The designed fiber targets applications in spatial division multiplexing of optical channels, without multiple-input-multiple-output (MIMO) digital signal processing, for short-reach optical interconnects.

  5. Somatotype-variables related to muscle torque and power output in female volleyball players.

    Science.gov (United States)

    Buśko, Krzysztof; Lewandowska, Joanna; Lipińska, Monika; Michalski, Radosław; Pastuszak, Anna

    2013-01-01

    The purpose of this study was to investigate the relationship between somatotype, muscle torque, maximal power output and height of rise of the body mass centre measured in akimbo counter movement jump (ACMJ), counter movement jump (CMJ) and spike jump (SPJ), and power output measured in maximal cycle ergometer exercise bouts in female volleyball players. Fourteen players participated in the study. Somatotype was determined using the Heath-Carter method. Maximal muscle torque was measured under static conditions. Power output was measured in 5 maximal cycle ergometer exercise bouts, 10 s each, at increasing external loads equal to 2.5, 5.0, 7.5, 10.0 and 12.5% of body weight (BW). All jump trials (ACMJ, SPJ and CMJ) were performed on a force plate. The mean somatotype of volleyball players was: 4.9-3.5-2.5. The value of the sum of muscle torque of the left upper extremities was significantly correlated only with mesomorphic component. Mesomorphic and ectomorphic components correlated significantly with values of maximal power measured during ACMJ and CMJ. Power output measured in maximal cycle ergometer exercise bouts at increasing external loads equal to 2.5, 5.0 and 7.5% of BW was significantly correlated with endomorphy, mesomorphy and ectomorphy.

  6. Integrating switch mode audio power amplifiers and electro dynamic loudspeakers for a higher power efficiency

    DEFF Research Database (Denmark)

    Poulsen, Søren; Andersen, Michael Andreas E.

    2004-01-01

    The work presented in this paper is related to integration of switch mode audio amplifiers and electro dynamic loudspeakers, using the speaker's voice coil as output filter, and the magnetic structure as heatsink for the amplifier.......The work presented in this paper is related to integration of switch mode audio amplifiers and electro dynamic loudspeakers, using the speaker's voice coil as output filter, and the magnetic structure as heatsink for the amplifier....

  7. 785-nm dual wavelength DBR diode lasers and MOPA systems with output powers up to 750 mW

    Science.gov (United States)

    Sumpf, Bernd; Maiwald, Martin; Klehr, Andreas; Müller, André; Bugge, Frank; Fricke, Jörg; Ressel, Peter; Erbert, Götz; Tränkle, Günther

    2015-03-01

    Raman lines are often superimposed by daylight, artificial light sources or fluorescence signals from the samples under study. Shifted excitation Raman difference spectroscopy (SERDS), i.e. exciting the sample alternatingly with two slightly shifted wavelengths, allows to distinguish between the Raman lines and sources of interference. In this work, monolithic dual wavelength Y-branch DBR ridge waveguide diode lasers and their application in master oscillator power amplifier (MOPA) systems at 785 nm suitable for Raman spectroscopy and SERDS will be presented. The definition of the wavelengths is made by implementing deeply-etched 10th order 500 μm long surface gratings with different periods using i-line wafer stepper lithography. Y-branch DBR lasers with a total length of 3 mm and a stripe width of 2.2 μm were manufactured and characterized. The monolithic devices reach output powers up to 215 mW with emission widths of about 20 pm. At 200 mW the conversion efficiency is 20%, i.e. the electrical power consumption is only 1 W. The spectral distance between the two laser cavities is about 0.6 nm, i.e. 10 cm-1 as targeted. The side mode suppression ratio is better than 50 dB. Amplifying these devices using a ridge waveguide amplifier an output power of about 750 mW could be achieved maintaining the spectral properties of the master oscillator.

  8. DC motor operation controlled from a DC/DC power converter in pulse mode with low duty cycle

    OpenAIRE

    Stefanov, Goce; Kukuseva, Maja; Citkuseva Dimitrovska, Biljana

    2016-01-01

    In this paper pulse mode of operation of DC motor controlled by DC/DC power converter is analyzed. DC motor operation with time intervals in which the motor operates without output load is of interest. In this mode it is possible the motor to restore energy. Also, in the paper are represented calculations for the amount of the restored energy in the pulse mode operation of the motor for different duty cycles.

  9. A New Maximum Power Point Estimator Control Strategy to Maximize Output Power of the Double Stator Permanent Magnet Generator

    Directory of Open Access Journals (Sweden)

    Norhisam Misron

    2016-08-01

    Full Text Available A new control estimator to maximize the power generated with a maximum power point estimator is introduced. The power mapping characteristics from the double-stator generator are modeled as a mathematical equation which is used to develop the estimator for maximum power tracking to maximize the generated power. The proposed estimator automatically traces the instantaneous maximum power at various load conditions. However, to stabilize the output voltage, a boost converter is used from the inverter side. The developed double-stator generator is tested with the new estimator for the maximizing power generation capability under laboratory conditions. The experimental results confirm that with the new estimator, the average power generation capability is increased by 12% and the peak value is increase by 22%.

  10. Factors that influence the radiofrequency power output of GSM mobile phones.

    Science.gov (United States)

    Erdreich, Linda S; Van Kerkhove, Maria D; Scrafford, Carolyn G; Barraj, Leila; McNeely, Mark; Shum, Mona; Sheppard, Asher R; Kelsh, Michael

    2007-08-01

    Epidemiological studies of mobile phone use and risk of brain cancer have relied on self-reported use, years as a subscriber, and billing records as exposure surrogates without addressing the level of radiofrequency (RF) power output. The objective of this study was to measure environmental, behavioral and engineering factors affecting the RF power output of GSM mobile phones during operation. We estimated the RF-field exposure of volunteer subjects who made mobile phone calls using software-modified phones (SMPs) that recorded output power settings. Subjects recruited from three geographic areas in the U.S. were instructed to log information (place, time, etc.) for each call made and received during a 5-day period. The largest factor affecting energy output was study area, followed by user movement and location (inside or outside), use of a hands-free device, and urbanicity, although the two latter factors accounted for trivial parts of overall variance. Although some highly statistically significant differences were identified, the effects on average energy output rate were usually less than 50% and were generally comparable to the standard deviation. These results provide information applicable to improving the precision of exposure metrics for epidemiological studies of GSM mobile phones and may have broader application for other mobile phone systems and geographic locations.

  11. Wind Farm Dynamic Equivalence Based on the Wind Turbine Output Active Power Sequence Clustering

    Directory of Open Access Journals (Sweden)

    Zhang Ge

    2016-01-01

    Full Text Available In order to reduce the complexity of simulation model containing wind farms in the context of keeping the accuracy static, this paper put forward a kind of Dynamic Equivalence method aiming at making output characteristic of the connecting point of wind farm consistent. Based on the output power sequence of wind turbines, geometric template matching algorithm is used to obtain the characteristic of that power sequence and then Attribute Threshold Clustering Algorithm is used to classify wind turbine. In each cluster, the parameter of wind turbine is made equal according to the principle of constant power output character and then be distinguished according to AMPSO. At last, this paper takes a practical wind farm as an example and respectively simulates the conditions of fault of system side and variation of wind speed, which is used in comparing the output characteristic of detailed model and Equivalent model. Results show that the output characteristic of the connecting point of wind farm keeps consistent after equivalent and that the Clustering Algorithm can reflect the operating characteristics of the wind turbine in the whole moment of any time period. It can also be saw that Equivalent method is reasonable and effective, which has certain value in engineering application.

  12. Increasing the recovery of heavy metal ions using two microbial fuel cells operating in parallel with no power output.

    Science.gov (United States)

    Wang, Xiaohui; Li, Jing; Wang, Zhao; Tursun, Hairti; Liu, Rui; Gao, Yanmei; Li, Yuan

    2016-10-01

    The present study aimed to improve the performance of microbial fuel cells (MFCs) by using an intermittent connection period without power output. Connecting two MFCs in parallel improved the voltage output of both MFCs until the voltage stabilized. Electric energy was accumulated in two MFCs containing heavy metal ions copper, zinc, and cadmium as electron acceptors by connection in parallel for several hours. The system was then switched to discharge mode with single MFCs with a 1000-Ω resistor connected between anode and cathode. This method successfully achieved highly efficient removal of heavy metal ions. Even when the anolyte was run in sequencing batch mode, the insufficient voltage and power needed to recover heavy metals from the cathode of MFCs can be complemented by the developed method. The average removal ratio of heavy metal ions in sequencing batch mode was 67 % after 10 h. When the discharge time was 20 h, the removal ratios of zinc, copper, and cadmium were 91.5, 86.7, and 83.57 %, respectively; the average removal ratio of these ions after 20 h was only 52.1 % for the control group. Therefore, the average removal efficiency of heavy metal ions increased by 1.75 times using the electrons stored from the bacteria under the open-circuit conditions in parallel mode. Electrochemical impedance data showed that the anode had lower solution resistance and polarization resistance in the parallel stage than as a single MFC, and capacitance increased with the length of time in parallel.

  13. New Driver For The Powerful Output Rf Amplifier Of Mmf Dtl Rf System

    CERN Document Server

    Kvasha, A I; Vassilyev, A G

    2004-01-01

    More than 30 years ago a few powerful vacuum tubes were specially designed and produced in the former design office Swetlana for the Moscow meson factory DTL RF system. Among them was tetrode GI-51A with output pulse RF power up to 300 kW at frequency 198.2 MHz, which was used as driver for RF power amplifier with output RF pulse power (2-3) MW. In connection with well-known events in our country manufacture of these tubes, including GI-51A was finished about 10 years ago. In "SED-SPb" (successor of the design office Swetlana) triode GI-57A was offered instead of GI-51A. In this paper results of calculations and design of RF amplifier with new triode are presented. Preliminary results of RF amplifier tests, also presented in the paper, showed that triode GI-57A will be able successfully used in the DTL RF system channels.

  14. Output power stability of a HCN laser using a stepping motor for the EAST interferometer system

    Science.gov (United States)

    Zhang, J. B.; Wei, X. C.; Liu, H. Q.; Shen, J. J.; Zeng, L.; Jie, Y. X.

    2015-11-01

    The HCN laser on EAST is a continuous wave glow discharge laser with 3.4 m cavity length and 120 mW power output at 337 μ m wavelength. Without a temperature-controlled system, the cavity length of the laser is very sensitive to the environmental temperature. An external power feedback control system is applied on the HCN laser to stabilize the laser output power. The feedback system is composed of a stepping motor, a PLC, a supervisory computer, and the corresponding control program. One step distance of the stepping motor is 1 μ m and the time response is 0.5 s. Based on the power feedback control system, a stable discharge for the HCN laser is obtained more than eight hours, which satisfies the EAST experiment.

  15. Application of output feedback sliding mode control to active flutter suppression of two-dimensional airfoil

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The effectiveness of the sliding mode control(SMC) method for active flutter suppression(AFS) and the issues concerning control system discretization and control input constraints were studied using a typical two-dimensional airfoil.The airfoil has a trailing-edge flap for flutter control.The aeroelastic system involves a two-degrees-of-freedom motion(pitch and plunge),and the equations were constructed by utilizing quasi-steady aerodynamic forces.The control system,designed by the output feedback SMC method,was incorporated to suppress the pitch-plunge flutter.Meanwhile,the system discretization and the flap deflection constraints were implemented.Then,a classical Runge-Kutta(RK) algorithm was utilized for numerical calculations.The results indicated that the close-loop system with the SMC system could be stable at a speed above the flutter boundary.However,when the flap deflection limits are reached,the close-loop system with the simple discretized control system loses control.Furthermore,control compensation developed by theoretical analysis was proposed to make the system stable again.The parameter perturbations and the time delay effects were also discussed in this paper.

  16. Generalized design of high performance shunt active power filter with output LCL filter

    DEFF Research Database (Denmark)

    Tang, Yi; Loh, Poh Chiang; Wang, Peng

    2012-01-01

    , the proposed SAPF offers superior switching harmonic suppression using much reduced passive filtering elements. Its output currents thus have high slew rate for tracking the targeted reference closely. Smaller inductance of the LCL filter also means smaller harmonic voltage drop across the passive output......This paper concentrates on the design, control, and implementation of an LCL-filter-based shunt active power filter (SAPF), which can effectively compensate for harmonic currents produced by nonlinear loads in a three-phase three-wire power system. With an LCL filter added at its output...... filter, which in turn minimizes the possibility of overmodulation, particularly for cases where high modulation index is desired. These advantages, together with overall system stability, are guaranteed only through proper consideration of critical design and control issues, like the selection of LCL...

  17. Switching power supplies with multiple isolated output and unitary power factor with an only switch; Fonte chaveada com multiplas saidas isoladas e fator de potencia unitario com um unico interruptor

    Energy Technology Data Exchange (ETDEWEB)

    Canesin, Carlos Alberto

    1990-09-01

    The analysis and implementation of switching power supplies with multiple output, through the use of the D C/D C Single Ended Primary Inductance Converter - SEPIC is presented. The structure has a single switch mode processing stage, improved input power factor, with the use of the variable current hysteresis control, or, constant on time control. The analysis of the D C/D C SEPIC, output characteristics and computer simulation is presented. A switching power supply practical design and experimental results are presented to demonstrate the validity of the theoretical analysis. (author)

  18. Analysis and design of sliding mode controller gains for boost power factor corrector.

    Science.gov (United States)

    Kessal, Abdelhalim; Rahmani, Lazhar

    2013-09-01

    This paper presents a systematic procedure to compute the gains of sliding mode controller based on an optimization scheme. This controller is oriented to drive an AC-DC converter operating in continuous mode with power factor near unity, and in order to improve static and dynamic performances with large variations of reference voltage and load. This study shows the great influence of the controller gains on the global performances of the system. Hence, a methodology for choosing the gains is detailed. The sliding surface used in this study contains two state variables, input current and output voltage; the advantage of this surface is getting reactions against various disturbances-at the power source, the reference of the output, or the value of the load. The controller is experimentally confirmed for steady-state performance and transient response.

  19. Output power levels from mobile phones in different geographical areas; implications for exposure assessment

    OpenAIRE

    Lonn, S; Forssen, U; P. Vecchia; Ahlbom, A; Feychting, M

    2004-01-01

    Background: The power level used by the mobile phone is one of the most important factors determining the intensity of the radiofrequency exposure during a call. Mobile phone calls made in areas where base stations are densely situated (normally urban areas) should theoretically on average use lower output power levels than mobile phone calls made in areas with larger distances between base stations (rural areas).

  20. Predictability of the Power Output of Three Wave Energy Technologies in the Danish North Sea

    DEFF Research Database (Denmark)

    Chozas, Julia Fernandez; Jensen, N. E. Helstrup; Sørensen, H. C.;

    2013-01-01

    The paper addresses an important challenge towards the integration of the electricity generated by wave energy converters into the electric grid. Particularly, it looks into the role of wave energy within day-ahead electricity markets. For that the predictability of the theoretical power outputs ....... The best compromise between forecast accuracy and mean power production results when considering the combined production of the three converters. © 2013 Elsevier Ltd. All rights reserved....

  1. Body size and countermovement depth confound relationship between muscle power output and jumping performance

    Science.gov (United States)

    Markovic, Srdjan; Dragan, Mirkov; Nedeljkovic, Aleksandar; Jaric, Slobodan

    2013-01-01

    A number of studies based on maximum vertical jumps have presumed that the maximum jump height reveals the maximum power of lower limb muscles, as well as the tested muscle power output predicts the jumping performance. The objective of the study was to test the hypothesis that both the body size and countermovement depth confound the relationship between the muscle power output and performance of maximum vertical jumps. Sixty young and physically active males were tested on the maximum countermovement (CMJ) and squat jumps (SJ). The jumping performance (Hmax), peak (Ppeak) and the average power output (Pavg) during the concentric phase, countermovement depth (only in CMJ) and body mass as an index of body size were assessed. To assess the power-performance relationship, the correlations between Hmax with both Ppeak and Pavg were calculated without and with controlling for the effects of body mass, as well as for the countermovement depth. The results revealed moderate power-performance relationships (range 0.55power output with the performance of maximum vertical jumps. Regarding routine assessments of muscle power from jumping performance and vice versa, the use of CMJ is recommended, while Ppeak, rather than Pavg, should be the variable of choice. PMID:24280557

  2. A High-Gain Three-Port Power Converter with Fuel Cell, Battery Sources and Stacked Output for Hybrid Electric Vehicles and DC-Microgrids

    Directory of Open Access Journals (Sweden)

    Ching-Ming Lai

    2016-03-01

    Full Text Available This paper proposes a novel high-gain three-port power converter with fuel cell (FC, battery sources and stacked output for a hybrid electric vehicle (HEV connected to a dc-microgrid. In the proposed power converter, the load power can be flexibly distributed between the input sources. Moreover, the charging or discharging of the battery storage device can be controlled effectively using the FC source. The proposed converter has several outputs in series to achieve a high-voltage output, which makes it suitable for interfacing with the HEV and dc-microgrid. On the basis of the charging and discharging states of the battery storage device, two power operation modes are defined. The proposed power converter comprises only one boost inductor integrated with a flyback transformer; the boost and flyback circuit output terminals are stacked to increase the output voltage gain and reduce the voltage stress on the power devices. This paper presents the circuit configuration, operating principle, and steady-state analysis of the proposed converter, and experiments conducted on a laboratory prototype are presented to verify its effectiveness.

  3. Output feedback hybrid-impulsive second order sliding mode control: Lyapunov approach

    NARCIS (Netherlands)

    Shtessel, Y.; Glumineau, A.; Plestan, F.; Weiss, M.

    2014-01-01

    A perturbed nonlinear system of relative degree two controlled by output feedbacks discontinuous-hybrid-impulsive control is studied. The output hybrid-impulsive terms serve to drive instantaneously the system's trajectory to the origin or to its small vicinity. The output feedback impulsive action

  4. Multilateral comparisons of output, productivity, and purchasing power parities in manufacturing

    NARCIS (Netherlands)

    Pilat, D; Rao, DSP

    This paper presents multilateral comparisons of output, productivity and purchasing power parities in manufacturing, for 1975 and 1987. Two multilateral approaches are considered, namely the Geary-Khamis method and the generalized Theil-Tornqvist method based on the EKS procedure. The paper

  5. Green Input-Output Model for Power Company Theoretical & Application Analysis

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Based on the theory of marginal opportunity cost, one kind of green input-output table and models of powercompany are put forward in this paper. For an appliable purpose, analysis of integrated planning, cost analysis, pricingof the power company are also given.

  6. Maximizing Output Power in a Cantilevered Piezoelectric Vibration Energy Harvester by Electrode Design

    Science.gov (United States)

    Du, Sijun; Jia, Yu; Seshia, Ashwin

    2015-12-01

    A resonant vibration energy harvester typically comprises of a clamped anchor and a vibrating shuttle with a proof mass. Piezoelectric materials are embedded in locations of high strain in order to transduce mechanical deformation into electric charge. Conventional design for piezoelectric vibration energy harvesters (PVEH) usually utilizes piezoelectric material and metal electrode layers covering the entire surface area of the cantilever with no consideration provided to examining the trade-off involved with respect to maximizing output power. This paper reports on the theory and experimental verification underpinning optimization of the active electrode area of a cantilevered PVEH in order to maximize output power. The analytical formulation utilizes Euler-Bernoulli beam theory to model the mechanical response of the cantilever. The expression for output power is reduced to a fifth order polynomial expression as a function of the electrode area. The maximum output power corresponds to the case when 44% area of the cantilever is covered by electrode metal. Experimental results are also provided to verify the theory.

  7. Increase of power output by change of ion transport direction in a plant microbial fuel cell

    NARCIS (Netherlands)

    Timmers, R.A.; Strik, D.P.B.T.B.; Hamelers, H.V.M.; Buisman, C.J.N.

    2013-01-01

    The plant microbial fuel cell (PMFC) is a technology for the production of renewable and clean bioenergy based on photosynthesis. To increase the power output of the PMFC, the internal resistance (IR) must be reduced. The objective of the present study was to reduce the membrane resistance by changi

  8. [Effect of Cu2+ on the power output of dual-chamber microbial fuel cell].

    Science.gov (United States)

    Mu, Shu-Jun; Li, Xiu-Fen; Ren, Yue-Ping; Wang, Xin-Hua

    2014-07-01

    After addition of Cu2+ into the anodic and/or cathodic chamber, the effect of Cu2+ on the internal resistance and its distribution, power output and coulombic efficiency of dual-chamber microbial fuel cell (MFC) was investigated in this manuscript with the aid of analyzing the distribution of copper speciation. It could provide helpful information for correlative research on treatment of copper-containing wastewater by MFC. It showed that the addition of 10 mg x L(-1) Cu2+ into the anodic chamber inhibited the microbial activity, and increased the anodic activation resistance as well as the apparent internal resistance, consequently reduced the power output and coulombic efficiency of the system. However, the addition of 500 mg x L(-1) Cu2+ into the cathodic chamber significantly reduced the cathodic activation resistance as well as the apparent internal resistance, while improved the power output and the coulombic efficiency. Cu2+ in the anodic chamber was not transfered into the cathodic chamber. When adding Cu2+ into the cathodic chamber, it was mainly reduced and deposited on the cathodic chamber. It could also be transferred/diffused to the anodic chamber across the proton exchange membrane (2.8%) because of its concentration difference, thus affecting the microbial activity and power output. Only a small amount of Cu2+ remained in the supernatant of the cathodic chamber at the end of experiment.

  9. Intelligent Monitoring and Predicting Output Power Losses of Solar Arrays Based on Particle Filtering

    Directory of Open Access Journals (Sweden)

    Hongzheng Fang

    2013-01-01

    Full Text Available Solar arrays are the main source of energy to the on-orbit satellite, whose output power largely determines the life cycle of on-orbit satellites. Monitoring and further forecasting the output power of solar arrays by using the real-time observational data are very important for the study of satellite design and on-orbit satellite control. In this paper, we firstly describe the dynamical model of output power with summarizing the influencing factors of attenuation for solar arrays and elaborating the evolution trend of influencing factors which change with time. Based on the empirical model, a particle filtering algorithm is formulated to predict the output power of solar arrays and update the model parameters, simultaneously. Finally, using eight-year observational data of voltage and current from a synchronous on-orbit satellite, an experiment is carried out to illustrate the reliability and accuracy of the particle filtering method. Comparative results with classical curve fitting also are presented with statistical root mean square error and mean relative error analysis.

  10. CMOS upconversion mixer with filterless carrier feedthrough cancelation and output power tuning

    NARCIS (Netherlands)

    Sanchez Gaspariano, Luis Abraham; Annema, Anne-Johan; Muniz Montero, Carlos; Diaz Sanchez, Alejandro

    2014-01-01

    The synthesis, design and implementation of a CMOS upconversion mixer that both can adjust, by means of a DC voltage control, its output power and that cancels the carrier feedthrough is presented. Aiming at very low cost medical implant applications, a prototype of the architecture was implemented

  11. A 5 cm single-discharge CO2 laser having high power output

    NARCIS (Netherlands)

    Ernst, G.J.; Boer, A.G.

    1980-01-01

    A single-discharge self-sustained CO2 laser has been constructed with a gap distance of 5 cm. The system has a very simple construction; it produces a very uniform discharge with an output power of 50 Joules per liter for a CO2 : N2 : He = 1 : 1 : 3 mixture. The efficiency can be as high as 19%.

  12. ABOUT SOME FEATURES OF TRANSMISSION MODE FOR ACTIVE POWER OF ELECTRICAL LINE

    Directory of Open Access Journals (Sweden)

    Paţiuc V.

    2013-12-01

    Full Text Available This paperwork examines the problem of maximum power transfer to the load of a long line mode change from idle line (XX to short-circuit ( SC. Load line changes from idle mode (IM to its short-circuit (SC . The line length varies from zero up to a length equal to the physical length of the electromagnetic wave. As a method of research it is used the method of the complex amplitudes (MCA. As independent variables were examined her load line length and that the system per unit change in the band plus minus unit to unit , so . It enteritis that for the active character load of the active power input and power output of the line, so functions , and functions that characterize developments efficiency , power factor at the input line and the load power factor when the variable z. For these points to the notion of critical value of the load . It founds the effect of " recession " critical resistance values and functions şi , which is not found for the other functions considered - efficiency and power factor. Load reactive power compensation can help to increase power output only for lines with length smaller than ¼ wave length electromagnitice wave. In non-distortional lines, such effect is not observed. The paper work represents the general data transmission mode the maximum power lines of different lengths to the load, which varies from idle mode (IM to short-circuit (SC regime. These data can be used for preliminary analysis of the efficiency of the electrical lines at variable load.

  13. Electrospun ion gel nanofibers for flexible triboelectric nanogenerator: electrochemical effect on output power

    Science.gov (United States)

    Ye, Byeong Uk; Kim, Byoung-Joon; Ryu, Jungho; Lee, Joo Yul; Baik, Jeong Min; Hong, Kihyon

    2015-10-01

    A simple fabrication route for ion gel nanofibers in a triboelectric nanogenerator was demonstrated. Using an electrospinning technique, we could fabricate a large-area ion gel nanofiber mat. The triboelectric nanogenerator was demonstrated by employing an ion gel nanofiber and the device exhibited an output power of 0.37 mW and good stability under continuous operation.A simple fabrication route for ion gel nanofibers in a triboelectric nanogenerator was demonstrated. Using an electrospinning technique, we could fabricate a large-area ion gel nanofiber mat. The triboelectric nanogenerator was demonstrated by employing an ion gel nanofiber and the device exhibited an output power of 0.37 mW and good stability under continuous operation. Electronic supplementary information (ESI) available: I. Experimental section. II. FTIR and XRD spectra of ion gel nanofiber. III. Output voltage of TENG with various polymer nanofibers. IV. Output voltage of TENG under different connection types. V. Output voltage of TENG with 20 wt% ion gel nanofibers. See DOI: 10.1039/c5nr02602d

  14. Power Enhancement Cavity for Burst-Mode Laser Pulses

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yun [ORNL

    2015-01-01

    We demonstrate a novel optical cavity scheme and locking method that can realize the power enhancement of picosecond UV laser pulses operating at a burst mode with arbitrary burst (macropulse) lengths and repetition rates.

  15. Design and Construction Multi Output Power Transmition with Single Prime Mover on Agricultural Products Machine

    Science.gov (United States)

    Koten, V. K.; Tanamal, C. E.

    2017-03-01

    Manufacturing agricultural products by the farmers, people or person who involve in medium industry, small industry, and households industry still be done in separately. Although the power on primemover is enough, in operations, primemover was only to move one of several agricultural products machine. This study attempts to design and construct power transmition multi output with single primemover; a single construction that allows primemover move some agricultur products machine in the same or not. This study begins with the determination of production capacity and the power to destroy products, the determination of resources and rotation, normalization of resources and rotation, the determination of the type material used, the size determination of each machine elements, construction machine elements, and assemble machine elements into a construction multi output power transmition with single primemover on agricultural products machine. The results show that with a input normalization 4 PK (2984 Watt), rotation 2000 rpm, the strength of material 60 kg/mm2, and several operating consideration, thus obtained size of machine elements through calculation. Based on the size, the machine elements is made through the use of some machine tools and assembled to form a multi output power transmition with single primemover.

  16. Wind tunnel study of the power output spectrum in a micro wind farm

    Science.gov (United States)

    Bossuyt, Juliaan; Howland, Michael F.; Meneveau, Charles; Meyers, Johan

    2016-09-01

    Instrumented small-scale porous disk models are used to study the spectrum of a surrogate for the power output in a micro wind farm with 100 models of wind turbines. The power spectra of individual porous disk models in the first row of the wind farm show the expected -5/3 power law at higher frequencies. Downstream models measure an increased variance due to wake effects. Conversely, the power spectrum of the sum of the power over the entire wind farm shows a peak at the turbine-to-turbine travel frequency between the model turbines, and a near -5/3 power law region at a much wider range of lower frequencies, confirming previous LES results. Comparison with the spectrum that would result when assuming that the signals are uncorrelated, highlights the strong effects of correlations and anti-correlations in the fluctuations at various frequencies.

  17. Output power enhancement from ZnO nanorods piezoelectric nanogenerators by Si microhole arrays.

    Science.gov (United States)

    Baek, Seong-Ho; Hasan, Md Roqibul; Park, Il-Kyu

    2016-02-12

    We demonstrate the enhancement of output power from a ZnO nanorod (NR)-based piezoelectric nanogenerator by using Si microhole (Si-μH) arrays. The depth-controlled Si-μH arrays were fabricated by using the deep reactive ion etching method. The ZnO NRs were grown along the Si-μH surface, in holes deeper than 20 μm. The polymer layer, polydimethylsiloxane, which acts a stress diffuser and electrical insulator, was successfully penetrated into the deep Si-μH arrays. Optical investigations show that the crystalline quality of the ZnO NRs on the Si-μH arrays was not degraded, even though they were grown on the deeper Si-μH arrays. As the depth of the Si-μH arrays increase from 0 to 20 μm, the output voltage was enhanced by around 8.1 times while the current did not increase. Finally, an output power enhancement of ten times was obtained. This enhancement of the output power was consistent with the increase in the surface area, and was mainly attributed to the accumulation of the potentials generated by the series-connected ZnO NR-based nanogenerators, whose number increases as the depth of the Si-μH increases.

  18. Theoretical study of enhancing the piezoelectric nanogenerator's output power by optimizing the external force's shape

    Science.gov (United States)

    Xu, Qi; Qin, Yong

    2017-07-01

    The average power is one of the key parameters of piezoelectric nanogenerators (PENGs). In this paper, we demonstrate that the PENG's output can be gigantically improved by choosing driving force with an appropriate shape. When the load resistance is 100 MΩ and the driven forces have a magnitude of 19.6 nN, frequency of 10 Hz, the average power of PENG driven by square shaped force is six orders of magnitude higher than that driven by triangular shaped and sinusoidal shaped forces. These results are of importance for optimizing the average power of the PENGs in practical applications.

  19. Linear Robust Output Regulation in a Class of Switched Power Converters

    Directory of Open Access Journals (Sweden)

    Josep M. Olm

    2010-01-01

    Full Text Available This article addresses the robust output regulation problem for a class of nonlinear switched power converters after its linearization by means of a change of the control vector variable. The methodology employs a dynamic state feedback control law and considers parametric uncertainty due to unknown values of resistive loads. Restrictions arising from the fact that the control gains exhibit fixed values are taken into account. The proposed technique is exemplified with the output voltage regulation of a Noninverting Buck-Boost converter and tested through realistic numerical simulations.

  20. Output Regulation of Large-Scale Hydraulic Networks with Minimal Steady State Power Consumption

    DEFF Research Database (Denmark)

    Jensen, Tom Nørgaard; Wisniewski, Rafal; De Persis, Claudio;

    2014-01-01

    that the system is overactuated is exploited for minimizing the steady state electrical power consumption of the pumps in the system, while output regulation is maintained. The proposed control actions are decentralized in order to make changes in the structure of the hydraulic network easy to implement.......An industrial case study involving a large-scale hydraulic network is examined. The hydraulic network underlies a district heating system, with an arbitrary number of end-users. The problem of output regulation is addressed along with a optimization criterion for the control. The fact...

  1. Dynamic Floating Output Stage for Low Power Buffer Amplifier for LCD Application

    Directory of Open Access Journals (Sweden)

    Hari Shanker Srivastava

    2015-02-01

    Full Text Available This topic proposes low-power buffer means low quiescent current buffer amplifier. A dynamic floating current node is used at the output of two-stage amplifier to increase the charging and discharging of output capacitor as well as settling time of buffer. It is designed for 10 bit digital analog converter to support for LCD column driver it is implemented in 180 nm CMOS technology with the quiescent current of 5 µA for 30 pF capacitance, the settling time calculated as 4.5µs, the slew rate obtained as 5V/µs and area on chip is 30×72µ

  2. High power low-order modes operation of a multimode fiber laser

    Institute of Scientific and Technical Information of China (English)

    Libo Li; Qihong Lou; Jun Zhou; Jingxing Dong; Yunrong Wei; Jinyan Li

    2007-01-01

    Coiling technique is used to suppress high-order modes of a large mode area (LMA) double clad multimode fiber. Output powers and beam quality factors M2 are measured under two different coiling radii. 217 W with M2 of 2.96 can be obtained for coiling radius of 165 mm and 160 W with M2 of 1.38 for 52 mm. The corresponding slope efficiencies are 60% and 48%. With smaller coiling radius, the brightness is 3.4 times as high as that of the larger one.

  3. SVPWM Technique with Varying DC-Link Voltage for Common Mode Voltage Reduction in a Matrix Converter and Analytical Estimation of its Output Voltage Distortion

    Science.gov (United States)

    Padhee, Varsha

    Common Mode Voltage (CMV) in any power converter has been the major contributor to premature motor failures, bearing deterioration, shaft voltage build up and electromagnetic interference. Intelligent control methods like Space Vector Pulse Width Modulation (SVPWM) techniques provide immense potential and flexibility to reduce CMV, thereby targeting all the afore mentioned problems. Other solutions like passive filters, shielded cables and EMI filters add to the volume and cost metrics of the entire system. Smart SVPWM techniques therefore, come with a very important advantage of being an economical solution. This thesis discusses a modified space vector technique applied to an Indirect Matrix Converter (IMC) which results in the reduction of common mode voltages and other advanced features. The conventional indirect space vector pulse-width modulation (SVPWM) method of controlling matrix converters involves the usage of two adjacent active vectors and one zero vector for both rectifying and inverting stages of the converter. By suitable selection of space vectors, the rectifying stage of the matrix converter can generate different levels of virtual DC-link voltage. This capability can be exploited for operation of the converter in different ranges of modulation indices for varying machine speeds. This results in lower common mode voltage and improves the harmonic spectrum of the output voltage, without increasing the number of switching transitions as compared to conventional modulation. To summarize it can be said that the responsibility of formulating output voltages with a particular magnitude and frequency has been transferred solely to the rectifying stage of the IMC. Estimation of degree of distortion in the three phase output voltage is another facet discussed in this thesis. An understanding of the SVPWM technique and the switching sequence of the space vectors in detail gives the potential to estimate the RMS value of the switched output voltage of any

  4. Incorrect calculation of power outputs masks the ergogenic capacity of creatine supplementation.

    Science.gov (United States)

    Havenetidis, Konstadinos; Cooke, Carlton B; Butterly, Ron; King, Roderick F G J

    2006-10-01

    This study assessed the effect of incorrect calculation of power output measurement on the ergogenic properties of creatine. Fifteen males performed repeated Wingate anaerobic tests, under baseline, placebo, and creatine conditions. Statistics showed significant differences (p supplemented conditions compared with placebo conditions, whereas no significant differences existed between the baseline and placebo conditions. However, the performance enhancement effect of creatine became significant only when the corrected (for the inertia of the flywheel) method was employed for measuring peak and minimum power. Mean (+/- SD) values across all cycle sprints for placebo versus creatine were 1033 +/- 100 W versus 1130 +/- 95 W for peak power and 385 +/- 78 W versus 427 +/- 70 W for minimum power. No significant differences were shown using the uncorrected method for peak power (756 +/- 97 W versus 786 +/- 88 W) and minimum power 440 +/- 64 W pre versus 452 +/- 65 W post). In conclusion, the present study suggests that the potentiating effect of creatine might be underestimated if the inertial effects of the flywheel are not considered in power output determination.

  5. Power dissipation by Higher Order Modes

    CERN Document Server

    Schuh, M

    2010-01-01

    The additional power loss due to HOMs in cavities and HOM couplers is estimated as function of the damping with analytic and beam dynamics simulation based models. Based on these results,HOM damping requirements for the Superconducting Proton Linac (SPL) can be defined to limit the additional heat load to the watt level.

  6. Relationships between muscle power output using the stretch-shortening cycle and eccentric maximum strength.

    Science.gov (United States)

    Miyaguchi, Kazuyoshi; Demura, Shinichi

    2008-11-01

    This study aimed to examine the relationships between muscle power output using the stretch-shortening cycle (SSC) and eccentric maximum strength under elbow flexion. Eighteen young adult males pulled up a constant light load (2 kg) by ballistic elbow flexion under the following two preliminary conditions: 1) the static relaxed muscle state (SR condition), and 2) using the SSC with countermovement (SSC condition).Muscle power was determined from the product of the pulling velocity and the load mass by a power measurement instrument that adopted the weight-loading method. We assumed the pulling velocity to be the subject's muscle power parameters as a matter of convenience, because we used a constant load. The following two parameters were selected in reference to a previous study: 1) peak velocity (m x s(-1)) (peak power) and 2) 0.1-second velocity during concentric contraction (m x s(-1)) (initial power). Eccentric maximum strength by elbow flexion was measured by a handheld dynamometer.Initial power produced in the SSC condition was significantly larger than that in the SR condition. Eccentric maximum strength showed a significant and high correlation (r = 0.70) with peak power in the SSC condition but not in the SR condition. Eccentric maximum strength showed insignificant correlations with initial power in both conditions. In conclusion, it was suggested that eccentric maximum strength is associated with peak power in the SSC condition, but the contribution of the eccentric maximum strength to the SSC potentiation (initial power) may be low.

  7. High output power reluctance electric motors with bulk high-temperature superconductor elements

    Science.gov (United States)

    Kovalev, L. K.; Ilushin, K. V.; Penkin, V. T.; Kovalev, K. L.; Larionoff, A. E.; M-A Koneev, S.; Modestov, K. A.; Larionoff, S. A.; Poltavets, V. N.; Akimov, I. I.; Alexandrov, V. V.; Gawalek, W.; Oswald, B.; Krabbes, G.

    2002-05-01

    We present new types of electric machines with the rotors containing bulk high-temperature superconductor (HTS) - YBCO and Bi-Ag - elements. We discuss different schematics of hysteresis, reluctance, 'trapped field' and composed synchronous HTS machines. The two-dimensional mathematical models describing the processes in such types of HTS machines were developed on the basis of the theoretical analysis of the electrodynamic and hysteresis processes in the single-domain and polycrystal YBCO ceramic samples and plate shape Bi-Ag elements. We give the test results of the series of hysteresis, reluctance, 'trapped field' and composed with permanent magnets HTS motors with an output power rating of 0.1-18 kW and current frequencies 50 Hz and 400 Hz. These results show that in the media of liquid nitrogen the specific output power per one unit weight of the HTS motor is four to seven times better than for conventional electric machines. A comparison of the theoretical and experimental characteristics of the developed HTS motors show that they are in good agreement. We discuss the test results for a liquid nitrogen cryogenic pump system with a hysteresis 500 W HTS motor. We describe several designs of new HTS motors operating in the media of liquid nitrogen with an output power 125 kW (and more) and a power factor of more than 0.8. We discuss future applications of new types of HTS motors for aerospace technology, on-land industry and transport systems.

  8. Simulation of one-minute power output from utility-scale photovoltaic generation systems.

    Energy Technology Data Exchange (ETDEWEB)

    Stein, Joshua S.; Ellis, Abraham; Hansen, Clifford W.

    2011-08-01

    We present an approach to simulate time-synchronized, one-minute power output from large photovoltaic (PV) generation plants in locations where only hourly irradiance estimates are available from satellite sources. The approach uses one-minute irradiance measurements from ground sensors in a climatically and geographically similar area. Irradiance is translated to power using the Sandia Array Performance Model. Power output is generated for 2007 in southern Nevada are being used for a Solar PV Grid Integration Study to estimate the integration costs associated with various utility-scale PV generation levels. Plant designs considered include both fixed-tilt thin-film, and single-axis-tracked polycrystalline Si systems ranging in size from 5 to 300 MW{sub AC}. Simulated power output profiles at one-minute intervals were generated for five scenarios defined by total PV capacity (149.5 MW, 222 WM, 292 MW, 492 MW, and 892 MW) each comprising as many as 10 geographically separated PV plants.

  9. Limits and Optimization of Power Input or Output of Actual Thermal Cycles

    Directory of Open Access Journals (Sweden)

    Emin Açıkkalp

    2013-08-01

    Full Text Available In classical thermodynamic, maximum power obtained from system (or minimum power supplied to system defined as availability (exergy, but availability term is only used for reversible systems. In reality, there is no reversible system, all systems are irreversible, because reversible cycles doesn’t include constrains like time or size and they operates in quasi-equilibrium state. Purpose of this study is to define limits of the all basic thermodynamic cycles and to provide finite-time exergy models for irreversible cycles and to obtain the maximum (or minimum available power for irreversible (finite-time exergy cycles. In this study, available power optimization and performance limits were defined all basic irreversible thermodynamic cycles, by using first and second law of thermodynamic. Finally, these results were evaluated in terms of cycles’ first and second law efficiency, COP, power output (or input and exergy destruction.

  10. Exploring the Power Output of Small Wind Turbines in Urban San Antonio, Texas

    Science.gov (United States)

    Casillas, Jose; Sperduti, Stephanie; Cardenas, Rosa

    2015-03-01

    The means of transporting power from a centralized power plant by transmission lines has several disadvantages. Electricity transmission and distribution networks are costly, require long planning processes and are unsightly to residents. These networks are also susceptible to natural disasters creating massive disruptions to consumers. For these reasons distributed power sources such as solar panels and small wind turbines are becoming a more desirable and viable means of energy production. We report on the status of a study to determine the maximum output power of small wind turbines in urban San Antonio, Texas. Wind speed data along with power measurements from small wind turbines in urban San Antonio will be reported. U.S. Department of Education Title V HSI-STEM and Articulation Award No. P031C110145.

  11. Estimation of marginal abatement costs for undesirable outputs in India's power generation sector: An output distance function approach.

    OpenAIRE

    Manish Gupta

    2005-01-01

    Many production activities generate undesirable byproducts in conjunction with the desirable outputs they produce. The present study uses an output distance function approach and its duality with the revenue function to estimate the marginal abatement cost of CO2 emissions from a sample of thermal plants in India. Two sets of exercises have been undertaken. The marginal abatement cost is first estimated without considering the distinction between the clean and the dirty plants (model-1) and t...

  12. Isotope scaling of the H mode power threshold on JET

    Science.gov (United States)

    Righi, E.; Bartlett, D. V.; Christiansen, J. P.; Conway, G. D.; Cordey, J. G.; Eriksson, L.-G.; DeEsch, H. P. L.; Fishpool, G. M.; Gowers, C. W.; de Haas, J. C. M.; Harbour, P. J.; Hawkes, N. C.; Jacquinot, J.; Jones, T. T. C.; Kerner, W.; King, Q. A.; Lowry, C. G.; Monk, R. D.; Nielsen, P.; Rimini, F. G.; Saibene, G.; Sartori, R.; Schunke, B.; Sips, A. C. C.; Smith, R. J.; Stamp, M. F.; Start, D. F. H.; Thomsen, K.; Tubbing, B. J. D.; Zornig, N.

    1999-03-01

    Results are presented from a series of dedicated experiments carried out on JET in tritium, DT, deuterium and hydrogen plasmas to determine the dependence of the H mode power threshold on the plasma isotopic mass. The Pthr propto Aeff-1 scaling is established over the whole isotopic range. This result makes it possible for a fusion reactor with a 50:50 DT mixture to access the H mode regime with about 20% less power than that needed in a DD mixture. Results on the first systematic measurements of the power necessary for the transition of the plasma to the type I ELM regime, which occurs after the transition to H mode, are also in agreement with the Aeff-1 scaling. For a subset of discharges, measurements of Te and Ti at the top of the profile pedestal have been obtained, indicating a weak influence of the isotopic mass on the critical edge temperature thought to be necessary for the H mode transition.

  13. High-Power Microwave Transmission and Mode Conversion Program

    Energy Technology Data Exchange (ETDEWEB)

    Vernon, Ronald J. [Univ. of Wisconsin, Madison, WI (United States)

    2015-08-14

    This is a final technical report for a long term project to develop improved designs and design tools for the microwave hardware and components associated with the DOE Plasma Fusion Program. We have developed basic theory, software, fabrication techniques, and low-power measurement techniques for the design of microwave hardware associated gyrotrons, microwave mode converters and high-power microwave transmission lines. Specifically, in this report we discuss our work on designing quasi-optical mode converters for single and multiple frequencies, a new method for the analysis of perturbed-wall waveguide mode converters, perturbed-wall launcher design for TE0n mode gyrotrons, quasi-optical traveling-wave resonator design for high-power testing of microwave components, and possible improvements to the HSX microwave transmission line.

  14. BB mode angular power spectrum of CMB from massive gravity

    CERN Document Server

    Malsawmtluangi, N

    2016-01-01

    The primordial massive gravitational waves are placed in the squeezed vacuum state and corresponding $BB$-mode correlation angular power spectrum of the cosmic microwave background is obtained for various slow roll inflation models. The angular power spectrum is compared with the limit of BICEP2/Keck and Planck joint analysis data and the hybrid inflation model is found favorable.

  15. Robust nanogenerators based on graft copolymers via control of dielectrics for remarkable output power enhancement

    Science.gov (United States)

    Lee, Jae Won; Cho, Hye Jin; Chun, Jinsung; Kim, Kyeong Nam; Kim, Seongsu; Ahn, Chang Won; Kim, Ill Won; Kim, Ju-Young; Kim, Sang-Woo; Yang, Changduk; Baik, Jeong Min

    2017-01-01

    A robust nanogenerator based on poly(tert-butyl acrylate) (PtBA)–grafted polyvinylidene difluoride (PVDF) copolymers via dielectric constant control through an atom-transfer radical polymerization technique, which can markedly increase the output power, is demonstrated. The copolymer is mainly composed of α phases with enhanced dipole moments due to the π-bonding and polar characteristics of the ester functional groups in the PtBA, resulting in the increase of dielectric constant values by approximately twice, supported by Kelvin probe force microscopy measurements. This increase in the dielectric constant significantly increased the density of the charges that can be accumulated on the copolymer during physical contact. The nanogenerator generates output signals of 105 V and 25 μA/cm2, a 20-fold enhancement in output power, compared to pristine PVDF–based nanogenerator after tuning the surface potential using a poling method. The markedly enhanced output performance is quite stable and reliable in harsh mechanical environments due to the high flexibility of the films. On the basis of these results, a much faster charging characteristic is demonstrated in this study. PMID:28560339

  16. Chatter free sliding mode control of a chaotic coal mine power grid with small energy inputs

    Institute of Scientific and Technical Information of China (English)

    Xu Yanqing; Jia Feng; Ma Caoyuan; Mao Jiasong; Zhang Shaowei

    2012-01-01

    An augmented proportional-integral sliding surface was designed for a sliding mode controller.A chatter free sliding mode control strategy for a chaotic coal mine power grid was developed.The stability of the control strategy was proven by Lyapunov stability theorem.The proposed sliding mode control strategy eliminated the chattering phenomenon by replacing the sign function with a saturation function,and by replacing the constant coefficients in the reaching law with adaptive ones.An immune genetic algorithm was used to optimize the parameters in the improved reaching.law.The cut-in time of the controllers was optimized to reduce the peak energy of their output.Simulations showed that the proposed sliding mode controller has good,chatter free performance.

  17. Super short term forecasting of photovoltaic power generation output in micro grid

    Science.gov (United States)

    Gong, Cheng; Ma, Longfei; Chi, Zhongjun; Zhang, Baoqun; Jiao, Ran; Yang, Bing; Chen, Jianshu; Zeng, Shuang

    2017-01-01

    The prediction model combining data mining and support vector machine (SVM) was built. Which provide information of photovoltaic (PV) power generation output for economic operation and optimal control of micro gird, and which reduce influence of power system from PV fluctuation. Because of the characteristic which output of PV rely on radiation intensity, ambient temperature, cloudiness, etc., so data mining was brought in. This technology can deal with large amounts of historical data and eliminate superfluous data, by using fuzzy classifier of daily type and grey related degree. The model of SVM was built, which can dock with information from data mining. Based on measured data from a small PV station, the prediction model was tested. The numerical example shows that the prediction model is fast and accurate.

  18. Mode Shift Control for a Hybrid Heavy-Duty Vehicle with Power-Split Transmission

    Directory of Open Access Journals (Sweden)

    Kun Huang

    2017-02-01

    Full Text Available Given that power-split transmission (PST is considered to be a major powertrain technology for hybrid heavy-duty vehicles (HDVs, the development and application of PST in the HDVs make mode shift control an essential aspect of powertrain system design. This paper presents a shift schedule design and torque control strategy for a hybrid HDV with PST during mode shift, intended to reduce the output torque variation and improve the shift quality (SQ. Firstly, detailed dynamic models of the hybrid HDV are developed to analyze the mode shift characteristics. Then, a gear shift schedule calculation method including a dynamic shift schedule and an economic shift schedule is provided. Based on the dynamic models and the designed shift schedule, a mode shift performance simulator is built using MATLAB/Simulink, and simulations are carried out. Through analysis of the dynamic equations, it is seen that the inertia torques of the motor–generator lead to the occurrence of transition torque. To avoid the unwanted transition torque, we use a mode shift control strategy that coordinates the motor–generator torque to compensate for the transition torque. The simulation and experimental results demonstrate that the output torque variation during mode shift is effectively reduced by the proposed control strategy, thereby improving the SQ.

  19. Picosecond laser with 11 W output power at 1342 nm based on composite multiple doping level Nd:YVO4 crystal

    Science.gov (United States)

    Rodin, Aleksej M.; Grishin, Mikhail; Michailovas, Andrejus

    2016-01-01

    We report results of design and optimization of high average output power picosecond and nanosecond laser operating at 1342 nm wavelength. Developed for selective micromachining, this DPSS laser is comprised of master oscillator, regenerative amplifier and output pulse control module. Passively mode-locked by means of semiconductor saturable absorber mirror and pumped with 808 nm wavelength Nd:YVO4 master oscillator emits 12.5 ps pulses at repetition rate of 55 MHz with average output power of ∼100 mW. The four-pass confocal delay line forms a longest part of the oscillator cavity in order to suppress thermo-mechanical misalignment. Picked from the train seed pulses were injected to the cavity of regenerative amplifier based on composite Nd:YVO4 crystal with diffusion-bonded segments of multiple Nd doping concentration end-pumped at 880 nm wavelength. Laser produces pulses of ∼13 ps duration at 300 kHz repetition rate with average output power of 11 W and nearly diffraction limited beam quality of M2∼1.03. Attained high peak power ∼2.8 MW facilitates conversion to the 2nd, 3rd and 6th harmonics at 671 nm, 447 nm and 224 nm wavelengths with 80%, 50% and 15% efficiency respectively. Without seeding the regenerative amplifier transforms to electro-optically cavity-dumped Q-switched laser providing 10 ns output pulses at high repetition rates with beam propagation factor of M2∼1.06.

  20. Efficiency at maximum power output of linear irreversible Carnot-like heat engines.

    Science.gov (United States)

    Wang, Yang; Tu, Z C

    2012-01-01

    The efficiency at maximum power output of linear irreversible Carnot-like heat engines is investigated based on the assumption that the rate of irreversible entropy production of the working substance in each "isothermal" process is a quadratic form of the heat exchange rate between the working substance and the reservoir. It is found that the maximum power output corresponds to minimizing the irreversible entropy production in two isothermal processes of the Carnot-like cycle, and that the efficiency at maximum power output has the form η(mP)=η(C)/(2-γη(C)), where η(C) is the Carnot efficiency, while γ depends on the heat transfer coefficients between the working substance and two reservoirs. The value of η(mP) is bounded between η(-)≡η(C)/2 and η(+)≡η(C)/(2-η(C)). These results are consistent with those obtained by Chen and Yan [J. Chem. Phys. 90, 3740 (1989)] based on the endoreversible assumption, those obtained by Esposito et al. [Phys. Rev. Lett. 105, 150603 (2010)] based on the low-dissipation assumption, and those obtained by Schmiedl and Seifert [Europhys. Lett. 81, 20003 (2008)] for stochastic heat engines which in fact also satisfy the low-dissipation assumption. Additionally, we find that the endoreversible assumption happens to hold for Carnot-like heat engines operating at the maximum power output based on our fundamental assumption, and that the Carnot-like heat engines that we focused on do not strictly satisfy the low-dissipation assumption, which implies that the low-dissipation assumption or our fundamental assumption is a sufficient but non-necessary condition for the validity of η(mP)=η(C)/(2-γη(C)) as well as the existence of two bounds, η(-)≡η(C)/2 and η(+)≡η(C)/(2-η(C)).

  1. The first in Poland demonstrative ORC power plant of low power output

    Energy Technology Data Exchange (ETDEWEB)

    Nowak, Wladyslaw; Borsukiewicz-Gozdur, Aleksandra; Stachel, Aleksander A. [West Pomeranian Univ. of Technology, Szczecin (Poland); Klonowicz, Wojciech; Hanausek, Pawel [Turboservice Sp. z o.o., Lodz (Poland); Klonowicz, Piotr; Magiera, Radomir [Lodz Univ. of Technology (Poland)

    2010-07-01

    A description of the power plant working according to the organic Clausius-Rankine cycle (ORC) and developed at the Department of Heat Engineering (KTC), West Pomeranian University of Technology in Szczecin, is presented. The ORC power plant is powered by the low temperature heat of hot water with the temperature of up to 100 C. The hot water heat is here converted into mechanical energy that is generated by a turbine and used to drive a centrifugal air compressor. The ORC turbine is supplied with dry, saturated vapour of the R227ea working fluid of low boiling point. The working fluid vapour is generated in a combined preheater-evaporator heat exchanger. The results of calculations and experimental measurements are presented and supplemented with conclusions derived from the ORC power plant operation. Perspective modernization of the ORC power plant scheme is also outlined. (orig.)

  2. Characterization of a pulsed mode high voltage power supply for nuclear detectors

    Science.gov (United States)

    Ghazali, A. B.; Ahmad, T. S.; Abdullah, N. A.

    2013-06-01

    This paper discusses the characterization of a pulsed mode high voltage power supply (HVPS) using LT1073 chip. The pulsed modulated signal generated from this chip is amplified using a step-up ferrite core transformer of 1:20 turn ratio and then further multiplied and converted into DC high voltage output using a diode-capacitor arrangement. The circuit is powered by a 9V alkaline battery but regulated at 5V supply. It was found that the output for this setup is 520V, 87 μA with 10% load regulation. This output is suitable to operate a pancake-type GM detector, typically model LND 7317 where the plateau is from 475V to 675V. It was also found that when a β-source with intensity of 120 cps is used, the power consumption of the circuit is 5 V, 10.1 mA only. When the battery was left 'on' for 40 hours continuously, the battery's voltage has dropped to 6.9V, meaning that the 5V supply as well as 520V output is still maintained. It is noted that the minimum output voltage of 475V has reached when the regulated supply has reduced to 4.6V and consequently the 9V battery dropped to 6.5V, and this had happened after approximately 3 days of continuous operation. The power efficiency for this circuitry was found to be 89.5%. This result has far better in performance since the commercial portable equipment of this type has normally specified that not less than 8 hours continuous operation only. On the circuit design for this power supply, it was found that the enveloped frequency is 133 Hz with approximately 50% duty cycle. The modulated frequency during 'on' state was found to be 256 KHz in which the majority of power consumption is required.

  3. Balancing Europe's wind power output through spatial deployment informed by weather regimes.

    Science.gov (United States)

    Grams, Christian M; Beerli, Remo; Pfenninger, Stefan; Staffell, Iain; Wernli, Heini

    2017-08-01

    As wind and solar power provide a growing share of Europe's electricity1, understanding and accommodating their variability on multiple timescales remains a critical problem. On weekly timescales, variability is related to long-lasting weather conditions, called weather regimes2-5, which can cause lulls with a loss of wind power across neighbouring countries6. Here we show that weather regimes provide a meteorological explanation for multi-day fluctuations in Europe's wind power and can help guide new deployment pathways which minimise this variability. Mean generation during different regimes currently ranges from 22 GW to 44 GW and is expected to triple by 2030 with current planning strategies. However, balancing future wind capacity across regions with contrasting inter-regime behaviour - specifically deploying in the Balkans instead of the North Sea - would almost eliminate these output variations, maintain mean generation, and increase fleet-wide minimum output. Solar photovoltaics could balance low-wind regimes locally, but only by expanding current capacity tenfold. New deployment strategies based on an understanding of continent-scale wind patterns and pan-European collaboration could enable a high share of wind energy whilst minimising the negative impacts of output variability.

  4. A New Method for Increasing Output Power of a Three-Cavity Transit-Time Oscillator

    Institute of Scientific and Technical Information of China (English)

    HE Jun-Tao; ZHONG Hui-Huang; QIAN Bao-Liang; LIU Yong-Gui

    2004-01-01

    We propose a new method to increase the output power of a three-cavity transit-time oscillator (TC-TTO).Conventional transit-time effect oscillators, such as the split-cavity oscillator (SCO), super-Reltron, and TC-TTO (or double-foil SCO), etc., have a common feature that the span of any modulating cavity is uniform. The new method is to vary the three-cavity spans from uniform to nonuniform. Its configuration is called the nonuniform three-cavity transit-time oscillator (NTC-TTO). Numerical simulations show that the electron-beam is modulated more deeply in certain NTC-TTOs than that in the TC-TTO with the same whole modulating length, and the output microwave power in certain NTC-TTOs is higher than that in the TC-TTO. The experimental results are in agreement with those of the numerical simulations. The results show that the new method can increase the output power of a microwave tube based on the TC-TTO.

  5. Diode end-pumped 1123-nm Nd:YAG laser with 2.6-W output power

    Institute of Scientific and Technical Information of China (English)

    Zhiqiang Cai; Meng Chen; Zhigang Zhang; Rui Zhou; Wuqi Wen; Xin Ding; Jianquan Yao

    2005-01-01

    We present a compact and high output power diode end-pumped Nd:YAG laser which operates at the wavelength of 1123 nm. Continuous wave (CW) laser output of 2.6 W was achieved at the incident pump power of 15.9 W, indicating an overall optical-optical conversion efficiency of 16.4%, and the slope efficiency was 18%.

  6. Use of variable cross-section pipes to stabilize the helium-neon laser radiation output power

    Energy Technology Data Exchange (ETDEWEB)

    Klimentova, T.M.; Leontiev, V.G.; Ostapchenko, E.P.; Pozdina, T.L.; Chernikov, P.N.

    1980-03-01

    The possibility for the use of the sectional active elements to increase the output power stability of a helium-neon laser at the wavelength of 0.63 ..mu..m is shown. It is found that at definite diameters and lengths of the sections the output power changes slightly with a change in the discharge current and the medium pressure.

  7. Some observations on stray magnetic fields and power outputs from short-wave diathermy equipment

    Energy Technology Data Exchange (ETDEWEB)

    Lau, R.W.M.; Dunscombe, P.B.

    1984-04-01

    Recent years have seen increasing interest in the possible hazards arising from the use of nonionizing electromagnetic radiation. Relatively large and potentially hazardous fields are to be found in the vicinity of short-wave and microwave equipment used in physiotherapy departments to produce therapeutic temperature rises. This note reports the results of measurements of the stray magnetic field and power output of a conventional short-wave diathermy unit when applied to tissue-equivalent phantoms. The dependence of these quantities on the variables, i.e. power setting of the unit, capacitor plate size, phantom size and phantom-capacitor plate separation, are discussed.

  8. Smoothing of wind farm output power using prediction based flywheel energy storage system

    Science.gov (United States)

    Islam, Farzana

    Being socially beneficial, economically competitive and environment friendly, wind energy is now considered to be the world's fastest growing renewable energy source. However, the stochastic nature of wind imposes a considerable challenge in the optimal management and operation of wind power system. Wind speed prediction is critical for wind energy conversion system since it greatly influences the issues related to effective energy management, dynamic control of wind turbine, and improvement of the overall efficiency of the power generation system. This thesis focuses on integration of energy storage system with wind farm, considering wind speed prediction in the control scheme to overcome the problems associated with wind power fluctuations. In this thesis, flywheel energy storage system (FESS) with adjustable speed rotary machine has been considered for smoothing of output power in a wind farm composed of a fixed speed wind turbine generator (FSWTG). Since FESS has both active and reactive power compensation ability, it enhances the stability of the system effectively. An efficient energy management system combined with supervisory control unit (SCU) for FESS and wind speed prediction has been developed to improve the smoothing of the wind farm output effectively. Wind speed prediction model is developed by artificial neural network (ANN) which has advantages over the conventional prediction scheme including data error tolerance and ease in adaptability. The model for prediction with ANN is developed in MATLAB/Simulink and interfaced with PSCAD/EMTDC. Effectiveness of the proposed control system is illustrated using real wind speed data in various operating conditions.

  9. Modeling and Optimization of Coordinative Operation of Hydro-wind-photovoltaic Considering Power Generation and Output Fluctuation

    Science.gov (United States)

    Wang, Xianxun; Mei, Yadong

    2017-04-01

    Coordinative operation of hydro-wind-photovoltaic is the solution of mitigating the conflict of power generation and output fluctuation of new energy and conquering the bottleneck of new energy development. Due to the deficiencies of characterizing output fluctuation, depicting grid construction and disposal of power abandon, the research of coordinative mechanism is influenced. In this paper, the multi-object and multi-hierarchy model of coordinative operation of hydro-wind-photovoltaic is built with the aim of maximizing power generation and minimizing output fluctuation and the constraints of topotaxy of power grid and balanced disposal of power abandon. In the case study, the comparison of uncoordinative and coordinative operation is carried out with the perspectives of power generation, power abandon and output fluctuation. By comparison from power generation, power abandon and output fluctuation between separate operation and coordinative operation of multi-power, the coordinative mechanism is studied. Compared with running solely, coordinative operation of hydro-wind-photovoltaic can gain the compensation benefits. Peak-alternation operation reduces the power abandon significantly and maximizes resource utilization effectively by compensating regulation of hydropower. The Pareto frontier of power generation and output fluctuation is obtained through multiple-objective optimization. It clarifies the relationship of mutual influence between these two objects. When coordinative operation is taken, output fluctuation can be markedly reduced at the cost of a slight decline of power generation. The power abandon also drops sharply compared with operating separately. Applying multi-objective optimization method to optimize the coordinate operation, Pareto optimal solution set of power generation and output fluctuation is achieved.

  10. Predictability of the Power Output of Three Wave Energy Technologies in the Danish North Sea

    DEFF Research Database (Denmark)

    Chozas, Julia Fernandez; Jensen, N. E. Helstrup; Sørensen, H. C.;

    2011-01-01

    of the study is to provide an indication on the accuracy of the forecast of i) wave parameters, ii) the normalised theoretical power productions from each of the selected technologies (Pelamis, Wave Dragon and Wavestar), and iii) the normalised theoretical power production of a combination of the three devices...... of the normalised theoretical power outputs of Pelamis, Wave Dragon and Wavestar are 44%, 52% and 62%, respectively. The best compromise between forecast accuracy and mean power production results when considering the combined production of the three devices.......The paper addresses an important challenge ahead the integration of the electricity generated by wave energy conversion technologies into the electric grid. Particularly, it looks into the role of wave energy within the day-ahead electricity market. For that the predictability of the theoretical...

  11. Research reactor power controller design using an output feedback nonlinear receding horizon control method

    Energy Technology Data Exchange (ETDEWEB)

    Etchepareborda, Andres [Department of Nuclear Engineering, Argentine National Atomic Energy Commission, Centro Atomico Bariloche, Av. E. Bustillo 9500, Bariloche 8400 (Argentina)]. E-mail: etche@cab.cnea.gov.ar; Lolich, Jose [INVAP S.E., Moreno 1089, Bariloche 8400 (Argentina)

    2007-02-15

    A constrained, output feedback nonlinear receding horizon control (NRHC) method is applied to design a research reactor power controller. The method uses a nonlinear plant model subject to state, control and terminal set constraints; a nonlinear cost function; and a high gain observer. The controller regulates reactor power from 1% to 100% of full power; considers known disturbances, such as reactivity insertions and changes in core inlet flow and temperature; and includes upper limits constraints on neutron flux, neutron flux rate, core outlet temperature and core inlet-outlet temperature difference. Simulation results show an excellent performance for power regulation and known disturbances rejection: all process variables are kept within the admissible limits avoiding the actuation of the safety systems.

  12. Maximum Output Power Control Using Short-Circuit Current and Open-Circuit Voltage of a Solar Panel

    Science.gov (United States)

    Kato, Takahiro; Miyake, Takuma; Tashima, Daisuke; Sakoda, Tatsuya; Otsubo, Masahisa; Hombu, Mitsuyuki

    2012-10-01

    A control method to optimize the output power of a solar cell is necessary because the output of a solar cell strongly depends on solar radiation. We here proposed two output power control methods using the short-circuit current and open-circuit voltage of a solar panel. One of them used a current ratio and a voltage ratio (αβ control), and the other used a current ratio and a short-circuit current-electric power characteristic coefficient (αγ control). The usefulness of the αβ and the αγ control methods was evaluated. The results showed that the output power controlled by our proposed methods was close to the maximum output power of a solar panel.

  13. Application of second order sliding mode algorithms for output feedback control in hydraulic cylinder drives with profound valve dynamics

    DEFF Research Database (Denmark)

    Schmidt, Lasse; Andersen, Torben O.

    2016-01-01

    The application of second order sliding mode algorithms for output feedback control in hydraulic valve-cylinder drives appear attractive due to their simple realization and parametrization, and strong robustness toward bounded parameter variations and uncertainties. However, intrinsic nonlinear...... input signals. The application of some popular second order sliding mode controllers and their smooth counterparts are analyzed and experimentally verified. The controllers are considered for output feedback control and compared with a conventional PI control approach. The controllers under...... consideration are applied for position tracking control of a hydraulic valve-cylinder drive exhibiting strong variations in inertia- and gravitational loads, and furthermore suffer from profound valve dynamics. Results demonstrate that both the twisting- and super twisting algorithms may be successfully applied...

  14. Increased mid-infrared supercontinuum bandwidth and average power by tapering large-mode-area chalcogenide photonic crystal fibers

    DEFF Research Database (Denmark)

    Petersen, Christian Rosenberg; Engelsholm, Rasmus Dybbro; Markos, Christos

    2017-01-01

    The trade-off between the spectral bandwidth and average output power from chalcogenide fiber-based mid-infrared supercontinuum sources is one of the major challenges towards practical application of the technology. In this paper we address this challenge through tapering of large-mode-area chalc...... m. (C) 2017 Optical Society of America...

  15. Contrastive study of two SESAMs for passive mode-locking in Nd:YVO4 laser with low pump power

    Institute of Scientific and Technical Information of China (English)

    Yang Liu; Liqun Sun; Yonggang Wang; Qian Tian; Xiaoyu Ma; Zhigang Zhang

    2005-01-01

    Two semiconductor saturable absorber mirrors (SESAMs), of which one is coated with 50% reflection film on the top and the other is not, were contrastively studied in passively mode-locked solid-state lasers which were pumped by low output power laser diode (LD). Experiments have shown that reducing the modulation depth of SESAM by coating partial reflection film, whose reflectivity is higher than that between SESAM and air interface, is an effective method to get continuous wave (CW) mode-locking instead of Q-switched power LD, in which no water-cooling system was used, could obtain CW mode-locking by the 50% reflector coated SESAM with average output power of ~ 20 mW.

  16. Power allocation and mode selection methods for cooperative communication in the rectangular tunnel

    Institute of Scientific and Technical Information of China (English)

    Zhai Wenyan; Sun Yanjing; Xu Zhao; Li Song

    2015-01-01

    For the multipath fading on electromagnetic waves of wireless communication in the confined areas, the rectangular tunnel cooperative communication system was established based on the multimode channel model and the channel capacity formula derivation was obtained. On the optimal criterion of the channel capacity, the power allocation methods of both amplifying and forwarding (AF) and decoding and forwarding (DF) cooperative communication systems were proposed in the limitation of the total power to maximize the channel capacity. The mode selection methods of single input single output (SISO) and single input multiple output (SIMO) models in the rectangular tunnel, through which the higher channel capacity can be obtained, were put forward as well. The theoretical analysis and simulation comparison show that, channel capacity of the wireless communication system in the rectangular tunnel can be effectively enhanced through the cooperative technology; channel capacity of the rectangular tunnel under complicated conditions is maximized through the proposed power allocation methods, and the optimal cooperative mode of the channel capacity can be chosen according to the cooperative mode selection methods given in the paper.

  17. Enhancing the power output of the VA-955 UHF-TV klystron

    Energy Technology Data Exchange (ETDEWEB)

    Bowen, O.N.; Lawson, J.Q.

    1977-01-01

    The Varian VA-955 UHF-TV klystron is rated at 50 kW CW, and four of these klystrons were used to provide 200 kW of RF power for lower hybrid heating experiments on the ATC machine at 800 MHz. These proven, production-type tubes were wanted to generate more power for larger type machines, such as the PDX. Varian was asked whether the tubes were capable of higher-power operation in pulsed applications. They replied that they had no experimental data but felt that the tubes were capable of greatly enhanced performance under pulsed conditions. By using cathode modulation instead of modulating anode control of the klystron, and thus limiting the time that high voltage is applied to the cathode, it was shown that the tube is capable of an output power of 200 kW for tens of milliseconds compared to its normal CW rating of 50 kW. A description is given of the experimental results, the required modifications to the klystron and output transmission circuit, the details of operation of the regulating modulator used to perform the experiment. Upgrade kits are now being fabricated to allow 200 kW operation of the two 50 kW units which were lent to General Atomic for Doublet II experiments.

  18. Predicting Power Output of Upper Body using the OMNI-RES Scale

    Science.gov (United States)

    Bautista, Iker J.; Chirosa, Ignacio J.; Tamayo, Ignacio Martín; González, Andrés; Robinson, Joseph E.; Chirosa, Luis J.; Robertson, Robert J.

    2014-01-01

    The main aim of this study was to determine the optimal training zone for maximum power output. This was to be achieved through estimating mean bar velocity of the concentric phase of a bench press using a prediction equation. The values for the prediction equation would be obtained using OMNI–RES scale values of different loads of the bench press exercise. Sixty males (age 23.61 2.81 year; body height 176.29 6.73 cm; body mass 73.28 4.75 kg) voluntarily participated in the study and were tested using an incremental protocol on a Smith machine to determine one repetition maximum (1RM) in the bench press exercise. A linear regression analysis produced a strong correlation (r = −0.94) between rating of perceived exertion (RPE) and mean bar velocity (Velmean). The Pearson correlation analysis between real power output (PotReal) and estimated power (PotEst) showed a strong correlation coefficient of r = 0.77, significant at a level of p = 0.01. Therefore, the OMNI–RES scale can be used to predict Velmean in the bench press exercise to control the intensity of the exercise. The positive relationship between PotReal and PotEst allowed for the identification of a maximum power-training zone. PMID:25713677

  19. Predicting Power Output of Upper Body using the OMNI-RES Scale

    Directory of Open Access Journals (Sweden)

    Bautista Iker J.

    2014-12-01

    Full Text Available The main aim of this study was to determine the optimal training zone for maximum power output. This was to be achieved through estimating mean bar velocity of the concentric phase of a bench press using a prediction equation. The values for the prediction equation would be obtained using OMNI-RES scale values of different loads of the bench press exercise. Sixty males ( voluntarily participated in the study and were tested using an incremental protocol on a Smith machine to determine one repetition maximum (1RM in the bench press exercise. A linear regression analysis produced a strong correlation (r = -0.94 between rating of perceived exertion (RPE and mean bar velocity (Velmean. The Pearson correlation analysis between real power output (PotReal and estimated power (PotEst showed a strong correlation coefficient of r = 0.77, significant at a level of p = 0.01. Therefore, the OMNI-RES scale can be used to predict Velmean in the bench press exercise to control the intensity of the exercise. The positive relationship between PotReal and PotEst allowed for the identification of a maximum power-training zone.

  20. The average output power of a wind turbine in a turbulent wind

    Energy Technology Data Exchange (ETDEWEB)

    Rosen, A.; Sheinman, Y. (Faculty of Aerospace Engineering, Technion, Israel Institute of Technology, Haifa (Israel))

    1994-05-01

    Turbulence has an important influence on the average output power of a wind turbine taken over a certain period of time. The wind dynamics is coupled to the turbine dynamic characteristics and results in a fairly complicated behavior. Thus, the common 'static' model of calculating the average power, which is based on the turbine power curve and the average wind speed, may result in increasing errors. This paper presents three different models for calculating the average output power, taking into account the dynamic characteristics of the phenomenon. These models include direct time integration using accurate wind data and a detailed dynamic model of the turbine, a quasi-steady approach which is much simpler to apply and takes into account the wind dynamics, and an improved efficient model that also includes the influence of the dynamic characteristics of the turbine. The last improved model is based on a study of the turbine response to a sinusoidal gust. All models are compared with field measurements in order to study their accuracy. The comparison exhibits the importance of including all the dynamic effects in the calculations

  1. Maximum Output Power Control System of Variable-Speed Small Wind Generators

    Science.gov (United States)

    Amano, Yoko; Kajiwara, Hiroyuki

    This paper proposes a maximum output power control system of variable-speed small wind generators. Paying attention to an optimum rotational speed of a single phase AC wind generator which can obtain maximum output power according to natural wind speed, the proposed method adjusts the rotational speed of the single phase AC generator to the optimum rotational speed. Since this adjustment is realized on line so that it can be adapted for variable-speed wind, a generated power brake links directly with the single phase AC generator, and the rotational speed of the single phase AC generator is adjusted by controlling the current that flows the FET (Field-Effect Transistor) device as the generated power brake. In order to reduce heat loss of the FET device, the PWM (Pulse Width Modulation) controller is introduced. Moreover, the experimental system of the proposed method is constituted and the experiment is performed. Finally, the validity and the practicality of the proposed method are confirmed by experimental results.

  2. Impact of CDMA wireless phone power output and puncture rate on hearing aid interference levels.

    Science.gov (United States)

    Fry, T L; Schlegel, R E; Grant, H

    2000-01-01

    Interference between digital wireless phones and hearing aids occurs when the radiofrequency bursts from the phone transmission are demodulated by the hearing aid amplifier. The amplified interference signal is heard as a "buzz" or "static" by the hearing aid wearer. Most research and standards development activity has focused on worst-case scenarios with the phone operating at its maximum power. Since this power level is often not typical in urban and suburban settings, it is of value to determine the impact of lower power levels on the overall level of audible interference. Using a frequency analyzer, and several hearings aids and code division multiple access (CDMA) phones, the audio frequency spectrum of interference was recorded for each phone-aid combination and for a range of power levels producing from no interference to maximum interference. As phone power is increased, the interference signal becomes distinguishable from the ambient noise level and a linear response region is observed in which a specified increase in power output results in a proportional increase in the overall input referenced interference level (OIRIL). As power is increased beyond the linear region, the hearing aid enters a saturation region where an additional power increase results in a reduction or no increase in the OIRIL. The numeric differences in interference documented in this study were used in conjunction with the results of a previous study by the authors to determine the impact of reduced power on speech intelligibility and annoyance. The amount of improvement for a given power reduction depends on the radiofrequency immunity of the hearing aid and is substantial for hearing aids with poor immunity. For high-immunity aids, the level of audible interference remains low even at high phone power levels.

  3. Output voltage regulation of a k15 mode piezoelectric transformer by an external L/C component.

    Science.gov (United States)

    Hu, Junhui; Chan, Kuang Hwee; Ng, Boon Siang

    2009-06-01

    Smooth regulation of output voltage of piezoelectric transformers can significantly widen the application range of piezoelectric transformers. So far the driving frequency of piezoelectric transformers has been used to regulate the output voltage at a matching load. However, the regulation range of voltage gain achieved by the method is usually very narrow within the acceptable range of efficiency. In this work, we investigate the possibility to regulate the output voltage of a k15 mode piezoelectric transformer by an external L/C component. The effects of an L/C component in series or parallel with the input and output ports on the voltage gain are investigated theoretically and experimentally. It is found that the voltage gain can be smoothly regulated in a relatively wide range by a tunable inductor that is in series with the input port. At a matching load of 80 Omega, the voltage gain can be regulated between 0.31 and 0.94 with efficiency larger than 90% and between 0.34 and 1.18 with efficiency about 80%. It is also found that a tunable capacitor in parallel or series with the output port can be used to regulate the voltage gain with efficiency higher than 90%.

  4. Lack of maintenance of shortwave diathermy equipment has a negative impact on power output.

    Science.gov (United States)

    Guirro, Rinaldo Roberto de Jesus; Guirro, Elaine Caldeira de Oliveira; Alves de Sousa, Natanael Teixeira

    2014-04-01

    Although shortwave diathermy has been widely used by physiotherapists, there are a few studies assessing the performance of the equipment in use. The aim of the present study was to evaluate the procedures adopted by physiotherapists as users of shortwave diathermy continuous (CSWD), as well as to measure the power output and frequency of CSWD equipment. [Subjects and Methods] Twenty-three physical therapists were interviewed and 23 CSWD equipment were evaluated. Admeasurement was carried out by using a standard phantom to simulate the electrode-skin distance, which ranged from 0.5 to 3.0 cm. Data analysis was performed by using descriptive statistics, ANOVA, and a post-hoc Tukey's test or Pearson's correlation coefficient. [Results] The questionnaires showed that 48% of the interviewees use the correct electrode-skin distance, 70% use a single electrical outlet, and 35% use a grounded electrical outlet, and that 48% of the physiotherapy tables and 61% of the plinths were made of wood. However, only 13% of the interviewees perform yearly preventive maintenance. The highest power (95.56 W) was achieved at electrode-skin distances ranging from 1.0 to 1.5 cm, with distances of 2.5 cm and 3.0 cm being null in four and eight equipment, respectively. There was a negative correlation between power output and electrode-skin distance as well as between power output and purchase date. [Conclusion] The physiotherapists involved in this study had inadequate knowledge about the correct use of CSWD equipment, which may adversely affect its performance and patient safety.

  5. Discharge current modes of high power impulse magnetron sputtering

    Directory of Open Access Journals (Sweden)

    Zhongzhen Wu

    2015-09-01

    Full Text Available Based on the production and disappearance of ions and electrons in the high power impulse magnetron sputtering plasma near the target, the expression of the discharge current is derived. Depending on the slope, six possible modes are deduced for the discharge current and the feasibility of each mode is discussed. The discharge parameters and target properties are simplified into the discharge voltage, sputtering yield, and ionization energy which mainly affect the discharge plasma. The relationship between these factors and the discharge current modes is also investigated.

  6. A review of output-only structural mode identification literature employing blind source separation methods

    Science.gov (United States)

    Sadhu, A.; Narasimhan, S.; Antoni, J.

    2017-09-01

    Output-only modal identification has seen significant activity in recent years, especially in large-scale structures where controlled input force generation is often difficult to achieve. This has led to the development of new system identification methods which do not require controlled input. They often work satisfactorily if they satisfy some general assumptions - not overly restrictive - regarding the stochasticity of the input. Hundreds of papers covering a wide range of applications appear every year related to the extraction of modal properties from output measurement data in more than two dozen mechanical, aerospace and civil engineering journals. In little more than a decade, concepts of blind source separation (BSS) from the field of acoustic signal processing have been adopted by several researchers and shown that they can be attractive tools to undertake output-only modal identification. Originally intended to separate distinct audio sources from a mixture of recordings, mathematical equivalence to problems in linear structural dynamics have since been firmly established. This has enabled many of the developments in the field of BSS to be modified and applied to output-only modal identification problems. This paper reviews over hundred articles related to the application of BSS and their variants to output-only modal identification. The main contribution of the paper is to present a literature review of the papers which have appeared on the subject. While a brief treatment of the basic ideas are presented where relevant, a comprehensive and critical explanation of their contents is not attempted. Specific issues related to output-only modal identification and the relative advantages and limitations of BSS methods both from theoretical and application standpoints are discussed. Gap areas requiring additional work are also summarized and the paper concludes with possible future trends in this area.

  7. Maximum Power Point Tracking of DC To DC Boost Converter Using Sliding Mode Control

    Directory of Open Access Journals (Sweden)

    Anusuyadevi R

    2013-07-01

    Full Text Available A sliding mode controller is used to estimate the maximum power point as a reference for it to track that point and force the PV system to operate in this point. In sliding mode control, the trajectories of the system are forced to reach a sliding manifold of surface, where it exhibit desirable features, in finite time and to stay on the manifold for all future time. The load is composed of a battery bank. It is obtained by controlling the duty cycle of a DC-DC converter using sliding mode control. This method has the advantage that it will guarantee the maximum output power possible by the array configuration while considering the dynamic parameters solar irradiance and delivering more power to charge the battery. The proposed system with sliding mode control is tested using MATLAB / SIMULINK platform in which a maximum power is tracked under constant and varying solar irradiance and delivered to the battery which increasing the current that is charging the battery and reduces the charging time.

  8. In situ measurements of wind and current speed and relationship between output power and turbulence

    Science.gov (United States)

    Duran Medina, Olmo; Schmitt, François G.; Sentchev, Alexei; Calif, Rudy

    2015-04-01

    In a context of energy transition, wind and tidal energy are sources of clean energy with the potential of partially satisfying the growing demand. The main problem of this type of energy, and other types of renewable energy remains the discontinuity of the electric power produced in different scales, inducing large fluctuations also called intermittency. This intermittency of wind and tidal energy is inherent to the turbulent nature of wind and marine currents. We consider this intermittent power production in strong relation with the turbulent intermittency of the resource. The turbulence theory is multifractal energy cascades models, a classic in physics of turbulence. From earlier studies in atmospheric sciences, we learn that wind speed and the aggregate power output are intermittent and multifractal over a wide range of scales [Calif and Schmitt 2014]. We want to extend this study to a marine current turbine and compare the scaling properties for those renewable energy sources. We consider here coupling between simultaneous velocity time series and output power from a wind turbine and a marine current turbine. Wind turbine data were obtained from Denmark and marine current data from Western Scheldt, Belgium where a prototype of a vertical and horizontal marine current turbines are tested. After an estimation of their Fourier density power spectra, we study their scaling properties in Kolmogorov's theory and the framework of fully developed turbulence. Hence, we employ a Hilbert-based methodology, namely arbitrary-order Hilbert spectral analysis [Calif et al. 2013a, 2013b] to characterize the intermittent property of the wind and marine current velocity in order to characterize the intermittent nature of the fluid. This method is used in order to obtain the spectrum and the corresponding power law for non-linear and non-stationary time series. The goal is to study the non-linear transfer characteristics in a multi-scale and multi-intensity framework.

  9. Very High Frequency Switch-Mode Power Supplies

    DEFF Research Database (Denmark)

    Madsen, Mickey Pierre

    The importance of technology and electronics in our daily life is constantly increasing. At the same time portability and energy efficiency are currently some of the hottest topics. This creates a huge need for power converters in a compact form factor and with high efficiency, which can supply...... these electronic devices. This calls for new technologies in order to miniaturize the power electronics of today. One way to do this is by increasing the switching frequency dramatically and develop very high frequency switch mode power supplies. If these converters can be designed to operate efficiently, a huge...... of technologies for very high frequency switch mode power supplies. At these highly elevated frequencies normal bulky magnetics with heavy cores consisting of rare earth materials, can be replaced by air core inductors embedded in the printed circuit board. This is investigated thoroughly and both spirals...

  10. Control Strategies for Smoothing of Output Power of Wind Energy Conversion Systems

    Science.gov (United States)

    Pratap, Alok; Urasaki, Naomitsu; Senju, Tomonobu

    2013-10-01

    This article presents a control method for output power smoothing of a wind energy conversion system (WECS) with a permanent magnet synchronous generator (PMSG) using the inertia of wind turbine and the pitch control. The WECS used in this article adopts an AC-DC-AC converter system. The generator-side converter controls the torque of the PMSG, while the grid-side inverter controls the DC-link and grid voltages. For the generator-side converter, the torque command is determined by using the fuzzy logic. The inputs of the fuzzy logic are the operating point of the rotational speed of the PMSG and the difference between the wind turbine torque and the generator torque. By means of the proposed method, the generator torque is smoothed, and the kinetic energy stored by the inertia of the wind turbine can be utilized to smooth the output power fluctuations of the PMSG. In addition, the wind turbines shaft stress is mitigated compared to a conventional maximum power point tracking control. Effectiveness of the proposed method is verified by the numerical simulations.

  11. Effect of Ultrasonic Output Power on Refining the Crystal Structures of Ingots and Its Experimental Simulation

    Institute of Scientific and Technical Information of China (English)

    Junwen LI; Tadashi MOMONO

    2005-01-01

    In this study, a series of tests were conducted by using aluminum-based alloy to determine the formation of grain refining structure based on the ultrasonic vibration (UV). Furthermore, the simulation test and effect of ultrasonic output power were studied using ammonium chloride. Finally, the mechanism of grain refinement was investigated.The results show that: (1) By applying the UV to aluminum-base alloy, the grain refining rate of ingots tended to increase with the increase of the output value of UV. (2) It was confirmed that time from after the pour to the beginning of crystallization as well as cloudiness tended to decrease with increasing the ultrasonic power value of UV. Moreover, it can be seen from each cooling curve that a uniform temperature gradient existed in the melt as the power of UV increased, that made the melt strongly stirred. (3) It was also considered that the grain refining effect of ingots, which was observed from the simulation tests, resulted from nucleation action and stirring division action by applying the UV.

  12. Performance characteristics and output power stability of a multichannel fibre laser

    Science.gov (United States)

    Kuzmenkov, A. I.; Lukinykh, S. N.; Nanii, O. E.; Odintsov, A. I.; Smirnov, A. P.; Fedoseev, A. I.; Treshchikov, V. N.

    2016-09-01

    The effect of the density and number of spectral channels on the output power stability in a multichannel cw laser has been studied theoretically and experimentally. In our calculations, we used a model in which the interaction between channels due to gain medium saturation was determined by channel frequency spacingdependent cross-saturation coefficients. The key features of lasing have been analysed and illustrated by the examples of three-, fiveand nine-channel lasers. It has been shown that, at a given excess of the pump power over threshold, the channel powers can be equalised by introducing additional losses into the highest power channels. At a sufficiently high channel density, raising the pump power then leads to termination of lasing in the even channels. As the number of channels increases, the laser system retains its stability, but the time needed for the transition to a steady state increases sharply. In our experiments, we used an erbium-doped fibre laser whose design ensured independent control over the powers of up to 40 spectral channels anchored on the telecommunication frequency grid. Our experimental data are in qualitative agreement with the calculation results. In particular, a long-term relative instability less than 3 dB was only observed at a number of channels less than seven and channel frequency spacings above 400 GHz. Instability was shown to increase with an increase in the number and density of channels.

  13. Functional Capacity, Muscle Fat Infiltration, Power Output, and Cognitive Impairment in Institutionalized Frail Oldest Old

    OpenAIRE

    Casas-Herrero, Alvaro; Eduardo L. Cadore; Zambom-Ferraresi, Fabricio; Idoate, Fernando; Millor, Nora; Martínez-Ramirez, Alicia; Gómez, Marisol; Rodriguez-Mañas, Leocadio; Marcellán, Teresa; de Gordoa, Ana Ruiz; Mário C. Marques; Izquierdo, Mikel

    2013-01-01

    This study examined the neuromuscular and functional performance differences between frail oldest old with and without mild cognitive impairment (MCI). In addition, the associations between functional capacities, muscle mass, strength, and power output of the leg muscles were also examined. Forty-three elderly men and women (91.9±4.1 years) were classified into three groups—the frail group, the frail with MCI group (frail+MCI), and the non-frail group. Strength tests were performed for upper ...

  14. Ferroelectric dipole electrets for output power enhancement in electrostatic vibration energy harvesters

    Science.gov (United States)

    Asanuma, Haruhiko; Oguchi, Hiroyuki; Hara, Motoaki; Yoshida, Ryo; Kuwano, Hiroki

    2013-10-01

    We propose a ferroelectric dipole electret composed of polarized lead zirconate titanate. Deep insight into the physics behind the parallel plate capacitor theoretically predicts that we can extract large electric field near the surface of the ferroelectric dipole electret by increasing its surface charge density and thickness. Experiment for ferroelectric dipole electret shows good agreement with the theory. The maximum output power density of electrostatic vibration energy harvesters using the ferroelectric dipole electret was 78 μW/cm3, a three-fold increase over a conventional polymer electret. Our results will pave the way for use of ferroelectrics as electrets.

  15. Zinc oxide integrated area efficient high output low power wavy channel thin film transistor

    KAUST Repository

    Hanna, A. N.

    2013-11-26

    We report an atomic layer deposition based zinc oxide channel material integrated thin film transistor using wavy channel architecture allowing expansion of the transistor width in the vertical direction using the fin type features. The experimental devices show area efficiency, higher normalized output current, and relatively lower power consumption compared to the planar architecture. This performance gain is attributed to the increased device width and an enhanced applied electric field due to the architecture when compared to a back gated planar device with the same process conditions.

  16. Efficiency at maximum power output of an irreversible Carnot-like cycle with internally dissipative friction.

    Science.gov (United States)

    Wang, Jianhui; He, Jizhou

    2012-11-01

    We investigate the efficiency at the maximum power output (EMP) of an irreversible Carnot engine performing finite-time cycles between two reservoirs at constant temperatures T(h) and T(c) (Carnot efficiency, whether the internally dissipative friction is considered or not. When dissipations of two "isothermal" and two "adiabatic" processes are symmetric, respectively, and the time allocation between the adiabats and the contact time with the reservoir satisfy a certain relation, the Curzon-Ahlborn (CA) efficiency η(CA) = 1-sqrt[T(c)/T(h)] is derived.

  17. Soft switching arc welding power source using output inductor as resonant inductor

    Institute of Scientific and Technical Information of China (English)

    陈树君; 王军; 卢振洋; 殷树言

    2002-01-01

    Full-bridge Zero-Voltage-Switch PWM converter combines advantages of the PWM control technique and resonant technique. However, Full ZVS is achieved only under large load current because resonant tank of this circuit is made up of the parasitic capacitance of the power semiconductors and the leakage inductor of the transformer primary. In this paper two saturable inductors as magnetic switches are added to secondary, so output inductor is always reflected to primary and assists resonant transition. Full ZVS is achieved under lower load current. The above-mentioned investigated results are validated by the computerized simulation and hardware circuit experiment.

  18. The Influence of Serial Carbohydrate Mouth Rinsing on Power Output during a Cycle Sprint.

    Science.gov (United States)

    Phillips, Shaun M; Findlay, Scott; Kavaliauskas, Mykolas; Grant, Marie Clare

    2014-05-01

    The objective of the study was to investigate the influence of serial administration of a carbohydrate (CHO) mouth rinse on performance, metabolic and perceptual responses during a cycle sprint. Twelve physically active males (mean (± SD) age: 23.1 (3.0) years, height: 1.83 (0.07) m, body mass (BM): 86.3 (13.5) kg) completed the following mouth rinse trials in a randomized, counterbalanced, double-blind fashion; 1. 8 x 5 second rinses with a 25 ml CHO (6% w/v maltodextrin) solution, 2. 8 x 5 second rinses with a 25 ml placebo (PLA) solution. Following mouth rinse administration, participants completed a 30 second sprint on a cycle ergometer against a 0.075 g·kg(-1) BM resistance. Eight participants achieved a greater peak power output (PPO) in the CHO trial, resulting in a significantly greater PPO compared with PLA (13.51 ± 2.19 vs. 13.20 ± 2.14 W·kg(-1), p sprint and lower for the remainder of the sprint compared with the PLA trial (p > 0.05). No significant between-trials difference was reported for fatigue index, perceived exertion, arousal and nausea levels, or blood lactate and glucose concentrations. Serial administration of a CHO mouth rinse may significantly improve PPO during a cycle sprint. This improvement appears confined to the first 5 seconds of the sprint, and may come at a greater relative cost for the remainder of the sprint. Key pointsThe paper demonstrates that repeated administration of a carbohydrate mouth rinse can significantly improve peak power output during a single 30 second cycle sprint.The ergogenic effect of the carbohydrate mouth rinse may relate to the duration of exposure of the oral cavity to the mouth rinse, and associated greater stimulation of oral carbohydrate receptors.The significant increase in peak power output with the carbohydrate mouth rinse may come at a relative cost for the remainder of the sprint, evidenced by non-significantly lower mean power output and a greater fatigue index in the carbohydrate vs. placebo

  19. Enhanced Power Output of a Triboelectric Nanogenerator Composed of Electrospun Nanofiber Mats Doped with Graphene Oxide

    Science.gov (United States)

    Huang, Tao; Lu, Mingxia; Yu, Hao; Zhang, Qinghong; Wang, Hongzhi; Zhu, Meifang

    2015-09-01

    We developed a book-shaped triboelectric nanogenerator (TENG) that consists of electrospun polyvinylidene fluoride (PVDF) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) nanofibers to effectively harvest mechanical energy. The dispersed graphene oxide in the PVDF nanofibers acts as charge trapping sites, which increased the interface for charge storage as well as the output performance of the TENG. The book-shaped TENG was used as a direct power source to drive small electronics such as LED bulbs. This study proved that it is possible to improve the performance of TENGs using composite materials.

  20. Maximal power output estimates the MLSS before and after aerobic training

    OpenAIRE

    Carolina Franco Wilke; Guilherme Passos Ramos; André Maia Lima; Christian Emmanuel Torres Cabido; Cristiano Lino Monteiro de Barros; Thiago Teixeira Mendes; Emerson Silami Garcia

    2014-01-01

    The purpose of this study is to present an equation to predict the maximal lactate steady state (MLSS) through a VO2peak incremental protocol. Twenty-six physically active men were divided in two groups (G1 and G2). They performed one maximal incremental test to determine their VO2peak and maximal power output (Wpeak), and also several constant intensity tests to determine MLSS intensity (MLSSw) on a cycle ergometer. Group G2 underwent six weeks of aerobic training at MLSSw. A regression equa...

  1. A non-endoreversible Otto cycle model: improving power output and efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Angulo-Brown, F. [Instituto Politecnico Nacional, Mexico City (Mexico). Escuela Superior de Fisica y Matematicas; Rocha-Martinez, J.A.; Navarrete-Gonzalez, T.D. [Universidad Autonoma Metropolitana-Azcapotzalco, Mexico City (Mexico). Dept. de Ciencias Basicas

    1996-01-14

    We propose a finite-time thermodynamics model for an Otto thermal cycle. Our model considers global losses in a simplified way lumped into a friction-like term, and takes into account the departure from an endoreversible regime through a parameter (R) arising from the Clausius inequality. Our numerical results suggest that the cycle`s power output and efficiency are very sensitive to that parameter. We find that R is the ratio of the constant-volume heat capacities of the reactants and products in the combustion reaction occurring inside the working fluid. Our results have implications in the search for new fuels for internal combustion engines. (author)

  2. Scaling of mechanical power output during burst escape flight in the Corvidae.

    Science.gov (United States)

    Jackson, Brandon E; Dial, Kenneth P

    2011-02-01

    Avian locomotor burst performance (e.g. acceleration, maneuverability) decreases with increasing body size and has significant implications for the survivorship, ecology and evolution of birds. However, the underlying mechanism of this scaling relationship has been elusive. The most cited mechanistic hypothesis posits that wingbeat frequency alone limits maximal muscular mass-specific power output. Because wingbeat frequency decreases with body size, it may explain the often-observed negative scaling of flight performance. To test this hypothesis we recorded in vivo muscular mechanical power from work-loop mechanics using surgically implanted sonomicrometry (measuring muscle length change) and strain gauges (measuring muscle force) in four species of Corvidae performing burst take-off and vertical escape flight. The scale relationships derived for the four species suggest that maximum muscle-mass-specific power scales slightly negatively with pectoralis muscle mass (M(-0.18)(m), 95% CI: -0.42 to 0.05), but less than the scaling of wingbeat frequency (M(-0.29)(m), 95% CI: -0.37 to -0.23). Mean muscle stress was independent of muscle mass (M(-0.02)(m), 95% CI: -0.20 to 0.19), but total muscle strain (percent length change) scaled positively (M(0.12)(m), 95% CI: 0.05 to 0.18), which is consistent with previous results from ground birds (Order Galliformes). These empirical results lend minimal support to the power-limiting hypothesis, but also suggest that muscle function changes with size to partially compensate for detrimental effects of size on power output, even within closely related species. Nevertheless, additional data for other taxa are needed to substantiate these scaling patterns.

  3. Team Modes and Power: Supervision of Doctoral Students

    Science.gov (United States)

    Robertson, Margaret J.

    2017-01-01

    Currently, team supervision in doctoral studies is widely practised across Australian universities. The interpretation of 'team' is broad and there is evidence of experimentation with supervisory models. This paper elaborates upon a taxonomy of team modes and power forms based on a recent qualitative study across universities in a number of states…

  4. Team Modes and Power: Supervision of Doctoral Students

    Science.gov (United States)

    Robertson, Margaret J.

    2017-01-01

    Currently, team supervision in doctoral studies is widely practised across Australian universities. The interpretation of 'team' is broad and there is evidence of experimentation with supervisory models. This paper elaborates upon a taxonomy of team modes and power forms based on a recent qualitative study across universities in a number of states…

  5. Utilizing Maximum Power Point Trackers in Parallel to Maximize the Power Output of a Solar (Photovoltaic) Array

    Science.gov (United States)

    2012-12-01

    portable devices where system size and efficiency are the primary design factors. Size and efficiency also govern the use of multiple MPPTs at the sub... mechanisms responsible for the energy losses in a switch-mode converter are the same. They include the components responsible for conduction, capacitor...designed to directly power a load as done in this test. The SPV-1020 may require an appropriate battery charger such as the STEVAL SEA05 battery

  6. Effect of Temperature on Power Output from Different Commercially available Photovoltaic Modules

    Directory of Open Access Journals (Sweden)

    P K Dash

    2015-01-01

    Full Text Available Photovoltaic (PV modules are rated at standard test condition (STC i.e. at irradiance of 1000 W/m2 , temperature at 25 0C and solar spectrum of Air Mass 1.5G. The actual output from the PV module in the field varies from its rated output due to change in ambient environmental conditions from the STC. The reduction in output due to temperature is determined by temperature coefficient which varies with the different types of solar module technologies. In this study, temperature coefficient of different types of commercially available solar modules is evaluated. The testing has been carried out at PV test facility of Solar Energy Centre, New Delhi. The modules are selected randomly from various manufactures. It is found that the average temperature coefficient of power for mono-crystalline, multi-crystalline and CdTe based modules are -0.446 %/°C, -0.387 %/°C and -0.172 %/°C respectively. In case of amorphous silicon module, only one sample is measured and the temperature coefficient is -0.234 %/°C. This study shows that the temperature coefficient for mono crystalline silicon module is higher than the other types of solar modules. This study provides an understanding on the variation in energy generation due to temperature correction between different cell technologies.

  7. Ultra-Fast Tracking Power Supply with 4th order Output Filter and Fixed-Frequency Hysteretic Control

    DEFF Research Database (Denmark)

    Høyerby, Mikkel Christian Wendelboe; Andersen, Michael Andreas E.

    2008-01-01

    A practical solution is presented for the design of a non-isolated DC/DC power converter with very low output ripple voltage and very fast output voltage step response. The converter is intended for use as an envelope tracking power supply for an RFPA (Radio Frequency Power Amplifier) in a Tetra2...... base station. A simple and effective fixed-frequency hysteretic control scheme for the converter (buck with 4th order output filter) is developed and analyzed. The proposed approach is verified experimentally by a 500W output prototype, capable of delivering any voltage in the range of 10-30V within 10......μs with 10mVpp of output ripple and efficiencies in the 88- 95% range....

  8. Semi-fuel cell studies for powering underwater devices: integrated design for maximized net power output

    Science.gov (United States)

    Cardenas-Valencia, Andres M.; Short, R. Timothy; Adornato, Lori; Langebrake, Larry

    2010-04-01

    Use of sensor systems in water bodies has applications that range from environmental and oceanographic research to port and homeland security. Power sources are often the limiting component for further reduction of sensor system size and weight. We present recent investigations of metal-anode water-activated galvanic cells, specifically water-activated Alcells using inorganic alkali peroxides and solid organic oxidizers (heterocyclic halamines), in a semi-fuel cell configuration (i.e., with cathode species generated in situ and flow-through cells). The oxidizers utilized are inexpensive solid materials that are generally (1) safer to handle than liquid solutions or gases, (2) have inherently higher current and energy capacity (as they are not dissolved), and, (3) if appropriately packaged, will not degrade over time. The specific energy (S.E.) of Al-alkali peroxide was found to be 230 Wh/kg (460 Wh/kg, considering only active materials) in a seven-gram cell. Interestingly, when the cell size was increased (making more area of the catalytic cathode electrode available), the results from a single addition of water in an Al-organic oxidizer cell (weighing ~18 grams) showed an S.E. of about 200 Wh/kg. This scalability characteristic suggests that values in excess of 400 Wh/kg could be obtained in a semi-fuel-cell-like system. In this paper, we also present design considerations that take into account the energy requirements of the pumping devices and show that the proposed oxidizers, and the possible control of the chemical equilibrium of these cathodes in solution, may help reduce this power requirement and hence enhance the overall energetic balance.

  9. New SRCO with explicit current-mode output using two CCs and grounded capacitors

    OpenAIRE

    Bhaskar, D. R.; ABDALLA, Kasim K.; Senani, Raj

    2011-01-01

    A new Grounded-Capacitor Single Resistance Controlled Sinusoidal Oscillator (SRCO) with explicit current output using two Current Conveyors (CCs) and five passive elements is presented. The proposed circuit offers (i) independent control of condition of oscillation and frequency of oscillation, (ii) low active and passive sensitivities, (iii) use of both the grounded capacitors (suitable for IC implementation) and (iv) reasonably good frequency stability. The workability of the propo...

  10. Determining the Frequency for Load-Independent Output Current in Three-Coil Wireless Power Transfer System

    Directory of Open Access Journals (Sweden)

    Longzhao Sun

    2015-09-01

    Full Text Available Conditions for load-independent output voltage or current in two-coil wireless power transfer (WPT systems have been studied. However, analysis of load-independent output current in three-coil WPT system is still lacking in previous studies. This paper investigates the output current characteristics of a three-coil WPT system against load variations, and determines the operating frequency to achieve a constant output current. First, a three-coil WPT system is modeled by circuit theory, and the analytical expression of the root-mean-square of the output current is derived. By substituting the coupling coefficients, the quality factor, and the resonant frequency of each coil, we propose a method of calculating the frequency for load-independent output current in a three-coil WPT system, which indicates that there are two frequencies that can achieve load-independent output current. Experiments are conducted to validate these analytical results.

  11. A High-Voltage class-D power amplifier with switching frequency regulation for improved high-efficiency output power range

    NARCIS (Netherlands)

    Ma, Haifeng; Zee, van der Ronan; Nauta, Bram

    2015-01-01

    This paper describes the power dissipation analysis and the design of an efficiency-improved high-voltage class-D power amplifier. The amplifier adaptively regulates its switching frequency for optimal power efficiency across the full output power range. This is based on detecting the switching outp

  12. Integrated Flight/Structural Mode Control for Very Flexible Aircraft Using L1 Adaptive Output Feedback Controller

    Science.gov (United States)

    Che, Jiaxing; Cao, Chengyu; Gregory, Irene M.

    2012-01-01

    This paper explores application of adaptive control architecture to a light, high-aspect ratio, flexible aircraft configuration that exhibits strong rigid body/flexible mode coupling. Specifically, an L(sub 1) adaptive output feedback controller is developed for a semi-span wind tunnel model capable of motion. The wind tunnel mount allows the semi-span model to translate vertically and pitch at the wing root, resulting in better simulation of an aircraft s rigid body motion. The control objective is to design a pitch control with altitude hold while suppressing body freedom flutter. The controller is an output feedback nominal controller (LQG) augmented by an L(sub 1) adaptive loop. A modification to the L(sub 1) output feedback is proposed to make it more suitable for flexible structures. The new control law relaxes the required bounds on the unmatched uncertainty and allows dependence on the state as well as time, i.e. a more general unmatched nonlinearity. The paper presents controller development and simulated performance responses. Simulation is conducted by using full state flexible wing models derived from test data at 10 different dynamic pressure conditions. An L(sub 1) adaptive output feedback controller is designed for a single test point and is then applied to all the test cases. The simulation results show that the L(sub 1) augmented controller can stabilize and meet the performance requirements for all 10 test conditions ranging from 30 psf to 130 psf dynamic pressure.

  13. High-power single spatial mode AlGaAs channeled-substrate-planar semiconductor diode lasers for spaceborne communications

    Science.gov (United States)

    Connolly, J. C.; Carlin, D. B.; Ettenberg, M.

    1989-01-01

    A high power single spatial mode channeled substrate planar AlGaAs semiconductor diode laser was developed. The emission wavelength was optimized at 860 to 880 nm. The operating characteristics (power current, single spatial mode behavior, far field radiation patterns, and spectral behavior) and results of computer modeling studies on the performance of the laser are discussed. Reliability assessment at high output levels is included. Performance results on a new type of channeled substrate planar diode laser incorporating current blocking layers, grown by metalorganic chemical vapor deposition, to more effectively focus the operational current to the lasing region was demonstrated. The optoelectronic behavior and fabrication procedures for this new diode laser are discussed. The highlights include single spatial mode devices with up to 160 mW output at 8600 A, and quantum efficiencies of 70 percent (1 W/amp) with demonstrated operating lifetimes of 10,000 h at 50 mW.

  14. Dynamic Output Feedback Power-Level Control for the MHTGR Based On Iterative Damping Assignment

    Directory of Open Access Journals (Sweden)

    Zhe Dong

    2012-06-01

    Full Text Available Because of its strong inherent safety features and high outlet temperature, the modular high temperature gas-cooled nuclear reactor (MHTGR is already seen as the central part of the next generation of nuclear plants. Such power plants are being considered for industrial applications with a wide range of power levels, and thus power-level control is an important technique for their efficient and stable operation. Stimulated by the high regulation performance provided by nonlinear controllers, a novel dynamic output-feedback nonlinear power-level regulator is developed in this paper based on the technique of iterative damping assignment (IDA. This control strategy can provide the L2 disturbance attenuation performance under modeling uncertainty or exterior disturbance, and can also guarantee the globally asymptotic closed-loop stability without uncertainty and disturbance. This newly built control strategy is then applied to the power-level regulation of the HTR-PM plant, and numerical simulation results show both the feasibility and high performance of this newly-built control strategy. Furthermore, the relationship between the values of the parameters and the performance of this controller is not only illustrated numerically but also analyzed theoretically.

  15. Adaptive controller design based on input-output signal selection for voltage source converter high voltage direct current systems to improve power system stability

    Institute of Scientific and Technical Information of China (English)

    Abdolkhalegh Hamidi; Jamal Beiza; Ebrahim Babaei; Sohrab Khanmohammadi

    2016-01-01

    An input-output signal selection based on Phillips-Heffron model of a parallel high voltage alternative current/high voltage direct current (HVAC/HVDC) power system is presented to study power system stability. It is well known that appropriate coupling of inputs-outputs signals in the multivariable HVDC-HVAC system can improve the performance of designed supplemetary controller. In this work, different analysis techniques are used to measure controllability and observability of electromechanical oscillation mode. Also inputs–outputs interactions are considered and suggestions are drawn to select the best signal pair through the system inputs-outputs. In addition, a supplementary online adaptive controller for nonlinear HVDC to damp low frequency oscillations in a weakly connected system is proposed. The results obtained using MATLAB software show that the best output-input for damping controller design is rotor speed deviation as out put and phase angle of rectifier as in put. Also response of system equipped with adaptive damping controller based on HVDC system has appropriate performance when it is faced with faults and disturbance.

  16. Efficiency at maximum power output of quantum heat engines under finite-time operation

    Science.gov (United States)

    Wang, Jianhui; He, Jizhou; Wu, Zhaoqi

    2012-03-01

    We study the efficiency at maximum power, ηm, of irreversible quantum Carnot engines (QCEs) that perform finite-time cycles between a hot and a cold reservoir at temperatures Th and Tc, respectively. For QCEs in the reversible limit (long cycle period, zero dissipation), ηm becomes identical to the Carnot efficiency ηC=1-Tc/Th. For QCE cycles in which nonadiabatic dissipation and the time spent on two adiabats are included, the efficiency ηm at maximum power output is bounded from above by ηC/(2-ηC) and from below by ηC/2. In the case of symmetric dissipation, the Curzon-Ahlborn efficiency ηCA=1-Tc/Th is recovered under the condition that the time allocation between the adiabats and the contact time with the reservoir satisfy a certain relation.

  17. Expansion machine for a low power-output steam Rankine-cycle engine

    Energy Technology Data Exchange (ETDEWEB)

    Badr, O.; Naik, S.; O' Callaghan, P.W.; Probert, S.D. (Cranfield Inst. of Tech., Bedford (United Kingdom). School of Mechanical Engineering)

    1991-01-01

    The performance of the expansion device in a rankine-cycle engine is one of the major parameters dictating the engine's overall energy-conversion efficiency. In this paper the screening process undertaken to choose the most suitable expansion machine for a steam Rankine-cycle engine, operating principally as a 'mini' combined heat-and-power unit, is described. In the low power-output range (i.e. 5-20 kW) envisaged rotary, positive-displacement machines offer many advantages compared with turbines and reciprocating-piston expanders. So rotary-vane, helical-screw and Wankel-type expansion devices were short listed. However further assessments, based upon operational problems and cost effectiveness, led finally to the choice of the Wankel-type expander for the proposed application. Nevertheless, for this machine to be commercially successful, existing designs need to be modified and optimised. (author).

  18. Efficiency at maximum power output of quantum heat engines under finite-time operation.

    Science.gov (United States)

    Wang, Jianhui; He, Jizhou; Wu, Zhaoqi

    2012-03-01

    We study the efficiency at maximum power, η(m), of irreversible quantum Carnot engines (QCEs) that perform finite-time cycles between a hot and a cold reservoir at temperatures T(h) and T(c), respectively. For QCEs in the reversible limit (long cycle period, zero dissipation), η(m) becomes identical to the Carnot efficiency η(C)=1-T(c)/T(h). For QCE cycles in which nonadiabatic dissipation and the time spent on two adiabats are included, the efficiency η(m) at maximum power output is bounded from above by η(C)/(2-η(C)) and from below by η(C)/2. In the case of symmetric dissipation, the Curzon-Ahlborn efficiency η(CA)=1-√(T(c)/T(h)) is recovered under the condition that the time allocation between the adiabats and the contact time with the reservoir satisfy a certain relation.

  19. Quantum Coherent Three-Terminal Thermoelectrics: Maximum Efficiency at Given Power Output

    Directory of Open Access Journals (Sweden)

    Robert S. Whitney

    2016-05-01

    Full Text Available This work considers the nonlinear scattering theory for three-terminal thermoelectric devices used for power generation or refrigeration. Such systems are quantum phase-coherent versions of a thermocouple, and the theory applies to systems in which interactions can be treated at a mean-field level. It considers an arbitrary three-terminal system in any external magnetic field, including systems with broken time-reversal symmetry, such as chiral thermoelectrics, as well as systems in which the magnetic field plays no role. It is shown that the upper bound on efficiency at given power output is of quantum origin and is stricter than Carnot’s bound. The bound is exactly the same as previously found for two-terminal devices and can be achieved by three-terminal systems with or without broken time-reversal symmetry, i.e., chiral and non-chiral thermoelectrics.

  20. Unbiased pseudo-Cl power spectrum estimation with mode projection

    CERN Document Server

    Elsner, Franz; Peiris, Hiranya V

    2016-01-01

    With the steadily improving sensitivity afforded by current and future galaxy surveys, a robust extraction of two-point correlation function measurements may become increasingly hampered by the presence of astrophysical foregrounds or observational systematics. The concept of mode projection has been introduced as a means to remove contaminants for which it is possible to construct a spatial map reflecting the expected signal contribution. Owing to its computational efficiency compared to minimum-variance methods, the sub-optimal pseudo-Cl (PCL) power spectrum estimator is a popular tool for the analysis of high-resolution data sets. Here, we integrate mode projection into the framework of PCL power spectrum estimation. In contrast to results obtained with optimal estimators, we show that the uncorrected projection of template maps leads to biased power spectra. Based on analytical calculations, we find exact closed-form expressions for the expectation value of the bias and demonstrate that they can be recast...

  1. Effect of isokinetic cycling versus weight training on maximal power output and endurance performance in cycling.

    Science.gov (United States)

    Koninckx, Erwin; Van Leemputte, Marc; Hespel, Peter

    2010-07-01

    The aim of this study was to compare the effects of a weight training program for the leg extensors with isokinetic cycling training (80 rpm) on maximal power output and endurance performance. Both strength training interventions were incorporated twice a week in a similar endurance training program of 12 weeks. Eighteen trained male cyclists (VO(2peak) 60 +/- 1 ml kg(-1) min(-1)) were grouped into the weight training (WT n = 9) or the isokinetic training group (IT n = 9) matched for training background and sprint power (P (max)), assessed from five maximal sprints (5 s) on an isokinetic bicycle ergometer at cadences between 40 and 120 rpm. Crank torque was measured (1 kHz) to determine the torque distribution during pedaling. Endurance performance was evaluated by measuring power, heart rate and lactate during a graded exercise test to exhaustion and a 30-min performance test. All tests were performed on subjects' individual race bicycle. Knee extension torque was evaluated isometrically at 115 degrees knee angle and dynamically at 200 degrees s(-1) using an isokinetic dynamometer. P (max) at 40 rpm increased in both the groups (~15%; P < 0.05). At 120 rpm, no improvement of P (max) was found in the IT training group, which was possibly related to an observed change in crank torque at high cadences (P < 0.05). Both groups improved their power output in the 30-min performance test (P < 0.05). Isometric knee extension torque increased only in WT (P < 0.05). In conclusion, at low cadences, P (max) improved in both training groups. However, in the IT training group, a disturbed pedaling technique compromises an improvement of P (max) at high cadences.

  2. Logarithmic and power law input-output relations in sensory systems with fold-change detection.

    Science.gov (United States)

    Adler, Miri; Mayo, Avi; Alon, Uri

    2014-08-01

    Two central biophysical laws describe sensory responses to input signals. One is a logarithmic relationship between input and output, and the other is a power law relationship. These laws are sometimes called the Weber-Fechner law and the Stevens power law, respectively. The two laws are found in a wide variety of human sensory systems including hearing, vision, taste, and weight perception; they also occur in the responses of cells to stimuli. However the mechanistic origin of these laws is not fully understood. To address this, we consider a class of biological circuits exhibiting a property called fold-change detection (FCD). In these circuits the response dynamics depend only on the relative change in input signal and not its absolute level, a property which applies to many physiological and cellular sensory systems. We show analytically that by changing a single parameter in the FCD circuits, both logarithmic and power-law relationships emerge; these laws are modified versions of the Weber-Fechner and Stevens laws. The parameter that determines which law is found is the steepness (effective Hill coefficient) of the effect of the internal variable on the output. This finding applies to major circuit architectures found in biological systems, including the incoherent feed-forward loop and nonlinear integral feedback loops. Therefore, if one measures the response to different fold changes in input signal and observes a logarithmic or power law, the present theory can be used to rule out certain FCD mechanisms, and to predict their cooperativity parameter. We demonstrate this approach using data from eukaryotic chemotaxis signaling.

  3. High order mode beam waveguide for technological medium power millimeter wave applications

    Energy Technology Data Exchange (ETDEWEB)

    Rio, C. del; Gonzalo, R.; Marin, M.; Sorolla, M.; Moebius, A.; Thumm, M. [Universidad Publica de Navarra, Pamplona (Spain)

    1995-12-31

    The use of medium power millimeter CW gyrotrons (10-30 kW and 30-100 GHz) has several potential applications in advanced materials processing. Since a stochastic field distribution in the applicator is desirable no pencil beam is necessary. Then the possibility to couple the circular symmetric gyrotron output to a higher order free space mode can be considered. Beam waveguides based on iterative reflection of such high order beams on properly disigned mirrors opens the possibility to increase the efficiency and to reduce costs of present compact transmission lines in gyrotron technological systems.

  4. Amalgam Surface Treatment by Different Output Powers of Er:YAG Laser:SEM Evaluation.

    Science.gov (United States)

    Hosseini, Mohammad Hashem; Hassanpour, Mehdi; Etemadi, Ardavan; Ranjbar Omrani, Ladan; Darvishpour, Hojat; Chiniforush, Nasim

    2015-01-01

    The purpose of this study was to evaluate amalgam surfaces treated by different output powers of erbium-doped yttrium aluminum garnet (Er:YAG) laser by scanning electron microscope (SEM). Twenty-one amalgam blocks (8 mm × 8 mm, 3 mm thickness) were prepared by condensing silver amalgam (into putty impression material. After keeping them for 24 hours in distilled water, they were divided into 7 groups as follow: G1: Er:YAG laser (1 W, 50 mJ), G2: Er:YAG laser (2 W, 100 mJ), G3: Er:YAG laser (3 W, 150 mJ), G4: Sandblast, G5: Sandblast + Er:YAG laser (1 W, 50 mJ), G6: Sandblast +Er:YAG laser (2 W, 100 mJ) and G7: Sandblast +Er:YAG laser (3 W, 150 mJ). Then after preparation of all samples, they were examined by SEM. The SEM results of amalgam surfaces treated by different output powers of Er:YAG laser showed some pitting areas with non-homogenous irregularities Conclusion: It seems that the application of sandblasting accompanied by Er:YAG laser irradiation can provide proper surface for bonding of orthodontic brackets.

  5. The role of sense of effort on self-selected cycling power output

    Directory of Open Access Journals (Sweden)

    Ryan James Christian

    2014-03-01

    Full Text Available Purpose: We explored the effects of the sense of effort and accompanying perceptions of peripheral discomfort on self-selected cycle power output under two different inspired O2 fractions.Methods: On separate days, eight trained males cycled for 5 minutes at a constant subjective effort (sense of effort of ‘3’ on a modified Borg CR10 scale, immediately followed by five 4-s progressive submaximal (sense of effort of 4, 5, 6, 7 and 8; 40 s between bouts and two 4-s maximal (sense of effort of 10; 3 min between bouts bouts under normoxia (NM: fraction of inspired O2 [FiO2] 0.21 and hypoxia (HY: [FiO2] 0.13. Physiological (Heart Rate, arterial oxygen saturation (SpO2 and quadriceps Root Mean Square (RMS electromyographical activity and perceptual responses (overall peripheral discomfort, difficulty breathing and limb discomfort were recorded.Results: Power output and normalized quadriceps RMS activity were not different between conditions during any exercise bout (p > 0.05 and remained unchanged across time during the constant-effort cycling. SpO2 was lower, while heart rate and ratings of perceived difficulty breathing were higher under HY, compared to NM, at all time points (p

  6. Advisory system for the diagnosis of lost electric output in nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Gyunyoung Heo; Soon Heung Chang [Korea Advanced Institute of Science and Technology, Daejeon (Korea). Dept. of Nuclear and Quantum Engineering; Seong Soo Choi [Atomic Creative Technology, Daejeon (Korea); Gwang Hee Choi; Moon Hak Jee [Korea Power Electric Research Institute, Daejeon (Korea)

    2005-11-15

    The enhancement of efficiency is world-wide trend to survive under intense competition. In recent years, the efficiency in the power industry is also one of the important topics. In case of nuclear power plants(NPPs), the period and quality of maintenance is an especially important factor to increase efficiency as well as availability. Therefore, the accurate identification of the root causes for lost electric output is indispensable to decrease the period and to increase quality of maintenance. The diagnosis in NPPs is more difficult because the turbine cycle of NPPs uses saturated steam as working fluid. In this study, authors tried to develop an advisory system with the quantitative diagnosis model consisting of statistical regression analysis and Bayesian network for the support of nuclear turbine cycle diagnosis. The proposed advisory system includes the knowledge-base representing the normal or abnormal behavior of nuclear turbine cycle. Authors selected 34 boundary parameters that independently influence to electric output. Using the data collected from a turbine cycle simulation tool, the statistical correlation between a boundary parameter and electric output was analyzed. To give the belief, that is the degree of accuracy, of root causes under various uncertainty sources, belief module for the boundary parameters is developed on the basis of Bayesian network. In conclusion, this diagnosis module can give the impacts of the root causes and their uncertainty simultaneously, so we call it 'Lost MW calculator'. After the validation using simulated data and actual performance data, this module was installed in Younggwang NPP units 3 and 4 in Korea. (author)

  7. Enhancement of output power in spin torque nano-oscillator using heterogeneous layer

    Energy Technology Data Exchange (ETDEWEB)

    Bhoomeeswaran, H.; Sabareesan, P., E-mail: sendtosabari@gmail.com [Centre for Nonlinear Science and Engineering, School of Electrical and Electronics Engineering, SASTRA University, Thanjavur - 613 401 (India)

    2016-05-23

    The article mainly focuses on the enrichment of the output power obtained from Spin torque nano-oscillator by introducing the heterogeneous structure in multilayer nanopillar device. Here we devised two homogeneous and two heterogeneous devices having NiFe and Co materials. The dynamics of the devices are governed by a famous Landu- Lifshitz -Gilbert-Solencskwei (LLGS) equation which can be solved numerically using embedded RK-4 procedure. The current density and the external magnetic field for four devices are taken as 5×l0{sup 11}A/m{sup 2} and 6×l0{sup −3} A/m respectively. The applied dc current is converted into spin polarized dc current while it passes through pinned layer. The generated spin polarized dc currents produces spin transfer torque with the free layer magnetization via spacer. Thus the magnetization of the free layer gets a sustained oscillation. The results obtained from the heterogeneous STNOs are really fascinating. The frequency of the NiFe/ Cu/NiFe and Co/Cu/NiFe devices have the same frequency but there is a tremendous change in the output power which is exactly twice that the NiFe/Cu/NiFe device. The similar behaviour is also obtained from Co/Cu/Co and NiFe/Cu/Co devices. The line width and the Q-factor of the output microwave signal are also computed. Among the four devices, the NiFe/Cu/Co heterogeneous device has low linewidth (408 MHz) and high Q-factor (4.77).

  8. Effect of absorbed pump power on the quality of output beam from monolithic microchip lasers

    Indian Academy of Sciences (India)

    Pranab K Mukhopadhyay; K Ranganathan; Jogy George; S K Sharma; T P S Nathan

    2002-04-01

    The dependence of the beam propagation factor (2 parameter) with the absorbed pump power in the case of monolithic microchip laser under face-cooled configuration is extensively studied. Our investigations show that the 2 parameter is related to the absorbed pump power through two parameters ( and ) whose values depend on the laser material properties and laser configuration. We have shown that one parameter arises due to the oscillation of higher order modes in the microchip cavity and the other parameter accounts for the spherical aberration associated with the thermal lens induced by the pump beam. Such dependency of 2 parameter with the absorbed pump power is experimentally verified for a face-cooled monolithic microchip laser based on Nd3+ - doped GdVO4 crystal and the values of and parameters were estimated from the experimentally measured data points.

  9. The effects of cold-water immersion on power output and heart rate in elite cyclists.

    Science.gov (United States)

    Schniepp, Jason; Campbell, Teri S; Powell, Kasey L; Pincivero, Danny M

    2002-11-01

    The purpose of this study was to examine the effects of cold-water immersion on power output, heart rate, and time to peak power in 10 well-trained cyclists. The Compu-trainer Professional Model 8001 computerized stationary trainer was used to evaluate maximum power, average power, and time to peak power during a simulated cycling sprint. The heart rate was measured using a Polar heart rate monitor. Subjects performed 2 maximum-effort sprints (for approximately 30 seconds) separated by either an experimental condition (15 minutes of cold-water immersion at 12 degrees C up to the level of the iliac crest) or a control condition (15 minutes of quiet sitting). All subjects participated under both control and experimental conditions in a counterbalanced design in which 5 subjects performed the experimental condition first and the other 5 subjects performed the control condition first. Each condition was separated by at least 2 days. The time to peak power was not different between the 2 conditions. Maximum and average powers declined by 13.7 and 9.5% for the experimental condition but only by 4.7 and 2.3% for the control condition, respectively. The results also demonstrated a significantly greater decline in maximum heart rate after cold-water immersion (8.1%) than under the control condition (2.4%). Average heart rate showed a decrease of 4.2% under the experimental condition, as compared with an increase of 1.5% under the control condition. The major findings of this study suggest that a relatively brief period of cold-water immersion can manifest significant physiological effects that can impair cycling performance.

  10. High-power solid-state sapphire whispering gallery mode maser.

    Science.gov (United States)

    Creedon, Daniel L; Benmessaï, Karim; Tobar, Michael E; Hartnett, John G; Bourgeois, Pierre-Yves; Kersale, Yann; Le Floch, Jean-Michel; Giordano, Vincent

    2010-03-01

    We present new results on a cryogenic solid-state maser frequency standard, which relies on the excitation of whispering gallery (WG) modes within a doped monocrystalline sapphire resonator (alpha-Al2O3). Included substitutively within the highest purity HEMEX-grade sapphire crystal lattice are Fe2+ impurities at a concentration of parts per million, an unavoidable result of the manufacturing process. Mass conversion of Fe2+ to Fe3+ ions was achieved by thermally annealing the sapphire in air. Above-threshold maser oscillation was then excited in the resonator at zero applied DC magnetic field by pumping high-Q WG modes coincident in frequency with the electron spin resonance (ESR) energy levels of the Fe3+ spin population. A 2 stage annealing process was undertaken for a sapphire resonator with exceptionally low Fe3+ concentration, resulting in an improvement of 6 orders of magnitude in output power for this particular crystal, and exceeding the previous best implementation of our scheme in another crystal by nearly 20 dB. This represents an output signal 7 orders of magnitude more powerful than a typical commercial hydrogen maser. At this power level, we estimate a limit on the frequency stability of order 1 x 10(-17)/square root(tau) due to the Schawlow-Townes fundamental thermal noise limit.

  11. High-power, surface-emitting quantum cascade laser operating in a symmetric grating mode

    Energy Technology Data Exchange (ETDEWEB)

    Boyle, C.; Sigler, C.; Kirch, J. D.; Botez, D.; Mawst, L. J., E-mail: mawst@engr.wisc.edu [Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Lindberg, D. F.; Earles, T. [Intraband, LLC, Madison, Wisconsin 53726 (United States)

    2016-03-21

    Grating-coupled surface-emitting (GCSE) lasers generally operate with a double-lobed far-field beam pattern along the cavity-length direction, which is a result of lasing being favored in the antisymmetric grating mode. We experimentally demonstrate a GCSE quantum-cascade laser design allowing high-power, nearly single-lobed surface emission parallel to the longitudinal cavity. A 2nd-order Au-semiconductor distributed-feedback (DFB)/distributed-Bragg-reflector (DBR) grating is used for feedback and out-coupling. The DFB and DBR grating regions are 2.55 mm- and 1.28 mm-long, respectively, for a total grating length of 5.1 mm. The lasers are designed to operate in a symmetric (longitudinal) grating mode by causing resonant coupling of the guided optical mode to the antisymmetric surface-plasmon modes of the 2nd-order metal/semiconductor grating. Then, the antisymmetric modes are strongly absorbed by the metal in the grating, causing the symmetric mode to be favored to lase, which, in turn, produces a single-lobed beam over a range of grating duty-cycle values of 36%–41%. Simulations indicate that the symmetric mode is always favored to lase, independent of the random phase of reflections from the device's cleaved ends. Peak pulsed output powers of ∼0.4 W were measured with nearly single-lobe beam-pattern (in the longitudinal direction), single-spatial-mode operation near 4.75 μm wavelength. Far-field measurements confirm a diffraction-limited beam pattern, in agreement with simulations, for a source-to-detector separation of 2 m.

  12. Probabilistic Physics-Based Risk Tools Used to Analyze the International Space Station Electrical Power System Output

    Science.gov (United States)

    Patel, Bhogila M.; Hoge, Peter A.; Nagpal, Vinod K.; Hojnicki, Jeffrey S.; Rusick, Jeffrey J.

    2004-01-01

    This paper describes the methods employed to apply probabilistic modeling techniques to the International Space Station (ISS) power system. These techniques were used to quantify the probabilistic variation in the power output, also called the response variable, due to variations (uncertainties) associated with knowledge of the influencing factors called the random variables. These uncertainties can be due to unknown environmental conditions, variation in the performance of electrical power system components or sensor tolerances. Uncertainties in these variables, cause corresponding variations in the power output, but the magnitude of that effect varies with the ISS operating conditions, e.g. whether or not the solar panels are actively tracking the sun. Therefore, it is important to quantify the influence of these uncertainties on the power output for optimizing the power available for experiments.

  13. Power Factor Correction and THD Minimization by Interleaved Boost Converter in Continuous Conduction Mode

    Directory of Open Access Journals (Sweden)

    Saubhik Maulik

    2014-02-01

    Full Text Available The electrical energy available in the utility grid is not suitable for direct use in many applications. In particular, applications requiring DC source must involve an interface device between the AC power line and the load requiring the DC voltage. Conventional AC/DC conversion involves diode rectifiers with large capacitor to reduce DC voltage ripple. The filter capacitor reduces the ripple present in the output voltage but draws non-sinusoidal line current which reduces the power factor. So power factor correction (PFC techniques are gaining increasing attention. The most popular topology for active PFC is boost converter as it draws continuous input current. This input current can be manipulated by average current mode control technique. But there are ripple in the input current due to inductor of boost converter which can be minimized by using two phase interleaved boost converter. Here average current mode controlled interleaved boost converter in continuous conduction mode using PI controller, is represented which provides high power factor and low THD.

  14. Enhancement of the output power of terahertz folded waveguide oscillator by two parallel electron beams

    Energy Technology Data Exchange (ETDEWEB)

    Li, Ke, E-mail: like.3714@163.com; Cao, Miaomiao, E-mail: mona486@yeah.net [Key Laboratory of High Power Microwave Sources and Technologies, Institute of Electronics, Chinese Academy of Sciences, Beijing 100190 (China); University of Chinese Academy of Sciences, Beijing 100190 (China); Liu, Wenxin, E-mail: lwenxin@mail.ie.ac.cn; Wang, Yong, E-mail: wangyong3845@sina.com [Key Laboratory of High Power Microwave Sources and Technologies, Institute of Electronics, Chinese Academy of Sciences, Beijing 100190 (China); Liao, Suying, E-mail: suying-liao@163.com [Air Force Airborne Academy, Guilin, Guangxi 541003 (China)

    2015-11-15

    A novel two-beam folded waveguide (FW) oscillator is presented for the purpose of gaining higher power with a small-size circuit compared with the normal FW oscillator. The high-frequency characteristics of the two-beam FW, including dispersion and interaction impedance, were investigated by the numerical simulation and compared with the one-beam FW. The radio-frequency loss of the two-beam FW was also analyzed. A 3-D particle-in-cell code CHIPIC was applied to analyze and optimize the performance of a G-band two-beam FW oscillator. The influences of the distance between the two beam tunnels, beam voltage, the number of periods, magnetic field, radius of beam tunnel, and the packing ratio on the circuit performance are investigated in detail. Compared with a one-beam circuit, a larger output power of the two-beam circuit with the same beam power was observed by the simulation. Moreover, the start-oscillation current of two-beam circuit is much lower than the one-beam circuit with better performance. It will favor the miniaturized design of the high-power terahertz oscillator.

  15. Power Supply Changes for NSTX Resistive Wall Mode Coils

    Energy Technology Data Exchange (ETDEWEB)

    Ramakrishnan, S S.

    2013-06-28

    The National Spherical Torus Experiment (NSTX) has been designed and installed in the existing facilities at Princeton Plasma Physics Laboratory (PPPL). Most of the hardware, plant facilities, auxiliary sub-systems, and power systems originally used for the Tokamak Fusion Test Reactor (TFTR) have been used with suitable modifications to reflect NSTX needs. Prior to 2004, the NSTX power system was feeding twelve (12) circuits in the machine. In 2004 the Resistive Wall Mode (RWM) Coils were installed on the machine to correct error fields. There are six of these coils installed around the machine in the mid-plane. Since these coils need fast and accurate controls, a Switching Power Amplifier (SPA) with three sub-units was procured, installed and commissioned along with other power loop components. Two RWM Coils were connected in series and fed from one SPA sub-unit. After the initial RWM campaign, operational requirements evolved such that each of the RWM coils now requires separate power and control. Hence a second SPA with three sub-units has been procured and installed. The second unit is of improved design and has the controls and power components completely isolated. The existing thyristor rectifier is used as DC Link to both of the Switching Power Amplifiers. The controls for the RWM are integrated into the overall computer control of the DC Power systems for NSTX. This paper describes the design changes in the RWM Power system for NSTX.

  16. Unbiased pseudo-Cℓ power spectrum estimation with mode projection

    Science.gov (United States)

    Elsner, Franz; Leistedt, Boris; Peiris, Hiranya V.

    2017-02-01

    With the steadily improving sensitivity afforded by current and future galaxy surveys, a robust extraction of two-point correlation function measurements may become increasingly hampered by the presence of astrophysical foregrounds or observational systematics. The concept of mode projection has been introduced as a means to remove contaminants for which it is possible to construct a spatial map, reflecting the expected signal contribution. Owing to its computational efficiency compared to minimum-variance methods, the sub-optimal pseudo-Cℓ (PCL) power spectrum estimator is a popular tool for the analysis of high-resolution data sets. Here, we integrate mode projection into the framework of PCL power spectrum estimation. In contrast to results obtained with optimal estimators, we show that the uncorrected projection of template maps leads to biased power spectra. Based on analytical calculations, we find exact closed-form expressions for the expectation value of the bias and demonstrate that they can be recast in a form which allows a numerically efficient evaluation, preserving the favourable O( ℓ_{max} ^3 ) time complexity of PCL estimator algorithms. Using simulated data sets, we assess the scaling of the bias with various analysis parameters and demonstrate that it can be reliably removed. We conclude that in combination with mode projection, PCL estimators allow for a fast and robust computation of power spectra in the presence of systematic effects - properties in high demand for the analysis of ongoing and future large-scale structure surveys.

  17. Electronically tunable voltage-mode universal filter with single-input five-output using simple OTAs

    Science.gov (United States)

    Kumngern, Montree; Suwanjan, Peerawut; Dejhan, Kobchai

    2013-08-01

    This article presents a new electronically tunable voltage-mode universal biquadratic filter with single-input five-output using simple operational transconductance amplifiers (OTAs) and grounded capacitors. The proposed configuration provides low-pass, band-pass, high-pass, band-stop and all-pass voltage responses at a high-impedance input terminal that enables easy cascading in voltage-mode. The natural frequency and the quality factor can be set orthogonally by adjusting the circuit components. The natural frequency can also be controlled electronically by adjusting the bias currents of the OTAs. For realising all the five standard filtering functions, no critical-matching conditions are imposed and all the incremental parameter sensitivities are low. Experimental and simulation results that confirm the theoretical predictions are given.

  18. Quantifying Image Quality Improvement Using Elevated Acoustic Output in B-Mode Harmonic Imaging.

    Science.gov (United States)

    Deng, Yufeng; Palmeri, Mark L; Rouze, Ned C; Trahey, Gregg E; Haystead, Clare M; Nightingale, Kathryn R

    2017-10-01

    Tissue harmonic imaging has been widely used in abdominal imaging because of its significant reduction in acoustic noise compared with fundamental imaging. However, tissue harmonic imaging can be limited by both signal-to-noise ratio and penetration depth during clinical imaging, resulting in decreased diagnostic utility. A logical approach would be to increase the source pressure, but the in situ pressures used in diagnostic ultrasound are subject to a de facto upper limit based on the U.S. Food and Drug Administration guideline for the mechanical index (tissues without gas bodies, but would only be justified if there were a concurrent improvement in image quality and diagnostic utility. This work evaluates image quality differences between normal and elevated acoustic output hepatic harmonic imaging using a transmit frequency of 1.8 MHz. The results indicate that harmonic imaging using elevated acoustic output leads to modest improvements (3%-7%) in contrast-to-noise ratio of hypo-echoic hepatic vessels and increases in imaging penetration depth on the order of 4 mm per mechanical index increase of 0.1 for a given focal depth. Difficult-to-image patients who suffer from poor ultrasound image quality exhibited larger improvements than easy-to-image study participants. Copyright © 2017 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

  19. Maximal power output during incremental cycling test is dependent on the curvature constant of the power-time relationship.

    Science.gov (United States)

    Souza, Kristopher Mendes; de Lucas, Ricardo Dantas; do Nascimento Salvador, Paulo Cesar; Guglielmo, Luiz Guilherme Antonacci; Caritá, Renato Aparecido Corrêa; Greco, Camila Coelho; Denadai, Benedito Sérgio

    2015-09-01

    The aim of this study was to investigate whether the maximal power output (Pmax) during an incremental test was dependent on the curvature constant (W') of the power-time relationship. Thirty healthy male subjects (maximal oxygen uptake = 3.58 ± 0.40 L·min(-1)) performed a ramp incremental cycling test to determine the maximal oxygen uptake and Pmax, and 4 constant work rate tests to exhaustion to estimate 2 parameters from the modeling of the power-time relationship (i.e., critical power (CP) and W'). Afterwards, the participants were ranked according to their magnitude of W'. The median third was excluded to form a high W' group (HIGH, n = 10), and a low W' group (LOW, n = 10). Maximal oxygen uptake (3.84 ± 0.50 vs. 3.49 ± 0.37 L·min(-1)) and CP (213 ± 22 vs. 200 ± 29 W) were not significantly different between HIGH and LOW, respectively. However, Pmax was significantly greater for the HIGH (337 ± 23 W) than for the LOW (299 ± 40 W). Thus, in physically active individuals with similar aerobic parameters, W' influences the Pmax during incremental testing.

  20. Modelling of the kinetics and parametric behaviour of a copper vapour laser: Output power limitation issues

    Energy Technology Data Exchange (ETDEWEB)

    Carman, R.J. [Centre for Lasers and Applications, Macquarie University, North Ryde, Sydney, New South Wales 2109 (Australia)

    1997-07-01

    A self-consistent computer model was used to simulate the plasma kinetics (radially resolved) and parametric behaviour of an 18 mm bore (6 W) copper vapour laser for a wide range of optimum and non-optimum operating conditions. Good quantitative agreement was obtained between modelled results and experimental data including the temporal evolution of the 4p{sup 2}P{sub 3/2}, 4s{sup 2} {sup 2}D{sub 5/2} and 4s{sup 2}{sup 2}D{sub 3/2} Cu laser level populations derived from hook method measurements. The modelled results show that the two most important parameters that affect laser behaviour are the ground state copper density and the peak electron temperature T{sub e}. For a given pulse repetition frequency (prf), maximum laser power is achieved by matching the copper atom density to the input pulse energy thereby maintaining the peak T{sub e} at around 3 eV. However, there is a threshold wall temperature (and copper density) above which the plasma tube becomes thermally unstable. At low prf ({lt}8 kHz), this thermal instability limits the attainable copper density (and consequently the laser output power) to values below the optimum for matching to the input pulse energy. For higher prf values ({gt}8 kHz), the copper density can be matched to the input pulse energy to give maximum laser power because the corresponding wall temperature then falls below the threshold temperature for thermal instability. For prf {gt}14 kHz, the laser output becomes highly annular across the tube diameter due to a severe depletion of the copper atom density on axis caused by radial ion pumping. {copyright} {ital 1997 American Institute of Physics.}

  1. Determination of the peak power output during maximal brief pedalling bouts.

    Science.gov (United States)

    Nakamura, Y; Mutoh, Y; Miyashita, M

    1985-01-01

    The purpose of this study was to propose an optimization procedure for determining power output during very brief maximal pedalling exercise. Twenty-six healthy male students (21-28 years) performed anaerobic tests on a Monark bicycle ergometer with maximal effort for less than 10 s at eight different loads ranging from 28.1 to 84.2 Nm in pedalling moment. The maximal pedalling rate was determined from the minimal time required for one rotation of the cycle wheel. Pedalling rate decreased linearly with the load. The relationship between load and pedalling rate was represented by two linear regression equations for each subject; one regression equation was determined from eight pairs of pedalling rates and loads (r less than -0.976) and the other from three pairs (at 28.1, 46.8, 65.5 Nm; r less than -0.969). The two regression coefficients of the respective regression equations were almost identical. Mean +/- S.D. of maximal power output (Pmax) which was determined for each subject based on the two linear regression equations for eight pairs and three pairs of pedalling rates and loads was 930 +/- 187 W (13.4 +/- 1.6 W kgBW-1) and 927 +/- 187 W (13.4 +/- 1.6 W kgBW-1), respectively. There was no statistically significant difference between the values of Pmax which were obtained from each equation. It was concluded that maximal anaerobic power could be simply determined by performing maximal cycling exercise at three different loads.

  2. Flexible, transparent and exceptionally high power output nanogenerators based on ultrathin ZnO nanoflakes

    Science.gov (United States)

    van Ngoc, Huynh; Kang, Dae Joon

    2016-02-01

    Novel nanogenerator structures composed of ZnO nanoflakes of less than 10 nm thickness were fabricated using a novel method involving a facile synthetic route and a rational design. The fabricated nanogenerators exhibited a short-circuit current density of 67 μA cm-2, a peak-to-peak open-circuit voltage of 110 V, and an overall output power density exceeding 1.2 mW cm-2, and to the best of our knowledge, these are the best values that have been reported so far in the literature on ZnO-based nanogenerators. We demonstrated that our nanogenerator design could instantaneously power 20 commercial green light-emitting diodes without any additional energy storage processes. Both the facile synthetic route for the ZnO nanoflakes and the straightforward device fabrication process present great scaling potential in order to power mobile and personal electronics that can be used in smart wearable systems, transparent and flexible devices, implantable telemetric energy receivers, electronic emergency equipment, and other self-powered nano/micro devices.Novel nanogenerator structures composed of ZnO nanoflakes of less than 10 nm thickness were fabricated using a novel method involving a facile synthetic route and a rational design. The fabricated nanogenerators exhibited a short-circuit current density of 67 μA cm-2, a peak-to-peak open-circuit voltage of 110 V, and an overall output power density exceeding 1.2 mW cm-2, and to the best of our knowledge, these are the best values that have been reported so far in the literature on ZnO-based nanogenerators. We demonstrated that our nanogenerator design could instantaneously power 20 commercial green light-emitting diodes without any additional energy storage processes. Both the facile synthetic route for the ZnO nanoflakes and the straightforward device fabrication process present great scaling potential in order to power mobile and personal electronics that can be used in smart wearable systems, transparent and flexible

  3. A Power Regulation and Droop Mode Control Method for a Stand-Alone Load Fed from a PV-Current Source Inverter

    Science.gov (United States)

    Khayamy, Mehdy; Ojo, Olorunfemi

    2015-04-01

    A current source inverter fed from photovoltaic cells is proposed to power an autonomous load when operating under either power regulation or voltage and frequency drooping modes. Input-output linearization technique is applied to the overall nonlinear system to achieve a globally stable system under feasible operating conditions. After obtaining the steady-state model that demarcates the modes of operation, computer Simulation results for variations in irradiance and the load power of the controlled system are generated in which an acceptable dynamic response of the power generator system under the two modes of operation is observed.

  4. Tunable GHz pulse repetition rate operation in high-power TEM(00)-mode Nd:YLF lasers at 1047 nm and 1053 nm with self mode locking.

    Science.gov (United States)

    Huang, Y J; Tzeng, Y S; Tang, C Y; Huang, Y P; Chen, Y F

    2012-07-30

    We report on a high-power diode-pumped self-mode-locked Nd:YLF laser with the pulse repetition rate up to several GHz. A novel tactic is developed to efficiently select the output polarization state for achieving the stable TEM(00)-mode self-mode-locked operations at 1053 nm and 1047 nm, respectively. At an incident pump power of 6.93 W and a pulse repetition rate of 2.717 GHz, output powers as high as 2.15 W and 1.35 W are generated for the σ- and π-polarization, respectively. We experimentally find that decreasing the separation between the gain medium and the input mirror not only brings in the pulse shortening thanks to the enhanced effect of the spatial hole burning, but also effectively introduces the effect of the spectral filtering to lead the Nd:YLF laser to be in a second harmonic mode-locked status. Consequently, pulse durations as short as 8 ps and 8.5 ps are obtained at 1053 nm and 1047 nm with a pulse repetition rate of 5.434 GHz.

  5. 275 C Downhole Switched-Mode Power Supply

    Energy Technology Data Exchange (ETDEWEB)

    Chris Hutchens; Vijay Madhuravasal

    2008-08-31

    A vee-square (V2) control based controller IC is developed for a switch mode power supply capable of operating at extreme temperature/harsh environment conditions. A buck type regulator with silicon carbide power junction field effect transistors (JFET) as power devices is used to analyze the performance of controller. Special emphases are made on the analog sub-blocks--voltage reference, operational transconductance amplifier and comparator as individual building blocks. Transformer coupled gate drives and high temperature operable magnetic cores and capacitors are identified and tested for use in the design. Conventional ceramic chip packaging of ICs combined with lead carrier type mounting of passive filter components is introduced for hybrid packaging of the complete product. The developed SMPS is anticipated to support the operation of down-hole microcontrollers and other electronics devices that require low/medium power filtered dc inputs over an operating temperature of 275 C.

  6. Comparison of nine theoretical models for estimating the mechanical power output in cycling

    Science.gov (United States)

    González‐Haro, Carlos; Ballarini, P A Galilea; Soria, M; Drobnic, F; Escanero, J F

    2007-01-01

    Objective To assess which of the equations used to estimate mechanical power output for a wide aerobic range of exercise intensities gives the closest value to that measured with the SRM training system. Methods Thirty four triathletes and endurance cyclists of both sexes (mean (SD) age 24 (5) years, height 176.3 (6.6) cm, weight 69.4 (7.6) kg and Vo2max 61.5 (5.9) ml/kg/min) performed three incremental tests, one in the laboratory and two in the velodrome. The mean mechanical power output measured with the SRM training system in the velodrome tests corresponding to each stage of the tests was compared with the values theoretically estimated using the nine most referenced equations in literature (Whitt (Ergonomics 1971;14:419–24); Di Prampero et al (J Appl Physiol 1979;47:201–6); Whitt and Wilson (Bicycling science. Cambridge: MIT Press, 1982); Kyle (Racing with the sun. Philadelphia: Society of Automotive Engineers, 1991:43–50); Menard (First International Congress on Science and Cycling Skills, Malaga, 1992); Olds et al (J Appl Physiol 1995;78:1596–611; J Appl Physiol 1993;75:730–7); Broker (USOC Sport Science and Technology Report 1–24, 1994); Candau et al (Med Sci Sports Exerc 1999;31:1441–7)). This comparison was made using the mean squared error of prediction, the systematic error and the random error. Results The equations of Candau et al, Di Prampero et al, Olds et al (J Appl Physiol 1993;75:730–7) and Whitt gave a moderate mean squared error of prediction (12.7%, 21.6%, 13.2% and 16.5%, respectively) and a low random error (0.5%, 0.6%, 0.7% and 0.8%, respectively). Conclusions The equations of Candau et al and Di Prampero et al give the best estimate of mechanical power output when compared with measurements obtained with the SRM training system. PMID:17341588

  7. Enhancement Mode Power Switching AlGaN HEMTs

    Science.gov (United States)

    2013-05-14

    the highest recorded off- state breakdown voltage for an AlGaN/ GaN HEMT device with a relatively small gate-drain spacing and no field plate...3. DATES COVERED (From - To) 03/01/2010-12/31/2012 4. TITLE AND SUBTITLE Enhancement Mode Power Switching AIGaN HEMTs 5a. CONTRACT NUMBER...AISiN is a preferred dielectric for high voltage AIGaN HEMTs for power switching applications. The grate-source capacitance will compare favorably

  8. Application of Extension Sliding Mode Strategy to Maximum Power Point Tracking in Human Power Generation Systems

    Directory of Open Access Journals (Sweden)

    Meng-Hui Wang

    2015-08-01

    Full Text Available Sliding mode strategy (SMS for maximum power point tracking (MPPT is used in this study of a human power generation system. This approach ensures maximum power at different rotation speeds to increase efficiency and corrects for the lack of robustness in traditional methods. The intelligent extension theory is used to reduce input saturation and high frequency switching in sliding mode strategy, as well as to increase the efficiency and response speed. The experimental results show that the efficiency of the extension SMS (ESMS is 5% higher than in traditional SMS, and the response is 0.5 s faster.

  9. Power transmission line operating modes calculation with controllable phase shifters

    Science.gov (United States)

    Astashev, M. G.; Novikov, M. A.; Panfilov, D. I.; Rashitov, P. A.; Remizevich, T. V.; Fedorova, M. I.

    2016-12-01

    The article contains the analysis of the influence of the phase shifter (PS) on the energy processes in the power transmission line in terms of the two-unit model of the electric network. The approach to synthesis of the models regulated by the phase shifter providing for both calculation of the steady operation modes of the electric networks with the phase shifters and research of the electromagnetic processes and designing of the device itself is offered.

  10. Suction power output and the inertial cost of rotating the neurocranium to generate suction in fish.

    Science.gov (United States)

    Van Wassenbergh, Sam; Day, Steven W; Hernández, L Patricia; Higham, Timothy E; Skorczewski, Tyler

    2015-05-07

    To expand the buccal cavity, many suction-feeding fishes rely on a considerable contribution from dorsal rotation of the dorsal part of the head including the brains, eyes, and several bones forming the braincase and skull roof (jointly referred to as the neurocranium). As the neurocranium takes up a large part of the total mass of the head, this rotation may incur a considerable inertial cost. If so, this would suggest a significant selective pressure on the kinematics and mass distribution of the neurocranium of suction feeders. Here, an inverse dynamic model is formulated to calculate the instantaneous power required to rotate the neurocranium, approximated by a quarter ellipsoid volume of homogeneous density, as well as to calculate the instantaneous suction power based on intra-oral pressure and head volume quantifications. We applied this model to largemouth bass (Micropterus salmoides) and found that the power required to rotate the neurocranium accounts for only about 4% of the power required to suck water into the mouth. Furthermore, recovery of kinetic energy from the rotating neurocranium converted into suction work may be possible during the phase of neurocranial deceleration. Thus, we suggest that only a negligible proportion of the power output of the feeding muscles is lost as inertial costs in the largemouth bass. Consequently, the feeding performance of piscivorous suction feeders with generalised morphology, comparable to our model species, is not limited by neurocranial motion during head expansion. This suggests that it is thus not likely to be a factor of importance in the evolution of cranial shape and size. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Functional Capacity, Muscle Fat Infiltration, Power Output, and Cognitive Impairment in Institutionalized Frail Oldest Old

    Science.gov (United States)

    Casas-Herrero, Alvaro; Cadore, Eduardo L.; Zambom-Ferraresi, Fabricio; Idoate, Fernando; Millor, Nora; Martínez-Ramirez, Alicia; Gómez, Marisol; Rodriguez-Mañas, Leocadio; Marcellán, Teresa; de Gordoa, Ana Ruiz; Marques, Mário C.

    2013-01-01

    Abstract This study examined the neuromuscular and functional performance differences between frail oldest old with and without mild cognitive impairment (MCI). In addition, the associations between functional capacities, muscle mass, strength, and power output of the leg muscles were also examined. Forty-three elderly men and women (91.9±4.1 years) were classified into three groups—the frail group, the frail with MCI group (frail+MCI), and the non-frail group. Strength tests were performed for upper and lower limbs. Functional tests included 5-meter habitual gait, timed up-and-go (TUG), dual task performance, balance, and rise from a chair ability. Incidence of falls was assessed using questionnaires. The thigh muscle mass and attenuation were assessed using computed tomography. There were no differences between the frail and frail+MCI groups for all the functional variables analyzed, except in the cognitive score of the TUG with verbal task, which frail showed greater performance than the frail+MCI group. Significant associations were observed between the functional performance, incidence of falls, muscle mass, strength, and power in the frail and frail+MCI groups (r=−0.73 to r=0.83, p<0.01 to p<0.05). These results suggest that the frail oldest old with and without MCI have similar functional and neuromuscular outcomes. Furthermore, the functional outcomes and incidences of falls are associated with muscle mass, strength, and power in the frail elderly population. PMID:23822577

  12. The Measurement of Maximal (Anaerobic Power Output on a Cycle Ergometer: A Critical Review

    Directory of Open Access Journals (Sweden)

    Tarak Driss

    2013-01-01

    Full Text Available The interests and limits of the different methods and protocols of maximal (anaerobic power ( assessment are reviewed: single all-out tests versus force-velocity tests, isokinetic ergometers versus friction-loaded ergometers, measure of during the acceleration phase or at peak velocity. The effects of training, athletic practice, diet and pharmacological substances upon the production of maximal mechanical power are not discussed in this review mainly focused on the technical (ergometer, crank length, toe clips, methodological (protocols and biological factors (muscle volume, muscle fiber type, age, gender, growth, temperature, chronobiology and fatigue limiting in cycling. Although the validity of the Wingate test is questionable, a large part of the review is dedicated to this test which is currently the all-out cycling test the most often used. The biomechanical characteristics specific of maximal and high speed cycling, the bioenergetics of the all-out cycling exercises and the influence of biochemical factors (acidosis and alkalosis, phosphate ions… are recalled at the beginning of the paper. The basic knowledge concerning the consequences of the force-velocity relationship upon power output, the biomechanics of sub-maximal cycling exercises and the study on the force-velocity relationship in cycling by Dickinson in 1928 are presented in Appendices.

  13. Study on electrical power output of floating photovoltaic and conventional photovoltaic

    Science.gov (United States)

    Azmi, Mohd Syahriman Mohd; Othman, Mohd Yusof Hj.; Ruslan, Mohd Hafidz Hj.; Sopian, Kamaruzzaman; Majid, Zafri Azran Abdul

    2013-11-01

    In this paper, several attempt were made to investigate the best electrical performance of a floating photovoltaic (FPV). In photovoltaic (PV) system, the electrical efficiency of the system decreases rapidly as the PV module temperature increases. Therefore, in order to achieve higher electrical efficiency, the PV module have to be cooled by removing the heat in some way. This paper presents study on a conventional photovoltaic (PV) module and floating photovoltaic (FPV) system. The objective of the study is to compare the performance of conventional PV module and FPV. At FPV, an absorber comprises of aluminum flat-box housing was attached to the back of the PV module to absorb heat. Water is used to cool the PV module by passing it under the bottom surface of the module. The system was tested under simulated solar intensity of 417 W/m2, 667 W/m2 and 834 W/m2. Current (I) - voltage (V) curves and power (P) - voltage (V) curves of the results were analyzed. The study found that the FPV has higher efficiency and total power gain than the conventional PV module. The average PV temperature in a FPV might be lower than that for a conventional PV module, thereby increasing its electrical power output. The simplicity of the system structure and aluminum as the chosen material enabled it to reduce the installation costs for a larger scale. Applicable as heat sink, this FPV system is convenient to place on lakes, ponds or rivers.

  14. A Power-Efficient Soft-Output Detector for Spatial-Multiplexing MIMO Communications

    Directory of Open Access Journals (Sweden)

    Hsiao-Chi Wang

    2012-01-01

    Full Text Available VLSI implementation of a configurable power-efficient MIMO detector is proposed to support 4×4 spatial multiplexing and modulation from QPSK to 64-QAM. A novel tree search algorithm is proposed to enable the detector to provide soft outputs and to be implemented in parallel and pipelined hardware architecture. The frame error rate (FER of the detector approaches the quasi-optimal sphere decoder, with 0.5-dB degradation. Moreover, the proposed detector can operate at the optimal voltage under different configurations and detect/recover timing error at run time by a novel adaptive voltage scaling technique with double sampling circuitry. The proposed detector, using TSMC 0.18 μm single-poly six-metal CMOS process with a core area of 1.17×1.17 mm2, provides fixed throughput of 45 Mbps in 64-QAM configuration, 120 Mbps in 16-QAM configuration, and 60 Mbps in QPSK configuration. The normalized power efficiency of the design for 64-QAM and 16-QAM configurations is 1.56 Mbps/mW and 2.53 Mbps/mW, respectively. Compared with the conservative margin-based design, the proposed design achieves a 48.8% power saving.

  15. Nanogenerator power output: influence of particle size and crystallinity of BaTiO3

    Science.gov (United States)

    Nutal Schädli, Gian; Büchel, Robert; Pratsinis, Sotiris E.

    2017-07-01

    Lead-free piezoelectric nanogenerators made with BaTiO3 offer an attractive energy harvesting solution towards portable, battery-free medical devices such as self-powered pacemakers. Here, we assembled nanogenerators made of thin, flexible poly(vinylidene fluoride-co-hexafluoropropylene) films containing either polycrystalline BaTiO3 nanoparticles of various sizes or commercial monocrystalline particles of 64 or 278 nm in average diameter. The nanoparticles were prepared by hydrogen-driven flame aerosol technology and had an average diameter of 24-50 nm with an average crystal size of about 10 nm. The rapid cooling during nanoparticle formation facilitated the synthesis of polycrystalline, multi-domain, piezoelectrically active tetragonal BaTiO3 with a high c/a lattice ratio. Using these particles, 2 μm thin polymer nanocomposites were formed, assembled into nanogenerators that exhibited a 1.4 V time-averaged output, almost twice that of the best commercial BaTiO3 particles. That output was maintained stable for over 45 000 cycles with each cycle corresponding to a heartbeat of 60 bpm. The exceptional piezoelectric performance of these nanogenerators is traced to their constituent polycrystalline nanoparticles, having high degree of domain orientation upon poling and exhibiting the flexoelectric effect, polarization induced by a strain gradient.

  16. Temperature-package power correlations for open-mode geologic disposal concepts.

    Energy Technology Data Exchange (ETDEWEB)

    Hardin, Ernest.

    2013-02-01

    Logistical simulation of spent nuclear fuel (SNF) management in the U.S. combines storage, transportation and disposal elements to evaluate schedule, cost and other resources needed for all major operations leading to final geologic disposal. Geologic repository reference options are associated with limits on waste package thermal power output at emplacement, in order to meet limits on peak temperature for certain key engineered and natural barriers. These package power limits are used in logistical simulation software such as CALVIN, as threshold requirements that must be met by means of decay storage or SNF blending in waste packages, before emplacement in a repository. Geologic repository reference options include enclosed modes developed for crystalline rock, clay or shale, and salt. In addition, a further need has been addressed for open modes in which SNF can be emplaced in a repository, then ventilated for decades or longer to remove heat, prior to permanent repository closure. For each open mode disposal concept there are specified durations for surface decay storage (prior to emplacement), repository ventilation, and repository closure operations. This study simulates those steps for several timing cases, and for SNF with three fuel-burnup characteristics, to develop package power limits at which waste packages can be emplaced without exceeding specified temperature limits many years later after permanent closure. The results are presented in the form of correlations that span a range of package power and peak postclosure temperature, for each open-mode disposal concept, and for each timing case. Given a particular temperature limit value, the corresponding package power limit for each case can be selected for use in CALVIN and similar tools.

  17. The mechanical power output of the pectoralis muscle of cockatiel (Nymphicus hollandicus): the in vivo muscle length trajectory and activity patterns and their implications for power modulation.

    Science.gov (United States)

    Morris, Charlotte R; Askew, Graham N

    2010-08-15

    In order to meet the varying demands of flight, pectoralis muscle power output must be modulated. In birds with pectoralis muscles with a homogeneous fibre type composition, power output can be modulated at the level of the motor unit (via changes in muscle length trajectory and the pattern of activation), at the level of the muscle (via changes in the number of motor units recruited), and at the level of the whole animal (through the use of intermittent flight). Pectoralis muscle length trajectory and activity patterns were measured in vivo in the cockatiel (Nymphicus hollandicus) at a range of flight speeds (0-16 m s(-1)) using sonomicrometry and electromyography. The work loop technique was used to measure the mechanical power output of a bundle of fascicles isolated from the pectoralis muscle during simulated in vivo length change and activity patterns. The mechanical power-speed relationship was U-shaped, with a 2.97-fold variation in power output (40-120 W kg(-1)). In this species, modulation of neuromuscular activation is the primary strategy utilised to modulate pectoralis muscle power output. Maximum in vivo power output was 22% of the maximum isotonic power output (533 W kg(-1)) and was generated at a lower relative shortening velocity (0.28 V(max)) than the maximum power output during isotonic contractions (0.34 V(max)). It seems probable that the large pectoralis muscle strains result in a shift in the optimal relative shortening velocity in comparison with the optimum during isotonic contractions as a result of length-force effects.

  18. Design of spherical electron gun for ultra high frequency, CW power inductive output tube

    Energy Technology Data Exchange (ETDEWEB)

    Kaushik, Meenu, E-mail: mkceeri@gmail.com; Joshi, L. M., E-mail: lmj1953@gmail.com [Microwave Tubes Division, CSIR-Central Electronics Engineering Research Institute (CEERI), Pilani, Rajasthan (India); Academy of Scientific and Innovative Research (AcSIR), New Delhi (India)

    2016-03-09

    Inductive Output Tube (IOT) is an amplifier that usually operates in UHF range. It is an electron tube whose basic structure is similar to conventional vacuum devices. This device is widely used in broadcast applications but is now being explored for scientific applications also specifically, particle accelerators and fusion plasma heating purposes. The paper describes the design approach of a spherical gridded electron gun of a 500 MHz, 100 kW CW power IOT. The electron gun structure has been simulated and optimized for operating voltage and current of 40kV and 3.5 A respectively. The electromagnetic analysis of this spherical electron gun has been carried out in CST and TRAK codes.

  19. Performance and stress analysis of oxide thermoelectric module architecture designed for maximum power output

    DEFF Research Database (Denmark)

    Wijesekara, Waruna; Rosendahl, Lasse; Wu, NingYu;

    Oxide thermoelectric materials are promising candidates for energy harvesting from mid to high temperature heat sources. In this work, the oxide thermoelectric materials and the final design of the high temperature thermoelectric module were developed. Also, prototypes of oxide thermoelectric...... generator were built for high temperature applications. This paper specifically discusses the thermoelectric module design and the prototype validations of the design. Here p type calcium cobalt oxide and n type aluminum doped ZnO were developed as the oxide thermoelectric materials. Hot side and cold side...... temperatures were used as 1100 K and 400 K respectively. Using analytical methods, the optimum thermoelement length and the thermoelements area ratio were explored in order to provide the maximum power output by the uni-couple and it is compared to methods reported in literature. Based on operating conditions...

  20. Design of spherical electron gun for ultra high frequency, CW power inductive output tube

    Science.gov (United States)

    Kaushik, Meenu; Joshi, L. M.

    2016-03-01

    Inductive Output Tube (IOT) is an amplifier that usually operates in UHF range. It is an electron tube whose basic structure is similar to conventional vacuum devices. This device is widely used in broadcast applications but is now being explored for scientific applications also specifically, particle accelerators and fusion plasma heating purposes. The paper describes the design approach of a spherical gridded electron gun of a 500 MHz, 100 kW CW power IOT. The electron gun structure has been simulated and optimized for operating voltage and current of 40kV and 3.5 A respectively. The electromagnetic analysis of this spherical electron gun has been carried out in CST and TRAK codes.

  1. A NOVEL HIGH PRECISION LOW POWER CURRENT MODE CMOS WINNER-TAKE-ALL CIRCUIT

    Directory of Open Access Journals (Sweden)

    K.L.Baishnab

    2010-05-01

    Full Text Available The design and simulation of winner-take –all Current Mode (WTA circuit is proposed. Inputs and outputs of the Circuits are current and voltage respectively, which makes the circuit appropriated forlow voltage neural hardware computation. The circuit was designed and simulated using Cadence gpdk090. The proposed novel current mode CMOS WTA operates at 0.7v with resolution of 0.001nA and a dynamic range from input current 10nA---1μA, which are much better than existing realizations. It is also observed that dynamic range can be raised further with increasing of power supply. Simulation results along withappropriate mathematical relations are reported.

  2. Synchronous Generator with HTS-2G field coils for Windmills with output power 1 MW

    Science.gov (United States)

    Kovalev, K.; Kovalev, L.; Poltavets, V.; Samsonovich, S.; Ilyasov, R.; Levin, A.; Surin, M.

    2014-05-01

    Nowadays synchronous generators for wind-mills are developed worldwide. The cost of the generator is determined by its size and weight. In this deal the implementation of HTS-2G generators is very perspective. The application of HTS 2G field coils in the rotor allows to reduce the size of the generator is 1.75 times. In this work the design 1 MW HTS-2G generator is considered. The designed 1 MW HTS-2G generator has the following parameters: rotor diameter 800 mm, active length 400 mm, phase voltage 690V, rotor speed 600 min-1 rotor field coils with HTS-2G tapes. HTS-2G field coils located in the rotating cryostat and cooled by liquid nitrogen. The simulation and optimization of HTS-2G field coils geometry allowed to increase feed DC current up to 50A. Copper stator windings are water cooled. Magnetic and electrical losses in 1 MW HTS-2G generator do not exceed 1.6% of the nominal output power. In the construction of HTS-2G generator the wave multiplier with ratio 1:40 is used. The latter allows to reduce the total mass of HTS-2G generator down to 1.5 tons. The small-scale model of HTS-2G generator with output power 50 kW was designed, manufactured and tested. The test results showed good agreement with calculation results. The manufacturing of 1 MW HTS-2G generator is planned in 2014. This work is done under support of Rosatom within the frames of Russian Project "Superconducting Industry".

  3. Warm-up Practices in Elite Boxing Athletes: Impact on Power Output.

    Science.gov (United States)

    Cunniffe, Brian; Ellison, Mark; Loosemore, Mike; Cardinale, Marco

    2017-01-01

    Cunniffe, B, Ellison, M, Loosemore, M, and Cardinale, M. Warm-up practices in elite boxing athletes: Iimpact on power output. J Strength Cond Res 31(1): 95-105, 2017-This study evaluated the performance impact of routine warm-up strategies in elite Olympic amateur boxing athletes and physiological implications of the time gap (GAP) between warm-up and boxing activity. Six male boxers were assessed while performing standardized prefight warm-up routines. Core and skin temperature measurements (Tcore and Tskin), heart rate, and upper- and lower-body power output (PO) were assessed before and after warm-up, during a 25-minutes GAP and after 3 × 2 minutes rounds of sparring. Reflected temperature (Tc) was also determined using high-resolution thermal images at fixed time-points to explore avenues for heat loss. Despite individual differences in warm-up duration (range 7.4-18.5 minutes), increases in Tcore and Tskin occurred (p ≤ 0.05). Corresponding increases (4.8%; p ≤ 0.05) in countermovement jump (CMJ) height and upward-rightward shifts in upper-body force-velocity and power-velocity curves were observed. Athletes remained inactive during the 25-minutes GAP with a gradual and significant increase in Tc occurring by the end of GAP suggesting the likelihood of heat loss. Decreases in CMJ height and upper-body PO were observed after 15 minutes and 25 minutes GAP (p ≤ 0.05). By the end of GAP period, all performance variables had returned to pre-warm-up values. Results suggest routine warm-ups undertaken by elite boxers have acute effects on power-generating capacity. Gradual decreases in performance variables are evident with inactivity and seem related to alterations in body temperature. Considering the constraints of major competitions and time spent in air conditioned holding areas before fights, practitioners should be aware of the potential of nullifying the warm-up effects.

  4. Muscle coordination limits efficiency and power output of human limb movement under a wide range of mechanical demands.

    Science.gov (United States)

    Blake, Ollie M; Wakeling, James M

    2015-12-01

    This study investigated the influence of cycle frequency and workload on muscle coordination and the ensuing relationship with mechanical efficiency and power output of human limb movement. Eleven trained cyclists completed an array of cycle frequency (cadence)-power output conditions while excitation from 10 leg muscles and power output were recorded. Mechanical efficiency was maximized at increasing cadences for increasing power outputs and corresponded to muscle coordination and muscle fiber type recruitment that minimized both the total muscle excitation across all muscles and the ineffective pedal forces. Also, maximum efficiency was characterized by muscle coordination at the top and bottom of the pedal cycle and progressive excitation through the uniarticulate knee, hip, and ankle muscles. Inefficiencies were characterized by excessive excitation of biarticulate muscles and larger duty cycles. Power output and efficiency were limited by the duration of muscle excitation beyond a critical cadence (120-140 rpm), with larger duty cycles and disproportionate increases in muscle excitation suggesting deteriorating muscle coordination and limitations of the activation-deactivation capabilities. Most muscles displayed systematic phase shifts of the muscle excitation relative to the pedal cycle that were dependent on cadence and, to a lesser extent, power output. Phase shifts were different for each muscle, thereby altering their mechanical contribution to the pedaling action. This study shows that muscle coordination is a key determinant of mechanical efficiency and power output of limb movement across a wide range of mechanical demands and that the excitation and coordination of the muscles is limited at very high cycle frequencies. Copyright © 2015 the American Physiological Society.

  5. Mode profiling of optical fibers at high laser powers

    DEFF Research Database (Denmark)

    Nielsen, Peter Carøe; Pedersen, David Bue; Simonsen, R.B.

    2008-01-01

    This paper describes the development of a measuring equipment capable of analysing the beam profile at high optical powers emitted by delivery fibers used in manufacturing processes. Together with the optical delivery system, the output beam quality from the delivery fiber and the shape...... of the focused spot can be determined. The analyser is based on the principle of a rotating wire being swept though the laser beam, while the reflected signal is recorded [1]. By changing the incident angle of the rotating rod from 0° to 360° in relation to the fiber, the full profile of the laser beam...... is obtained. Choosing a highly reflective rod material and a sufficiently high rotation speed, these measurements can be done with high laser powers, without any additional optical elements between the fiber and analyzer. The performance of the analyzer was evaluated by coupling laser light into different...

  6. Design of a 300-Watt Isolated Power Supply with Minimized Circuit Input-to-Output Parasitic Capacitance

    DEFF Research Database (Denmark)

    Nguyen-Duy, Khiem; Petersen, Lars Press; Knott, Arnold;

    2014-01-01

    This paper presents the design of a 300-Watt isolated power supply for MOS gate driver circuit in medium and high voltage applications. The key feature of the developed power supply is having a very low circuit input-to-output parasitic capacitance, thus maximizing its noise immunity. This makes ...

  7. A comprehensive analysis and hardware implementation of control strategies for high output voltage DC-DC boost power converter

    DEFF Research Database (Denmark)

    Padmanaban, Sanjeevikumar; Grandi, Gabriele; Blaabjerg, Frede

    2017-01-01

    Classical DC-DC converters used in high voltage direct current (HVDC) power transmission systems, lack in terms of efficiency, reduced transfer gain and increased cost with sensor (voltage/current) numbers. Besides, the internal self-parasitic behavior of the power components reduces the output v...

  8. 8.5-W mode-locked Yb:Lu$_{1.5}$Y$_{1.5}$Al$_5$O$_{12}$ laser with master oscillator power amplifiers

    CERN Document Server

    Wang, Fuyong; Xie, Guoqiang; Yuan, Peng; Qian, Liejia; Xu, Xiaodong; Xu, Jun

    2014-01-01

    We report on a diode-pumped passively mode-locked Yb:Lu$_{1.5}$Y$_{1.5}$Al$_5$O$_{12}$ (Yb:LuYAG) laser for the first time to our knowledge. With the mixed crystal of Yb:LuYAG as gain medium, the mode-locked laser generated 2.2 W of average output power with a repetition rate of 83.9 MHz and pulse duration of 2.2 ps at the wavelength of 1030 nm. In order to obtain higher output power, the output from the mode-locked oscillator was further amplified to 8.5 W by two-stage single-pass amplifiers. The high-power picosecond laser is very useful for applications such as pumping of mid-infrared optical parametric oscillators, material micro-processing, and UV light generation, etc.

  9. A Comparative Study of Analog Voltage-mode Control Methods for Ultra-Fast Tracking Power Supplies

    DEFF Research Database (Denmark)

    Høyerby, Mikkel Christian Wendelboe; Andersen, Michael Andreas E.

    2007-01-01

    This paper presents a theoretical and experimental comparison of the standard PWM/PID voltage-mode control method for single-phase buck converters with two highperformance self-oscillating (a.k.a. sliding mode) control methods. The application considered is ultra-fast tracking power supplies...... (UFTPSs) for RF power amplifiers, where the switching converter needs to track a varying reference voltage precisely and quickly while maintaining low output impedance. The small-signal analyses performed on the different controllers show that the hysteretic-type controller can achieve the highest loop......-oscillating control is shown to reduce the worst-case UFTPS output impedance by a factor of 10....

  10. Power output of skinned skeletal muscle fibres from the cheetah (Acinonyx jubatus).

    Science.gov (United States)

    West, Timothy G; Toepfer, Christopher N; Woledge, Roger C; Curtin, Nancy A; Rowlerson, Anthea; Kalakoutis, Michaeljohn; Hudson, Penny; Wilson, Alan M

    2013-08-01

    Muscle samples were taken from the gluteus, semitendinosus and longissimus muscles of a captive cheetah immediately after euthanasia. Fibres were 'skinned' to remove all membranes, leaving the contractile filament array intact and functional. Segments of skinned fibres from these cheetah muscles and from rabbit psoas muscle were activated at 20°C by a temperature-jump protocol. Step and ramp length changes were imposed after active stress had developed. The stiffness of the non-contractile ends of the fibres (series elastic component) was measured at two different stress values in each fibre; stiffness was strongly dependent on stress. Using these stiffness values, the speed of shortening of the contractile component was evaluated, and hence the power it was producing. Fibres were analysed for myosin heavy chain content using gel electrophoresis, and identified as either slow (type I) or fast (type II). The power output of cheetah type II fibre segments was 92.5±4.3 W kg(-1) (mean ± s.e., 14 fibres) during shortening at relative stress 0.15 (the stress during shortening/isometric stress). For rabbit psoas fibre segments (presumably type IIX) the corresponding value was significantly higher (Pcheetah was less than that of rabbit when maximally activated at 20°C, and does not account for the superior locomotor performance of the cheetah.

  11. Frequency-multiplication high-output triboelectric nanogenerator for sustainably powering biomedical microsystems.

    Science.gov (United States)

    Zhang, Xiao-Sheng; Han, Meng-Di; Wang, Ren-Xin; Zhu, Fu-Yun; Li, Zhi-Hong; Wang, Wei; Zhang, Hai-Xia

    2013-03-13

    An attractive method to response the current energy crisis and produce sustainable nonpolluting power source is harvesting energy from our living environment. However, the energy in our living environment always exists in low-frequency form, which is very difficult to be utilized directly. Here, we demonstrated a novel sandwich-shape triboelectric nanogenerator to convert low-frequency mechanical energy to electric energy with double frequency. An aluminum film was placed between two polydimethylsiloxane (PDMS) membranes to realize frequency multiplication by twice contact electrifications within one cycle of external force. The working mechanism was studied by finite element simulation. Additionally, the well-designed micro/nano dual-scale structures (i.e., pyramids and V-shape grooves) fabricated atop PDMS surface was employed to enhance the device performance. The output peak voltage, current density, and energy volume density achieved 465 V, 13.4 μA/cm(2), and 53.4 mW/cm(3), respectively. This novel nanogenerator was systematically investigated and also demonstrated as a reliable power source, which can be directly used to not only lighten five commercial light-emitting diodes (LEDs) but also drive an implantable 3-D microelectrode array for neural prosthesis without any energy storage unit or rectification circuit. This is the first demonstration of the nanogenerator for directly driving biomedical microsystems, which extends the application fields of the nanogenerator and drives it closer to practical applications.

  12. Single-Frequency, Yb-Free, Resonantly Cladding-Pumped Large Mode Area Er Fiber Amplifier for Power Scaling

    Science.gov (United States)

    2008-07-25

    report results for a single-frequency SF resonantly cladding-pumped Yb-free large mode area LMA erbium-doped fiber amplifier EDFA with nearly 50...original demonstration of a SF resonantly cladding-pumped LMA EDFA . We obtained a diffraction-limited SF output of 9.3 W, which is also a record power...output obtained for resonantly cladding-pumped LMA EDFA . © 2008 American Institute of Physics. DOI: 10.1063/1.2964189 Recent advances in eye-safe 1.5

  13. Study of dopant concentrations on thermal induced mode instability in high power fiber amplifiers

    CERN Document Server

    Tao, Rumao; Wang, Xiaolin; Zhou, Pu; Liu, Zejin

    2015-01-01

    Dependence of mode instabilities (MI) on ytterbium dopant concentrations in high power fiber amplifiers has been investigated. It is theoretically shown that, by only varying the fiber length to maintain the same total small-signal pump absorption, the MI threshold is independent of dopant concentration. MI thresholds of gain fibers with ytterbium dopant concentration of 5.93X10^25/m3 and 1.02X10^26/m3 have been measured, which exhibit similar thresholds and agree with theoretical results. The result indicates that heavy doping of active fiber can be adopted to suppress nonlinear effects without decreasing MI threshold, which provides a method of maximizing the power output of fiber laser, taking into account the stimulated Brillouin scattering, stimulated Raman Scattering, and MI thresholds simultaneously.

  14. Wind tunnel measurements of the power output variability and unsteady loading in a micro wind farm model

    Science.gov (United States)

    Bossuyt, Juliaan; Howland, Michael; Meneveau, Charles; Meyers, Johan

    2015-11-01

    To optimize wind farm layouts for a maximum power output and wind turbine lifetime, mean power output measurements in wind tunnel studies are not sufficient. Instead, detailed temporal information about the power output and unsteady loading from every single wind turbine in the wind farm is needed. A very small porous disc model with a realistic thrust coefficient of 0.75 - 0.85, was designed. The model is instrumented with a strain gage, allowing measurements of the thrust force, incoming velocity and power output with a frequency response up to the natural frequency of the model. This is shown by reproducing the -5/3 spectrum from the incoming flow. Thanks to its small size and compact instrumentation, the model allows wind tunnel studies of large wind turbine arrays with detailed temporal information from every wind turbine. Translating to field conditions with a length-scale ratio of 1:3,000 the frequencies studied from the data reach from 10-4 Hz up to about 6 .10-2 Hz. The model's capabilities are demonstrated with a large wind farm measurement consisting of close to 100 instrumented models. A high correlation is found between the power outputs of stream wise aligned wind turbines, which is in good agreement with results from prior LES simulations. Work supported by ERC (ActiveWindFarms, grant no. 306471) and by NSF (grants CBET-113380 and IIA-1243482, the WINDINSPIRE project).

  15. Curvilinear VO(2):power output relationship in a ramp test in professional cyclists: possible association with blood hemoglobin concentration.

    Science.gov (United States)

    Lucía, Alejandro; Hoyos, Jesús; Santalla, Alfredo; Pérez, Margarita; Chicharro, José L

    2002-02-01

    The purpose of this study was to determine (1) if there exists an additional, nonlinear increase (DeltaVO(2)) in the oxygen uptake observed (VO2 (obs)) at the maximal power output reached during a ramp cycle ergometer test and that expected (VO2 (exp)) from the linear relationship between VO(2) and power output below the lactate threshold (LT) in professional riders, and (2) the relationship between DeltaVO(2) and possible explanatory mechanisms. Each of 12 professional cyclists (25 +/- 1 years; VO(2 max): 71.3 +/- 1.2 ml x kg(-1) x min(-1)) performed a ramp test until exhaustion (power output increases of 25 W x min(-1)) during which several gas-exchange and blood variables were measured (including lactate, HCO(3)(-) and K(+)). VO(2) was linearly related to power output until the LT in all subjects. Afterward, a nonlinear deflection was observed in the VO(2):power output relationship (DeltaVO(2) = 2492 +/- 55 ml x min(-1) and p < 0.05 for VO2 (obs) vs. VO2 (exp)). A significant negative correlation was encountered between DeltaVO(2) and resting hemoglobin levels before the tests (r = 20.61; p < 0.05). In conclusion, professional cyclists exhibit an attenuation of the VO(2) rise above the LT.

  16. Towards high power output of scaled-up benthic microbial fuel cells (BMFCs) using multiple electron collectors.

    Science.gov (United States)

    Liu, Bingchuan; Williams, Isaiah; Li, Yan; Wang, Lei; Bagtzoglou, Amvrossios; McCutcheon, Jeffrey; Li, Baikun

    2016-05-15

    This study aimed at achieving high power output of benthic microbial fuel cells (BMFCs) with novel geometric anode setups (inverted tube granular activated charcoal (IT-GAC) and carbon cloth roll (CCR)) and multiple anodes/electron collectors. The lab-scale tests showed the power density of IT-GAC and CCR anodes achieved at 2.92 and 2.55 W m(-2), the highest value ever reported in BMFCs. The power density of BMFCs substantially increased with electron collector number (titanium rods) in anodes. The connection of multiple electron collectors with multiple cathodes had much higher total voltage/current output than that with single cathode. The possibility of maintaining high power density at scaled-up BMFCs was explored by arranging multiple anodes in sediment. The compact configuration of multiple CCR anodes contacting each other did not deteriorate the performance of individual anodes, showing the feasibility of maximizing anode numbers per sediment footprint and achieving high power output. Multiple IT-GAC and CCR anodes with multiple collectors effectively utilized sediment at both horizontal and vertical directions and enhanced electron collection efficiency. This study demonstrated that bacterial adhesion and electron collection should be optimized on small anodes in order to maintain high power density and achieve high power output in the scaled-up BMFCs.

  17. Lowest of AC-DC power output for electrostrictive polymers energy harvesting systems

    Science.gov (United States)

    Meddad, Mounir; Eddiai, Adil; Hajjaji, Abdelowahed; Guyomar, Daniel; Belkhiat, Saad; Boughaleb, Yahia; Chérif, Aida

    2013-11-01

    Advances in technology led to the development of electronic circuits and sensors with extremely low electricity consumption. At the same time, structural health monitoring, technology and intelligent integrated systems created a need for wireless sensors in hard to reach places in aerospace vehicles and large civil engineering structures. Powering sensors with energy harvesters eliminates the need to replace batteries on a regular basis. Scientists have been forced to search for new power source that are able to harvested energy from their surrounding environment (sunlight, temperature gradients etc.). Electrostrictive polymer belonging to the family of electro-active polymers, offer unique properties for the electromechanical transducer technology has been of particular interest over the last few years in order to replace conventional techniques such as those based on piezoelectric or electromagnetic, these materials are highly attractive for their low-density, with large strain capability that can be as high as two orders of magnitude greater than the striction-limited, rigid and fragile electroactive ceramics. Electrostrictive polymers sensors respond to vibration with an ac output signal, one of the most important objectives of the electronic interface is to realize the required AC-DC conversion. The goal of this paper is to design an active, high efficiency power doubler converter for electrostrictive polymers exclusively uses a fraction of the harvested energy to supply its active devices. The simulation results show that it is possible to obtain a maximum efficiency of the AC-DC converter equal to 80%. Premiliminary experimental measurements were performed and the results obtained are in good agreement with simulations.

  18. Controlled self-assembly of organic composite microdisks for efficient output coupling of whispering-gallery-mode lasers.

    Science.gov (United States)

    Wei, Cong; Liu, Si-Yun; Zou, Chang-Ling; Liu, Yingying; Yao, Jiannian; Zhao, Yong Sheng

    2015-01-14

    Flexible microdisk whispering-gallery-mode (WGM) resonators with high quality factors were achieved through the controlled assembly of organic materials with an emulsion-solvent-evaporation method. The high material compatibility of the assembled microdisks enabled us to realize low-threshold WGM lasers by doping with organic dyes as gain media. Furthermore, the emulsion-assisted self-assembly provided a strategy for the one-step fabrication of microwire-waveguide-connected microdisk heterostructures, which can be utilized for the efficient output of the isotropic WGM lasers from the coupled waveguides. We hope that these results will pave an avenue for the construction of new types of flexible WGM-based components for photonic integration.

  19. High brightness direct diode laser with kW output power

    Science.gov (United States)

    Fritsche, Haro; Kruschke, Bastian; Koch, Ralf; Ferrario, Fabio; Kern, Holger; Pahl, Ulrich; Pflueger, Silke; Gries, Wolfgang

    2014-03-01

    High power, high brightness diode lasers are beginning to challenge solid state lasers, i.e. disk and fiber lasers. The core technologies for brightness scaling of diode lasers are optical stacking and dense spectral combining (DSC), as well as improvements of the diode material. Diode lasers will have the lowest cost of ownership, highest efficiency and most compact design among all lasers. In our modular product design tens of single emitters are combined in a compact package and launched into a 200 μm fiber with 0.08 NA. Dense spectral combining enables power scaling from 80 W to kilowatts. Volume Bragg Gratings and dichroic filters yield high optical efficiencies of more than 80% at low cost. Each module emits up to 500 W with a beam quality of 5.5 mm*mrad and less than 20 nm linewidth. High speed switching power supplies are integrated into the module and rise times as short as 6 μs have been demonstrated. Fast control algorithms based on FPGA and embedded microcontroller ensure high wall plug efficiency with a unique control loop time of only 30 μs. Individual modules are spectrally combined to result in direct diode laser systems with kilowatts of output power at identical beam quality. For low loss fiber coupling a 200 μm fiber is used and the NA is limited to 0.08 corresponding to a beam quality of 7.5 mm*mrad. The controller architecture is fully scalable without sacrificing loop time. We leverage automated manufacturing for cost effective, high yield production. A precision robotic system handles and aligns the individual fast axis lenses and tracks all quality relevant data. Similar technologies are also deployed for dense spectral combining aligning the VBG and dichroic filters. Operating at wavelengths between 900 nm and 1100 nm, these systems are mainly used in cutting and welding, but the technology can also be adapted to other wavelength ranges, such as 793 nm and 1530 nm. Around 1.5 μm the diodes are already successfully used for resonant

  20. Maximizing output power of wind turbine generator by output current control. Shutsuryoku denryu seigyo ni yoru furyoku hatsuden system no denryoku saidaika

    Energy Technology Data Exchange (ETDEWEB)

    Kawahito, T. (Takamatsu National College of Technology, Kagawa (Japan)); Suzuki, T. (Tokushima University, Tokushima (Japan))

    1994-03-20

    This paper reports a method in a wind power generation system to control output current from a generator so that it fits automatically the wind turbine characteristics where the turbine characteristics are unknown and the generator characteristics are known. The paper details the following methods: a method that rotation speed of a wind turbine is observed to make the output current from the generator proportional to a square of the turbine rotation speed, and optimize the proportion coefficient so that the generator output at an equilibrium operation point of this system (wind turbine generated torque is in equilibrium with the generator driven torque) is maximized; and a method to derive an optimal proportion coefficient in discrete time control using a digital computer. The paper then describes the following matters: a simulation that assumes a pseudo natural wind velocity has verified the effectiveness of this control method; discovering an optimal proportion coefficient has required about ten minutes; and the way this control method handles fluctuation in wind velocity has a room of further improvement. 16 refs., 10 figs., 1 tab.

  1. 16 W output power by high-efficient spectral beam combining of DBR-tapered diode lasers

    DEFF Research Database (Denmark)

    Müller, André; Vijayakumar, Deepak; Jensen, Ole Bjarlin;

    2011-01-01

    output power achieved by spectral beam combining of two single element tapered diode lasers. Since spectral beam combining does not affect beam propagation parameters, M2-values of 1.8 (fast axis) and 3.3 (slow axis) match the M2- values of the laser with lowest spatial coherence. The principle......Up to 16 W output power has been obtained using spectral beam combining of two 1063 nm DBR-tapered diode lasers. Using a reflecting volume Bragg grating, a combining efficiency as high as 93.7% is achieved, resulting in a single beam with high spatial coherence. The result represents the highest...... of spectral beam combining used in our experiments can be expanded to combine more than two tapered diode lasers and hence it is expected that the output power may be increased even further in the future....

  2. 16 W output power by high-efficient spectral beam combining of DBR-tapered diode lasers.

    Science.gov (United States)

    Müller, André; Vijayakumar, Deepak; Jensen, Ole Bjarlin; Hasler, Karl-Heinz; Sumpf, Bernd; Erbert, Götz; Andersen, Peter E; Petersen, Paul Michael

    2011-01-17

    Up to 16 W output power has been obtained using spectral beam combining of two 1063 nm DBR-tapered diode lasers. Using a reflecting volume Bragg grating, a combining efficiency as high as 93.7% is achieved, resulting in a single beam with high spatial coherence. The result represents the highest output power achieved by spectral beam combining of two single element tapered diode lasers. Since spectral beam combining does not affect beam propagation parameters, M2-values of 1.8 (fast axis) and 3.3 (slow axis) match the M2-values of the laser with lowest spatial coherence. The principle of spectral beam combining used in our experiments can be expanded to combine more than two tapered diode lasers and hence it is expected that the output power may be increased even further in the future.

  3. PI and Fuzzy Control Strategies for High Voltage Output DC-DC Boost Power Converter - Hardware Implementation and Analysis

    DEFF Research Database (Denmark)

    Padmanaban, Sanjeevi Kumar; Blaabjerg, Frede; Siano, Pierluigi

    2016-01-01

    converter with inbuilt voltage-lift technique and overcome the aforementioned deficiencies. Further, the control strategy is adapted based on proportional-integral (P-I) and fuzzy logic, closed-loop controller to regulate the outputs and ensure the performances. Complete hardware prototype of EHV converter......This paper presents the control strategies by Proportional-Integral (P-I) and Fuzzy Logic (FL) for a DC-DC boost power converter for high output voltage configuration. Standard DC-DC converters are traditionally used for high voltage direct current (HVDC) power transmission systems. But, lack its...... performances in terms of efficiency, reduced transfer gain and increased cost with sensor units. Moreover, the internal self-parasitic components reduce the output voltage and efficiency of classical high voltage converters (HVC). This investigation focused on extra high-voltage (EHV) DC-DC boost power...

  4. Design of a high power TM01 mode launcher optimized for manufacturing by milling

    Energy Technology Data Exchange (ETDEWEB)

    Dal Forno, Massimo [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2016-12-15

    Recent research on high-gradient rf acceleration found that hard metals, such as hard copper and hard copper-silver, have lower breakdown rate than soft metals. Traditional high-gradient accelerating structures are manufactured with parts joined by high-temperature brazing. The high temperature used in brazing makes the metal soft; therefore, this process cannot be used to manufacture structures out of hard metal alloys. In order to build the structure with hard metals, the components must be designed for joining without high-temperature brazing. One method is to build the accelerating structures out of two halves, and join them by using a low-temperature technique, at the symmetry plane along the beam axis. The structure has input and output rf power couplers. We use a TM01 mode launcher as a rf power coupler, which was introduced during the Next Linear Collider (NLC) work. The part of the mode launcher will be built in each half of the structure. This paper presents a novel geometry of a mode launcher, optimized for manufacturing by milling. The coupler was designed for the CERN CLIC working frequency f = 11.9942 GHz; the same geometry can be scaled to any other frequency.

  5. Minimizing Crosstalk in Self Oscillating Switch Mode Audio Power Amplifiers

    DEFF Research Database (Denmark)

    Knott, Arnold; Ploug, Rasmus Overgaard

    2012-01-01

    The varying switching frequencies of self oscillating switch mode audio amplifiers have been known to cause interchannel intermodulation disturbances in multi channel configurations. This crosstalk phenomenon has a negative impact on the audio performance. The goal of this paper is to present...... a method to minimize this phenomenon by improving the integrity of the various power distribution systems of the amplifier. The method is then applied to an amplifier built for this investigation. The results show that the crosstalk is suppressed with 30 dB, but is not entirely eliminated...

  6. A Study on Estimation of Average Power Output Fluctuation of Clustered Photovoltaic Power Generation Systems in Urban District of a Few km2

    Science.gov (United States)

    Kato, Takeyoshi; Suzuoki, Yasuo

    The fluctuation of the total power output of clustered PV systems would be smaller than that of single PV system because of the time difference in the power output fluctuation among PV systems at different locations. This effect, so called smoothing-effect, must be taken into account properly when the impact of clustered PV systems on electric power system is assessed. If the average power output of clustered PV systems can be estimated from the power output of single PV system, it is very useful and helpful for the impact assessment. In this study, we propose a simple method to estimate the total power output fluctuation of clustered PV systems. In the proposed method, a smoothing effect is assumed to be caused as a result of two factors, i.e. time difference of overhead clouds passing among PV systems and the random change in the size and/or shape of clouds. The first one is formulated as a low-pass filter, assuming that output fluctuation is transmitted to the same direction as the wind direction at the constant speed. The second one is taken into account by using a Fourier transform surrogate data. The parameters in the proposed method were selected, so that the estimated fluctuation can be similar with that of ensemble average fluctuation of data observed at 5 points used as a training data set. Then, by using the selected parameters, the fluctuation property was estimated for other data set. The results show that the proposed method is useful for estimating the total power output fluctuation of clustered PV systems.

  7. Development of an Environment-Aware Locomotion Mode Recognition System for Powered Lower Limb Prostheses.

    Science.gov (United States)

    Liu, Ming; Wang, Ding; Helen Huang, He

    2016-04-01

    This paper aimed to develop and evaluate an environment-aware locomotion mode recognition system for volitional control of powered artificial legs. A portable terrain recognition (TR) module, consisting of an inertia measurement unit and a laser distance meter, was built to identify the type of terrain in front of the wearer while walking. A decision tree was used to classify the terrain types and provide either coarse or refined information about the walking environment. Then, the obtained environmental information was modeled as a priori probability and was integrated with a neuromuscular-mechanical-fusion-based locomotion mode (LM) recognition system. The designed TR module and environmental-aware LM recognition system was evaluated separately on able-bodied subjects and a transfemoral amputee online. The results showed that the TR module provided high quality environmental information: TR accuracy is above 98% and terrain transitions are detected over 500 ms before the time required to switch the prosthesis control mode. This enabled smooth locomotion mode transitions for the wearers. The obtained environmental information further improved the performance of LM recognition system, regardless of whether coarse or refined information was used. In addition, the environment-aware LM recognition system produced reliable online performance when the TR output was relatively noisy, which indicated the potential of this system to operate in unconstructed environment. This paper demonstrated that environmental information should be considered for operating wearable lower limb robotic devices, such as prosthetics and orthotics.

  8. Crystal Quality and Light Output Power of GaN-Based LEDs Grown on Concave Patterned Sapphire Substrate.

    Science.gov (United States)

    Wu, YewChung Sermon; Isabel, A Panimaya Selvi; Zheng, Jian-Hsuan; Lin, Bo-Wen; Li, Jhen-Hong; Lin, Chia-Chen

    2015-04-22

    The crystal quality and light output power of GaN-based light-emitting diodes (LEDs) grown on concave patterned sapphire substrate (CPSS) were investigated. It was found that the crystal quality of GaN-based LEDs grown on CPSS improved with the decrease of the pattern space (percentage of c-plane). However, when the pattern space decreased to 0.41 μm (S0.41-GaN), the GaN crystallinity dropped. On the other hand, the light output power of GaN-based LEDs was increased with the decrease of the pattern space due to the change of the light extraction efficiency.

  9. The influence of Thomson effect on the maximum power output and maximum efficiency of a thermoelectric generator

    Science.gov (United States)

    Chen, Jincan; Yan, Zijun; Wu, Liqing

    1996-06-01

    Considering a thermoelectric generator as a heat engine cycle, the general differential equations of the temperature field inside thermoelectric elements are established by means of nonequilibrium thermodynamics. These equations are used to study the influence of heat leak, Joule's heat, and Thomson heat on the performance of the thermoelectric generator. New expressions are derived for the power output and the efficiency of the thermoelectric generator. The maximum power output is calculated and the optimal matching condition of load is determined. The maximum efficiency is discussed by a representative numerical example. The aim of this research is to provide some novel conclusions and redress some errors existing in a related investigation.

  10. Evaluation of Resting Cardiac Power Output as a Prognostic Factor in Patients with Advanced Heart Failure.

    Science.gov (United States)

    Yildiz, Omer; Aslan, Gamze; Demirozu, Zumrut T; Yenigun, Cemal Deniz; Yazicioglu, Nuran

    2017-09-15

    If the heart is represented by a hydraulic pump, cardiac power represents the hydraulic function of the heart. Cardiac pump function is frequently determined through left ventricular ejection fraction using imaging. This study aims to validate resting cardiac power output (CPO) as a predictive biomarker in patients with advanced heart failure (HF). One hundred and seventy-two patients with HF severe enough to warrant cardiac transplantation were retrospectively reviewed at a single tertiary care institution between September 2010 and July 2013. Patients were initially evaluated with simultaneous right-sided and left-sided cardiac catheter-based hemodynamic measurements, followed by longitudinal follow-up (median of 52 months) for adverse events (cardiac mortality, cardiac transplantation, or ventricular assist device placement). Median resting CPO was 0.54 W (long rank chi-square = 33.6; p < 0.0001). Decreased resting CPO (<0.54 W) predicted increased risk for adverse outcomes. Fifty cardiac deaths, 10 cardiac transplants, and 12 ventricular assist device placements were documented. The prognostic relevance of resting CPO remained significant after adjustment for age, gender, left ventricular ejection fraction, mean arterial pressure, pulmonary vascular resistance, right atrial pressure, and estimated glomerular filtration rate (HR, 3.53; 95% confidence interval, 1.66 to 6.77; p = 0.0007). In conclusion, lower resting CPO supplies independent prediction of adverse outcomes. Thus, it could be effectively used for risk stratification in patients with advanced HF. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Effect of Carbohydrate Intake on Maximal Power Output and Cognitive Performances

    Directory of Open Access Journals (Sweden)

    Laura Pomportes

    2016-10-01

    Full Text Available The present study aimed to assess the beneficial effect of acute carbohydrate (7% CHO intake on muscular and cognitive performances. Seventeen high levels athletes in explosive sports (fencing and squash participated in a randomized, double-blind study consisting in series of 6 sprints (5s with a passive recovery (25s followed by 15 min submaximal cycling after either maltodextrine and fructose (CHO or placebo (Pl intake. Cognitive performances were assessed before and after sprint exercise using a simple reaction time (SRT task at rest, a visual scanning task (VS and a Go/Nogo task (GNG during a submaximal cycling exercise. Results showed a beneficial effect of exercise on VS task on both conditions (Pl: −283 ms; CHO: −423 ms and on SRT only during CHO condition (−26 ms. In the CHO condition, SRT was faster after exercise whereas no effect of exercise was observed in the Pl condition. According to a qualitative statistical method, a most likely and likely positive effect of CHO was respectively observed on peak power (+4% and tiredness (−23% when compared to Pl. Furthermore, a very likely positive effect of CHO was observed on SRT (−8% and a likely positive effect on visual scanning (−6% and Go/Nogo tasks (−4% without any change in accuracy. In conclusion acute ingestion of 250 mL of CHO, 60 min and 30 min before exercise, improve peak power output, decrease muscular tiredness and speed up information processing and visual detection without changing accuracy.

  12. A Switching-Mode Power Supply Design Tool to Improve Learning in a Power Electronics Course

    Science.gov (United States)

    Miaja, P. F.; Lamar, D. G.; de Azpeitia, M.; Rodriguez, A.; Rodriguez, M.; Hernando, M. M.

    2011-01-01

    The static design of ac/dc and dc/dc switching-mode power supplies (SMPS) relies on a simple but repetitive process. Although specific spreadsheets, available in various computer-aided design (CAD) programs, are widely used, they are difficult to use in educational applications. In this paper, a graphic tool programmed in MATLAB is presented,…

  13. Voltage-Mode Multifunction Biquadratic Filters Using New Ultra-Low-Power Differential Difference Current Conveyors

    Directory of Open Access Journals (Sweden)

    M. Kumngern

    2013-06-01

    Full Text Available This paper presents two low-power voltage-mode multifunction biquadratic filters using differential difference current conveyors. Each proposed circuit employs three differential difference current conveyors, two grounded capacitors and two grounded resistors. The low-voltage ultra-low-power differential difference current conveyor is used to provide low-power consumption of the proposed filters. By appropriately connecting the input and output terminals, the proposed filters can provide low-pass, band-pass, high-pass, band-stop and all-pass voltage responses at high-input terminals, which is a desirable feature for voltage-mode operations. The natural frequency and the quality factor can be orthogonally set by adjusting the circuit components. For realizing all the filter responses, no inverting-type input signal requirements as well as no component-matching conditional requirements are imposed. The incremental parameter sensitivities are also low. The characteristics of the proposed circuits are simulated by using PSPICE simulators to confirm the presented theory.

  14. The Influence of Serial Carbohydrate Mouth Rinsing on Power Output during a Cycle Sprint

    Directory of Open Access Journals (Sweden)

    Shaun M. Phillips, Scott Findlay, Mykolas Kavaliauskas, Marie Clare Grant

    2014-06-01

    Full Text Available The objective of the study was to investigate the influence of serial administration of a carbohydrate (CHO mouth rinse on performance, metabolic and perceptual responses during a cycle sprint. Twelve physically active males (mean (± SD age: 23.1 (3.0 years, height: 1.83 (0.07 m, body mass (BM: 86.3 (13.5 kg completed the following mouth rinse trials in a randomized, counterbalanced, double-blind fashion; 1. 8 x 5 second rinses with a 25 ml CHO (6% w/v maltodextrin solution, 2. 8 x 5 second rinses with a 25 ml placebo (PLA solution. Following mouth rinse administration, participants completed a 30 second sprint on a cycle ergometer against a 0.075 g·kg-1 BM resistance. Eight participants achieved a greater peak power output (PPO in the CHO trial, resulting in a significantly greater PPO compared with PLA (13.51 ± 2.19 vs. 13.20 ± 2.14 W·kg-1, p 0.05. No significant between-trials difference was reported for fatigue index, perceived exertion, arousal and nausea levels, or blood lactate and glucose concentrations. Serial administration of a CHO mouth rinse may significantly improve PPO during a cycle sprint. This improvement appears confined to the first 5 seconds of the sprint, and may come at a greater relative cost for the remainder of the sprint.

  15. Enhancement of light output power from LEDs based on monolayer colloidal crystal.

    Science.gov (United States)

    Geng, Chong; Wei, Tongbo; Wang, Xiaoqing; Shen, Dezhong; Hao, Zhibiao; Yan, Qingfeng

    2014-05-14

    One of the major challenges for the application of GaN-based light emitting diodes (LEDs) in solid-state lighting lies in the low light output power (LOP). Embedding nanostructures in LEDs has attracted considerable interest because they may improve the LOP of GaN-based LEDs efficiently. Recent advances in nanostructures derived from monolayer colloidal crystal (MCC) have made remarkable progress in enhancing the performance of GaN-based LEDs. In this review, the current state of the art in this field is highlighted with an emphasis on the fabrication of ordered nanostructures using large-area, high-quality MCCs and their demonstrated applications in enhancement of LOP from GaN-based LEDs. We describe the remarkable achievements that have improved the internal quantum efficiency, the light extraction efficiency, or both from LEDs by taking advantages of diverse functions that the nanostructures provided. Finally, a perspective on the future development of enhancement of LOP by using the nanostructures derived from MCC is presented. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Efficiency at maximum power output for an engine with a passive piston

    Science.gov (United States)

    Sano, Tomohiko G.; Hayakawa, Hisao

    2016-08-01

    Efficiency at maximum power (MP) output for an engine with a passive piston without mechanical controls between two reservoirs is studied theoretically. We enclose a hard core gas partitioned by a massive piston in a temperature-controlled container and analyze the efficiency at MP under a heating and cooling protocol without controlling the pressure acting on the piston from outside. We find the following three results: (i) The efficiency at MP for a dilute gas is close to the Chambadal-Novikov-Curzon-Ahlborn (CNCA) efficiency if we can ignore the sidewall friction and the loss of energy between a gas particle and the piston, while (ii) the efficiency for a moderately dense gas becomes smaller than the CNCA efficiency even when the temperature difference of the reservoirs is small. (iii) Introducing the Onsager matrix for an engine with a passive piston, we verify that the tight coupling condition for the matrix of the dilute gas is satisfied, while that of the moderately dense gas is not satisfied because of the inevitable heat leak. We confirm the validity of these results using the molecular dynamics simulation and introducing an effective mean-field-like model which we call the stochastic mean field model.

  17. The Effect of High Intensity Intermittent Exercise on Power Output for the Upper Body

    Directory of Open Access Journals (Sweden)

    Leonie Harvey

    2015-06-01

    Full Text Available The aim of the present study was to examine and measure high intensity, intermittent upper body performance, in addition to identifying areas of the body that affect the variance in total work done during the 5 × 6 s sprint test. Fifteen males completed an upper body 5 × 6 s sprint test on a modified electro-magnetically braked cycle ergometer, which consisted of five maximal effort sprints, each 6 s in duration, separated by 24 s of passive recovery. A fly wheel braking force corresponding to 5% of the participants’ body weight was used as the implemented resistance level. Body composition was measured using dual-energy X-ray absorptiometry (DEXA. Percent (% decrement was calculated as 100 − (Total work/ideal work × 100. Significant (P < 0.05 differences were found between sprints for both absolute and relative (W, W·kg−1, W·kg−1 Lean body mass (LBM and W·kg−1 Upper body lean body mass (UBLBM peak (PP and mean (MP power. The % decrement in total work done over the five sprints was 11.4%. Stepwise multiple linear regression analysis revealed that UBLBM accounts for 87% of the variance in total work done during the upper body 5 × 6 s sprint test. These results provide a descriptive analysis of upper body, high intensity intermittent exercise, demonstrating that PP and MP output decreased significantly during the upper body 5 × 6 s sprint test.

  18. Balancing Power Output and Structural Fatigue of Wave Energy Converters by Means of Control Strategies

    Directory of Open Access Journals (Sweden)

    Francesco Ferri

    2014-04-01

    Full Text Available In order to reduce the cost of electricity produced by wave energy converters (WECs, the benefit of selling electricity as well as the investment costs of the structure has to be considered. This paper presents a methodology for assessing the control strategy for a WEC with respect to both energy output and structural fatigue loads. Different active and passive control strategies are implemented (proportional (P controller, proportional-integral (PI controller, proportional-integral-derivative with memory compensation (PID controller, model predictive control (MPC and maximum energy controller (MEC, and load time-series resulting from numerical simulations are used to design structural parts based on fatigue analysis using rain-flow counting, Stress-Number (SN curves and Miner’s rule. The objective of the methodology is to obtain a cost-effective WEC with a more comprehensive analysis of a WEC based on a combination of well known control strategies and standardised fatigue methods. The presented method is then applied to a particular case study, the Wavestar WEC, for a specific location in the North Sea. Results, which are based on numerical simulations, show the importance of balancing the gained power against structural fatigue. Based on a simple cost model, the PI controller is shown as a viable solution.

  19. Maximal power output estimates the MLSS before and after aerobic training

    Directory of Open Access Journals (Sweden)

    Carolina Franco Wilke

    2014-06-01

    Full Text Available The purpose of this study is to present an equation to predict the maximal lactate steady state (MLSS through a VO2peak incremental protocol. Twenty-six physically active men were divided in two groups (G1 and G2. They performed one maximal incremental test to determine their VO2peak and maximal power output (Wpeak, and also several constant intensity tests to determine MLSS intensity (MLSSw on a cycle ergometer. Group G2 underwent six weeks of aerobic training at MLSSw. A regression equation was created using G1 subjects Wpeak and MLSSw to estimate the MLSS intensity (MLSSweq before and after training for G2 (MLSSweq = 0.866 x Wpeak-41.734. The mean values were not different (150±27W vs 148±27W, before training / 171±26W vs 177±24W, after training and significant correlations were found between the measured and the estimated MLSSw before (r²=0.49 and after training (r²=0.62 in G2. The proposed equation was effective to estimate the MLSS intensity before and after aerobic training.

  20. Sliding Mode Control Strategy for Wind Turbine Power Maximization

    Directory of Open Access Journals (Sweden)

    Oscar Barambones

    2012-07-01

    Full Text Available The efficiency of the wind power conversions systems can be greatly improved using an appropriate control algorithm. In this work, a sliding mode control for variable speed wind turbine that incorporates a doubly fed induction generator is described. The electrical system incorporates a wound rotor induction machine with back-to-back three phase power converter bridges between its rotor and the grid. In the presented design the so-called vector control theory is applied, in order to simplify the electrical equations. The proposed control scheme uses stator flux-oriented vector control for the rotor side converter bridge control and grid voltage vector control for the grid side converter bridge control. The stability analysis of the proposed sliding mode controller under disturbances and parameter uncertainties is provided using the Lyapunov stability theory. Finally simulated results show, on the one hand, that the proposed controller provides high-performance dynamic characteristics, and on the other hand, that this scheme is robust with respect to the uncertainties that usually appear in the real systems.

  1. Challenges in higher order mode Raman amplifiers

    DEFF Research Database (Denmark)

    Rottwitt, Karsten; Nielsen, Kristian; Friis, Søren Michael Mørk;

    2015-01-01

    A higher order Raman amplifier model that take random mode coupling into account ispresented. Mode dependent gain and signal power fluctuations at the output of the higher order modeRaman amplifier are discussed......A higher order Raman amplifier model that take random mode coupling into account ispresented. Mode dependent gain and signal power fluctuations at the output of the higher order modeRaman amplifier are discussed...

  2. Challenges in higher order mode Raman amplifiers

    DEFF Research Database (Denmark)

    Rottwitt, Karsten; Nielsen, Kristian; Friis, Søren Michael Mørk

    2015-01-01

    A higher order Raman amplifier model that take random mode coupling into account ispresented. Mode dependent gain and signal power fluctuations at the output of the higher order modeRaman amplifier are discussed......A higher order Raman amplifier model that take random mode coupling into account ispresented. Mode dependent gain and signal power fluctuations at the output of the higher order modeRaman amplifier are discussed...

  3. Low Voltage Power Efficient Tunable Shaper Circuit With Rail-To-Rail Output Range for the HYDE Detector at FAIR

    Science.gov (United States)

    Galán, J.; López-Ahumada, R.; Sánchez-Rodríguez, T.; Torralba, A.; Carvajal, R. G.; Martel, I.

    2014-04-01

    This paper presents a low voltage, low power readout front-end system implemented in 130 nm CMOS technology. A conventional architecture that consists of charge sensitive amplifier, pole/zero cancellation and shaper has been used. The work focuses on the design of novel circuit topologies in low voltage environment minimizing the power consumption in modern deep submicron CMOS technologies. An operational amplifier with rail-to-rail output swing that uses a gain boosting technique and class-AB output stage without extra power consumption has been used for the shaper. The circuit combines excellent performances with simplicity of design and suitability for low voltage operation. The system is intended to work with silicon detectors for nuclear physics applications and is optimized to match an input capacitance of 10 pF. The system features a peaking time of 500 ns, a power dissipation of 1.57 mW/channel and an equivalent noise charge of 201 e-.

  4. GaAs-based superluminescent diodes with window-like facet structure for low spectral modulation at high output powers

    Science.gov (United States)

    Ghazal, O. M. S.; Childs, D. T.; Stevens, B. J.; Babazadeh, N.; Hogg, R. A.; Groom, K. M.

    2016-04-01

    We demonstrate a GaAs-based superluminescent diode (SLD) based on the incorporation of a window-like back facet into a self-aligned stripe structure in order to reduce the effective facet reflectivity. This allows the realisation of SLDs with low spectral modulation depth (SMD) at high power spectral density (PSD), without the application of anti-reflection coatings to either facet. This approach is therefore compatible with ultra-broadband gain active elements. We show that 30 mW output power can be attained in a narrow bandwidth, corresponding to 2.2 mW nm-1 PSD with only 5% SMD, centred about 990 nm. We discuss the design criteria for high power and low SMD and the deviation from a linear dependence of SMD on output power, resulting from Joule heating in the self-aligned stripe.

  5. Refractive beam shapers for material processing with high power single mode and multimode lasers

    Science.gov (United States)

    Laskin, Alexander; Laskin, Vadim

    2013-02-01

    The high power multimode fiber-coupled laser sources, like solid state lasers or laser diodes as well as single mode and multimode fiber lasers, are now widely used in various industrial laser material processing technologies like metal or plastics welding, cladding, hardening, brazing, annealing. Performance of these technologies can be essentially improved by varying the irradiance profile of a laser beam with using beam shaping optics, for example, the field mapping refractive beam shapers like piShaper. Operational principle of these devices presumes transformation of laser beam irradiance distribution from Gaussian to flattop, super-Gauss, or inverse-Gauss profile with high flatness of output wave front, conserving of beam consistency, providing collimated output beam of low divergence, high transmittance, extended depth of field. Important feature of piShaper is in capability to operate with TEM00 and multimode lasers, the beam shapers can be implemented not only as telescopic optics but also as collimating systems, which can be connected directly to fiber-coupled lasers or fiber lasers, thus combining functions of beam collimation and irradiance transformation. This paper will describe some features of beam shaping of high-power laser sources, including multimode fiber coupled lasers, and ways of adaptation of beam shaping optical systems design to meet requirements of modern laser technologies. Examples of real implementations will be presented as well.

  6. Design and Study on Sliding Mode Extremum Seeking Control of the Chaos Embedded Particle Swarm Optimization for Maximum Power Point Tracking in Wind Power Systems

    Directory of Open Access Journals (Sweden)

    Jui-Ho Chen

    2014-03-01

    Full Text Available This paper proposes a sliding mode extremum seeking control (SMESC of chaos embedded particle swarm optimization (CEPSO Algorithm, applied to the design of maximum power point tracking in wind power systems. Its features are that the control parameters in SMESC are optimized by CEPSO, making it unnecessary to change the output power of different wind turbines, the designed in-repetition rate is reduced, and the system control efficiency is increased. The wind power system control is designed by simulation, in comparison with the traditional wind power control method, and the simulated dynamic response obtained by the SMESC algorithm proposed in this paper is better than the traditional hill-climbing search (HCS and extremum seeking control (ESC algorithms in the transient or steady states, validating the advantages and practicability of the method proposed in this paper.

  7. The H-mode power threshold in JET

    Energy Technology Data Exchange (ETDEWEB)

    Start, D.F.H.; Bhatnagar, V.P.; Campbell, D.J.; Cordey, J.G.; Esch, H.P.L. de; Gormezano, C.; Hawkes, N.; Horton, L.; Jones, T.T.C.; Lomas, P.J.; Lowry, C.; Righi, E.; Rimini, F.G.; Saibene, G.; Sartori, R.; Sips, G.; Stork, D.; Thomas, P.; Thomsen, K.; Tubbing, B.J.D.; Von Hellermann, M.; Ward, D.J. [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking

    1994-07-01

    New H-mode threshold data over a range of toroidal field and density values have been obtained from the present campaign. The scaling with n{sub e} B{sub t} is almost identical with that of the 91/92 period for the same discharge conditions. The scaling with toroidal field alone gives somewhat higher thresholds than the older data. The 1991/2 database shows a scaling of P{sub th} (power threshold) with n{sub e} B{sub t} which is approximately linear and agrees well with that observed on other tokamaks. For NBI and carbon target tiles the threshold power is a factor of two higher with the ion {Nu}B drift away from the target compared with the value found with the drift towards the target. The combination of ICRH and beryllium tiles appears to be beneficial for reducing P{sub th}. The power threshold is largely insensitive to plasma current, X-point height and distance between the last closed flux surface and the limiter, at least for values greater than 2 cm. (authors). 3 refs., 6 figs.

  8. Observer-based higher order sliding mode control of power factor in three-phase AC/DC converter for hybrid electric vehicle applications

    Science.gov (United States)

    Liu, Jianxing; Laghrouche, Salah; Wack, Maxime

    2014-06-01

    In this paper, a full-bridge boost power converter topology is studied for power factor control, using output higher order sliding mode control. The AC/DC converters are used for charging the battery and super-capacitor in hybrid electric vehicles from the utility. The proposed control forces the input currents to track the desired values, which can control the output voltage while keeping the power factor close to one. Super-twisting sliding mode observer is employed to estimate the input currents and load resistance only from the measurement of output voltage. Lyapunov analysis shows the asymptotic convergence of the closed-loop system to zero. Multi-rate simulation illustrates the effectiveness and robustness of the proposed controller in the presence of measurement noise.

  9. Optimal Velocity to Achieve Maximum Power Output – Bench Press for Trained Footballers

    Directory of Open Access Journals (Sweden)

    Richard Billich

    2015-03-01

    Full Text Available Optimal Velocity to Achieve Maximum Power Output – Bench Press for Trained Footballers In today’s world of strength training there are many myths surrounding effective exercising with the least possible negative effect on one’s health. In this experiment we focus on the finding of a relationship between maximum output, used load and the velocity with which the exercise is performed. The main objective is to find the optimal speed of the exercise motion which would allow us to reach the maximum mechanic muscle output during a bench press exercise. This information could be beneficial to sporting coaches and recreational sportsmen alike in helping them improve the effectiveness of fast strength training. Fifteen football players of the FK Třinec football club participated in the experiment. The measurements were made with the use of 3D cinematic and dynamic analysis, both experimental methods. The research subjects participated in a strength test, in which the mechanic muscle output of 0, 10, 30, 50, 70, 90% and one repetition maximum (1RM was measured. The acquired result values and other required data were modified using Qualisys Track Manager and Visual 3D software (C-motion, Rockville, MD, USA. During the bench press exercise the maximum mechanic muscle output of the set of research subjects was reached at 75% of maximum exercise motion velocity. Optimální rychlost pohybu pro dosažení maxima výstupního výkonu – bench press u trénovaných fotbalistů Dnešní svět silového tréninku přináší řadu mýtů o tom, jak cvičit efektivně a zároveň s co nejmenším negativním vlivem na zdraví člověka. V tomto experimentu se zabýváme nalezením vztahu mezi maximálním výkonem, použitou zátěží a rychlostí. Hlavním úkolem je nalezení optimální rychlosti pohybu pro dosažení maximálního mechanického svalového výkonu při cvičení bench press, což pomůže nejenom trenérům, ale i rekreačním sportovc

  10. Picosecond pulses of variable duration from a high-power passively mode-locked Nd:YVO(4) laser free of spatial hole burning.

    Science.gov (United States)

    Nadeau, Marie-Christine; Petit, Stéphane; Balcou, Philippe; Czarny, Romain; Montant, Sébastien; Simon-Boisson, Christophe

    2010-05-15

    We report on a high-power passively mode-locked TEM(00)Nd:YVO(4) oscillator, 888 nm diode-pumped, with pulse durations adjustable between 46 ps and 12 ps. The duration tunability was obtained by varying the output coupler (OC) transmission while avoiding resorting to spatial hole burning (SHB) for pulse shortening. At a repetition rate of 91 MHz and for an output power ranging from 15 Wto45 W, we produced SHB-free 12-ps-to32-ps-long pulses. Within this range of power, these are the shortest pulse durations obtained directly from Nd:YVO(4) oscillators.

  11. Measuring the kinetic power of active galactic nuclei in the radio mode

    Science.gov (United States)

    Merloni, Andrea; Heinz, Sebastian

    2007-10-01

    -ray luminosity. As an example, we suggest that Sgr A* may follow the same correlations of radio-mode AGN, based on its observed radiative output as well as on estimates of the accretion rate both at the Bondi radius and in the inner flow. If this is the case, the supermassive black hole in the Galactic Centre is the source of ~5 × 1038 erg s-1 of mechanical power, equivalent to about 1.5 supernovae every 105 yr.

  12. Power characteristics of planar index-antiguided waveguide lasers with transverse mode competition

    Directory of Open Access Journals (Sweden)

    Chaofan Wang

    2016-12-01

    Full Text Available We report comprehensive analysis of output characteristics of homogeneously broadened index-antiguided slab lasers with transverse mode competition. Robust single fundamental mode operation is achieved when the distributive modal loss due to index antiguiding dominates the output coupling loss. Maximal laser efficiency under single fundamental mode operation is investigated numerically for various combinations of single-pass gains and losses. We show analytically that an asymptotic limit of such efficiency exists that is solely determined by the loss ratio between the fundamental and 1st higher-order modes, which equals 66.7% for planar index antiguided lasers.

  13. Wavelength-agile high-power sources via four-wave mixing in higher-order fiber modes.

    Science.gov (United States)

    Demas, J; Prabhakar, G; He, T; Ramachandran, S

    2017-04-03

    Frequency doubling of conventional fiber lasers in the near-infrared remains the most promising method for generating integrated high-peak-power lasers in the visible, while maintaining the benefits of a fiber geometry; but since the shortest wavelength power-scalable fiber laser sources are currently restricted to either the 10XX nm or 15XX nm wavelength ranges, accessing colors other than green or red remains a challenge with this schematic. Four-wave mixing using higher-order fiber modes allows for control of dispersion while maintaining large effective areas, thus enabling a power-scalable method to extend the bandwidth of near-infrared fiber lasers, and in turn, the bandwidth of potential high-power sources in the visible. Here, two parametric sources using the LP0,7 and LP0,6 modes of two step-index multi-mode fibers are presented. The output wavelengths for the sources are 880, 974, 1173, and 1347 nm with peak powers of 10.0, 16.2, 14.7, and 6.4 kW respectively, and ~300-ps pulse durations. The efficiencies of the sources are analyzed, along with a discussion of wavelength tuning and further power scaling, representing an advance in increasing the bandwidth of near-infrared lasers as a step towards high-peak-power sources at wavelengths across the visible spectrum.

  14. The Study on the Variation of the Cavity Length's Influence on the Output Pulse Train of the Actively Mode-Locked Fiber Laser

    Institute of Scientific and Technical Information of China (English)

    LUO Hong-e; TIAN Xiao-jian; GAO Bo

    2005-01-01

    The influence of actively mode-locked Erbium-Doped Fiber Laser(EDFL) cavity length variation on the noises of an optical pulse train is investigated, in theory and in MATLAB simulation. Using a simple model, the noise characteristics of the output pulse train are studied. The results show that the noises of the output pulse train increase with the increasing of the variation of the cavity length. The theory analysis and the simulation results agree well. This result is very significant for us to improve the reliability and the stability of the actively mode-locked fiber laser.

  15. Integrating switch mode audio amplifiers and electro dynamic loudspeakers for a higher power efficiency

    DEFF Research Database (Denmark)

    Poulsen, Søren; Andersen, Michael Andreas E.

    2004-01-01

    The work presented in this paper is related to integration of switch mode audio amplifiers and electro dynamic loudspeakers, using the speaker's voice coil as output filter, and the magnetic structure as heatsink for the amplifier.......The work presented in this paper is related to integration of switch mode audio amplifiers and electro dynamic loudspeakers, using the speaker's voice coil as output filter, and the magnetic structure as heatsink for the amplifier....

  16. A coordinated MIMO control design for a power plant using improved sliding mode controller.

    Science.gov (United States)

    Ataei, Mohammad; Hooshmand, Rahmat-Allah; Samani, Siavash Golmohammadi

    2014-03-01

    For the participation of the steam power plants in regulating the network frequency, boilers and turbines should be co-ordinately controlled in addition to the base load productions. Lack of coordinated control over boiler-turbine may lead to instability; oscillation in producing power and boiler parameters; reduction in the reliability of the unit; and inflicting thermodynamic tension on devices. This paper proposes a boiler-turbine coordinated multivariable control system based on improved sliding mode controller (ISMC). The system controls two main boiler-turbine parameters i.e., the turbine revolution and superheated steam pressure of the boiler output. For this purpose, a comprehensive model of the system including complete and exact description of the subsystems is extracted. The parameters of this model are determined according to our case study that is the 320MW unit of Islam-Abad power plant in Isfahan/Iran. The ISMC method is simulated on the power plant and its performance is compared with the related real PI (proportional-integral) controllers which have been used in this unit. The simulation results show the capability of the proposed controller system in controlling local network frequency and superheated steam pressure in the presence of load variations and disturbances of boiler.

  17. A low power dual-band multi-mode RF front-end for GNSS applications

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Hao; Li Zhiqun; Wang Zhigong, E-mail: zhhseu@gmail.com [Institute of RF- and OE- ICs, Southeast University, Nanjing 210096 (China)

    2010-11-15

    A CMOS dual-band multi-mode RF front-end for the global navigation satellite system receivers of all GPS, Bei-Dou, Galileo and Glonass systems is presented. It consists of a reconfigurable low noise amplifier (LNA), a broadband active balun, a high linearity mixer and a bandgap reference (BGR) circuit. The effect of the input parasitic capacitance on the input impedance of the inductively degenerated common source LNA is analyzed in detail. By using two different LC networks at the input port and the switched capacitor at the output port, the LNA can work at two different frequency bands (1.2 GHz and 1.5 GHz) under low power consumption. The active balun uses a hybrid-connection structure to achieve high bandwidth. The mixer uses the multiple gated transistors technique to acquire a high linearity under low power consumption but does not deteriorate other performances. The measurement results of the proposed front-end achieve a noise figure of 2.1/2.0 dB, again of 33.9/33.8 dB and an input 1-dB compression point of 0/1 dBm at 1227.6/1575.42 MHz. The power consumption is about 16 mW under a 1.8 V power supply.

  18. Comparison of high power large mode area and single mode 1908nm Tm-doped fiber lasers

    Science.gov (United States)

    Johnson, Benjamin R.; Creeden, Daniel; Limongelli, Julia; Pretorius, Herman; Blanchard, Jon; Setzler, Scott D.

    2016-03-01

    We compare large mode area (LMA) and single-mode (SM) double-clad fiber geometries for use in high power 1908nm fiber lasers. With a simple end-pumped architecture, we have generated 100W of 1908nm power with LMA fiber at 40% optical efficiency and 117W at 52.2% optical efficiency with single-mode fiber. We show the LMA fiber is capable of generating >200W and the SM fiber is capable of >300W at 1908nm. In all cases, the fiber lasers are monolithic power-oscillators with no free-space coupling.

  19. Leg joint power output during progressive resistance FES-LCE cycling in SCI subjects: developing an index of fatigue

    Directory of Open Access Journals (Sweden)

    Faghri Pouran D

    2008-04-01

    Full Text Available Abstract Background The purpose of this study was to investigate the biomechanics of the hip, knee and ankle during a progressive resistance cycling protocol in an effort to detect and measure the presence of muscle fatigue. It was hypothesized that knee power output can be used as an indicator of fatigue in order to assess the cycling performance of SCI subjects. Methods Six spinal cord injured subjects (2 incomplete, 4 complete between the ages of twenty and fifty years old and possessing either a complete or incomplete spinal cord injury at or below the fourth cervical vertebra participated in this study. Kinematic data and pedal forces were recorded during cycling at increasing levels of resistance. Ankle, knee and hip power outputs and resultant pedal force were calculated. Ergometer cadence and muscle stimulation intensity were also recorded. Results The main findings of this study were: (a ankle and knee power outputs decreased, whereas hip power output increased with increasing resistance, (b cadence, stimulation intensity and resultant pedal force in that combined order were significant predictors of knee power output and (c knowing the value of these combined predictors at 10 rpm, an index of fatigue can be developed, quantitatively expressing the power capacity of the knee joint with respect to a baseline power level defined as fatigue. Conclusion An index of fatigue was successfully developed, proportionalizing knee power capacity during cycling to a predetermined value of fatigue. The fatigue index value at 0/8th kp, measured 90 seconds into active, unassisted pedaling was 1.6. This indicates initial power capacity at the knee to be 1.6 times greater than fatigue. The fatigue index decreased to 1.1 at 2/8th kp, representing approximately a 30% decrease in the knee's power capacity within a 4 minute timespan. These findings suggest that the present cycling protocol is not sufficient for a rider to gain the benefits of FES and thus

  20. Temporal Shaping of High Peak Power Pulse Trains from a Burst-Mode Laser System

    Directory of Open Access Journals (Sweden)

    Jörg Körner

    2015-12-01

    Full Text Available It has been shown in the past that pulsed laser systems operating in the so-called “burst mode” are a beneficial approach to generate high peak power laser pulses at high repetition rates suitable for various applications. So far, most high-energy burst-mode laser systems put great effort into generating a homogeneous energy distribution across the burst duration, e.g., by shaping the pump pulse. In this work, we present a new shaping technique, which is able to produce arbitrary energy distributions within the burst by pre-shaping the seed pulse burst with a Pockels cell. Furthermore, this technique allows for the precompensation of any static modulations across the burst, which may be introduced during the subsequent amplification process. Therefore, a pulse burst with a uniform energy distribution can also be generated. The method is tested with an ultra-short pulse burst mode laser amplifier system producing bursts of a 1 ms duration with a pulse repetition rate of 1 MHz and a maximum output power of 800 W during the burst. Furthermore, a method to predict the influence of the amplifier on a non-uniformly shaped burst is presented and successfully tested to produce a pre-defined pulse shape after amplification.

  1. A low-cost biofuel cell with pH-dependent power output based on porous carbon as matrix.

    Science.gov (United States)

    Liu, Ying; Wang, Mingkui; Zhao, Feng; Liu, Baifeng; Dong, Shaojun

    2005-08-19

    A glucose/O2 biofuel cell (BFC) possessing a pH-dependent power output was fabricated by taking porous carbon (PC) as the matrix to load glucose oxidase or fungi laccase as the catalysts. The electrolytes in the anode and cathode compartments contain ferrocene monocarboxylic acid and 2,2'-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid) diammonium salt as the mediators, respectively. The power of the BFC was enhanced significantly by using PC as the matrix, rather than glassy carbon electrode. Additionally, the power output of the BFC decreases as the pH of the solution increases from 4.0 to 7.0, which provides a simple and efficient method to achieve the required power output. More importantly, the BFC can operate at pH 6.0, and even at pH 7.0, which overcomes the requirement for cathode solutions of pHBFC at neutral pH may provide a means to power medical devices implanted in physiological systems. The facile and low-cost fabrication of this BFC may enable its development for other applications.

  2. Evolutionary programming-based methodology for economical output power from PEM fuel cell for micro-grid application

    Science.gov (United States)

    El-Sharkh, M. Y.; Rahman, A.; Alam, M. S.

    This paper presents a methodology for finding the optimal output power from a PEM fuel cell power plant (FCPP). The FCPP is used to supply power to a small micro-grid community. The technique used is based on evolutionary programming (EP) to find a near-optimal solution of the problem. The method incorporates the Hill-Climbing technique (HCT) to maintain feasibility during the solution process. An economic model of the FCPP is used. The model considers the production cost of energy and the possibility of selling and buying electrical energy from the local grid. In addition, the model takes into account the thermal energy output from the FCPP and the thermal energy requirement for the micro-grid community. The results obtained are compared against a solution based on genetic algorithms. Results are encouraging and indicate viability of the proposed technique.

  3. Analysis of Possible Application of High-Temperature Nuclear Reactors to Contemporary Large-Output Steam Power Plants on Ships

    Directory of Open Access Journals (Sweden)

    Kowalczyk T.

    2016-04-01

    Full Text Available This paper is aimed at analysis of possible application of helium to cooling high-temperature nuclear reactor to be used for generating steam in contemporary ship steam-turbine power plants of a large output with taking into account in particular variable operational parameters. In the first part of the paper types of contemporary ship power plants are presented. Features of today applied PWR reactors and proposed HTR reactors are discussed. Next, issues of load variability of the ship nuclear power plants, features of the proposed thermal cycles and results of their thermodynamic calculations in variable operational conditions, are presented.

  4. Work output and efficiency at maximum power of linear irreversible heat engines operating with a finite-sized heat source.

    Science.gov (United States)

    Izumida, Yuki; Okuda, Koji

    2014-05-01

    We formulate the work output and efficiency for linear irreversible heat engines working between a finite-sized hot heat source and an infinite-sized cold heat reservoir until the total system reaches the final thermal equilibrium state with a uniform temperature. We prove that when the heat engines operate at the maximum power under the tight-coupling condition without heat leakage the work output is just half of the exergy, which is known as the maximum available work extracted from a heat source. As a consequence, the corresponding efficiency is also half of its quasistatic counterpart.

  5. Fast Reactive Power Sharing, Circulating Current and Resonance Suppression for Parallel Inverters Using Resistive-Capacitive Output Impedance

    DEFF Research Database (Denmark)

    Chen, Yandong; Guerrero, Josep M.; Shuai, Zhikang

    2016-01-01

    virtual impedance loop, the inverter provides fast transient response. Based on the RC-type inverter modeling, the comparative frequency-domain analysis of equivalent output impedances are discussed, and the impact of the virtual complex impedance over the circulating currents and high......In this paper, an inverter using resistivecapacitive output impedance (RC-type inverter) is proposed not only to provide fast reactive power sharing to support microgrid voltage, and but also to reduce circulating currents and damp high-frequency resonances among inverters. Introducing the RC...

  6. Acute effects of dynamic stretching exercise on power output during concentric dynamic constant external resistance leg extension.

    Science.gov (United States)

    Yamaguchi, Taichi; Ishii, Kojiro; Yamanaka, Masanori; Yasuda, Kazunori

    2007-11-01

    The purpose of the present study was to clarify the acute effect of dynamic stretching exercise on muscular performance during concentric dynamic constant external resistance (DCER, formally called isotonic) muscle actions under various loads. Concentric DCER leg extension power outputs were measured in 12 healthy male students after 2 types of pretreatment. The pretreatments were: (a) dynamic stretching treatment including 2 types of dynamic stretching exercises of leg extensors and the other 2 types of dynamic stretching exercises simulating the leg extension motion (2 sets of 15 times each with 30-second rest periods between sets; total duration: about 8 minutes), and (b) nonstretching treatment by resting for 8 minutes in a sitting position. Loads during measurement of the power output were set to 5, 30, and 60% of the maximum voluntary contractile (MVC) torque with isometric leg extension in each subject. The power output after the dynamic stretching treatment was significantly (p after the nonstretching treatment under each load (5% MVC: 468.4 +/- 102.6 W vs. 430.1 +/- 73.0 W; 30% MVC: 520.4 +/- 108.5 W vs. 491.0 +/- 93.0 W; 60% MVC: 487.1 +/- 100.6 W vs. 450.8 +/- 83.7 W). The present study demonstrated that dynamic stretching routines, such as dynamic stretching exercise of target muscle groups and dynamic stretching exercise simulating the actual motion pattern, significantly improve power output with concentric DCER muscle actions under various loads. These results suggested that dynamic stretching routines in warm-up protocols enhance power performance because common power activities are carried out by DCER muscle actions under various loads.

  7. MODES OF OPERATION OF THE SYSTEM OF TRACTION POWER AC USING REACTIVE POWER COMPENSATION DEVICES

    Directory of Open Access Journals (Sweden)

    I.V. Domanskyi

    2015-06-01

    Full Text Available The paper presents a systematic analysis of existing methods of reactive power compensation. The study of operating modes of the systems external and traction power supply is carried out. The methodology for selecting promising compensation schemes and energy-saving in the traction networks AC electrified railway lines is offered. The comparative evaluation of prospective controlled compensation devices shows that use of seamlessly adjustable devices with unregulated condensing the battery and with parallel translator regulated with thyristor unit and with filters to reduce harmonics bond to the large capital investments. For traction networks of domestic railways payback period is more than 10-15 years. The most promising for traction power supply today is a stepwise adjustable devices of reactive power compensation. For the efficient allocation of investments in programs and projects of modernization of system traction power supply developed by the methodology of selecting parameters and places placement devices transverse compensation in the system traction power supply, which is based on the use of software systems with imitation of interconnected instant circuits moving loads of electric rolling stock. Based on the results of multiple calculations full factor experiment when simulating work of the systems traction power supply during the day marked the most influencing factors on energy-saving in process freight on electric traction and established the extent of their influence. These include the overflows of power, the resistance of traction network, reactive power compensation, power supply circuits and the organization of trains. Innovative technologies energy-saving railways from positions of consideration their close connection with the systems external power supply are proposed.

  8. Practical considerations for integrating switch mode audio amplifiers and loudspeakers for a higher power efficiency

    DEFF Research Database (Denmark)

    Poulsen, Søren; Andersen, Michael Andreas E.

    2004-01-01

    An integration of electrodynamic loudspeakers and switch mode amplifiers has earlier been proposed in [1]. The work presented in this paper is related to the practical aspects of integration of switch mode audio amplifiers and electro dynamic loudspeakers, using the speaker’s voice coil as output...

  9. Practical considerations for integrating switch mode audio amplifiers and loudspeakers for a higher power efficiency

    DEFF Research Database (Denmark)

    Poulsen, Søren; Andersen, Michael Andreas E.

    2004-01-01

    An integration of electrodynamic loudspeakers and switch mode amplifiers has earlier been proposed in [1]. The work presented in this paper is related to the practical aspects of integration of switch mode audio amplifiers and electro dynamic loudspeakers, using the speaker’s voice coil as output...... filter, and the magnetic structure as heat sink for the amplifier....

  10. High Efficiency, High Linearity, Switch Mode Power Amplifiers for Varying envelop Signal Applications

    DEFF Research Database (Denmark)

    Tong, Tian; Sira, Daniel; Nielsen, Michael;

    2009-01-01

    using switch-mode power amplifier aided by various linearization techniques can present a feasible way to achieve both high linearity and high power efficiency. In this paper two different implementations of the switch-mode power amplifier a re p resented for varying envelop applications: the RF pulse...

  11. Low Power Continuous-Time Delta-Sigma ADC with Current Output DAC

    DEFF Research Database (Denmark)

    Marker-Villumsen, Niels; Jørgensen, Ivan Harald Holger; Bruun, Erik

    2015-01-01

    The paper presents a continuous-time (CT) DeltaSigma (∆Σ) analog-to-digital converter (ADC) using a current output digital-to-analog converter (DAC) for the feedback. From circuit analysis it is shown that using a current output DAC makes it possible to relax the noise requirements of the 1st...... integrator of the loopfilter, and thereby reduce the current consumption. Furthermore, the noise of the current output DAC being dependent on the ADC input signal level, enabling a dynamic range that is larger than the peak signal-to-noise ratio (SNR). The current output DAC is used in a 3rd order multibit...... CT ∆Σ ADC for audio applications, designed in a 0.18 µm CMOS process, with active-RC integrators, a 7-level Flash ADC quantizer and current output DAC for the feedback. From simulations the ADC achieves a dynamic range of 95.0 dB in the audio band, with a current consumption of 284 µA for a 1.7 V...

  12. Distributed mode filtering rod fiber amplifier delivering 292W with improved mode stability

    DEFF Research Database (Denmark)

    Laurila, Marko; Jørgensen, Mette Marie; Hansen, Kristian Rymann

    2012-01-01

    We demonstrate a high power fiber (85μm core) amplifier delivering up to 292Watts of average output power using a mode-locked 30ps source at 1032nm. Utilizing a single mode distributed mode filter bandgap rod fiber, we demonstrate 44% power improvement before the threshold-like onset of mode...

  13. Challenges and implementation aspects of switched-mode power supplies with digital control for automotive applications

    Science.gov (United States)

    Quenzer-Hohmuth, Samuel; Rosahl, Thoralf; Ritzmann, Steffen; Wicht, Bernhard

    2016-09-01

    Switched-mode power supplies (SMPS) convert an input DC-voltage into a higher or lower output voltage. In automotive, analog control is mostly used in order to keep the required output voltages constant and resistant to disturbances. The design of robust analog control for SMPS faces parameter variations of integrated and external passive components. Using digital control, parameter variations can be eliminated and the required area for the integrated circuit can be reduced at the same time. Digital control design bears challenges like the prevention of limit cycle oscillations and controller-wind-up. This paper reviews how to prevent these effects. Digital control loops introduce new sources for dead times in the control loop, for example the latency of the analog-to-digital-converter (ADC). Dead times have negative influence on the stability of the control loop, because they lead to phase delays. Consequently, low latency is one of the key requirements for analog-to-digital-converters in digitally controlled SMPS. Exploiting the example of a 500 kHz-buck converter with a crossover frequency of 70 kHz, this paper shows that the 5 µs-latency of a ΔΣ-analog-to-digital-converter leads to a reduction in phase margin of 126°. The latency is less critical for boost converters because of their inherent lower crossover frequencies. Finally, the paper shows a comparison between analog and digital control of SMPS with regard to chip area and test costs.

  14. The left ventricle as a mechanical engine: from Leonardo da Vinci to the echocardiographic assessment of peak power output-to-left ventricular mass.

    Science.gov (United States)

    Dini, Frank L; Guarini, Giacinta; Ballo, Piercarlo; Carluccio, Erberto; Maiello, Maria; Capozza, Paola; Innelli, Pasquale; Rosa, Gian M; Palmiero, Pasquale; Galderisi, Maurizio; Razzolini, Renato; Nodari, Savina

    2013-03-01

    The interpretation of the heart as a mechanical engine dates back to the teachings of Leonardo da Vinci, who was the first to apply the laws of mechanics to the function of the heart. Similar to any mechanical engine, whose performance is proportional to the power generated with respect to weight, the left ventricle can be viewed as a power generator whose performance can be related to left ventricular mass. Stress echocardiography may provide valuable information on the relationship between cardiac performance and recruited left ventricular mass that may be used in distinguishing between adaptive and maladaptive left ventricular remodeling. Peak power output-to-mass, obtained during exercise or pharmacological stress echocardiography, is a measure that reflects the number of watts that are developed by 100 g of left ventricular mass under maximal stimulation. Power output-to-mass may be calculated as left ventricular power output per 100 g of left ventricular mass: 100× left ventricular power output divided by left ventricular mass (W/100 g). A simplified formula to calculate power output-to-mass is as follows: 0.222 × cardiac output (l/min) × mean blood pressure (mmHg)/left ventricular mass (g). When the integrity of myocardial structure is compromised, a mismatch becomes apparent between maximal cardiac power output and left ventricular mass; when this occurs, a reduction of the peak power output-to-mass index is observed.

  15. Discussion on Power Market Mode of Central China

    Institute of Scientific and Technical Information of China (English)

    He Zhaocheng; Ye Qing

    2007-01-01

    @@ Central China power system is one of the large regional power grids carrying out power market demonstrative project. Because of lacking power market experience, a lot of problems need to be thoroughly discussed.

  16. Estimation of peak oxygen uptake from maximal power output among 9-10 year-old children in Lhasa, Tibet

    DEFF Research Database (Denmark)

    Bianba, B; Berntsen, S; Andersen, Lars Bo

    2010-01-01

    Chinese children aged 9-10 years, living in Lhasa at 3700 meters above sea level, V.O2peak was measured directly using a portable oxygen analyzer, and predicted from maximal power output (Wmax) using a maximal cycle ergometer test. RESULTS: In multiple regression analyses with V.O2peak as dependent......AIM: The aims of the present study of Tibetan and Han Chinese children were to establish prediction equations for peak oxygen uptake (V.O2peak) using conventional power output measures, and to compare with prediction models based on data from sea level. METHODS: In 25 Tibetan children and 15 Han...... with the equations from the present study. None of the three could accurately predict the direct measured V.O2peak, and predictions differed in an unsystematic manner, including over- or underestimation and no differentiation between genders. CONCLUSION: Peak oxygen uptake could be estimated from Wmax and sex...

  17. Moderate intensity, but not high intensity, treadmill exercise training alters power output properties in myocardium from aged rats.

    Science.gov (United States)

    Chung, Eunhee; Diffee, Gary M

    2012-11-01

    Aging is characterized by a progressive decline in cardiac function, but endurance exercise training has been shown to retard a number of deleterious effects of aging. However, underlying mechanisms by which exercise training improves age-related decrements in myocardial contractile function are not well understood. The purpose of this study was to determine the effects of exercise training on power output properties in permeablized (skinned) myocytes of old rats. Thirty-month-old rats were divided into sedentary control (C) and groups undergoing 11 weeks of treadmill exercise training at moderate intensity (MI) and at high intensity (HI). Peak power output normalized to maximal force was significantly increased in MI but not in HI compared to C with significant increases in atrial myosin light chain 1 in ventricle. These results suggest that MI exercise training is beneficial as a significant increase was seen in the ability of the myocardium to do work, but this effect was not seen with HI training.

  18. Measuring cutaneous thermal nociception in group-housed pigs using laser technique - effects of laser power output

    DEFF Research Database (Denmark)

    Herskin, Mette S.; Ladevig, Jan; Arendt-Nielsen, Lars

    2009-01-01

    of the metatarsus were examined using 15 gilts kept in one group and tested in individual feeding stalls after feeding. Increasing the power output led to gradually decreasing latency to respond (P ... are available, especially methodology which is applicable for pigs kept in group-housing without disturbing the daily routines of the animals. To validate a laser-based method to measure thermal nociception in group-housed pigs, we performed two experiments observing the behavioural responses toward cutaneous...... nociceptive stimulation from a computer-controlled CO2-laser beam applied to either the caudal part of the metatarsus on the hind legs or the shoulder region of gilts. In Exp. 1, effects of laser power output (0, 0.5, 1, 1.5 and 2 W) on nociceptive responses toward stimulation on the caudal aspects...

  19. Edge-facet pumped, multi-aperture, thin-disk laser geometry for very high average power output scaling

    Energy Technology Data Exchange (ETDEWEB)

    Zapata, Luis E.

    2004-12-21

    The average power output of a laser is scaled, to first order, by increasing the transverse dimension of the gain medium while increasing the thickness of an index matched light guide proportionately. Strategic facets cut at the edges of the laminated gain medium provide a method by which the pump light introduced through edges of the composite structure is trapped and passes through the gain medium repeatedly. Spontaneous emission escapes the laser volume via these facets. A multi-faceted disk geometry with grooves cut into the thickness of the gain medium is optimized to passively reject spontaneous emission generated within the laser material, which would otherwise be trapped and amplified within the high index composite disk. Such geometry allows the useful size of the laser aperture to be increased, enabling the average laser output power to be scaled.

  20. 670 nm nearly diffraction limited tapered lasers with more than 30% conversion efficiency and 1 W cw and 3 W pulsed output power

    Science.gov (United States)

    Sumpf, B.; Adamiec, P.; Zorn, M.; Wenzel, H.; Erbert, G.; Tränkle, G.

    2011-02-01

    Highly efficient 670 nm-tapered lasers with a vertical divergence of 31° (FWHM) will be presented. The devices are based on a GaInP single quantum well embedded in AlGaInP waveguide layers. Compared to previously reported material, the structure has an improved material quality with a transparency current density jtr = 165 A/cm2, an internal efficiency ηi = 0.75, small internal losses αi = 1.2 cm-1, and a good temperature stability with T0 = 120 K. 2 mm long tapered lasers were fabricated in a standard process, using reactive ion etching for the index-guided structures and ion implantation for the definition of the contact window in the tapered section. The properties of devices with 500 μm or 750 μm long ridge waveguide (RW) section and a flared section with 3° or 4° taper angle will be compared. In CW-operation an output power up to P = 1 W with a conversion efficiency of 30% and a beam propagation ratio M2 (2nd moments) smaller than 2.3 were obtained. In pulsed mode up to 3.3 W output power was measured.

  1. EDGE2D-EIRENE modelling of near SOL E r: possible impact on the H-mode power threshold

    Science.gov (United States)

    Chankin, A. V.; Delabie, E.; Corrigan, G.; Harting, D.; Maggi, C. F.; Meyer, H.; Contributors, JET

    2017-04-01

    Recent EDGE2D-EIRENE simulations of JET plasmas showed a significant difference between radial electric field (E r) profiles across the separatrix in two divertor configurations, with the outer strike point on the horizontal target (HT) and vertical target (VT) (Chankin et al 2016 Nucl. Mater. Energy, doi: 10.1016/j.nme.2016.10.004). Under conditions (input power, plasma density) where the HT plasma went into the H-mode, a large positive E r spike in the near scrape-off layer (SOL) was seen in the code output, leading to a very large E × B shear across the separatrix over a narrow region of a fraction of a cm width. No such E r feature was obtained in the code solution for the VT configuration, where the H-mode power threshold was found to be twice as high as in the HT configuration. It was hypothesised that the large E × B shear across the separatrix in the HT configuration could be responsible for the turbulence suppression leading to an earlier (at lower input power) L-H transition compared to the VT configuration. In the present work these ideas are extended to cover some other experimental observations on the H-mode power threshold variation with parameters which typically are not included in the multi-machine H-mode power threshold scalings, namely: ion mass dependence (isotope H-D-T exchange), dependence on the ion ∇B drift direction, and dependence on the wall material composition (ITER-like wall versus carbon wall in JET). In all these cases EDGE2D-EIRENE modelling shows larger positive E r spikes in the near SOL under conditions where the H-mode power threshold is lower, at least in the HT configuration.

  2. Low spectral modulation high-power output from a new AlGaAs superluminescent diode/optical amplifier structure

    Energy Technology Data Exchange (ETDEWEB)

    Alphonse, G.A.; Connolly, J.C.; Dinkel, N.A.; Palfrey, S.L.; Gilbert, D.B. (David Sarnoff Research Center, Princeton, New Jersey 08543-5300 (US))

    1989-11-27

    A double-heterojunction angled stripe AlGaAs device consisting of an index-guided ridge waveguide with gain-guided facet regions has produced cw output powers of 20 mW with less than 1% spectral modulation from a 300-{mu}m-long diode. These properties enable these devices to have important use in high-sensitivity fiber optic gyroscopes and as broadband traveling-wave optical amplifiers.

  3. Enhanced output power of GaN-based LEDs with embedded AlGaN pyramidal shells.

    Science.gov (United States)

    Tu, Shang-Ju; Sheu, Jinn-Kong; Lee, Ming-Lun; Yang, Chih-Ciao; Chang, Kuo-Hua; Yeh, Yu-Hsiang; Huang, Feng-Wen; Lai, Wei-Chih

    2011-06-20

    In this article, the characteristics of GaN-based LEDs grown on Ar-implanted GaN templates to form inverted Al0.27Ga0.83N pyramidal shells beneath an active layer were investigated. GaN-based epitaxial layers grown on the selective Ar-implanted regions had lower growth rates compared with those grown on the implantation-free regions. This resulted in selective growth, and formation of V-shaped concaves in the epitaxial layers. Accordingly, the inverted Al0.27Ga0.83N pyramidal shells were formed after the Al0.27Ga0.83N and GaN layers were subsequently grown on the V-shaped concaves. The experimental results indicate that the light-output power of LEDs with inverted AlGaN pyramidal shells was higher than those of conventional LEDs. With a 20 mA current injection, the output power was enhanced by 10% when the LEDs were embedded with inverted Al0.27Ga0.83N pyramidal shells. The enhancement in output power was primarily due to the light scattering at the Al0.27Ga0.83N/GaN interface, which leads to a higher escape probability for the photons, that is, light-extraction efficiency. Based on the ray tracing simulation, the output power of LEDs grown on Ar-implanted GaN templates can be enhanced by over 20% compared with the LEDs without the embedded AlGaN pyramidal shells, if the AlGaN layers were replaced by Al0.5Ga0.5N layers.

  4. Acute effects of dynamic stretching exercise on power output during concentric dynamic constant external resistance leg extension

    OpenAIRE

    YAMAGUCHI, TAICHI; Ishii, Kojiro; Yamanaka, Masanori; YASUDA, KAZUNORI

    2007-01-01

    AbstractThe purpose of the present study was to clarify the acute effect of dynamic stretching exercise on muscular performance during concentric dynamic constant external resistance (DCER, formally called isotonic) muscle actions under various loads. Concentric DCER leg extension power outputs were measured in 12 healthy male students after 2 types of pretreatment. The pre- treatments were: (a) dynamic stretching treatment including 2 types of dynamic stretching exercises of leg extensors an...

  5. Impact of power allocation strategies in long-haul few-mode fiber transmission systems.

    Science.gov (United States)

    Rafique, Danish; Sygletos, Stylianos; Ellis, Andrew D

    2013-05-06

    We report for the first time on the limitations in the operational power range of few-mode fiber based transmission systems, employing 28 Gbaud quadrature phase shift keying transponders, over 1,600 km. It is demonstrated that if an additional mode is used on a preexisting few-mode transmission link, and allowed to optimize its performance, it will have a significant impact on the pre-existing mode. In particular, we show that for low mode coupling strengths (weak coupling regime), the newly added variable power mode does not considerably impact the fixed power existing mode, with performance penalties less than 2dB (in Q-factor). On the other hand, as mode coupling strength is increased (strong coupling regime), the individual launch power optimization significantly degrades the system performance, with penalties up to ~6 dB. Our results further suggest that mutual power optimization, of both fixed power and variable power modes, reduces power allocation related penalties to less than 3 dB, for any given coupling strength, for both high and low differential mode delays.

  6. Sliding mode control of an autonomous parallel fuel cell-super capacitor power source

    Energy Technology Data Exchange (ETDEWEB)

    More, Jeronimo J. [Universidad Nacional de La Plata (UNLP), La Plata, Buenos Aires (Argentina). Facultad de Ingenieria. Lab. de Electronica Industrial, Control e Instrumentacion], Email: jmore@ing.unlp.edu.ar; Puleston, Paul F. [Consejo de Investigaciones Cientificas y Tecnicas (CONICET), Buenos Aires (Argentina); Kunusch, Cristian; Colomer, Jordi Riera I. [Universitat Politecnica de Catalunya, Barcelona (Spain). Inst. de Robotica i Informatica Industrial (IRII)

    2010-07-01

    Nowadays, hydrogen fuel cell (FC) based systems emerge as one promising renewable alternative to fossil fuel systems in automotive and residential applications. However, their output dynamic response is relatively slow, mostly due to water and reactant gases dynamics. To overcome this limitation, FC-super capacitors (SCs) topologies can be used. The latter is capable of managing very fast power variations, presenting in addition high power density, long life cycle and good charge/discharge efficiency. In this work, a FC-SCs-based autonomous hybrid system for residential applications is considered. The FC and SCs are connected in parallel, through two separate DC/DC converters, to a DC bus. Under steady state conditions, the FC must deliver the load power requirement, while maintaining the SCs voltage regulated to the desired value. Under sudden load variations, the FC current rate must be limited to assure a safe transition to the new point of operation. During this current rate limitation mode, the SCs must deliver or absorb the power difference. To this end, a sliding mode strategy is proposed to satisfy to control objectives. The main one is the robust regulation of the DC bus voltage, even in the presence of system uncertainties and disturbances, such as load changes and FC voltage variations. Additionally, a second control objective is attained, namely to guarantee the adequate level of charge in the SCs, once the FC reaches the new steady state operation point. In this way, the system can meet the load power demand, even under sudden changes, and it can also satisfy a power demand higher than the nominal FC power, during short periods. The proposed control strategy is evaluated exhaustively by computer simulation considering fast load variations. The results presented in this work, corresponds to the first stage of a R and D collaboration project for the design and development of a novel FC-SCs-based autonomous hybrid system. In the next phase, the proposed

  7. 10kV SiC MOSFET split output power module

    DEFF Research Database (Denmark)

    Beczkowski, Szymon; Li, Helong; Uhrenfeldt, Christian

    2015-01-01

    The poor body diode performance of the first generation of 10kV SiC MOSFETs and the parasitic turn-on phenomenon limit the performance of SiC based converters. Both these problems can potentially be mitigated using a split output topology. In this paper we present a comparison between a classical...

  8. Output regulation of large-scale hydraulic networks with minimal steady state power consumption

    NARCIS (Netherlands)

    Jensen, Tom Nørgaard; Wisniewski, Rafał; De Persis, Claudio; Kallesøe, Carsten Skovmose

    2014-01-01

    An industrial case study involving a large-scale hydraulic network is examined. The hydraulic network underlies a district heating system, with an arbitrary number of end-users. The problem of output regulation is addressed along with a optimization criterion for the control. The fact that the syste

  9. Maximizing Power Output in Homogeneous Charge Compression Ignition (HCCI) Engines and Enabling Effective Control of Combustion Timing

    Science.gov (United States)

    Saxena, Samveg

    Homogeneous Charge Compression Ignition (HCCI) engines are one of the most promising engine technologies for the future of energy conversion from clean, efficient combustion. HCCI engines allow high efficiency and lower CO2 emission through the use of high compression ratios and the removal of intake throttle valves (like Diesel), and allow very low levels of urban pollutants like nitric oxide and soot (like Otto). These engines, however, are not without their challenges, such as low power density compared with other engine technologies, and a difficulty in controlling combustion timing. This dissertation first addresses the power output limits. The particular strategies for enabling high power output investigated in this dissertation focus on avoiding five critical limits that either damage an engine, drastically reduce efficiency, or drastically increase emissions: (1) ringing limits, (2) peak in-cylinder pressure limits, (3) misfire limits, (4) low intake temperature limits, and (5) excessive emissions limits. The research shows that the key factors that enable high power output, sufficient for passenger vehicles, while simultaneously avoiding the five limits defined above are the use of: (1) high intake air pressures allowing improved power output, (2) highly delayed combustion timing to avoid ringing limits, and (3) using the highest possible equivalence ratio before encountering ringing limits. These results are revealed by conducting extensive experiments spanning a wide range of operating conditions on a multi-cylinder HCCI engine. Second, this dissertation discusses strategies for effectively sensing combustion characteristics on a HCCI engine. For effective feedback control of HCCI combustion timing, a sensor is required to quantify when combustion occurs. Many laboratory engines use in-cylinder pressure sensors but these sensors are currently prohibitively expensive for wide-scale commercialization. Instead, ion sensors made from inexpensive sparkplugs

  10. Effect of pedal cadence on mechanical power output and physiological variables

    Directory of Open Access Journals (Sweden)

    Jefferson da Silva Novaes

    2007-09-01

    Full Text Available The objective of this study was to compare the responses of the variables maximal power output (POmax, heart rate (HR, rating of perceived exertion (RPE, systolic blood pressure (SBP, diastolic blood pressure (DBP and double product (DP in the maximum reached load and during 60 and 90 rev.min-1 tests. The study sample consisted of 14 men (26.5 ± 3.5 years, 78.5 ± 7.8 kg and 178.1 ± 7.0 cm engaged in indoor cycling classes, who undertook two tests of maximum effort using Balke’s incremental protocol. The fi rst test (test60 consisted of a pedal cadence of 60 rev.min-1 throughout the test, until voluntary exhaustion or the appearance of signs or symptom limits. The second test (test90 was at a pedal cadence of 90 rev.min-1. There were no signifi cant difference between the cadences tested in terms of HRmax (test60: 189.7±12.0 beats.min-1; test90: 190.9±10.7 beats.min-1, RPEmax (test60: 20.0±0.3; test90: 20.0±1.0 or DBPmean (test60: 76.7±4.9 mmHg; test90: 79.1 ± 5.3 mmHg. On the other hand, the values of POmax (test60: 344.6±70.1 W; test90: 285.7±61.8 W, SBPmax (test60: 186.1±14.7 mmHg; test90: 202.1±21.5 mmHg and DPmax (test60: 35402.9±4431.7; test90: 38655.0±5270.5 were different. In relation to the behavior of the variables during the tests, there were signifi cant difference in HR between the tests up to a level of 225 W. It was observed that neither RPE or DBP indicated signifi cant difference in absolute power. There were only differences in SBP and DP between the cadences at 300 W absolute power. With this, it is clear that to carry out maximum tests, even in protocols that do not prescribe the pedal cadence, it appears thet a 60 rev.min-1 pedalling speed is indicated. ABSTRACT O objetivo deste estudo foi comparar as respostas das variáveis potência máxima (Pmax, freqüência cardíaca (FC, percepção de esforço (PE, pressão arterial sistólica (PAS, pressão arterial diastólica (PAD e duplo produto (DP na carga m

  11. The relationship between passive stiffness and muscle power output: influence of muscle cross-sectional area normalization.

    Science.gov (United States)

    Palmer, Ty B; Jenkins, Nathaniel D M; Thompson, Brennan J; Smith, Douglas B; Cramer, Joel T

    2014-01-01

    We examined the relationship between passive stiffness of posterior hip and thigh muscles and muscle power output before and after normalization of passive stiffness to muscle cross-sectional area (CSA). Pearson correlation coefficients (r) were used to assess the relationships between the normalized and non-normalized slopes of the initial (phase 1) and final (phase 2) portions of the angle-torque curve and peak power output (Pmax). A significant positive relationship was observed between the non-normalized slope of phase 1 and Pmax (r = 0.723; P ≤ 0.001); however, no correlations were observed between the normalized slope of phase 1 and Pmax (r = 0.244; P = 0.299) nor between Pmax and the normalized and non-normalized slopes of phase 2 (r = -0.159-0.418; P = 0.067-0.504). The findings suggest that muscle size, rather than stiffness, accounted for a significant portion of the variance in muscle power output. Copyright © 2013 Wiley Periodicals, Inc.

  12. CFD Study on Aerodynamic Power Output Changes with Inter-Turbine Spacing Variation for a 6 MW Offshore Wind Farm

    Directory of Open Access Journals (Sweden)

    Nak Joon Choi

    2014-11-01

    Full Text Available This study examined the aerodynamic power output change of wind turbines with inter-turbine spacing variation for a 6 MW wind farm composed of three sets of 2 MW wind turbines using computational fluid dynamics (CFD. The wind farm layout design is becoming increasingly important as the use of wind energy is steadily increasing. Among the many wind farm layout design parameters, the inter-turbine spacing is a key factor in the initial investment cost, annual energy production and maintenance cost. The inter-turbine spacing should be determined to maximize the annual energy production and minimize the wake effect, turbulence effect and fatigue load during the service lifetime of wind turbines. Therefore, some compromise between the aerodynamic power output of wind turbines and the inter-turbine spacing is needed. An actuator disc model with the addition of a momentum source was not used, and instead, a full 3-dimensional model with a tower and nacelle was used for CFD analysis because of its great technical significance. The CFD analysis results, such as the aerodynamic power output, axial direction wind speed change, pressure drop across the rotor of wind turbine, and wind speed deficit due to the wake effect with inter-turbine spacing variation, were studied. The results of this study can be applied effectively to wind farm layout design and evaluation.

  13. Detecting, categorizing and forecasting large romps in wind farm power output using meteorological observations and WPPT

    DEFF Research Database (Denmark)

    Cutler, N.; Kay, M.; Jacka, K.

    2007-01-01

    are not as complicated as Woolnorth Bluff Point. Large ramps are considered critical events for a wind power forecast for energy trading as well as managing power system security. A methodology is developed to detect large ramp events in the wind farm power data. Forty-one large ramp events are detected over I year...

  14. Power Restriction in Parts of Henan Province Will Affect Lead Output

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    <正>Since late July,temporary power cuts have been implemented in parts of Henan Province. Some smelting factories were informed by the local government that due to shortage of future power supply in this region,power outage would be implemented if necessary.

  15. 340 W average power output of diode-pumped composite ceramic YAG/Nd:YAG disk laser

    Science.gov (United States)

    Jia, Kai; Jiang, Yong; Yang, Feng; Deng, Bo; Hou, Tianjin; Guo, Jiawei; Chen, Dezhang; Wang, Hongyuan; Yang, Chuang; Peng, Chun

    2016-11-01

    We report on a diode-pumped composite ceramic disk laser in this paper. The composite ceramic YAG/Nd:YAG disk consists of 4 mm thick pure YAG and 2 mm thick Nd:YAG with 1.0 at.% doping concentration. The slope efficiency of the composite ceramic disk laser is 36.6% corresponding to the maximum optical-optical efficiency of 29.2%. Furthermore, 340 W average power output was achieved at the absorbed pump power of 1290 W.

  16. >220W output power at 355nm from a Q-switched diode-pumped solid-state laser

    Science.gov (United States)

    Hay, Nick; Slavinskis, Nerijus; Rodin, Aleksej M.; Kwon, Young Key

    2014-02-01

    We demonstrate 220 W average power at 355 nm from a diode-pumped acousto-optically Q-switched Nd:YAG laser using intracavity second harmonic generation and sum frequency mixing in a nested sub-cavity design. The laser generates linearly polarised pulses with duration 65 ns at repetition rate 10 kHz. Polarisation multiplexing is used to combine two orthogonal beams giving total output pulse energy 22 mJ with peak power cost of ownership DPSS lasers for high-throughput industrial processes in the UV.

  17. Plasma and cyclotron frequency effects on output power of the plasma wave-pumped free-electron lasers

    Science.gov (United States)

    Zolghadr, S. H.; Jafari, S.; Raghavi, A.

    2016-05-01

    Significant progress has been made employing plasmas in the free-electron lasers (FELs) interaction region. In this regard, we study the output power and saturation length of the plasma whistler wave-pumped FEL in a magnetized plasma channel. The small wavelength of the whistler wave (in sub-μm range) in plasma allows obtaining higher radiation frequency than conventional wiggler FELs. This configuration has a higher tunability by adjusting the plasma density relative to the conventional ones. A set of coupled nonlinear differential equations is employed which governs on the self-consistent evolution of an electromagnetic wave. The electron bunching process of the whistler-pumped FEL has been investigated numerically. The result reveals that for a long wiggler length, the bunching factor can appreciably change as the electron beam propagates through the wiggler. The effects of plasma frequency (or plasma density) and cyclotron frequency on the output power and saturation length have been studied. Simulation results indicate that with increasing the plasma frequency, the power increases and the saturation length decreases. In addition, when density of background plasma is higher than the electron beam density (i.e., for a dense plasma channel), the plasma effects are more pronounced and the FEL-power is significantly high. It is also found that with increasing the strength of the external magnetic field frequency, the power decreases and the saturation length increases, noticeably.

  18. The Influence of the Heat Source Temperature on the Multivane Expander Output Power in an Organic Rankine Cycle (ORC System

    Directory of Open Access Journals (Sweden)

    Piotr Kolasiński

    2015-04-01

    Full Text Available Organic Rankine Cycle (ORC power systems are nowadays an option for local and domestic cogeneration of heat and electric power. Very interesting are micropower systems for heat recovery from low potential (40–90 °C waste and renewable heat sources. Designing an ORC system dedicated to heat recovery from such a source is very difficult. Most important problems are connected with the selection of a suitable expander. Volumetric machines, such as scroll and screw expanders, are adopted as turbine alternative in small-power ORC systems. However, these machines are complicated and expensive. Vane expanders on the other hand are simple and cheap. This paper presents a theoretical and experimental analysis of the operation of a micro-ORC rotary vane expander under variable heat source temperature conditions. The main objective of this research was therefore a comprehensive analysis of relation between the vane expander output power and the heat source temperature. A series of experiments was performed using the micropower ORC test-stand. Results of these experiments are presented here, together with a mathematical description of multivane expanders. The analysis presented in this paper indicates that the output power of multivane expanders depend on the heat source temperature, and that multivane expanders are cheap alternatives to other expanders proposed for micropower ORC systems.

  19. Electrical output of bryophyte microbial fuel cell systems is sufficient to power a radio or an environmental sensor.

    Science.gov (United States)

    Bombelli, Paolo; Dennis, Ross J; Felder, Fabienne; Cooper, Matt B; Madras Rajaraman Iyer, Durgaprasad; Royles, Jessica; Harrison, Susan T L; Smith, Alison G; Harrison, C Jill; Howe, Christopher J

    2016-10-01

    Plant microbial fuel cells are a recently developed technology that exploits photosynthesis in vascular plants by harnessing solar energy and generating electrical power. In this study, the model moss species Physcomitrella patens, and other environmental samples of mosses, have been used to develop a non-vascular bryophyte microbial fuel cell (bryoMFC). A novel three-dimensional anodic matrix was successfully created and characterized and was further tested in a bryoMFC to determine the capacity of mosses to generate electrical power. The importance of anodophilic microorganisms in the bryoMFC was also determined. It was found that the non-sterile bryoMFCs operated with P. patens delivered over an order of magnitude higher peak power output (2.6 ± 0.6 µW m(-2)) than bryoMFCs kept in near-sterile conditions (0.2 ± 0.1 µW m(-2)). These results confirm the importance of the microbial populations for delivering electrons to the anode in a bryoMFC. When the bryoMFCs were operated with environmental samples of moss (non-sterile) the peak power output reached 6.7 ± 0.6 mW m(-2). The bryoMFCs operated with environmental samples of moss were able to power a commercial radio receiver or an environmental sensor (LCD desktop weather station).

  20. Electrical output of bryophyte microbial fuel cell systems is sufficient to power a radio or an environmental sensor

    Science.gov (United States)

    Dennis, Ross J.; Felder, Fabienne; Cooper, Matt B.; Royles, Jessica; Harrison, Susan T. L.; Smith, Alison G.; Howe, Christopher J.

    2016-01-01

    Plant microbial fuel cells are a recently developed technology that exploits photosynthesis in vascular plants by harnessing solar energy and generating electrical power. In this study, the model moss species Physcomitrella patens, and other environmental samples of mosses, have been used to develop a non-vascular bryophyte microbial fuel cell (bryoMFC). A novel three-dimensional anodic matrix was successfully created and characterized and was further tested in a bryoMFC to determine the capacity of mosses to generate electrical power. The importance of anodophilic microorganisms in the bryoMFC was also determined. It was found that the non-sterile bryoMFCs operated with P. patens delivered over an order of magnitude higher peak power output (2.6 ± 0.6 µW m−2) than bryoMFCs kept in near-sterile conditions (0.2 ± 0.1 µW m−2). These results confirm the importance of the microbial populations for delivering electrons to the anode in a bryoMFC. When the bryoMFCs were operated with environmental samples of moss (non-sterile) the peak power output reached 6.7 ± 0.6 mW m−2. The bryoMFCs operated with environmental samples of moss were able to power a commercial radio receiver or an environmental sensor (LCD desktop weather station). PMID:27853542

  1. Coordinated Power Dispatch of a PMSG based Wind Farm for Output Power Maximizing Considering the Wake Effect and Losses

    DEFF Research Database (Denmark)

    Zhang, Baohua; Hu, Weihao; Hou, Peng;

    2016-01-01

    The energy loss in a wind farm (WF) caused by wake interaction between wind turbines (WTs) is quite high, which can be reduced by proper active power dispatch. The electrical loss inside a WF by improper active power and reactive power dispatch is also considerable. In this paper, a coordinated a...

  2. Study on the Characteristics of Expander Power Output Used for Offsetting Pumping Work Consumption in Organic Rankine Cycles

    Directory of Open Access Journals (Sweden)

    Yu-Ting Wu

    2014-07-01

    Full Text Available The circulation pump in an organic Rankine cycle (ORC increases the pressure of the liquid working fluid from low condensing pressure to high evaporating pressure, and the expander utilizes the pressure difference to generate work. A portion of the expander output power is used to offset the consumed pumping work, and the rest of the expander power is exactly the net work produced by the ORC system. Because of the relatively great theoretical pumping work and very low efficiency of the circulation pump reported in previous papers, the characteristics of the expander power used for offsetting the pumping work need serious consideration. In particular, the present work examines those characteristics. It is found that the characteristics of the expander power used for offsetting the pumping work are satisfactory only under the condition that the working fluid absorbs sufficient heat in the evaporator and its specific volume at the evaporator outlet is larger than or equal to a threshold value.

  3. Sampled grating tunable twin-guide laser diodes with wide tuning range (40 nm) and large output power (10 mW)

    Science.gov (United States)

    Todt, R.; Jacke, T.; Meyer, R.; Adler, J.; Laroy, R.; Morthier, G.; Amann, M.-C.

    2006-03-01

    The sampled grating tunable twin-guide (SG-TTG) laser diode is a DFB-like tunable laser that employs Vernier-effect tuning to achieve wide wavelength tuning. In contrast to most other monolithic widely tunable lasers (which are usually DBR-type lasers), a phase tuning section is not needed and, hence, the SG-TTG laser requires at least one tuning current less than comparable devices.The devices provide full wavelength coverage over a 40 nm-broad tuning range that is centered at 1.54 μm. Its tuning behavior is quasi-continuous with up to 8.2 nm broad continuous tuning regions. High side-mode suppression (SMSR 35 dB) as well as large output power (P 10 mW) are obtained over the whole wavelength range from 1520.5 to 1561.5 nm.

  4. Supercontinuum generation based on all-normal-dispersion Yb-doped fiber laser mode-locked by nonlinear polarization rotation: Influence of seed's output port

    Science.gov (United States)

    Xiao, Xiaosheng; Hua, Yi

    2016-10-01

    All-normal-dispersion (ANDi) mode-locked Yb-doped fiber laser is a promising seed source for supercontinuum (SC) generation, due to its compact structure and broadband output. The influences of output ports of the ANDi laser mode-locked by nonlinear polarization rotation (NPR), on the generated SC are investigated. Two output ports of ANDi laser are considered, one of which is the conventional nonlinear polarization rotation (NPR) port and the other is extracted from a coupler after the NPR port. It is found that, the SC originated from the coupler port is much broader than that from the NPR port, which is validated by lots of experiments with different output parameters. Furthermore, the conclusion is verified and generalized to general ANDi lasers by numerical simulations, because the output pulse from coupler port could be cleaner than that from NPR port. Besides, there are no significant differences in the phase coherence and temporal stability between the SCs generated from both ports. Hence for the SC generation based on ANDi laser, it is preferred to use the pulse of coupler port (i.e. pulse after NPR port) serving as the seed source.

  5. Radiation monitoring data of the HTTR rise-to-power test. Results up to 30 MW operation on the rated operation mode

    Energy Technology Data Exchange (ETDEWEB)

    Ashikagaya, Yoshinobu; Yoshino, Toshiaki; Yasu, Katsuji; Sawa, Kazuhiro [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment; Kurosawa, Yoshiaki [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2002-12-01

    The High Temperature Engineering Test Reactor (HTTR) have completed the Rise-to-Power test of 9 MW (the single and parallel loaded operation) in the rated operation mode, the rated operation mode and the high-temperature test operation mode with a thermal output of 20 MW (the single and parallel loaded operation). After that the Rise-to-Power test in the rated operation mode (the reactor outlet coolant temperature of 850degC) with a thermal output of 30 MW (the single and parallel loaded operation) were performed between October 20, 2001 and March 11, 2002. This report describes the radiation monitoring data carried out during the HTTR Rise-to-Power test in the rated operation mode with a thermal output of 30 MW. The dose equivalent rate the radioactive air concentration in the working place where the radiation workers enter during the reactor operation were respectively the back ground level and the lower detection limit. There were no release of the radioactive gaseous effluents to the environment through the stack. These radiation monitoring showed clearly the radiation level were very low. This report also describes the part of radiation monitoring data in the HTTR first cycle operation carried out during July 6, 2002 from March 20, 2002. (author)

  6. Radiation monitoring data of the HTTR rise-to-power test. Results up to 30 MW operation on the rated operation mode

    Energy Technology Data Exchange (ETDEWEB)

    Ashikagaya, Yoshinobu; Yoshino, Toshiaki; Yasu, Katsuji; Sawa, Kazuhiro [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment; Kurosawa, Yoshiaki [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2002-12-01

    The High Temperature Engineering Test Reactor (HTTR) have completed the Rise-to-Power test of 9 MW (the single and parallel loaded operation) in the rated operation mode, the rated operation mode and the high-temperature test operation mode with a thermal output of 20 MW (the single and parallel loaded operation). After that the Rise-to-Power test in the rated operation mode (the reactor outlet coolant temperature of 850degC) with a thermal output of 30 MW (the single and parallel loaded operation) were performed between October 20, 2001 and March 11, 2002. This report describes the radiation monitoring data carried out during the HTTR Rise-to-Power test in the rated operation mode with a thermal output of 30 MW. The dose equivalent rate the radioactive air concentration in the working place where the radiation workers enter during the reactor operation were respectively the back ground level and the lower detection limit. There were no release of the radioactive gaseous effluents to the environment through the stack. These radiation monitoring showed clearly the radiation level were very low. This report also describes the part of radiation monitoring data in the HTTR first cycle operation carried out during July 6, 2002 from March 20, 2002. (author)

  7. Quality engineering tools focused on high power LED driver design using boost power stages in switch mode

    Science.gov (United States)

    Ileana, Ioan; Risteiu, Mircea; Marc, Gheorghe

    2016-12-01

    This paper is a part of our research dedicated to high power LED lamps designing. The boost-up selected technology wants to meet driver producers' tendency in the frame of efficiency and disturbances constrains. In our work we used modeling and simulation tools for implementing scenarios of the driver work when some controlling functions are executed (output voltage/ current versus input voltage and fixed switching frequency, input and output electric power transfer versus switching frequency, transient inductor voltage analysis, and transient out capacitor analysis). Some electrical and thermal stress conditions are also analyzed. Based on these aspects, a high reliable power LED driver has been designed.

  8. Efficient ways for setting up the operation of nuclear power stations in power systems in the base load mode

    Science.gov (United States)

    Aminov, R. Z.; Shkret, A. F.; Burdenkova, E. Yu.; Garievskii, M. V.

    2011-05-01

    The results obtained from studies of efficient ways and methods for organizing the operation of developing nuclear power stations in the base load mode are presented. We also show comparative efficiency of different scenarios for unloading condensing thermal power stations, cogeneration stations, combined-cycle power plants, nuclear power stations, and using off-peak electric energy for electricity-intensive loads: pumped-hydroelectric storage, electric-powered heat supply, and electrolysis of water for producing hydrogen and oxygen.

  9. Dynamics of 1.55 μm Wavelength Single-Mode Vertical-Cavity Surface-Emitting Laser Output under External Optical Injection

    Directory of Open Access Journals (Sweden)

    Kyong Hon Kim

    2012-01-01

    Full Text Available We review the temporal dynamics of the laser output spectrum and polarization state of 1.55 μm wavelength single-mode (SM vertical-cavity surface-emitting lasers (VCSELs induced by external optical beam injection. Injection of an external continuous-wave laser beam to a gain-switched SM VCSEL near the resonance wavelength corresponding to its main polarization-mode output was critical for improvement of its laser pulse generation characteristics, such as pulse timing-jitter reduction, linewidth narrowing, pulse amplitude enhancement, and pulse width shortening. Pulse injection of pulse width shorter than the cavity photon lifetime into the SM VCSEL in the orthogonal polarization direction with respect to its main polarization mode caused temporal delay of the polarization recovery after polarization switching (PS, and its delay was found to be the minimum at an optimized bias current. Polarization-mode bistability was observed even in the laser output of an SM VCSEL of a standard circularly cylindrical shape and used for all-optical flip-flop operations with set and reset injection pulses of very low pulse energy of order of the 3.5~4.5 fJ.

  10. State-of-the-art piezoelectric transformer-based switch mode power supplies

    DEFF Research Database (Denmark)

    Ekhtiari, Marzieh; Zhang, Zhe; Andersen, Michael A. E.

    2014-01-01

    Inductorless switch mode power supplies based on piezoelectric transformers are used to replace conventional transformers in high power density switch mode power supplies. Even though piezoelectric-based converters exhibit a high d egree of nonlinearity, it is desirable to use piezoelectric transfo...... discusses power supplies with the trend evaluation of piezoelectric transformer-based converter topologies and control methods. The challenges of piezoelectric transformers regarding soft switching capability and nonlinearity are addressed. This paper can be used as a guideline f or choosing a proper...... topology of piezoelectric-based switch mode power supply and a control method for the required application....

  11. Research on Interactive Control of Electrolytic Aluminum Load and Wind Power Output

    Directory of Open Access Journals (Sweden)

    Ge Simin

    2016-01-01

    Full Text Available With the large-scale wind power generation connected to Gansu power grid, electrolytic aluminium load has reached a certain scale at the same time, the vast majority of electrolytic aluminium load directly connects to power grid using 330kV transmission line. According to the physical characteristics and historical data, the continuous adjustment characteristic of electrolytic aluminium load is analysed. Based on this characteristic, a mathematical model for the electrolytic aluminium load is established. Aiming at reducing power network loss and wind power consumption, an optimization model based on the load regulation characteristics of electrolytic aluminium is constructed, which is optimized by particle swarm optimization algorithm. Based on the case data of Gansu power grid, the optimal method based on the load regulation characteristics of electrolytic aluminium is analysed and its feasibility is verified.

  12. Direct-conversion switching-mode audio power amplifier with active capacitive voltage clamp

    DEFF Research Database (Denmark)

    Ljusev, Petar; Andersen, Michael Andreas E.

    2005-01-01

    This paper discusses the advantages and problems when implementing direct energy conversion switching-mode audio power amplifiers. It is shown that the total integration of the power supply and Class D audio power amplifier into one compact direct converter can simplify the design, increase...... efficiency, reduce the product volume and lower its cost. As an example, the principle of operation and the measurements made on a direct-conversion switching-mode audio power amplifier with active capacitive voltage clamp are presented....

  13. Tuning beam power-splitting characteristics through modulating a photonic crystal slab’s output surface

    Science.gov (United States)

    Feng, Shuai; Xiao, Ting-Hui; Gan, Lin; Wang, Yi-Quan

    2017-01-01

    Light-beam-splitting characteristics are theoretically and experimentally studied in 2D square-lattice photonic crystals (PhCs) with delicately designed and modulated output surfaces. Compared with the traditional branch-waveguide and self-collimation-type PhC splitters, our proposed structure can not only split the input light beam into different numbers of branches but also realize the adjustment of their relative light intensities in each branch. Moreover, the influence of a light beam’s incident angle on both the output branch beams’ relative intensity and propagation direction is investigated. This proposed light beam splitter is able to work within a broad frequency range, and the propagation directions of the output split beams can be modified with the incident beam’s frequency. In addition, when the PhC device becomes thicker, a kind of light-beam-focusing phenomenon is observed. Advantageously, our light-beam-splitting device has no restriction as to the incident light beam’s location and width, so it is much more convenient and practical for achieving optical connection with other functional devices in complicated, large-scale, all-optical integrated circuits.

  14. Design of High-Voltage Switch-Mode Power Amplifier Based on Digital-Controlled Hybrid Multilevel Converter

    Directory of Open Access Journals (Sweden)

    Yanbin Hou

    2016-01-01

    Full Text Available Compared with conventional Class-A, Class-B, and Class-AB amplifiers, Class-D amplifier, also known as switching amplifier, employs pulse width modulation (PWM technology and solid-state switching devices, capable of achieving much higher efficiency. However, PWM-based switching amplifier is usually designed for low-voltage application, offering a maximum output voltage of several hundred Volts. Therefore, a step-up transformer is indispensably adopted in PWM-based Class-D amplifier to produce high-voltage output. In this paper, a switching amplifier without step-up transformer is developed based on digital pulse step modulation (PSM and hybrid multilevel converter. Under the control of input signal, cascaded power converters with separate DC sources operate in PSM switch mode to directly generate high-voltage and high-power output. The relevant topological structure, operating principle, and design scheme are introduced. Finally, a prototype system is built, which can provide power up to 1400 Watts and peak voltage up to ±1700 Volts. And the performance, including efficiency, linearity, and distortion, is evaluated by experimental tests.

  15. Output Filter Design for a Novel Dual-Input PV-Wind Power Converter by Energy Balance Principle

    Directory of Open Access Journals (Sweden)

    Chih-Lung Shen

    2016-09-01

    Full Text Available In this paper, a detailed and systematic derivation of the output filter in a novel dual-input photovoltaic (PV-wind converter (DIPWC is presented. The theoretical derivation is based on an energy balance principle. While the DIPWC operates in steady state, the amount of charged energy of the output filter will be equal to that of the energy pumped away within one switching cycle. From this zero net change in energy, the minimum value of the output filter can be found. With the determined value, the DIPWC is able to operate in continuous conduction for high power applications. The developed procedure of the inductance determination can be applied to other types of dual-input converters. Therefore, it makes significant contributions to the design toward a green-energy, multi-input converter. To verify the correctness of the mathematical analysis, the DIPWC—with the derived output inductance—is built and tested. Practical measurements and results have verified the inductance determination.

  16. Piezoelectric generator based on torsional modes for power harvesting from angular vibrations

    Institute of Scientific and Technical Information of China (English)

    CHEN Zi-guang; HU Yuan-tai; YANG Jia-shi

    2007-01-01

    Torsional vibration of a circular piezoelectric shell of polarized ceramics mounted on a rotationally vibrating base is analyzed. The shell is properly electroded and connected to a circuit such that an electric output is generated. The structure analyzed represents a piezoelectric generator for converting mechanical energy from angular vibrations to electrical energy. Analytical expressions and numerical results for the output voltage, current, power, efficiency and power density are given.

  17. Intra-Minute Cloud Passing Forecasting Based on a Low Cost IoT Sensor-A Solution for Smoothing the Output Power of PV Power Plants.

    Science.gov (United States)

    Sukič, Primož; Štumberger, Gorazd

    2017-05-13

    Clouds moving at a high speed in front of the Sun can cause step changes in the output power of photovoltaic (PV) power plants, which can lead to voltage fluctuations and stability problems in the connected electricity networks. These effects can be reduced effectively by proper short-term cloud passing forecasting and suitable PV power plant output power control. This paper proposes a low-cost Internet of Things (IoT)-based solution for intra-minute cloud passing forecasting. The hardware consists of a Raspberry PI Model B 3 with a WiFi connection and an OmniVision OV5647 sensor with a mounted wide-angle lens, a circular polarizing (CPL) filter and a natural density (ND) filter. The completely new algorithm for cloud passing forecasting uses the green and blue colors in the photo to determine the position of the Sun, to recognize the clouds, and to predict their movement. The image processing is performed in several stages, considering selectively only a small part of the photo relevant to the movement of the clouds in the vicinity of the Sun in the next minute. The proposed algorithm is compact, fast and suitable for implementation on low cost processors with low computation power. The speed of the cloud parts closest to the Sun is used to predict when the clouds will cover the Sun. WiFi communication is used to transmit this data to the PV power plant control system in order to decrease the output power slowly and smoothly.

  18. Intra-Minute Cloud Passing Forecasting Based on a Low Cost IoT Sensor—A Solution for Smoothing the Output Power of PV Power Plants

    Science.gov (United States)

    Sukič, Primož; Štumberger, Gorazd

    2017-01-01

    Clouds moving at a high speed in front of the Sun can cause step changes in the output power of photovoltaic (PV) power plants, which can lead to voltage fluctuations and stability problems in the connected electricity networks. These effects can be reduced effectively by proper short-term cloud passing forecasting and suitable PV power plant output power control. This paper proposes a low-cost Internet of Things (IoT)-based solution for intra-minute cloud passing forecasting. The hardware consists of a Raspberry PI Model B 3 with a WiFi connection and an OmniVision OV5647 sensor with a mounted wide-angle lens, a circular polarizing (CPL) filter and a natural density (ND) filter. The completely new algorithm for cloud passing forecasting uses the green and blue colors in the photo to determine the position of the Sun, to recognize the clouds, and to predict their movement. The image processing is performed in several stages, considering selectively only a small part of the photo relevant to the movement of the clouds in the vicinity of the Sun in the next minute. The proposed algorithm is compact, fast and suitable for implementation on low cost processors with low computation power. The speed of the cloud parts closest to the Sun is used to predict when the clouds will cover the Sun. WiFi communication is used to transmit this data to the PV power plant control system in order to decrease the output power slowly and smoothly. PMID:28505078

  19. Downscaling Solar Power Output to 4-Seconds for Use in Integration Studies: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Hummon, M.; Weekley, A.; Searight, K.; Clark, K.

    2013-10-01

    High penetration renewable integration studies require solar power data with high spatial and temporal accuracy to quantify the impact of high frequency solar power ramps on the operation of the system. Our previous work concentrated on downscaling solar power from one hour to one minute by simulation. This method used clearness classifications to categorize temporal and spatial variability, and iterative methods to simulate intra-hour clearness variability. We determined that solar power ramp correlations between sites decrease with distance and the duration of the ramp, starting at around 0.6 for 30-minute ramps between sites that are less than 20 km apart. The sub-hour irradiance algorithm we developed has a noise floor that causes the correlations to approach ~0.005. Below one minute, the majority of the correlations of solar power ramps between sites less than 20 km apart are zero, and thus a new method to simulate intra-minute variability is needed. These intra-minute solar power ramps can be simulated using several methods, three of which we evaluate: a cubic spline fit to the one-minute solar power data; projection of the power spectral density toward the higher frequency domain; and average high frequency power spectral density from measured data. Each of these methods either under- or over-estimates the variability of intra-minute solar power ramps. We show that an optimized weighted linear sum of methods, dependent on the classification of temporal variability of the segment of one-minute solar power data, yields time series and ramp distributions similar to measured high-resolution solar irradiance data.

  20. Resistance training priming activity improves upper body power output in rugby players: Implications for game day performance.

    Science.gov (United States)

    Mason, Billy R J; Argus, Christos K; Norcott, Ben; Ball, Nick

    2016-07-05

    'Priming' or pre-activation strategies performed in the hours leading into competition have been suggested to improve game day performance. Therefore, this study assessed the effectiveness of a resistance training priming activity on eliciting changes in lower- and upper-body power output, along with perceptual measures. To assess these changes, 13 state level rugby players (aged 18.5 ± 0.5 years) completed a test retest protocol using a counterbalanced crossover design. Perceptual (readiness to perform questionnaire) and performance measures (20 kg counter-movement jump (CMJ), 20 kg bench throw) were completed prior to either a control (rest) or priming activity (four sets of three banded back squats and banded bench press). Following a one hour and 45 minute recovery period, perceptual and performance measures were repeated. Readiness to perform showed no meaningful differences pre and post intervention. Bench throw peak power (8.5 ± 5.8%, 90% confidence limit; ppriming activity when compared to the control trial. CMJ peak power (3.4 ± 4.9%; p>0.05) had a small decrease following the priming activity when compared with the control trial. Therefore, completing a priming activity one hour and 45 minutes prior to competition is recommended to improve upper body power output. However, further research into lower body priming protocols should be conducted before implementing a lower body priming activity prior to competition.

  1. Power-ratio tunable dual-wavelength laser using linearly variable Fabry-Perot filter as output coupler.

    Science.gov (United States)

    Wang, Xiaozhong; Wang, Zhongfa; Bu, Yikun; Chen, Lujian; Cai, Guoxiong; Huang, Wencai; Cai, Zhiping; Chen, Nan

    2016-02-01

    For a linearly variable Fabry-Perot filter, the peak transmission wavelengths change linearly with the transverse position shift of the substrate. Such a Fabry-Perot filter is designed and fabricated and used as an output coupler of a c-cut Nd:YVO4 laser experimentally in this paper to obtain a 1062 and 1083 nm dual-wavelength laser. The peak transmission wavelengths are gradually shifted from 1040.8 to 1070.8 nm. The peak transmission wavelength of the Fabry-Perot filter used as the output coupler for the dual-wavelength laser is 1068 nm and resides between 1062 and 1083 nm, which makes the transmissions of the desired dual wavelengths change in opposite slopes with the transverse shift of the filter. Consequently, powers of the two wavelengths change in opposite directions. A branch power, oppositely tunable 1062 and 1083 nm dual-wavelength laser is successfully demonstrated. Design principles of the linear variable Fabry-Perot filter used as an output coupler are discussed. Advantages of the method are summarized.

  2. Quantifying the Impact of Wind Turbine Wakes on Power Output at Offshore Wind Farms

    DEFF Research Database (Denmark)

    Barthelmie, Rebecca Jane; Pryor, Sara; Frandsen, Sten Tronæs;

    2010-01-01

    . Detailed data ensembles of power losses due to wakes at the large wind farms at Nysted and Horns Rev are presented and analyzed. Differences in turbine spacing (10.5 versus 7 rotor diameters) are not differentiable in wake-related power losses from the two wind farms. This is partly due to the high...... to an unacceptably high degree of uncertainty....

  3. Human Muscle Power Output during Upper- and Lower-Body Exercises.

    Science.gov (United States)

    Siegel, Judith A.; Gilders, Roger M.; Staron, Robert S.; Hagerman, Fredrick C.

    2002-01-01

    Evaluated the use of traditional resistance training equipment in measuring muscular power, measuring the velocity of movement through a measured distance during maximal effort lifts using a Smith rack. Data collected on male volunteers indicated that this method of evaluating muscle power was reliable, although it was not predictive of muscle…

  4. Powering low-power implants using PZT transducer discs operated in the radial mode

    Science.gov (United States)

    Sanni, Ayodele; Vilches, Antonio

    2013-11-01

    This paper reports experimental results that are used to compare operation characteristics of lead zirconate titanate (PZT) piezoelectric ceramic discs operated in the radial mode. The devices are driven to radially vibrate at their lowest fundamental resonant frequency and thus transmit and receive power when immersed in a liquid phantom. A number of 1 mm × 10 mm (thickness × diameter) PZT discs are characterized experimentally within a propagation tank and results discussed. On the basis of these measured characteristics, a novel application is developed and reported for the first time. This consists of a tuned LC resonator circuit which is used at the receiving disc to maximize sensitivity as well as a Seiko start-up IC S-882Z which is employed to charge a capacitor that drives a PIC microcontroller (μC) once the voltage exceeds 2 V DC. We show that a mean input power of 486 mW RMS results in 976 μW RMS received over a range of 80 mm and that this is sufficient to periodically (every 60 s) power the μC to directly drive a red LED for 5 ms with a current of 4.8 mA/flash. This approach is suitable for low-power, periodically activated analogue bio-implant applications.

  5. Modeling Operating Modes for the Monju Nuclear Power Plant

    DEFF Research Database (Denmark)

    Lind, Morten; Yoshikawa, Hidekazu; Jørgensen, Sten Bay

    2012-01-01

    The specification of supervision and control tasks in complex processes requires definition of plant states on various levels of abstraction related to plant operation in start-up, normal operation and shut-down. Modes of plant operation are often specified in relation to a plant decomposition...... of the process plant, its function and its structural elements. The paper explains how the means-end concepts of MFM can be used to provide formalized definitions of plant operation modes. The paper will introduce the mode types defined by MFM and show how selected operation modes can be represented...

  6. Strength, power output and symmetry of leg muscles: effect of age and history of falling.

    Science.gov (United States)

    Perry, Mark C; Carville, Serena F; Smith, I Christopher H; Rutherford, Olga M; Newham, Di J

    2007-07-01

    Risk factors for medically unexplained falls may include reduced muscle power, strength and asymmetry in the lower limbs. Conflicting reports exist about strength and there is little information about power and symmetry. Forty-four healthy young people (29.3 +/- 0.6 years), 44 older non-fallers (75.9 +/- 0.6 years), and 34 older fallers (76.4 +/- 0.8 years) were studied. Isometric, concentric and eccentric strength of the knee and ankle muscles and leg extension power were measured bilaterally. The younger group was stronger in all muscles and types of contraction than both older groups (P muscles and types of contraction but overall the fallers had 85% of the strength and 79% of the power of the non-fallers (P muscles and some contraction types. This was similar overall in the two older groups. Both older groups had greater asymmetry in power than the young (P muscle groups.

  7. Anodic microbial community diversity as a predictor of the power output of microbial fuel cells.

    Science.gov (United States)

    Stratford, James P; Beecroft, Nelli J; Slade, Robert C T; Grüning, André; Avignone-Rossa, Claudio

    2014-03-01

    The relationship between the diversity of mixed-species microbial consortia and their electrogenic potential in the anodes of microbial fuel cells was examined using different diversity measures as predictors. Identical microbial fuel cells were sampled at multiple time-points. Biofilm and suspension communities were analysed by denaturing gradient gel electrophoresis to calculate the number and relative abundance of species. Shannon and Simpson indices and richness were examined for association with power using bivariate and multiple linear regression, with biofilm DNA as an additional variable. In simple bivariate regressions, the correlation of Shannon diversity of the biofilm and power is stronger (r=0.65, p=0.001) than between power and richness (r=0.39, p=0.076), or between power and the Simpson index (r=0.5, p=0.018). Using Shannon diversity and biofilm DNA as predictors of power, a regression model can be constructed (r=0.73, pmicrobial communities.

  8. Core Power Control of the fast nuclear reactors with estimation of the delayed neutron precursor density using Sliding Mode method

    Energy Technology Data Exchange (ETDEWEB)

    Ansarifar, G.R., E-mail: ghr.ansarifar@ast.ui.ac.ir; Nasrabadi, M.N.; Hassanvand, R.

    2016-01-15

    Highlights: • We present a S.M.C. system based on the S.M.O for control of a fast reactor power. • A S.M.O has been developed to estimate the density of delayed neutron precursor. • The stability analysis has been given by means Lyapunov approach. • The control system is guaranteed to be stable within a large range. • The comparison between S.M.C. and the conventional PID controller has been done. - Abstract: In this paper, a nonlinear controller using sliding mode method which is a robust nonlinear controller is designed to control a fast nuclear reactor. The reactor core is simulated based on the point kinetics equations and one delayed neutron group. Considering the limitations of the delayed neutron precursor density measurement, a sliding mode observer is designed to estimate it and finally a sliding mode control based on the sliding mode observer is presented. The stability analysis is given by means Lyapunov approach, thus the control system is guaranteed to be stable within a large range. Sliding Mode Control (SMC) is one of the robust and nonlinear methods which have several advantages such as robustness against matched external disturbances and parameter uncertainties. The employed method is easy to implement in practical applications and moreover, the sliding mode control exhibits the desired dynamic properties during the entire output-tracking process independent of perturbations. Simulation results are presented to demonstrate the effectiveness of the proposed controller in terms of performance, robustness and stability.

  9. Myosin light chain phosphorylation is required for peak power output of mouse fast skeletal muscle in vitro.

    Science.gov (United States)

    Bowslaugh, Joshua; Gittings, William; Vandenboom, Rene

    2016-11-01

    The skeletal myosin light chain kinase (skMLCK) catalyzed phosphorylation of the myosin regulatory light chain (RLC) is associated with potentiation of force, work, and power in rodent fast twitch muscle. The purpose of this study was to compare concentric responses of EDL from wild-type (WT) and skMLCK devoid (skMLCK(-/-)) muscles at a range of shortening speeds (0.05 to 0.70 V max) around that expected to produce maximal power (in vitro, 25 °C) both before (unpotentiated) and after (potentiated) a potentiating stimulus (PS). When collapsed across all speeds tested, neither unpotentiated force, work, or power differed between genotypes (all data n = 10, P muscles. For example, when collapsed across the six fastest speeds we tested, both concentric force and power were increased 30-34 % in WT but only 15-17 % in skMLCK(-/-) muscles. In contrast, at the two slowest speeds, these parameters were increased in WT but decreased in skMLCK(-/-) muscles (8-10 and 7-9 %, respectively). Intriguingly, potentiation of concentric force and power was optimal near speeds producing maximal power in both genotypes. Because the PS elevated RLC phosphorylation above resting levels in WT but not in skMLCK(-/-) muscles, our data suggest that skMLCK-catalyzed phosphorylation of the RLC is required for maximal concentric power output of mouse EDL muscle stimulated at high frequency in vitro.

  10. Impact of gain saturation on the mode instability threshold in high-power fiber amplifiers

    DEFF Research Database (Denmark)

    Hansen, Kristian Rymann; Lægsgaard, Jesper

    2014-01-01

    We present a coupled-mode model of transverse mode instability in high-power fiber amplifiers, which takes the effect of gain saturation into account. The model provides simple semi-analytical formulas for the mode instability threshold, which are valid also for highly saturated amplifiers...

  11. Effect of light concentration by flat mirror reflectors on the electrical power output of the photovoltaic panel

    Directory of Open Access Journals (Sweden)

    Sathyanarayana P.

    2014-03-01

    Full Text Available Renewable energy area is gaining more prominence in recent times. In particular, conversion of solar energy in to electricity by using PV Panel has attracted significant researchers. In this work, the effect of light concentration by reflectors and inclination of PV panel on power output of PV panel has been investigated. Flat mirror reflectors were fixed to PV panel to increase the light intensity. The panel was kept either horizontally or at 30° inclination to horizontal. The effect on I-V curve, power curve, fill factor and efficiency are discussed. A significant improvement in short circuit current, power and a small increase in efficiency is perceived with the introduction of reflectors.

  12. ONU power saving modes in next generation optical access networks: progress, efficiency and challenges.

    Science.gov (United States)

    Dixit, Abhishek; Lannoo, Bart; Colle, Didier; Pickavet, Mario; Demeester, Piet

    2012-12-10

    The optical network unit (ONU), installed at a customer's premises, accounts for about 60% of power in current fiber-to-the-home (FTTH) networks. We propose a power consumption model for the ONU and evaluate the ONU power consumption in various next generation optical access (NGOA) architectures. Further, we study the impact of the power savings of the ONU in various low power modes such as power shedding, doze and sleep.

  13. The acute effect of lower-body training on average power output measured by loaded half-squat jump exercise

    Directory of Open Access Journals (Sweden)

    Matúš Krčmár

    2015-09-01

    Full Text Available Background: High muscular power output is required in many athletic endeavors in order for success to be achieved. In the scientific community postactivation potentiation and its effect on performance are often discussed. There are many studies where the effect of resistance exercise on motor performance (such as vertical jump performance and running speed has been investigated but only a few of them studied power output. Objective: The purpose of this study was to determine the acute responses to a 2 set loaded half-squat jumps and 2 set loaded back half-squat protocols designed to induce the acute maximum average power output during loaded half-squat jumps. Methods: A randomized cross-over design was used. 11 participants of this study performed 3 trials in randomized order separated by at least 48 hours where maximum average power output was measured. The specific conditioning activities were comprised of 2 sets and 4 repetitions of half-squat jumps, 2 sets and 4 repetitions of back half-squat exercises and a control protocol without an intervention by specific a conditioning activity. Participants were strength trained athletes with different sport specializations (e.g. ice-hockey, volleyball. Mean age of the athletes was 22 ± 1.8 years, body mass 80 ± 7.1 kg and body height 185 ± 6.5 cm. Analysis of variance with repeated measures was used to determine differences between pre- and post-condition in each protocol, as well as between conditioning protocols, and also effect size was used to evaluate practical significance. Results: Maximum average power was significantly enhanced after application of the half-squat jump condition protocol (1496.2 ± 194.5 to 1552 ± 196.1 W, Δ ~ 3.72%, p < .001 and after application of the back half-squat protocol (1500.7 ± 193.2 to 1556 ± 191.2 W, Δ ~ 3.68%, p < .001 after 10 min of rest. Power output after control protocol was

  14. Influence of nonlinearities on the power output of the Self-Oscillating Fluidic Heat Engine (SOFHE)

    Science.gov (United States)

    Tessier-Poirier, A.; Monin, T.; Léveillé, E.; Formosa, F.; Monfray, S.; Fréchette, L. G.

    2016-11-01

    In this paper, it is shown that two non-linearities drive the oscillations amplitude and the potential power density of the Self-Oscillating Fluidic Heat Engine (SOFHE). This new type of engine converts thermal energy into mechanical energy by producing self-sustained oscillations of a liquid column from a continuous heat source to power wireless sensors from waste heat. The underlying theoretical modeling shows that the pressure and the temperature nonlinearities limit the final oscillations amplitude, hence its achievable power density.

  15. Technical Design of Flexible Thin-Film Solar Heating Clothes with Switchable Output Power

    Directory of Open Access Journals (Sweden)

    Zhao Yu Xiao

    2016-01-01

    Full Text Available This research focuses on the research and development of thermal clothes through technical design, by adopting unique removable electronic equipment and applying carbon fiber material to thermal clothes against cold, so as to meet the requirements of active heating and passive warmth retention. Firstly, the specification of power supply system was determined in accordance with the requirements of power system, and the specification of charging system was determined according to the specification of power system. Then circuit system was designed and tested. Fianlly, the electronic device was configured on the clothes appropriately, so that it should be conforms to ergonomic principles, convenient and fast.

  16. Local and regional effects of large scale atmospheric circulation patterns on winter wind power output in Western Europe

    Science.gov (United States)

    Zubiate, Laura; McDermott, Frank; Sweeney, Conor; O'Malley, Mark

    2014-05-01

    Recent studies (Brayshaw, 2009, Garcia-Bustamante, 2010, Garcia-Bustamante, 2013) have drawn attention to the sensitivity of wind speed distributions and likely wind energy power output in Western Europe to changes in low-frequency, large scale atmospheric circulation patterns such as the North Atlantic Oscillation (NAO). Wind speed variations and directional shifts as a function of the NAO state can be larger or smaller depending on the North Atlantic region that is considered. Wind speeds in Ireland and the UK for example are approximately 20 % higher during NAO + phases, and up to 30 % lower during NAO - phases relative to the long-term (30 year) climatological means. By contrast, in southern Europe, wind speeds are 15 % lower than average during NAO + phases and 15 % higher than average during NAO - phases. Crucially however, some regions such as Brittany in N.W. France have been identified in which there is negligible variability in wind speeds as a function of the NAO phase, as observed in the ERA-Interim 0.5 degree gridded reanalysis database. However, the magnitude of these effects on wind conditions is temporally and spatially non-stationary. As described by Comas-Bru and McDermott (2013) for temperature and precipitation, such non-stationarity is caused by the influence of two other patterns, the East Atlantic pattern, (EA), and the Scandinavian pattern, (SCA), which modulate the position of the NAO dipole. This phenomenon has also implications for wind speeds and directions, which has been assessed using the ERA-Interim reanalysis dataset and the indices obtained from the PC analysis of sea level pressure over the Atlantic region. In order to study the implications for power production, the interaction of the NAO and the other teleconnection patterns with local topography was also analysed, as well as how these interactions ultimately translate into wind power output. The objective is to have a better defined relationship between wind speed and power

  17. Peak current mode control of three-phase boost rectifiers in discontinuous conduction mode for small wind power generators

    Energy Technology Data Exchange (ETDEWEB)

    Carranza, O. [Escuela Superior de Computo, Instituto Politecnico Nacional (Mexico); Garcera, G.; Figueres, E. [Grupo de Sistemas Electronicos Industriales del Departamento de Ingenieria Electronica, Universidad Politecnica de Valencia (Spain); Gonzalez, L.G. [Departamento de Ingenieria Electronica y Comunicaciones, Universidad de los Andes (Venezuela)

    2010-08-15

    This paper presents a peak current mode control scheme of a boost rectifier with low distortion of the input current for wind power systems based on permanent magnet synchronous generators with variable speed operation. The three-phase boost rectifier is operated in discontinuous conduction mode (DCM), and power factor correction techniques are applied. It is shown that the DCM operation significantly reduces the total harmonic distortion of the currents in the permanent magnet synchronous generator, increasing the power factor of the system, so that the vibrations and mechanical stress of the generator are minimized. The characteristics of the DCM boost rectifier are studied considering: (1) the series resistance of the inductors; (2) the modeling and adjustment of peak current mode control yielding a stable loop; (3) the design of an input filter that reduces the switching noise in the currents of the generator. (author)

  18. 电激励连续波DF化学激光器输出功率的实验研究%Experimental Study on Output Power of Discharge Exited CW DF Chemical Laser

    Institute of Scientific and Technical Information of China (English)

    刘现魁; 赵海涛; 孟昭荣; 王振华; 周小红

    2011-01-01

    The relationship between output power of discharge exited CW I)F chemical Laser when mass flux controller is used as flux monitoring system and N2, main-He, NF3, assistant-He, D2 is investigated. Considering output instability of the laser and measurement error of power meter, maximum output power about 12.5W and continuous running time about 30min of the laser fundamental mode is realized. Compared with output power of the same laser when rotameter in use, higher mass flux stability was got and the laser ran output higher power and has the better output -stability when mass flux controller in use.%电激励连续波DF化学激光器使用质量流量控制器作为流量监控系统时,对其输出功率与N2气、主He、NF3气、副He、D2气的流量关系进行了研究.考虑到激光器的输出不稳定性和功率计的测量误差,实现了激光器基模最大输出功率约为12.5 W,连续运行时间约30 min.并与使用浮子流量计做为流量监控系统的同一激光器的输出功率进行了比较,结果显示,使用质量流量控制器时,流量稳定性更高,激光器可以输出更高功率,且具有更好的功率稳定性.

  19. Mitigation of Output Power Fluctuations in Utility Grid using Three Phase Distribution Generation

    Directory of Open Access Journals (Sweden)

    K.Sri Chandan,

    2010-12-01

    Full Text Available Renewable electricity generation has never seen the level of investment and incentives that have been put in place by governments around the world during the last decade. However, despite the envisaged environmental and security of supply benefits that the harvesting of indigenous, renewable sources might bring about, their integration into the power system creates significant challenges to both the network operators and developers. The power quality challenges become even greater when large volumes of renewable generation capacity are connected to distribution networks, traditionally designed to be passive circuits with unidirectional power flows. This paper presents two schemes to meet the different power quality challenges in the utility grid due to Distribution Generation. In this first scheme is DSTATCOM and second is three phase Distributed Generation. This work is aimed at demonstrating, from the planning perspective, the benefits that the adoption of the different compensators might bring the system to a ‘fit and forget’ approach.

  20. Multi-Purpose Low Voltage Dual Output DC-DC Converter For 100V Power Bus Telecom Platform

    Science.gov (United States)

    Galiana, D.; Mollard, J. M.

    2011-10-01

    The decreasing supply voltages of digital electronic and high speed ADC (Analog to Digital Converter) and DAC (Digital to Analog Converter) require flexible and high current secondary power distribution system. In the frame of the Inmarsat I-XL program, a 12 kW geomobile SatCom satellite, with 100 V regulated power bus, a multi purpose dual output converter was developed for the payload processor as a building block. After a short introduction on the main performance requirements, the baseline architecture is presented. The main drivers of the architecture are reliability, adjustability, radiation tolerant and single event free, volume and mass. The combination of all these constraints highlights the need of significant breakthrough in various domains. Many research results related to packaging and power electronic topics are brought up. These results directly drive the adopted solution presented in the next step followed by a description of the integration of the defined building block in the Inmarsat I-XL payload IP (Integrated Processor). Finally, the main electrical performances such as output ripple and spikes, load step transient and stability are summarized.