Sample records for zero-voltage-transition pwm switching

  1. A new Zero-Voltage-Transition PWM switching cell

    Grigore, V. [Electronics and Telecommunications Faculty `Politebuica` University Bucharest (Romania); Kyyrae, J. [Helsinki University of Technology, Otaniemi (Finland): Institute of Intelligent Power Electronics


    In this paper a new Zero-Voltage-Transition (ZVT) PWM switching cell is presented. The proposed switching cell is composed of the normal hard-switched PWM cell (consisting of one active switch and one passive switch), plus an auxiliary circuit (consisting of one active switch and some reactive components). The auxiliary circuit is inactive during the ON and OFF intervals of the switches in the normal PWM switch. However, the transitions between the two states are controlled by the auxiliary circuit. Prior to turn-on, the voltage across the active switch in the PWM cell is forced to zero, thus the turn-on losses of the active switch are practically eliminated. At turn-off the auxiliary circuit behaves like a non-dissipative passive snubber reducing the turn-off losses to a great extent. Zero-Voltage-Transition switching technique almost eliminates switching losses. The active switch operates under ZVT conditions, the passive switch (diode) has a controlled reverse recovery, and the switch in the auxiliary circuit operates under Zero-Current-Switching (ZCS) conditions. (orig.) 6 refs.

  2. 零电压转换PWMDC/DC变换器的研究%Research on Zero-voltage-transition PWM DC/DC Converters

    高原; 邱新芸


    介绍了PWM DC/DC变换器的软开关控制.阐述了零电压转换PWM DC/DC变换器的缺点.研究了带吸收电容的零电压转换PWM DC/DC变换器电路.给出了仿真电路和仿真结果.

  3. High Frequency Soft Switching Of PWM Boost Converter Using Auxiliary Resonant Circuit

    C. P. Sai Kiran


    Full Text Available This thesis presents High frequency Soft Switching DC-DC boost Converter. The circuit consists of a general Boost Converter with an additional resonant circuit which has a switch, inductor, capacitor and a diode.In general Boost Converter circuits have snubber circuits where switching losses are dissipated in external passive resistors; which is known as hard switching. As the switching frequency of PWM converters is increased its switching losses and conduction losses also increases. This restricts the use of PWM technique. New Zero Voltage Transition-Zero Current Transition (ZVT-ZCT PWM converter equipped with the snubber provides the most desirable features of both ZVT and ZCT converters presented previously. Moreover all semiconductors devices operate with soft switching and hence losses are reduced.

  4. A High-Precision Control for a ZVT PWM Soft-Switching Inverter to Eliminate the Dead-Time Effect

    Baoquan Kou


    Full Text Available Attributing to the advantages of high efficiency, low electromagnetic interference (EMI noise and closest to the pulse-width-modulation (PWM converter counterpart, zero-voltage-transition (ZVT PWM soft-switching inverters are very suitable for high-performance applications. However, the conventional control algorithms intended for high efficiency generally results in voltage distortion. Thus, this paper, for the first time, proposes a high-precision control method to eliminate the dead-time effect through controlling the auxiliary current in the auxiliary resonant snubber inverter (ARSI, which is a typical ZVT PWM inverter. The dead-time effect of ARSI is analyzed, which is distinguished from hard-switching inverters. The proposed high-precision control is introduced based on the investigation of dead-time effect. A prototype was developed to verify the effectiveness of the proposed control. The experimental results shows that the total harmonic distortion (THD of the output current of the ARSI can be reduced compared with that of the hard-switching inverter, because the blanking delay error is eliminated. The quality of the output current and voltage can be further improved by utilizing the proposed control method.

  5. PWM Switching Strategy for Torque Ripple Minimization in BLDC Motor

    Salah, Wael A.; Ishak, Dahaman; Hammadi, Khaleel J.


    This paper describes a new PWM switching strategy to minimize the torque ripples in BLDC motor which is based on sensored rotor position control. The scheme has been implemented using a PIC microcontroller to generate a modified Pulse Width Modulation (PWM) signals for driving power inverter bridge. The modified PWM signals are successfully applied to the next up-coming phase current such that its current rise is slightly delayed during the commutation instant. Experimental results show that the current waveforms of the modified PWM are smoother than that in conventional PWM technique. Hence, the output torque exhibits lower ripple contents.

  6. A new Zero-Current-Transition PWM switching cell

    Grigore, V. [Electronics and Telecommunications Faculty, `Politechnica` University Bucharest (Romania); Kyyrae, J. [Helsinki University of Technology, Otaniemi (Finland): Institute of Intelligent Power Electronics


    In this paper a new Zero-Current-Transition (ZCT) PWM switching cell is presented. The proposed switching cell is composed of the normal hard-switched PWM cell (consisting of one active switch and one passive switch), plus as auxiliary circuit. The auxiliary circuit is inactive during the ON ad OFF intervals of the switches in the normal PWM switch. The transitions between the two states are controlled by the auxiliary circuit. Prior to turn-off, the current through the active switch in the PWM cell is forced to zero, thus the turn-off losses of the active switch are practically eliminated. At turn-on the auxiliary circuit slows down the growing rate of the current through the main switch. Thus, turn-on losses are also very much reduced. The active switch operates under ZCT conditions, the passive switch (diode) has a controlled reverse recovery, while the switch in the auxiliary circuit operates under Zero-Current-Switching (ZCS) conditions. (orig.) 3 refs.

  7. New PWM switched-mode converter topologies

    Hua, Gui-Chao; Huang, Shi-Peng

    Two augmented switching cells are proposed from which four novel topologies can be derived: an augmented buck converter, an augmented boost converter, a novel switching power amplifier, and a novel switching controlled rectifier. The augmented buck and the augmented boost converters realize higher step-down and step-up ratios, respectively, under a given switch duty ratio by proper design of the turn ratios of the transformer and coupled inductor. The switching power amplifier achieves four-quadrant output by the use of two bidirectional current switches and a single power supply, while the inverse converter can be used as a switching controlled rectifier. The experimental verification of the power amplifier is presented.

  8. A Novel Soft-Switching Synchronous Buck Converter for Portable Applications

    Anup Kumar Panda


    Full Text Available This paper proposes a zero-voltage-transition (ZVT pulse-width-modulated (PWM synchronous buck converter, which is designed to operate at low voltage and high efficiency typically required for portable systems. A new passive auxiliary circuit that allows the main switch to operate with zero-voltage switching has been incorporated in the conventional PWM synchronous buck converter. The operation principles and a detailed steady-state analysis of the ZVT-PWM synchronous converter implemented with the auxiliary circuit are presented. Besides, the main switch and all of the semiconductor devices operate under soft-switching conditions. Thus, the auxiliary circuit provides a larger overall efficiency. The feasibility of the auxiliary circuit is confirmed by simulation and experimental results.

  9. Soft-switching PWM full-bridge converters topologies, control, and design

    Ruan, Xinbo


    Soft-switching PWM full-bridge converters have been widely used in medium-to-high power dc-dc conversions for topological simplicity, easy control and high efficiency. Early works on soft-switching PWM full-bridge converter by many researchers included various topologies and modulation strategies.  However, these works were scattered, and the relationship among these topologies and modulation strategies had not been revealed. This book intends to describe systematically the soft-switching techniques for pulse-width modulation (PWM) full-bridge converters, including the topologies, control and

  10. PWM Switching Frequency Effects on Eddy Current Sensors for Magnetically Suspended Flywheel Systems

    Jansen, Ralph; Lebron, Ramon; Dever, Timothy P.; Birchenough, Arthur G.


    A flywheel magnetic bearing (MB) pulse width modulated power amplifier (PWM) configuration is selected to minimize noise generated by the PWMs in the flywheel position sensor system. Two types of noise are addressed: beat frequency noise caused by variations in PWM switching frequencies, and demodulation noise caused by demodulation of high order harmonics of the switching voltage into the MB control band. Beat frequency noise is eliminated by synchronizing the PWM switch frequencies, and demodulation noise is minimized by selection of a switching frequency which does not have harmonics at the carrier frequency of the sensor. The recommended MB PWM system has five synchronized PWMs switching at a non-integer harmonic of the sensor carrier.

  11. Three Phase Six-Switch PWM Buck Rectifier with Power Factor Improvement

    Zafar Ullah Khan, M; Mohsin Naveed, M.; Hussain, Dil Muhammad Akbar


    Conventional Phase Controlled Rectifier injects low order current harmonics into the AC mains. Large size filtering components are required to attenuate these harmonics. In this paper, Three Phase Six-Switch PWM Buck Rectifier[1] is presented which operates at nearly unity power factor and provides...

  12. Three Phase Six-Switch PWM Buck Rectifier with Power Factor Improvement

    Zafar Ullah Khan, M; Mohsin Naveed, M.; Hussain, Dil Muhammad Akbar


    Conventional Phase Controlled Rectifier injects low order current harmonics into the AC mains. Large size filtering components are required to attenuate these harmonics. In this paper, Three Phase Six-Switch PWM Buck Rectifier[1] is presented which operates at nearly unity power factor and provid...

  13. Microcontroller based PWM controlled four switch three phase inverter fed induction motor drive

    Mohanty Kant Nalin


    Full Text Available This paper presents PIC microcontroller based PWM inverter controlled four switch three phase inverter (FSTPI fed Induction Motor drive. The advantage of this inverter that uses of 4 switches instead of conventional 6 switches is lesser switching losses, lower electromagnetic interference (EMI, less complexity of control algorithms and reduced interface circuits. Simulation and experimental work are carried out and results presented to demonstrate the feasibility of the proposed approach. Simulation is carried out using MATLAB SIMULINK and in the experimental work a prototype model is built to verify the simulation results. PIC microcontroller (PIC 16F877A is used to generate the PWM pulses for FSTPI to drive the 0.5 hp 3-phase Induction Motor.

  14. Soft Switching Full-Bridge PWM DC/DC Converter Using Secondary Snubber

    Jaroslav Dudrik


    Full Text Available A novel full-bridge PWM DC/DCconverter with controlled secondary side rectifier usingsecondary snubber is presented in this paper.Limitation of the circulating current as well as softswitching for all power switches of the inverter isachieved for full load range from no-load to shortcircuit by using controlled rectifier and snubber on thesecondary side. Phase shift PWM control strategy isused for the converter. The principle of operation isexplained and analyzed and the experimental resultson a 1kW, 50 kHz laboratory model of the converterare presented.

  15. Simulation on Soft-Switching PWM Converter with High Power Factor


    A new PWM converter based on soft-switching is introduced. The converter uses a minimum number of devices, and requires less switching operations than conventional techniques. Switching is realized solely in a ZVS (zero voltage switching) mode,therefore the loss is reduced and EMI (electromagnetic interference) is suppressed. The paper analyzes the operation of ZVS, and discusses the methods for maintaining a unit power factor and constant DC voltage. Changing the modulation index M and the phase angle θ keeps the input current in phase with the voltage. It also keeps the current sinusoidal, and ensures a constant output voltage.

  16. A Study of Novel ZVZCT SoftSwitching PWM Boost Converters%新型ZVZCT软开关PWM Boost 变换器的研究

    林国庆; 张冠生; 陈为; 黄是鹏


    The paper presents a novel ZVZCT softswitching PWM converter:the voltage and current waveforms of the transistor are laddershaped and stagger each other,and auxiliary switches are turned on and off under zero current.It is very attractive for high power application where IGBT is predomi nantly used as the power switches.Theoretical analysis,parameters selection,comp uter simulation,and experiment results are presented to explain the proposed sch eme.

  17. A single leg switched PWM method for three-phase H-Bridge Voltage Source Converters

    Senturk, Osman Selcuk; Helle, Lars; Munk-Nielsen, Stig;


    This paper proposes a single leg switched or a hybrid PWM (HPWM) method for three-phase three-level H-Bridge Voltage Source Converters (3L-HB-VSCs). By means of the proposed modulation, a 3L-HB-VSC can generate the same output as a three-level neutral point clamped (3L-NPC) VSC with phase...... disposition (PD) PWM provided that the outputs of 3L-HBVSC are isolated by transformers or connected to open winding machines. Thus, the proposed method is called PD-HPWM. Moreover, it is emphasized that 3L-HB-VSC with HPWM utilizes its switches similar to 3L-NPC-VSC. Compared to 3L-NPC-VSCs, 3L......-HB-VSCs (without neutral point clamping diodes) have simpler, more modular, and more reliable 2L circuit structure. Therefore, this method encourages the use of 3L-HB-VSCs in the applications utilizing transformers such as grid-side converters of multi-MW wind turbines. The proposed PWM method's performance...

  18. Sample-Data Modeling of a Zero Voltage Transition DC-DC Converter for On-Board Battery Charger in EV

    Teresa R. Granados-Luna


    Full Text Available Battery charger is a key device in electric and hybrid electric vehicles. On-board and off-board topologies are available in the market. Lightweight, small, high performance, and simple control are desired characteristics for on-board chargers. Moreover, isolated single-phase topologies are the most common system in Level 1 battery charger topologies. Following this trend, this paper proposes a sampled-data modelling strategy of a zero voltage transition (ZVT DC-DC converter for an on-board battery charger. A piece-wise linear analysis of the converter is the basis of the technique presented such that a large-signal model and, therefore, a small-signal model of the converter are derived. Numerical and simulation results of a 250 W test rig validate the model.

  19. Analysis of Current Source PWM Inverter for Different Levels with No-Insulating Switching Device

    Kumar Abhishek


    Full Text Available This paper gives the new set-up of inverter having DC current source (CSI having no insulated switching device. In the proposed new CSI topology every switching device are connected across a common-source level, thus a single power supply gate drive circuit is required and no insulated power supply and the customary bootstrap circuit is applied. This CSI topology is even legitimate for utmost level of current waveform output, where the power switches number increases. As a turn up, gate drive complexity is reduced, and it also eliminates the cost of capacitors and transformers in switching devices, driver circuits. In addition, this new topology of current-source PWM inverter (CSI can operate even at utmost switching frequency, as every switches will be connected across a common source level. In this paper the different level of proposed CSI operation principle, its design using computer simulation (MATLAB with its total harmonic distortion (THD is analyzed. The computer simulation using MATLAB determines the feasibility of this topology with the analysis of different level which results in reduction of its complexity and the physical size.

  20. Extension of Characteristic Equation Method to Stability Analysis of Equilibrium Points for Closed—Loop PWM Power Switching Converters8

    YanfengCHEN; ShuishengQIU; 等


    An extension of characteristic equation analysis method to the stability analysis of equilibrium points for closed-loop PWM power switching converters is introduced based on equivalent small parameter method.The basic principle of the method is described in detail.The provided example shows that the method,incorporating with the system's state-plane trajectories,offers the advantages of both simplicity and practicality.

  1. A Novel Prototype of Auxiliary Edge Resonant Bridge Leg-Link Snubber-Assisted Soft-Switching Sinewave PWM Inverter

    Nakamura, Mantaro; Yamazaki, Takayuki; Fujii, Yuma; Ahmed, Tarek; Nakaoka, Mutsuo

    This paper proposes a new circuit topology of the three-phase soft switching PWM inverter and PFC converter using IGBT power modules, which has the improved active auxiliary switch and edge resonant bridge leg-commutation-link soft-switching snubber circuit with pulse current regenerative feedback loop as compared with the typical auxiliary resonant pole snubber discussed previously. This three-phase soft switching PWM double converter is more suitable and acceptable for a large capacity uninterruptible power supply, PFC converter, utility-interactive bi-directional converter and so forth. In this paper, the soft switching operation and optimum circuit design of the novel type active auxiliary edge resonant bridge leg commutation link snubber treated here are described for high power applications. Both the main active power switches and the auxiliary active power switches achieve soft switching under the principles of ZVS or ZCS in this three-phase inverter switching. This three-phase soft switching commutation scheme can effectively minimize the switching surge related electromagnetic noise and the switching power losses of the power semiconductor devices; IGBTs and modules used here. This three-phase inverter and rectifier coupled double converter system does not need any sensing circuit and its peripheral logic control circuits to detect the voltage or the current and does not require any unwanted chemical electrolytic capacitor to make the neutral point of the DC power supply voltage source. The performances of this power conditioner are proved on the basis of the experimental and simulation results. Because the power semiconductor switches (IGBT module packages) have the relation of the trade-off in the switching fall time and tail current interval characteristics as well as the conductive saturation voltage characteristics, this three-phase soft-switching PWM double converter can perform to improve actual efficiency in the output power ranges with a trench

  2. A Novel Soft Switching PWM Power Frequency Converter with Non DC Smoothing Filter Link for Consumer High Frequency Induction Heating

    Sugimura, Hisayuki; Muraoka, Hidekazu; Hiraki, Eiji; Hirota, Izuo; Yasui, Kenji; Omori, Hideki; Lee, Hyun-Woo; Nakaoka, Mutsuo

    In this paper, high frequency power converter without DC smoothing electrolytic capacitor filter link which convert the 100V/200Vrms and 60Hz single phase utility frequency AC power into a high frequency AC. This proposed high frequency AC power converter without electrolytic capacitor filter can operate under a principle of soft switching PWM based on a lossless capacitor snubber is proposed and demonstrated for consumer high frequency induction heating (IH). In particular, this high frequency power converter capable of producing a high frequency AC more than 20kHz is developed for consumer IH applications as hot water producer and steamer based on the specially designed spiral type IH-Dual Packs Heater (DPH), which includes the dual mode pulse modulation control scheme based on soft switching PWM for high output power setting and commercial frequency AC zero voltage soft switching pulse density modulation (PDM) for low output power settings. This developed high frequency power frequency converter using trench gate IGBTs is clarified on the basis of experimental and simulation results for its circuit operation of the utility frequency AC to high frequency AC frequency PWM power converter without the electrolytic capacitor bank DC filter link for the IH hot water and IH steamer. These IH appliances are based upon an innovative electromagnetic IH-DPH for fluid heating as heat exchanger in consumer pipeline. Finally, its power regulation characteristics, power conversion efficiency and harmonic current components characteristics including power factor in utility AC grid side are evaluated and discussed from an experimental point of view. The practical effectiveness of this utility frequency AC to high frequency AC soft switching high power frequency converter defined conveniently as high frequency soft switching cyclo-inverter is proved as one of the important products effective for next generation IH application all electricity power utilizations.

  3. Quality Assessment of Soft-Switching Based Single-phase Pulse Width Modulated Voltage Source Inverter (PWM VSI

    Z.A. Jaffery


    Full Text Available The authors present the design, simulation and analysis of a single phase voltage source inverter using soft switching techniques. The performance of the inverter has been compared in terms of harmonic contents present in output voltage and current. The research works for a PWM inverter along with a LLCC filter has been investigated. This paper also investigated the performance of the same inverter with a feedback controller with a closed loop feedback path to maintain rated output voltage. This work is helpful for the inverter used in application where high quality ac wave is prime requirement

  4. Zero-Voltage Switching PWM Strategy Based Capacitor Current-Balancing Control for Half-Bridge Three-Level DC/DC Converter

    Liu, Dong; Deng, Fujin; Zhang, Qi


    The current imbalance among the two input capacitors is one of the important issues of the half-bridge threelevel (HBTL) DC/DC converter, which would affect system performance and reliability. In this paper, a zero-voltage switching (ZVS) pulse-wide modulation (PWM) strategy including two operation...... modes is proposed. Based on the proposed ZVS PWM strategy, a capacitor current-balancing control is proposed for the HBTL DC/DC converter, where the currents on the two input capacitors can be kept balanced by alternating the two operation modes of the proposed ZVS PWM strategy. Therefore, the proposed...... control strategy can improve the performance and reliability of the converter in the aspect of balancing the thermal stresses and lifetimes among the two input capacitors. Finally, simulation and experimental studies are conducted and results verify the proposed control strategy....

  5. Development of Digital Hysteresis Current Control with PLL Loop Gain Compensation Strategy for PWM Inverters with Constant Switching Frequency

    N. Belhaouchet


    Full Text Available Hysteresis current control is one of the simplest techniques used to control the magnitude and phase angle of motor current for motor drives systems. However, this technique presents several disadvantages such as operation at variable switching frequency which can reveal problems of filtering, interference between the phases in the case of the three-phase systems with insulated neutral connection or delta connection, and irregularity of the modulation pulses which especially causes an acoustic noise on the level of the machine for the high power drive. In this paper, a new technique is proposed for a variable-hysteresis-band controller based on dead beat control applied to three phase voltage source PWM inverters feeding AC motors. Its main aim is firstly ensure a constant switching frequency and secondly the synchronization of modulation pulses using the phase-locked-loop with loop gain compensation in order to ensure a better stability. The behavior of the proposed technique is verified by simulation.

  6. Analysis of Current Source PWM Inverter for Different Levels with No-Insulating Switching Device

    Kumar Abhishek; K.Parkavi Kathirvelu; Balasubramanian, R.


    This paper gives the new set-up of inverter having DC current source (CSI) having no insulated switching device. In the proposed new CSI topology every switching device are connected across a common-source level, thus a single power supply gate drive circuit is required and no insulated power supply and the customary bootstrap circuit is applied. This CSI topology is even legitimate for utmost level of current waveform output, where the power switches number increases. As a turn up, gate driv...

  7. Reduction of Switching Losses in Active Power Filters With a New Generalized Discontinuous-PWM Strategy

    Blaabjerg, Frede; Asiminoaei, Lucian; Malinowski, M.


    . It achieves a clamped voltage pattern, with variable lengths depending on the magnitude of the inverter current. This property reduces the current stress and minimizes the inverter switching losses. The proposed modulation strategy is described, analyzed, and validated on a three-phase voltage source inverter...... the switching losses in any operating point. This paper proposes a new DPWM strategy for shunt APFs. The proposed modulation strategy detects the current vector position relative to the inverter voltage reference and determines the optimum clamped duration for each phase, in terms of switching power losses...

  8. High frequency three-phase PWM grid connected drive using silicon-carbide switches

    Kouchaki, Alireza; Pedersen, Jacob Lykke; Nymand, Morten


    and with this compensation. The controller is designed for a 5 kW SiC based three-phase rectifier (switching frequency 50 kHz) connected to a 7.5kW SiC based inverter (switching frequency 32 kHz). Experimental results are also carried out to validate the operation of the controller under different operating conditions....... A failure test is also conducted to highlight the drawbacks of feedforward with high forward gain....

  9. PWM inverter technology

    Perra, Andre


    The use of pulse-width-modulated (PWM) inverter technology by on-line uninterruptible power supplies (UPSs) of 250 VA-750 kVA rating improves transient performance, lowers harmonic distortion, and enhances nonlinear load performance. An account is presently given of the means employed for optimization of a PWM inverter used in a multi-kHz UPS. By using computer modeling to optimize the feedback control loop, the best level of response was furnished, while minimizing switching losses and achieving the highest level of efficiency.

  10. Research on Double PWM Converter Based on the Soft-Switch Technology%零压变换软开关的双PWM变换器的研究

    胡正轩; 冷光夺; 袁冬柏; 王建任


    Double Pulse Width Modulation (PWM) converter in wind power system is used widely, the power switch device Insulated Gate Bipolar Transistor (IGBT) has the good switching characteristics. However,the circuit which is opened or turn off will produce switch loss and noise pollution. These interference in small power circuits can be ignored, but it should be avoid in the larger wind power system. In order to reduce or even avoid these disadvantages influence to the running of system smoothly, this paper design a Double PWM converter which is based on the soft-switching technology, and it combines with Space Vector Pulse Width Modulation (SVPWM) technique and PR control method. The simulation test and analysis results proved that optimal converter can be a good improvement in input and output performance of traditional converter.%对于双脉宽调制(PWM)变换器,当电路开通或关断的时候都会产生开关损耗和噪声污染.这些干扰在小功率电路中可以被忽略,但在较大型的风力发电系统中是应该极力避免的.为了减小甚至避免这些不利因素影响系统的平稳运行,设计了一种基于零电压变换软开关技术的双PWM变换器,并且结合了空间矢量脉宽调制技术和PR控制方法.通过仿真试验和结果分析,验证了优化的变换器能够很好地改善传统变换器的输入和输出性能.

  11. Advanced High Power DC-DC Converter using A Novel Type Voltage Source Full-Bridge Soft-Switching PWM Inverter with High Frequency Transformer Link for Arc Welding Applications

    Morimoto, Keiki; Doi, Toshimitsu; Manabe, Haruhiko; Ahmed, Tarek; Hiraki, Eiji; Lee, Hyun-Woo; Nakaoka, Mutsuo

    This paper presents a new circuit topology of full-bridge soft-switching PWM inverter linked DC-DC power converter composed of conventional full-bridge high frequency PWM inverter with high frequency transformer and an active quasi-resonant snubber consisting of an additional power switching device in series with DC busline and a lossless capacitor in parallel with DC busline. Under this proposed high frequency soft-switching PWM inverter linked DC-DC converter, four power switches in the full-bridge arms and DC busline series switch can achieve ZVS at turn-off commutation. By developing the advanced soft-switching PWM high frequency inverter type DC-DC converter, although the conduction power loss of DC busline series power switch increases a little, the total turn-off switching loss of full-bridge high frequency inverter power modules can be sufficiently lowered more and more in the higher frequency range of 60kHz. As a result, when the switching frequency of high frequency inverter power stage using IGBT power modules is designed so as to be more than about 10kHz, the more the switching frequency of inverter increases, the more this high frequency soft-switching DC-DC converter has remarkable advantage as for the power conversion efficiency as compared with the conventional hard-switching PWM inverter DC-DC converter. Its practical effectiveness of high power density and high performance is actually proved for TIG arc welding equipment in industry.

  12. Smooth-Transition Simple Digital PWM Modulator for Four-Switch Buck-Boost Converters

    Rodriguez, Alberto; Rodriguez, Miguel; Vazquez, Aitor; Maija, Pablo F.; Sebastian, Javier


    Four Switch non-inverting Buck-Boost (4SBB) converters are extensively used in non-isolated applications where voltage step-up and step-down are required. In order to achieve high efficiency operation it is preferred to control the 4SBB as a Buck or Boost converter, depending on the input/output voltage ratio. However, when input and output voltages are close this approach requires near- unity conversion ratios, which are difficult to achieve in practice. Several alternative operating modes have been proposed in the literature to overcome this issue. In particular, operating the 4SBB as a Buck and Boost at the same time (Buck+Boost mode) has proven to be adequate to achieve near-unity conversion ratios.This paper proposes a simple, hardware-efficient digital pulse width modulator for a 4SBB that enables operation in Buck, Boost and Buck+Boost modes, thus allowing near-unity conversion ratios, while achieving smooth transitions between the different modes. The proposed modulator is simulated with Simulink and experimentally demonstrated using a 500W 4SBB converter with 24V input voltage and 12V-36V output voltage range.

  13. Selection of Carrier Waveforms for PWM Inverter

    陈国呈; 屈克庆; 许春雨; 孙承波


    In this paper the influence of different carrier waveforms upon the output characteristics of PWM inverter is described in detail. When a triangular carrier waveform is used in hard-switching PWM inverters, harmonics exist in the neighborhood of the output frequency of the inverter output voltage and current due to the dead time. The triangular carrier waveform used in soft-switching PWM inverter will cause difficulties in controlling resonance-trigger time, higher loss in the resonant circuit, and less utilization of the DC bus voltage. If a sawtooth carrier is used in hard-switching PWM inverter, there will be severe distortion in the current waveform. When sawtooth carriers with alternate positive and negative slopes are used in soft-switching PWM inverters, the resonancetrigger time is easy to control, and distortion in the output voltage and current caused by the dead time will not appear.

  14. A New Multilevel Converter Structure For High-Power Applications using Multi-carrier PWM Switching Strategy

    Rasoul Shalchi Alishah


    Full Text Available In recent, several numbers of multilevel inverter structures have been introduced that the numbers of circuit devices have been reduced.  This paper introduces a new structure for multilevel inverter which can be used in high-power applications. The proposed topology is based on cascaded connection of basic units. This topology consists of minimum number of circuit components such as IGBT, gate driver circuit and antiparallel diode. For proposed topology, two methods are presented for determination of dc voltage sources values. Multi-carrier PWM method for 25-level proposed topology is used. Verification of the analytical results is done using MATLAB simulation.

  15. AC Small Signal Modeling of PWM Y-Source Converter by Circuit Averaging and Averaged Switch Modeling Technique

    Forouzesh, Mojtaba; Siwakoti, Yam Prasad; Blaabjerg, Frede


    Magnetically coupled Y-source impedance network is a newly proposed structure with versatile features intended for various power converter applications e.g. in the renewable energy technologies. The voltage gain of the Y-source impedance network rises exponentially as a function of turns ratio......, which is inherited from a special coupled inductor with three windings. Due to the importance of modeling in the converter design procedure, this paper is dedicated to dc and ac small signal modeling of the PWM Y-source converter. The derived transfer functions are presented in detail and have been...

  16. A Comparative Study on Various Unipolar PWM Strategies for Single Phase Seven Switch Asymmetric 15-Level Inverter

    V. Arun


    Full Text Available This study presents a modified single phase cascaded 15 level inverter with reduced switch count that operates in asymmetric mode. The proposed multilevel inverter produce DC voltage levels similar to other topologies with less number of semiconductor switches. This study also presents various modulating techniques include sinusoidal pulse width modulation, advance modulating technique. i.e., Trapezoidal reference with triangular carrier waves. Different performance measures like THD, VRMS and CF have also been evaluated by simulation. The simulation of proposed circuit is carried out using MATLAB/SIMULINK and the result for the same are presented in this study.

  17. Discrete/PWM Ballast-Resistor Controller

    King, Roger J.


    Circuit offers low switching loss and automatic compensation for failure of ballast resistor. Discrete/PWM ballast-resistor controller improved shunt voltage-regulator circuit designed to supply power from high-resistance source to low-impedance bus. Provides both coarse discrete voltage levels (by switching of ballast resistors) and continuous fine control of voltage via pulse-width modulation.

  18. Research on Flow Characteristic of Switch Solenoid Valve Based on PWM Technology%基于P WM技术的开关电磁阀流量特性研究

    蔡胜年; 朱亮; 庞宝林


    在分析开关电磁阀工作过程的基础上,给出了基于PWM技术控制开关电磁阀流量时,根据开关电磁阀的临界频率和截止频率设计PWM频率的方法。基于开关电磁阀的电压平衡方程、运动学方程以及流体方程导出了开关电磁阀的临界频率和截止频率的表达式。实验结果表明:利用开关电磁阀模型计算的临界频率和截止频率与实测值基本一致,误差达到了工程设计的标准。并分析了占空比、流量与PWM控制频率之间的关系。%Based on analyzing the working process of switch solenoid valve, the design method of PWM frequency based on the valve’s critical frequency and cut-off frequency was given, by using PWM technology to control the valve.Using the switch valve’s voltage balance equation, kinematics equation and fluid equation, the expressions of the critical frequency and cut-off frequency were given.The experimental results show that the critical frequency and cut-off frequency are basically the same with the measured values and the error meets engineering design standards.The relationship of the PWM duty ratio, the flow and the PWM frequency was ana-lyzed.

  19. Leakage Current Paths in PV Transformer-Less Single-Phase Inverter Topology and Its Mitigation through PWM for Switching

    M. N. H. Khan


    Full Text Available The Photovoltaic (PV is a part and parcel and well known for cost-effective and easy to operatefeatures when it is used with transformer-less inverter-based grid-tied distribution generation systems. It reduces the leakage current issue that actually occurs making paths from PV penal to ground. In this paper has been addressed this issue as main problem for reducing leakage current. Moreover, here iscompared the proposed topology’s results to AC and DC-based transformer-less topologies. The possibilities of larger number of leakage current paths indicatepower loss, which is the focus of work in this paper for different switching conditions. The results on leakage current paths using PSpice with different parasitic capacitance values from inverters of different topologies are compared with the simulation results of the topology proposed in this paper.

  20. New Type AC PWM Switch and Its Microgrid Mode-Transfer Application Based on Switched Capacitor Technology%基于开关电容技术的新型交流PWM开关及其在微电网模式切换中的应用

    王玉斌; 王广柱


    基于开关电容技术,提出一种新型交流PWM切换开关,其等值阻抗与开关频率成反比,给出了其基本原理和基本电路拓扑。将其与高速机械开关并联,构成一种新型混合固态切换开关,可应用于电路模式切换等多种场合,有效地限制暂态电流和开关分断时的电弧。探讨了这种新型混合固态切换开关在故障电流限制、微电网模式切换中的具体应用。仿真和实验结果验证了这种新型开关的合理性及有效性。%A new type AC PWM transfer switch based on switched capacitor technology, with its principle and basic circuit topology, is put forward in this paper, which has inverse ratio characteristic between its equivalent resistance and switching frequency. A new hybrid solid-state transfer switch is then put forward, wherein this new AC PWM switch is connected in parallel with a mechanical switch, which can be used in circuit mode transfer application to effectively limit the transient current and eliminate voltage arc due to switch turning off. Furthermore, applications of this new hybrid solid-state switch in fault current limiting, and microgrid mode transfer are studied for more detail. The feasibility and effectiveness of switched capacitor based new AC PWM transfer switch are verified by simulation and experimental results.

  1. Improvement on Switching Characteristics and Switching Losses of IGBT by ZVS—PWM①

    ZHANGChunjiang; GUHerong; 等


    The principle of ZVS-PWM inverting circuit is first described by means of inverting welder supply.The contrastive study is made on switching characteristics and switching losses of IGBT between ZVS-PWM and hard-switching.

  2. Loss Distribution Analysis of Three-Level Active Neutral-Point-Clamped (3L-ANPC) Converter with Different PWM Strategies

    Zhang, Gang; Yang, Yongheng; Iannuzzo, Francesco


    of the 3L-ANPC topology. This paper presents a novel loss balancing modulation strategy - Splitting Switching Loss Distribution PWM (SSLD-PWM) strategy to achieve more even loss distribution in the 3L-ANPC converter. Basically, in the proposed PWM strategy, the switching-on losses and switching-off losses...

  3. Self oscillating PWM modulators, a topological comparison

    Poulsen, Søren; Andersen, Michael Andreas E.


    or fs/ð range respectively, where fs is the switching frequency of the converter. For some applications this will require unacceptable high switching frequency to achieve enough control loop bandwidth for the desired dynamic performance. With self oscillating modulators, the open loop bandwidth is equal...... to fs which makes this type of modulators an excellent choice for a wide range of applications. Self oscillating PWM modulators can be made in a number of ways, either as voltage or current mode modulators, and the self oscillating behavior can be achieved either by using hysteresis control......High precision control of the output voltage or current of a switch mode converter with fast response is required for a number of applications. Dependent on the type of application, the desired precision and transient response can be difficult, if not impossible, to achieve with standard PWM...

  4. 三相电压型PWM整流器准定频直接功率控制%Novel Quasi Direct Power Control for Three-phase Voltage-source PWM Rectifiers With a Fixed Switching Frequency

    杨达亮; 卢子广; 杭乃善; 李国进


    建立三相电压型脉宽调制(pulse width modulation,PWM)整流器在不同坐标系下的数学模型,分析直接功率控制(direct power control,DPC)的工作原理。针对直接功率控制中开关频率变化问题,通过对PWM整流器瞬时功率分析推导,提出一种内环直接采用电流控制的新型准定频直接功率控制策略。仿真验证了算法的可行性。采用PM300DVAl20智能功率模块,设计50kVA的三相电压型PWM整流器控制实验,在10kHz、5us的开关频率下获得良好的实验结果。实验结果表明,所提方法实现单位功率因数运行,与现行的DPC—SVM定频控制方法相比,具有更好的动静态响应性能。%This paper established the three-phase voltage-source pulse width modulation (PWM) rectifier mathematical models in different coordinate systems and analyzed the principle of direct power control (DPC). To alleviate the problem of variable switching frequency, a novel quasi DPC control strategy with current loop was represented through the analysis of PWM rectifier instantaneous power. The novel control strategy was proved feasible by the Matlab/Simulink simulation results. The 50kVA three-phase voltage-source PWM rectifier control experiment system was designed using PM300DVA120 intelligent power module (IPM), the excellent experiment results were given at the 10kHz switching frequency with 5μs dead time. The experimental results indicate that the PWM rectifier system achieves unity power factor operation and has better performance of dynamic and static response compared to the present space vector modulation (SVM) DPC fixed-frequency control method.

  5. Controlling DC Motor using Microcontroller (PIC16F72) with PWM

    Shruti Shrivastava, Jageshwar Rawat, Amit Agrawal


    Motion control plays a vital role in industrial atomization. Different types of motors AC, DC, SERVO or stepper are used depending upon the application; of these DC motors are widely used because of easier controlling. Among the different control methods for DC motor armature voltage control method using pulse width modulation (PWM) is best one. We can realize the PWM using H-bridge built with IGBT switches or transistors. To generate PWM signals we use PIC16F7...

  6. PWM Converter Power Density Barriers

    Kolar, Johann W.; Drofenik, Uwe; Biela, Juergen; Heldwein, Marcelo; Ertl, Hans; Friedli, Thomas; Round, Simon

    Power density of power electronic converters has roughly doubled every 10 years since 1970. Behind this trajectory is the continuous advancement of power semiconductor devices, which has increased the converter switching frequencies by a factor of 10 every decade. However, today's cooling concepts and passive components are major barriers for a continuation of this trend. To identify such technological barriers, this paper investigates the volume of the cooling system and passive components as a function of the switching frequency for power electronic converters and determines the switching frequency that minimizes the total volume. A power density limit of 28kW/dm3 at 300kHz is calculated for an isolated DC-DC converter, 44kW/dm3 at 820kHz for a three-phase unity power factor PWM rectifier, and 26kW/dm3 at 21kHz for a sparse matrix converter. For single-phase AC-DC conversion a general limit of 35kW/dm3 results from the DC link capacitor. These power density limits highlight the need to broaden the scope of power electronics research to include cooling systems, high frequency electromagnetics, interconnection and packaging technology, and multi-domain modelling and simulation to ensure further advancement along the power density trajectory.

  7. Simple PWM modulator topology with excellent dynamic behavior

    Poulsen, Søren; Andersen, Michael Andreas E.


    This paper proposes a new PWM modulator topology. The modulator is used in switch mode audio power amplifiers, but the topology can be used in a wide range of applications. Due to excellent transient behavior, the modulator is very suited for VRMs or other types of DC-DC or DC-AC applications....

  8. Research on Passivity Based Controller of Three Phase Voltage Source PWM Rectifier

    Yin Hongren


    Full Text Available Euler-Lagrange (EL model of voltage source PWM rectifier is set up based on its model in synchronous dq coordinates. Passivity based controller is designed on the basis of passivity and EL model of voltage source PWM rectifier. Three switching function are educed by passivity based controller. A switching function is only realized in engineering consequently. Voltage source PWM rectifier using passivity based controller has many advantages, such as simpler structure, low total harmonic distortion, and good disturbance rejection performance. Passivity based control law is proved feasible by simulink simulation.  

  9. Asymmetric Carrier Random PWM

    Mathe, Laszlo; Lungeanu, Florin; Rasmussen, Peter Omand;


    This paper presents a new fixed carrier frequency random PWM method, where a new type of carrier wave is proposed for modulation. Based on the measurements, it is shown that the spread effect of the discrete components from the motor current spectra is very effective independent of the modulation...... index. The flat motor current spectrum generates an acoustical noise close to the white noise, which may improve the acoustical performance of the drive. The new carrier wave is easy to implement digitally, without employing any external circuits. The modulation method can be used in open, as well...

  10. Small-signal, continuous, exact model of PWM voltage regulators

    Burkhardt, W.; Maranesi, P.; Varoli, V.


    The small-signal time-continuous open-loop response of buck, boost, and buck-boost pulse-width-modulation (PWM) voltage regulators using MOSFET switches in their power stages is modeled, applying a time-domain sampling theorem (Woodward, 1953) to obtain the Fourier open-loop transfer function corresponding to the comb function describing the response at the chopping instants only. The results are presented graphically along with simplified circuit diagrams of the PWM devices, and the accuracy and computational efficiency of the analytical approach are indicated.

  11. Noise Shaping Filter Compensating PWM Distortion for Fully Digital Amplifier

    Yoneya, Akihiko

    The full-digital audio amplifiers have several merits such as a high power enabling a small size of the amplifier and digital implementation of the signal processing which allows desired precision of the processing except for the final stage switching amplifiers. Unfortunately, the pulse width modulation (PWM) causes signal distortions because of the non-linearity of the modulation from the viewpoint of the transient response. This paper proposes a compensation method of the PWM distortion with feedback approach. In the noise-shaping filter of the delta-sigma modulator to calculate the pulse codes for the PWM, the distortion caused by the PWM is evaluated and fed it back to compensate the distortion. Eventually the filter is implemented as a state-variable filter with non-linear feedback from the quantizer. The calculation of the filter elements is also described. By using proposed filters, PWM signals with small distortions and small floor noise can be obtained to realize high-fidelity audio amplifiers.




    Full Text Available This paper presents different types of bipolar Pulse Width Modulation (PWM strategies for the chosen Cascaded MultiLevel Inverter (CMLI. The main purpose of MLI is to use power semiconductor devices of lower voltage ratings to realize high voltage levels at inverter output. Due to their ability to obtain refined output voltage waveforms, reduced Total Harmonic Distortion (THD and reduced EMI problems by reducing the switching dv/dt. In this paper, a three phase CMLI is controlled with Sinusoidal PWM strategy with Phase Disposition PWM (PDPWM, Phase Opposition and Disposition PWM (PODPWM, Alternative Phase Opposition and Disposition PWM (APODPWM, Phase Shift PWM (PSPWM and hybrid modulation strategy and the variation of THD in their outputs are observed by varying the modulation index. Simulations are performed using MATLAB-SIMULINK. It is observed that APODPWM and PSPWM provide output with relatively low distortion. It is also seen that PS, APOD and hybrid PWM are found to perform better since they provide relatively higher fundamental RMS output voltage. From hardware results it is seen that POD PWM provides output with relatively low distortion. It is also observed that PSPWM is found to perform better since it provide relatively higher fundamental RMS output voltage.

  13. Electrical machine PWM loss evaluation basics

    Ruderman, A. [The School of Engineering, Bar-Ilan Univ., Ramat-Gan (Israel); Welch, R. Jr. [IEEE, Welch Enterprise, Oakdale (United States)


    Modern power converters utilize pulse-width modulation (PWM) voltage control. Output voltage high frequency harmonics induce additional electrical machine loss. As there is no accepted PWM loss theory, PWM loss is usually accounted for by machine power de-rating. In-depth understanding of PWM loss mechanisms is important for predicting losses and improving energy efficiency of electrical machines. In this paper we suggest a new time domain PWM loss approach. It assumes that PWM eddy current iron loss dominates over PWM copper and hysteresis iron losses and comprises theoretical normalized PWM loss evaluation and experimental characterization. Once maximal PWM loss is measured, it can be scaled for an arbitrary operating point using simple formula. Theoretical results are shown to be in a good agreement with a published experimental data. (orig.)

  14. Modeling and Analysis of Buck/Boost Bidirectional DC/DC Converter with Developed PWM Switch Model%基于发展的PWM Switch模型的Buck/Boost双向直直变换器建模及分析

    王建华; 张方华; 龚春英


    提出了双向功率流动场合的PWM Switch模型,同时选取典型的Buck/Boost双向变换器作为评估平台.小信号分析结果表明,Buck/Boost双向直直变换器通过仅控制Buck模式主控管可以对电池充放电模式进行切换.其提供了对变换器稳态及动态性能研究的一种快速仿真方法.基于改进PWM Switch模型及器件级电路的详尽仿真对比验证了模型的精确性.

  15. A new power supply regulated PWM-ZCS supplied in current: analysis, project and experiments; Uma nova fonte chaveada PWM-ZCS alimentada em corrente: analise, projeto e experimentacao

    Barbosa, Peter Mantovanelli


    This work introduces a new power supply by PWM, operating at constant frequency, with soft communication. The new topology uses only two active switches and absorbs the transformer leakage inductance. Besides, the soft communication takes place with no conduction loss penalty, in comparison with conventional hard switch PWM converters. Principle of operation, analysis, design and experimentation results taken from laboratory prototype rated at 400 W/48 v, 40 Khz, using IGBT are presented. (author) 10 refs., 71 figs.

  16. Performance Comparison of Phase Shifted PWM and Sorting Method for Modular Multilevel Converters

    Haddioui, Marcos Rejas; Máthé, Lászlo; Burlacu, Paul Dan;


    Modular Multilevel Converters (MMC) are the solution of preference in HVDC applications due to modularity, scalability, low losses and low filtering requirement. Carrier-based (PWM) and carrier-less (nearest level control) modulation can be applied. By using advanced sorting methods focusing...... on keeping the capacitor voltage ripple under some limit, unnecessary switching events are eliminated leading to reduced switching losses. This paper presents a comparison between the steady-state performances in terms of output voltage THD and equivalent switching frequency of the Phase Shifted Carrier PWM...

  17. Dynamics of IGBT based PWM Converter A Case Study

    Vijay Shukla


    Full Text Available Optimizing the efficiency and dynamics of power converters is a critical tradeoff in power electronics. The increase of switching frequency can improve the dynamics of power converters, but theefficiency may be degraded as well as the switching losses. As power semiconductor devices like diodes, MOSFETS, IGBTs, Thyristors, BJTs have their own characterstics and dynamic responses. It is desired toanalyze and observe the dynamics of different semiconductor devices before they actually employed in the model. Inclusion of different PWM techniques help in the removal of power line interferences like harmonic losses, unwanted ripples, chopped frequencies, spikes. In this paper, we have studied and analyzed the dynamics of IGBT based PWM converter with subjected to different conditions like transient state, steady state feeding the RLC load. Snubber circuits are used to reduce the switching losses. The IGBT based PWM converter reflects the better dynamics with improved efficiency and reduced harmonics as compared to some other power semiconductor devices when FFT is performed and subjected to standard parameterized RLC load understeady state and transient analysis.

  18. Interleaved Boost-Half-Bridge Dual–Input DC-DC Converter with a PWM plus Phase-Shift Control for Fuel Cell Applications

    Zhang, Zhe; Andersen, Michael A. E.


    This paper presents an isolated dual-input DC-DC converter with a PWM plus phase-shift control for fuel cell hybrid energy systems. The power switches are controlled by phase shifted PWM signals with a variable duty cycle, and thus the two input voltages as well as the output voltage can...

  19. Synchronized Scheme of Continuous Space-Vector PWM with the Real-Time Control Algorithms

    Oleschuk, V.; Blaabjerg, Frede


    This paper describes in details the basic peculiarities of a new method of feedforward synchronous pulsewidth modulation (PWM) of three-phase voltage source inverters for adjustable speed ac drives. It is applied to a continuous scheme of voltage space vector modulation. The method is based...... on a representation of the pulse patterns as a function of the fundamental and switching frequencies of the drive system. Accurate trigonometric algorithms of vector PWM have been analysed, and also compared with the algebraic ones based on linear approximation of the durations of active switching states from...

  20. Elimination of output voltage oscillations in DC-DC converter using PWM with PI controller

    Sreenivasappa Veeranna Bhupasandra


    Full Text Available In this paper the SIMULINK model of a PWM controlled DC-DC converter is modeled using switching function concept to control the speed of the DC motor. The presence of the voltage oscillation cycles due to higher switching frequency in the DC-DC converter is identified. The effect of these oscillations on the output voltage of the converter, Armature current, Developed torque and Speed of the DC motor is analyzed. In order to minimize the oscillation cycles the PI controller is proposed in the PWM controller.

  1. Closed loop control of ZVS half bridge DC-DC converter with DCS PWM Control



    Full Text Available

    The main drawback of the conventional symmetric control is that both primary switches in the converter operate at hard switching condition. Moreover, during the off-time period of two switches, the oscillation between the transformer leakage inductance and junction capacitance of the switches results in energy dissipation and electromagnetic interference (EMI emissions due to reverse recovery of MOSFETs body diodes. The asymmetric (complementary control was proposed to achieve ZVS operation for HB switches. However, asymmetric stresses distribution on the corresponding components may occur due to the asymmetric duty cycle distribution for the two primary switches. A new control scheme, to be known as duty-cycle shifted PWM (DCS PWM control, is proposed and applied to the conventional HB dc–dc converters to achieve ZVS for both the  switches without adding extra components and without adding asymmetric penalties of the complementary control. The concept of this new control scheme is shifting one of the two symmetric PWM driving signals close to the other, such that ZVS may be achieved for the lagging switch due to the shortened resonant interval. Moreover, based on the DCS PWM control, a new half-bridge topology is proposed to achieve ZVS for both the main switches and auxiliary switch by adding an auxiliary switch and diode in the proposed half bridge. ZVS for the  switch is achieved by utilizing the energy trapped in the leakage inductance. There are two control schemes. One is open loop and the other is closed loop. In open loop scheme, the given dc-dc converter is operating under disturbance. This disturbance effect is eliminated in closed loop scheme.


  2. OFDM-PWM scheme for visible light communications

    Zhang, Tian; Ghassemlooy, Zabih; Rajbhandari, Sujan; Popoola, Wasiu O.; Guo, Shuxu


    In this paper, we propose an improved hybrid optical orthogonal frequency division multiplexing (O-OFDM) and pulse-width modulation (PWM) scheme for visible light communications. In this scheme, a bipolar O-OFDM signal is converted into a PWM format where the leading and trailing edges convey the frame synchronization and modulated information, respectively. The proposed scheme is insensitive to the non-linearity of the light emitting diode (LED) as LEDs are switched 'on' and 'off' between two points. Therefore, the tight requirement on the high peak-to-average-power-ratio (PAPR) in O-OFDM is no longer a major issue. The simulation and experimental results demonstrate that the proposed scheme offers an improved bit error rate performance compared to the traditional asymmetrically clipped O-OFDM (ACO-OFDM).

  3. The efficiency of three-level Active NPC converter for different PWM strategies

    Floricau, D.; Gateau, G.; Leredde, A.;


    The efficiency of power conversion is an important factor to design static converters. The paper is focused on the calculus of total losses of 3L-NPC and 3L-Active-NPC converters for different PWM strategies. The calculus was made in the most critical operating points when certain switches have...

  4. New PWM method and commutation strategy for HF-link converters for fuel cells and photovoltaics

    Ljusev, Petar; Andersen, Michael Andreas E.


    This paper presents a new PWM method and commutation strategy for HF-link converters, which leads to safe commutation of the load current in the output bidirectional bridge. The proposed implementation is independent of the particular HF-link converter topology and bidirectional switch selection...

  5. Six-Phase Vehicular Drive with Renewable DC Sources and Hybrid PWM Control of Four Inverters

    Oleschuk, Valentin; Ermuratskii, Vladimir; Blaabjerg, Frede


    The paper presents results of research of quad-inverter-based automotive system with combined scheme of PWM control of inverters, supplied by two renewable dc sources (by fuel cells and by battery). It has been shown, that hybrid switching techniques can be used successfully for control of vehicle...

  6. Power Electronic Transformer based Three-Phase PWM AC Drives

    Basu, Kaushik

    A Transformer is used to provide galvanic isolation and to connect systems at different voltage levels. It is one of the largest and most expensive component in most of the high voltage and high power systems. Its size is inversely proportional to the operating frequency. The central idea behind a power electronic transformer (PET) also known as solid state transformer is to reduce the size of the transformer by increasing the frequency. Power electronic converters are used to change the frequency of operation. Steady reduction in the cost of the semiconductor switches and the advent of advanced magnetic materials with very low loss density and high saturation flux density implies economic viability and feasibility of a design with high power density. Application of PET is in generation of power from renewable energy sources, especially wind and solar. Other important application include grid tied inverters, UPS e.t.c. In this thesis non-resonant, single stage, bi-directional PET is considered. The main objective of this converter is to generate adjustable speed and magnitude pulse width modulated (PWM) ac waveforms from an ac or dc grid with a high frequency ac link. The windings of a high frequency transformer contains leakage inductance. Any switching transition of the power electronic converter connecting the inductive load and the transformer requires commutation of leakage energy. Commutation by passive means results in power loss, decrease in the frequency of operation, distortion in the output voltage waveform, reduction in reliability and power density. In this work a source based partially loss-less commutation of leakage energy has been proposed. This technique also results in partial soft-switching. A series of converters with novel PWM strategies have been proposed to minimize the frequency of leakage inductance commutation. These PETs achieve most of the important features of modern PWM ac drives including 1) Input power factor correction, 2) Common

  7. PWM DC/DC Converter

    Chen, Juan


    This report is the result of a Master Thesis work done at Seaward Electronics Inc. in Beijing, China from June to December in 2007. The main goal for this thesis is to verify and improve the performance of Honey-PWM DC-DC converter, which has been fabricated by a standard 0.6um CMOS processes. The project was started with studying of Buck converter structure. After the understanding of the converter structure, the project goes in to the analyses phase for each sub-cells, including the theory,...

  8. Modified discontinuous PWM for size reduction of the circulating current filter in parallel interleaved converters

    Gohil, Ghanshyamsinh Vijaysinh; Maheshwari, Ram Krishan; Bede, Lorand;


    for the maximum value of the flux linkage are derived for each of these PWM schemes. In addition, the effect of the proposed PWM scheme on the line current ripple and the switching losses is also analyzed and compared. To verify the analysis, experimental results are presented, which prove the effectiveness......Parallel voltage-source converters (VSCs) require an inductive filter to suppress the circulating current. The size of this filter can be minimized by reducing either the maximum value of the flux linkage or the core losses. This paper presents a modified discontinuous pulsewidth modulation (DPWM......) scheme to reduce the maximum value of the flux linkage and the core losses in the circulating current filter. In the proposed PWM scheme, the dwell time of an active vector is divided within a half-carrier cycle to ensure simultaneous occurrence of the same zero vectors in both VSCs. A function to decide...




    Full Text Available This paper presents the comparison of unipolar multicarrier Pulse Width Modulation (PWM techniques for the Flying Capacitor Multi Level Inverter (FCMLI. Due to switch combination redundancies, there are certain degrees of freedom to generate the five level AC output voltage. This paper presents the use of Control Freedom Degree (CFD combination. The effectiveness of the PWM strategies developed using CFD are demonstrated by simulation and experimentation. The results indicate that the multilevel inverter triggered by the developed USHPWM strategy exhibits reduced harmonics. PWM strategies developed are implemented in real time using dSPACE/Real Time Interface (RTI. The simulation and experimental output closely match with each other validating the strategies presented.

  10. Three-Phase PWM Power Conversion--The Route to Ultra High Power Density and Efficiency

    J W Kolar; J Minib(o)ck; T Nussbaumer


    A review of three-phase PWM converter topologies which do show a low complexity/high reliability and high efficiency and power density and are therefore of main interest for a future industrial application is presented.A three-switch/level Boost-type PWM rectifier (VIENNA Rectifier),a Buck+Boost-type PWM rectifier with wide output voltage range and the AC/AC Sparse Matrix Converter concept are discussed in detail and topics to be treated in the course of further research are identified. Finally,it is shown how the aspects being relevant for the realization of highly compact converter systems could be integrated into education in the field.

  11. Analysis of Discontinuous Space Vector PWM Techniques for a Seven-Phase Voltage Source Inverter

    Mohd. Arif Khan


    Full Text Available This paper presents discontinuous space vector PWM (DPWM techniques for a seven-phase voltage source inverter (VSI. Space vector model of a seven-phase VSI shows that there exist 128 space vectors with different lengths and maps into fourteen sided polygons. A number of possibilities could arise to implement modulation of inverter legs due to large number of available space voltage vectors. Two strategies are adopted here; one utilising large and two middle sets of space vectors to implement discontinuous space vector PWM. Clamping of legs of inverter to either positive or negative dc bus leads to discontinuity in the switching and consequently offers reduced switching loss modulation strategy. A significant reduction in switching losses can be achieved while employing DPWM in a seven-phase VSI. A generalised method is also proposed to realize the DPWM in a seven-phase VSI. Comparison of continuous and discontinuous PWM is presented in terms of switching current ripple. The experimental set-up is illustrated and the experimental results are presented.

  12. PWM Technique for Non-Isolated Three-Phase Buck-Boost PFC Converter

    Morizane, Toshimitsu; Shimomori, Wataru; Taniguchi, Katsunori; Kimura, Noriyuki; Ogawa, Masanori

    The buck-boost power factor corrected (PFC) converter has the wide range of the dc output voltage. A new non-isolated three-phase hard-switching and a soft-switching buck-boost PFC converter are proposed. Removing the three-phase transformer from the converters makes their size more compact and their costs lower. In addition, the new control method based on the PWM technique is proposed in this paper to achieve the high power factor. Complete soft-switching is also achieved under the discontinuous current mode (DCM) operation.

  13. Windowed SHE-PWM of Interleaved Four-Quadrant Converters for Resonance Suppression in Traction Power Supply Systems

    Song, Kejian; Konstantinou, Georgios; Mingli, Wu


    AC electric locomotives that use a number of interleaved four-quadrant converters generate high-frequency switching harmonics which may stimulate certain resonances in traction power supply systems (TPSSs). A windowed selective harmonic elimination pulse-width modulation (SHE-PWM) method...

  14. High-Frequency Link Inverter for Fuel CellsBased on Multiple-Carrier PWM


    A similar circuit as Fig. 12 can be realized with MOSFET or IGBT devices configured as bi-directional pairs in the output bridge. In this case, the complete process in Fig. 8 would be needed to generate the complete 50% gate drive pulses. The 50% gate pulses still support pulse transformer coupling, retaining the simplicity of the gate drive isolation. The PWM cycloconverter process scales directly to higher switching speeds possible with these devices.

  15. A novel PWM control for a bi-directional full-bridge DC-DC converter with smooth conversion mode transitions

    Lorentz, V. R. H.; Schwarzmann, H.; März, M.; Bauer, A. J.; Ryssel, H.; Frey, L.; Poure, P.; Braun, F.


    A novel CMOS integrated pulse-width modulation (PWM) control circuit allowing smooth transitions between conversion modes in full-bridge based bi-directional DC-DC converters operating at high switching frequencies is presented. The novel PWM control circuit is able to drive full-bridge based DC-DC converters performing step-down (i.e. buck) and step-up (i.e. boost) voltage conversion in both directions, thus allowing charging and discharging of the batteries in mobile systems. It provides smooth transitions between buck, buck-boost and boost modes. Additionally, the novel PWM control loop circuit uses a symmetrical triangular carrier, which overcomes the necessity of using an output phasing circuit previously required in PWM controllers based on sawtooth oscillators. The novel PWM control also enables to build bi-directional DC-DC converters operating at high switching frequencies (i.e. up to 10 MHz and above). Finally, the proposed PWM control circuit also allows the use of an average lossless inductor-current sensor for sensing the average load current even at very high switching frequencies. In this article, the proposed PWM control circuit is modelled and the integrated CMOS schematic is given. The corresponding theory is analysed and presented in detail. The circuit simulations realised in the Cadence Spectre software with a commercially available 0.18 µm mixed-signal CMOS technology from UMC are shown. The PWM control circuit was implemented in a monolithic integrated bi-directional CMOS DC-DC converter ASIC prototype. The fabricated prototype was tested experimentally and has shown performances in accordance with the theory.

  16. Research on Direct Power Control of Three-phase PWM Rectifier with Constant Switch Frequency%三相恒频PWM整流器的直接功率控制研究

    唐雄民; 朱燕飞


    A predictive direct power control strategy for three-phase pulse width modulation rectifier was presented. Based on instantaneous active and reactive power theory, the rectifier s active and reactive power variations were predicted in the next sampling period and control vector of rectifier was directly calculated. With control vector of rectifier,space vector modulation was used to generate the required switch pulse of con verter in a constant switching frequency. The impact of sampling delay and online calculation delay on the accu racy of active and reactive power was analyzed,and the compensation method was achieved. Simulation results validate the control strategy and compensation method.%提出了一种基于功率预测模型的三相PWM整流器控制策略.控制策略利用瞬时功率理论预测下一个固定周期内电路的有功和无功变化,直接求取整流器交流侧的电压矢量,并采用空间矢量调制方法来保证整流器工作频率的恒定.还对由于采样、实时计算等原因引起的延时对电路有功和无功的影响进行探讨,并给出了补偿方法.仿真结果验证了控制策略和补偿方法的有效性.

  17. Impact of frequency modulation ratio on capacitor cells balancing in phase-shifted PWM based chain-link STATCOM

    Behrouzian, Ehsan; Bongiorno, Massimo; Teodorescu, Remus


    The purpose of this paper is to investigate the impact of switching harmonics on the instantaneous power that flows in the cells of a chain-link based STATCOM when using Phase-Shifted PWM. Two different cases are investigated for the converter cells: low, and high switching frequency. It is shown...... distribution among cells of the same phase leg, thus contributing to the capacitors balancing. Theoretical conclusions are validated through PSCAD simulation results....

  18. 软开关脉宽调制变频技术%Soft-Switching Technique in Pulse Width Modulation Inverters

    陈国呈; 谷口胜则; 中村博人


    In this paper, a new soft-switching inverter using a minimum number of devices, and a new PWM (pulse-width modulation)method suitable for 3-phase soft-switching inverters are proposed. The circuit is used as an interface between the DC supply and the conventional voltage source of a PWM inverter. The number of switching operations can be reduced by using the PWM strategy. Increasing the amplitude of the fundamental component contained in the output waveform results in an effective utilization of the DC supply, a reduction of nominated capacity of the inverter elements, and a reduction of switching loss in the switching devices.

  19. A digitally controlled PWM/PSM dual-mode DC/DC converter

    Zhen Shaowei; Zhang Bo; Luo Ping; Hou Sijian; Ye Jingxin; Ma Xiao


    A digitally controlled pulse width modulation/pulse skip modulation (PWM/PSM) dual-mode buck DC/DC converter is proposed.Its operation mode can be automatically chosen as continuous conduction mode (CCM) or discontinuous conduction mode (DCM).The converter works in PSM at DCM and in 2 MHz PWM at CCM.Switching loss is reduced at a light load by skipping cycles.Thus high conversion efficiency is realized in a wide load current.The implementations of PWM control blocks,such as the ADC,the digital pulse width modulator (DPWM) and the loop compensator,and PSM control blocks are described in detail.The parameters of the loop compensator can be programmed for different external component values and switching frequencies,which is much more flexible than its analog rivals.The chip is manufactured in 0.13 μm CMOS technology and the chip area is 1.21 mm2.Experimental results show that the conversion efficiency is high,being 90% at 200 mA and 67% at 20 mA.Meanwhile,the measured load step response shows that the proposed dual-mode converter has good stability.

  20. A ZVS PWM control strategy with balanced capacitor current for half-bridge three-level DC/DC converter

    Liu, Dong; Deng, Fujin; Chen, Zhe


    The capacitor current would be imbalanced under the conventional control strategy in the half-bridge three-level (HBTL) DC/DC converter due to the effect of the output inductance of the power supply and the input line inductance, which would affect the converter's reliability. This paper proposes...... a pulse-wide modulation (PWM) strategy composed of two operation modes for the HBTL DC/DC converter, which can realize the zero-voltage switching (ZVS) for the efficiency improvement. In addition, a capacitor current balancing control is proposed by alternating the two operation modes of the proposed ZVS...... PWM strategy, which can eliminate the current imbalance among the two input capacitors. Therefore, the proposed control strategy can improve the converter's performance and reliability in: 1) reducing the switching losses and noises of the power switches; 2) balancing the thermal stresses...

  1. Fundamental Approach in Digital Circuit Design for 1-MHz Frequency PWM Gate Drive Application

    Nor Zaihar Yahaya


    Full Text Available This paper discusses the design of a digital programmable logic circuit to produce a 5 V - output square wave pulses for four high power MOSFET switches using a fixed PWM circuit. It will be applied to drive the synchronous rectifier buck converter(SRBC circuit. The PWM signals with multiple fixed time delay of 15 ns, 232 ns, 284 ns and 955 ns are generated. The steps taken to analyze each propagation time delay of each logic gate used and its combination are carefully studied. A multiplexer is added at the output of the logic circuit to select and produce the desired output pulses of 20% duty ratio. The logic outputs are compared with the analog pulses and results match each other within 1% in difference.


    ShenZhongting; YanYangguang


    A novel concept of neural network based control in pulse-width modulation(PWM)voltage source inverters is presented.On the one hand,the optimal switching an-gles are obtained in real time by the neural network based controller;on the other hand,the output voltage is ad-justed to fit the expected value by neural network when input voltage or loads change.The structure of neural network is simple and easy to be realized by DSP hard-ware system.No large memory used for the existing opti-mal PWM schemes is required in the system.Theoreticalanlysis of the proposed so-called sparse neural network is provided,and the stability of the system is proved.Un-der the control of neural network the error of output volt-age descends sharply,and the system outputs ac voltage with high precision.

  3. Practical switching power supply design

    Brown, Martin C


    Take the ""black magic"" out of switching power supplies with Practical Switching Power Supply Design! This is a comprehensive ""hands-on"" guide to the theory behind, and design of, PWM and resonant switching supplies. You'll find information on switching supply operation and selecting an appropriate topology for your application. There's extensive coverage of buck, boost, flyback, push-pull, half bridge, and full bridge regulator circuits. Special attention is given to semiconductors used in switching supplies. RFI/EMI reduction, grounding, testing, and safety standards are also deta

  4. Large-signal stability analysis of PWM converters

    Huynh, P.T. [Philips Labs., Briarcliff Manor, NY (United States); Cho, B.H. [Seoul National Univ. (Korea, Republic of). Dept. of Electrical Engineering


    Investigation of the effects of existing nonlinearities on the stability of PWM converters is performed. The bilinear structure, the duty cycle saturation, and the opamp saturation are the principal nonlinearities in PWM converters. These nonlinearities are incorporated in the large-signal analytical models of PWM converters, and the basic input-output stability theory is applied to analyze their stability. Design and optimization of the small-signal loop gains to counteract the undesirable nonlinear effects are also discussed.

  5. Dynamic Sliding Mode Evolution PWM Controller for a Novel High-Gain Interleaved DC-DC Converter in PV System

    Taizhou Bei


    Full Text Available Considering the disadvantages of the traditional high-gain DC-DC converter such as big size, high voltage stress of switches, and large input current ripple, a novel high-gain interleaved boost converter with coupled-inductor and switched-capacitor was proposed correspondingly and the operation principle together with the steady-state analysis of this converter was also described. Besides, a new control approach-dynamic sliding mode evolution PWM controller (DSME PWM for the novel topological converter based on both dynamic evolution and sliding mode control was also presented. From the simulation results and experimental validation the proposed converter can fulfill high-gain boost, low ripple of both the input current and the output voltage. Furthermore, MPPT technique can be also achieved in a short time by simulation. The efficiency and stability of the converter proposed in this paper can be improved.

  6. AC Motor Drive Fed by Renewable Energy Sources with PWM

    J. Pavalam


    Full Text Available In this fast aproaching nature of technology the ned of Electricity becomes a mandatory in developing technology. The ned of Electricity increases the power demand where the power demand met by the conventional sources of energy has some disadvantage of polution, this disadvantage can be decreased by the use of the Renewable energy sources like Fuel Cel and available solar energy. When a FUEL cel produces AC power, basicaly two stages are required for conversion first a bosting stage and second is inversion stage. In this paper the Bost inverter topology is achieved where in the conventional methods the normal DC - AC power conversion method is used where as in this paper the PWM based DC - AC inverter has ben used which is useful in reducing the harmonics in the output of the Inverter. The voltage controled output is produced in the bost inverter the curent controled output is taken from dc-dc bidirectional converter. The Fuel cel canot be relied as a whole so a Solar PV module is conected acros the Load so while the Sunlight days the PV arays generate power and in the night time the Fuel cel is used to generate power for the load. Since, the Fuel cel and PV arays can generate power in Partial load they are prefered than any other sources. When the output from the Solar PV aray is low or when the sunlight available is not eficient in generating the power a automatic switch over is provided in the junction betwen the Solar PV aray and Fuel cel so that whenever it hapens the switch automaticaly switch over to another source. The simulation results are presented to confirm the operational feature of the proposed system.

  7. Full Bridge ZVT—PWM DC—DC Converter①

    WEIYanjun; QIHanhong; 等


    A new FB-ZVT-PWM converter is proposed.The new converter operates at a fixed frequency and implements ZVS for power devices without increasing voltage in both turn-on and turn-off transient.A 80kHz/50 W FB-ZVT-PWM boost converter using MOSFETs is analysed theoretically.

  8. Modelling and Controller Design of Electro-Pneumatic Actuator Based on PWM

    Behrouz Najjari


    Full Text Available In this paper, a nonlinear model associated to the fast switching on-off solenoid valve and pneumatic cylinder was dynamically presented. Furthermore, an investigation into the electrical, magnetic, mechanical and fluid subsystems are made. Two common control policies to track valve position, a Proportional Integrator (PI based on Pulse Width Modulation (PWM and hysteresis controllers, are investigated. To control cylinder position, a Programmable Logic Controller (PLC on a simulated unit and an experimental setup regulated with AVR microcontroller are carried out. Experimental results show effective validation to the simulation results from PLC.

  9. High-Frequency Link Inverter for Fuel Cells Based on Multiple-Carrier PWM


    HIGH-FREQUENCY (I-IF) ac link inverter topologies, with or without soft switching, have important practical advantages compared to more conventional dc link inverters in terms of isolation, size of magnetics, and other properties. It is possible to obtain these basic advantages directly in a conventional PWM inverter with trans former-coupled output, but only if the transformer can handle the low modulating frequency. HF link topologies have not been common for medium power (1 to 20kW), largely because of the number of power stages and control complexity.

  10. Design of a ZVS PWM inverter for a brushless DC motor in an EMA application

    Bell, J. Brett; Nelms, R. M.; Shepherd, Michael T.


    The Component Development Division of the Propulsion Laboratory at Marshall Space Flight Center (MSFC) is currently investigating the use of electromechanical actuators for use in space transportation applications such as Thrust Vector Control (TVC). These high power servomechanisms will require rugged, reliable, and compact power electronic modules capable of modulating several hundred amperes of current at up to 270 Vdc. This paper will discuss the design and implementation of a zero-voltage-switched PWM (Pulse Width Modulation) inverter which operates from a 270 Vdc source at currents up to 100 A.

  11. Modeling and the analysis of control logic for a digital PWM controller based on a nano electronic single electron transistor

    Rathnakannan Kailasam


    Full Text Available This paper describes the modelling and the analysis of control logic for a Nano-Device- based PWM controller. A comprehensive simple SPICE schematic model for Single Electron transistor has been proposed. The operation of basic Single Electron Transistor logic gates and SET flip flops were successfully designed and their performances analyzed. The proposed design for realizing the logic gates and flip-flops is used in constructing the PWM controller utilized for switching the buck converter circuit. The output of the converter circuit is compared with reference voltage, and when the error voltage and the reference are matched the latch is reset so as to generate the PWM signal. Due to the simplicity and accuracy of the compact model, the simulation time and speed are much faster, which makes it potentially applicable in large-scale circuit simulation. This study confirms that the SET-based PWM controller is small in size, consumes ultra low power and operates at high speeds without compromising any performance. In addition these devices are capable of measuring charges of extremely high sensitivity.

  12. PWM-Statcom system additionally having active filter function

    Matsui, K.; Kojima, H.; Yamamoto, I.; Hasegawa, M. [Chubu Univ., Kasugai Aichi (Japan); Ando, K. [Nitto Kogyo Corp., Nagakute, Aichi (Japan)


    The harmonic characteristics of static synchronous compensators (Statcom) were discussed with particular reference to the difference between symmetrical and asymmetrical modulation strategies that influence a quality of output waveform. The asymmetrical modulation strategy is the better approach in higher power factor applications such as alternating current (AC) motor drives. It was noted that in cases requiring a passive filter with a very large scale Statcom, a symmetrical modulation strategy is superior. Therefore, in this study, a symmetrical modulation was preferred for a neutral point clamped (NPC) pulse width modulation (PWM) inverter. Due to switching in a limited narrow frequency band, such output harmonics can be eliminated using a simple passive filter and harmonics such as the fifth and the seventh, can be suppressed using the proposed Statcom scheme in which the feedback signals for the fifth and seventh harmonics are injected into the Statcom. Using these feedback signals, the harmonics in the power system were significantly reduced. This result was also confirmed by simulation. It was concluded that, in addition to the proper operation of the Statcom, it is possible to perform an active filtering function . 10 refs., 1 tab., 9 figs.

  13. Design of a PWM Speed - governing System for DC Motor Based on PLC%基于PLC的直流电机PWM调速系统设计

    何新霞; 邢瑞军


    设计了基于SIMATIC S7-200 PLC直流电机PWM调速系统.主电路采用双极式可逆PWM变换器,选用集成驱动器M57962L,通过设计其驱动外围电路,实现了对IGBT的导通和关断控制.采用硬件延时电路,防止上、下桥臂直通事故的发生.利用PLC的高速计数功能实现了对电机转速的测量,设计开发了基于PLC的PI控制程序及PWM信号产生程序.从而实现了直流电机的PWM调速,并实现了转速的无静差调节.%The paper presents the design of PWM speed - governing system for DC motor based on S7 - 200 - PLC. The double - polar reversible PWM converter is used and integrated drive electronics M57962 is selected in main circuit. The conduction and switch control of IGBT is realized by designing the peripheral driving circuitry. The delayed circuit is adopted to prevent the shoot -through phenomenon between upper and lower bridge arm in a PWM. Programs for PLC PI control and for PWM signal generation are developed to implement PWM speed- governing for DC motor and floating control on speed.

  14. Analysis of Input and Output Ripples of PWM AC Choppers

    Pekik Argo Dahono


    Full Text Available This paper presents an analysis of input and output ripples of PWM AC choppers. Expressions of input and output current and voltage ripples of single-phase PWM AC choppers are first derived. The derived expressions are then extended to three-phase PWM AC choppers. As input current and output voltage ripples specification alone cannot be used to determine the unique values of inductance and capacitance of the LC filters, an additional criterion based on the minimum reactive power is proposed. Experimental results are included in this paper to show the validity of the proposed analysis method.

  15. Three-Phase Back PWM-PFC Rectifier

    Yasuyuki Nishida


    A new 3-phase back (or current-source-type) PWM-PFC rectifier is proposed in this paper. The necessity,the advantages and disadvantages of this type PWM rectifier are discussed first.Then,the new power circuit topology and the modulation scheme to eliminate or mitigate the disadvantages and obtain further new advantages of the buck PWM rectifier are introduced.The features of the new rectifier, i.e., high efficiency, simple modulation process, robustness of the line-current modulation for distortion of the utility voltages and DC current ripples have been confirmed through experimental results obtained from a 12kW prototype.

  16. Hysteresis controller with constant switching frequency

    Poulsen, Søren; Andersen, Michael Andreas E.


    Switch mode audio power amplifiers are showing up on market in still greater numbers because of advantages in form of high efficiency and low total system cost, especially for high power amplifiers. Several different modulator topologies have been made, ranging from standard PWM to various self-o...

  17. Hybrid zero-voltage switching (ZVS) control for power inverters

    Amirahmadi, Ahmadreza; Hu, Haibing; Batarseh, Issa


    A power inverter combination includes a half-bridge power inverter including first and second semiconductor power switches receiving input power having an intermediate node therebetween providing an inductor current through an inductor. A controller includes input comparison circuitry receiving the inductor current having outputs coupled to first inputs of pulse width modulation (PWM) generation circuitry, and a predictive control block having an output coupled to second inputs of the PWM generation circuitry. The predictive control block is coupled to receive a measure of Vin and an output voltage at a grid connection point. A memory stores a current control algorithm configured for resetting a PWM period for a switching signal applied to control nodes of the first and second power switch whenever the inductor current reaches a predetermined upper limit or a predetermined lower limit.

  18. Comparative Analysis of PWM Techniques for Three Level Diode Clamped Voltage Source Inverter

    Zulkifilie Bin Ibrahim


    Full Text Available Multilevel inverters are increasingly being used in high-power medium voltage industrial drive applications due to their superior performance compared to conventional two-level inverters. Thre are a number of Pulse width modulation (PWM techniques applied in recent years. The most widely applied PWM techniques are Sine Pulse Width Modulation (SPWM and Space Vector Pulse Width Modulation (SVPWM.  SPWM is the most simple modulation technique that can realize easily in analog circuit.  However, it has some drawbacks such as higher total harmonic distortion (THD, lower effective DC utilization and lower switching frequency. Space vector pulse width modulation (SVPWM is widely used because of their easier digital realization and better DC bus utilization and lower THD. The complexity is due to the difficulty in determining the reference vector location, on times calculation, and switching states selection. This paper presents a simple SVPWM algorithm for diode clamped three level inverters based on standard two-level SVPWM which can easily determine the location of reference vector, calculate the on-times, the selection of switching states. Three level diode clamped inverter (3LDCI using space vector modulation technique has been modeled and simulated using MATLAB/SIMULINK and Origin 6.1 with a passive R-L load that can be extended to any level. Simulation results are presented to verify the proposed SVPWM control in terms of THD. The results are compared with conventional sinusoidal pulse width modulation (SPWM where SVPWM shows better performance than SPWM in terms of THD.

  19. EMC Increasing of PWM Rectifier in Comparison with Classical Rectifier

    R. Dolecek


    Full Text Available Pulse width modulated rectifier is a very popular topic nowadays. The modern industrial production demands continuous and lossless conversion of electrical energy parameters. This need leads to wide spread of power semiconductor converters. The rapid development in power electronics and microprocessor technology enables to apply sophisticated control methods that eliminate negative side effects of the power converters on the supply network. The phase controlled thyristor rectifiers overload the supply network with higher harmonics and reactive power consumption. That is why the PWM rectifier is being examined. In comparison with the phase controlled rectifier it can be controlled to consume nearly sinusoidal current with power factor equal to unity. Another advantage is its capability of energy recuperation. The PWM rectifier can assert itself for its good behavior in many applications, for example as an input rectifier in indirect frequency converter, or in traction. Traction vehicles equipped with PWM rectifier do not consume reactive power, do not load the supply network with higher harmonics, and the recuperation is possible. The paper deals with the PWM rectifier functional model realization and examination. Electromagnetic compatibility of PWM rectifier and classical phase controlled rectifier is compared on the basis of the input current harmonic analysis.

  20. Inverter Output Filter Effect on PWM Motor Drives of a Flywheel Energy Storage System

    Santiago, Walter


    NASA Glenn Research Center (GRC) has been involved in the research and development of high speed flywheel systems for small satellite energy storage and attitude control applications. One research and development area has been the minimization of the switching noise produced by the pulsed width modulated (PWM) inverter that drives the flywheel permanent magnet motor/generator (PM M/G). This noise can interfere with the flywheel M/G hardware and the system avionics hampering the full speed performance of the flywheel system. One way to attenuate the inverter switching noise is by placing an AC filter at the three phase output terminals of the inverter with the filter neutral point connected to the DC link (DC bus) midpoint capacitors. The main benefit of using an AC filter in this fashion is the significant reduction of the inverter s high dv/dt switching and its harmonics components. Additionally, common mode (CM) and differential mode (DM) voltages caused by the inverter s high dv/dt switching are also reduced. Several topologies of AC filters have been implemented and compared. One AC filter topology consists of a two-stage R-L-C low pass filter. The other topology consists of the same two-stage R-L-C low pass filter with a series connected trap filter (an inductor and capacitor connected in parallel). This paper presents the analysis, design and experimental results of these AC filter topologies and the comparison between the no filter case and conventional AC filter.

  1. A Dual-Bridge LLC Resonant Converter with Fixed-Frequency PWM Control for Wide Input Applications

    Xiaofeng, Sun; Li, Xiaohua; Shen, Yanfeng;


    . Compared with the traditional pulse frequency modulation (PFM) controlled HB/FB LLC resonant converter, the voltage gain range is independent of the quality factor and the magnetizing inductor has little influence on the voltage gain, which can simplify the parameter selection process and benefit...... the design of magnetic components as well. Over the full load range, zero voltage switching (ZVS) and zero current switching (ZCS) can be achieved for primary switches and secondary rectifier diodes, respectively. Detailed analysis on the modulation schedule and operating principle of the proposed converter......This paper proposes a dual-bridge (DB) LLC resonant converter for wide input applications. The topology is an integration of a half-bridge (HB) LLC circuit and a full-bridge (FB) LLC circuit. The fixed-frequency PWM control is employed and a range of twice the minimum input voltage can be covered...

  2. Neural network based PWM AC chopper fed induction motor drive

    Venkatesan Jamuna


    Full Text Available In this paper, a new Simulink model for a neural network controlled PWM AC chopper fed single phase induction motor is proposed. Closed loop speed control is achieved using a neural network controller. To maintain a constant fluid flow with a variation in pressure head, drives like fan and pump are operated with closed loop speed control. The need to improve the quality and reliability of the drive circuit has increased because of the growing demand for improving the performance of motor drives. With the increased availability of MOSFET's and IGBT's, PWM converters can be used efficiently in low and medium power applications. From the simulation studies, it is seen that the PWM AC chopper has a better harmonic spectrum and lesser copper loss than the Phase controlled AC chopper. It is observed that the drive system with the proposed model produces better dynamic performance, reduced overshoot and fast transient response. .

  3. Improved Switching Performance Analysis of Space Vector Pulse Width Modulation on Field Programmable Gate Array

    Nagalingam RAJESWARAN


    Full Text Available Nowadays VLSI (Very Large Scale Integration technology is being successfully implemented by using Pulse Width Modulation (PWM in applications like power electronics and drives. The main problems in PWM viz. harmonic distortion and switching speed are overcome by implementing the Space-Vector PWM (SVPWM technique by using the Xilinx tool VHDL (Verilog High Speed Integrated Circuit (VHSIC Hardware Description Language and tested in programmable Integrated Circuits of Field Programmable Gate Array (FPGA. The results are provided along with simulation analysis in terms of hardware utilization and schematic, power report, computing time and usage of memory.

  4. Synchronised PWM Schemes for Three-level Inverters with Zero Common-mode Voltage

    Oleschuk, Valentin; Blaabjerg, Frede


    PWM with synchronous smooth pulses-ratio changing and a quarter-wave symmetry of the voltage waveforms. Three basic versions of both algebraic and trigonometric synchronised PWM have been analysed. Simulations give the behaviour of the proposed methods and show some advantage of synchronised PWM...

  5. Synchronised PWM Schemes for Three-level Inverters with Zero Common-mode Voltage

    Oleschuk, Valentin; Blaabjerg, Frede


    PWM with synchronous smooth pulses-ratio changing and a quarter-wave symmetry of the voltage waveforms. Three basic versions of both algebraic and trigonometric synchronised PWM have been analysed. Simulations give the behaviour of the proposed methods and show some advantage of synchronised PWM...


    A. G. Stryzhniou


    Full Text Available The article describes a process of synthesis and qualitative assessment of the harmonic composition of voltages of multiple and single PWM pulses in time regulation, being, along with amplitude, frequency and phase method, one of control methods of an asynchronous motor. The main point of time regulation is that a pause after any two single PWM pulses with different polarity or after any two groups of multiple PWM pulses with different polarity changes during a process of regulation. Feature of time regulation is that a motor has fast response in the range of small-signal of control and good linearity of speed-torque characteristics in the whole control range. Analytical expressions of parameters of PWM pulses ai and ti are obtained which allow to simplify considerably a process of formation and implementation of time regulation using tabular or indexed-tabular methods. These expressions allow not only to define voltage amplitude of  harmonic but also to perform qualitative assessment of harmonic composition of output voltages at time regulation. It is specified that harmonic frequencies wi = w0/q change in inverse proportion to magnitude of parameter q during a process of regulation and there is a replacement of a fundamental frequency by frequencies of higher harmonics.The offered approach allows to synthesize voltage of uniform single and multiple PWM pulses and to perform their comparative and qualitative analysis and the obtained expressions can be used at modeling of AC motor work. Voltage of multiple PWM pulses which is formed using stepped reference voltage with even quantity of steps in a half period and a pause on a zero level has the best parameters by criterion of a minimum of harmonic components and a maximum of a factor of anharmonicity Kнс at time regulation.

  7. Partially resonant active filter using the digital PWM control circuit with the DSP

    Matsuo, Hirofumi; Kurokawa, Fujio; Luo, Zongxin; Makino, Yutaka; Ishizuka, Yoichi [Nagasaki Univ. (Japan); Oshikata, Tetsuya [Shindengen Elect. Mfg. Co. Ltd. (Japan)


    The partially resonant active filter, as a pre-regulator, using the digital PWM control circuit with the DSP is proposed to improve the power factor and input current harmonic distortion factor. The steady-state and dynamic characteristics of this active filter are analysed and the relationship among the circuit parameters, variables and performance characteristics such as the pre-regulation of the output voltage, input power factor, input current harmonic distortion, boundaries of stability and so forth are defined. Using the partially resonant active filter, the high power efficiency over 91% is obtained and the high frequency switching noise is suppressed. Also, the digital control with the DSP is versatile and consequently, the power factor over 0.99 and total harmonic distortion factor less than 1% are easily realized. (orig.)

  8. Pwm Control Strategy For Controlling Of Parallel Rectifiers In Single Phase To Three Phase Drive System

    Ramakrishna Manohar Anaparthi


    Full Text Available This paper explains that how to develop and design, control of single phase to three phase drive system. The proposed topology of drive system consisting of two parallel connected rectifiers, inverter and induction motor, connected through inductor and capacitor, where used to produce balanced output to the motor drive. The main objective of this proposed method is to reduce the circulating currents and harmonic distortions at the converter input side, here the control strategy of drive system is PWM (pulse width modulations techniques control strategy, the proposed topology also provides fault compensation in the case of short circuit faults and failure of switches for uninterrupted Power supplies. We also develop and simulate the MATLAB models for proposed drive system, by using MATLAB/ Simulink the output results simulate and observed.

  9. Analysis of Capacitive Parasitism in PWM Inverter-Fed Motor


    The effects of parasitic capacitance in induction motor system are unnoticed when it is fed from the AC line. but they are obvious when supplied directly from a PWM inverter. Consequently. many parasitic problems occur, such as motor-to-earth leakage current, bearing current, incoming line current distortion and uneven distribution of electrical stresses along the winding. On the ba sis of the uniform transmission line principle, a complete equivalent circuit of the PWM inverter-fed motor system is presented, based on which all the capacitive parasitic problems mentioned above are analyzed and simulated by means of PSPICE. All the results are consistent with the existing ones.

  10. A New Improved Variable Frequency Triangular Carrier-PWM with MOPSO Algorithm for Carrier Based PWM Techniques in Inverters

    Mohammad Sadegh Orfi Yegane


    Full Text Available This paper investigates multi-carrier PWM methods in multi-level inverters. Two new MCPWM methods are introduced. This study proposes a new optimized MCPWM method to improve the output voltage characteristics like THD and LOH. The proposed method is based on variable frequency with a specific range. It means each carrier wave has a determined frequency. It is calling Variable Frequency Triangular Carrier-PWM. MOPSO algorithm is used to optimize the answers. This work considers some different levels of inverters like five, seven and nine levels. The results are compared with SPWM method.

  11. Design of a new phase-shift PWM generator based on FPGA%一种基于FPGA的新型移相PWM发生器



    在逆变开关电源中,隔离变压器通常要求正、反方向的磁通变化量相等,以防止偏磁等现象发生,在移相全桥DC-DC开关电源中尤为重要.介绍了一种基于FPGA的移相PWM(pulse width modulation)发生器,该发生器主要包括分频模块、计数模块、比较模块和死区控制模块等;该发生器不仅将移相PWM数字化,且考虑了逆变全桥DC-DC开关电源中隔离变压器的工作特点.仿真结果表明,该发生器实现了移相PWM输出,可以满足逆变电源的工作要求.%In inverter switch power,the magnetic change in positive and negative in insulating transformer is needed equal,which prevent magnetic flow,specially in phase shift full bridge DC-DC switch power. A phase shift PWM pulse width modulation generator based on FPGA is introduced in this paper,which consists of dividing frequency module,counter module,composition module,and dead area control module, etc .The design of the generator not only make phase shift PWM with digitization, but also consider the working characteristics of insulating transformer in inverter full bridge DC-DC switch power.The simulation results show that realize the output of phase shift PWM, and meet the working requirements of inverter power source.

  12. Spread Spectrum Modulation by Using Asymmetric-Carrier Random PWM

    Mathe, Laszlo; Lungeanu, Florin; Sera, Dezso;


    This paper presents a new fixed carrier frequency random PWM method, where a new type of carrier wave is proposed for modulation. Based on simulations and experimental measurements, it is shown that the spread effect of the discrete components from the motor current spectra and acoustic spectra i...

  13. An Approach to Average Modeling and Simulation of Switch-Mode Systems

    Abramovitz, A.


    This paper suggests a pedagogical approach to teaching the subject of average modeling of PWM switch-mode power electronics systems through simulation by general-purpose electronic circuit simulators. The paper discusses the derivation of PSPICE/ORCAD-compatible average models of the switch-mode power stages, their software implementation, and…

  14. Analysis of a novel phase-shifted soft switch converter

    蒋志宏; 黄立培; 张义


    In this paper, on the basis of the phase-shifted controlled zero-voltage-switch (ZVS) full-bridge converter with pulse width modulation (PWM), a novel zero-voltage and zero-current switch (ZVZCS) PWM converter using a simple auxiliary circuit was designed. The ZVZCS soft switch is achieved by the resonance among the resisting electromagnetic deflection capacitor, the capacitor of the simple auxiliary network and the leakage inductor of transformer. There are no dissipation devices of the saturation inductor and the auxiliary switch in the converter, meantime the capacitor of the auxiliary circuit is also used to clamp the voltage of the rectifier, and there is no additional clamped circuit. There is no big circulating current in the converter, all the active and passive devices work on the condition of the low current and voltage stress, and the proposed converter has wide load range and small duty loss.

  15. Switching power converters medium and high power

    Neacsu, Dorin O


    An examination of all of the multidisciplinary aspects of medium- and high-power converter systems, including basic power electronics, digital control and hardware, sensors, analog preprocessing of signals, protection devices and fault management, and pulse-width-modulation (PWM) algorithms, Switching Power Converters: Medium and High Power, Second Edition discusses the actual use of industrial technology and its related subassemblies and components, covering facets of implementation otherwise overlooked by theoretical textbooks. The updated Second Edition contains many new figures, as well as

  16. Dual Z-Source Inverter With Three-Level Reduced Common-Mode Switching

    Gao, Feng; Loh, Poh Chiang; Blaabjerg, Frede;


    . Modulationwise, the dual inverter can be controlled using a carefully designed carrier-based pulsewidth-modulation (PWM) scheme that will always ensure balanced voltage boosting of the Z-source network while simultaneously achieving reduced common-mode switching. Because of the omission of dead-time delays...... in the dual-inverter PWM scheme, its switched common-mode voltage can be completely eliminated, unlike in traditional inverters, where narrow common-mode spikes are still generated. Under semiconductor failure conditions, the presented PWM schemes can easily be modified to allow the inverter to operate......This paper presents the design of a dual Z-source inverter that can be used with either a single dc source or two isolated dc sources. Unlike traditional inverters, the integration of a properly designed Z-source network and semiconductor switches to the proposed dual inverter allows buck...

  17. On the Well-posedness of the PWM Control System

    FAN Qi-fu; SHI Song-jiao


    One of the basic issues in the study of hybrid systems is the well-posedness (existence and uniqueness of solutions) problem of discontinuous dynamical systems.This paper addresses this problem for a class of piecewise affine discontinuous systems with affine inequalities such as systems with pulse-width modulator under the definition lexicographic inequalities and the smooth continuation property of solutions.Furthermore,it is clear that when carrier signal h(t)=0,closed-loop pulse-width modulation (PWM) DC-DC converters are not well posed,and when some condition is satisfied,the closed-loop PWM DC-DC converters with a P controller are well posed.

  18. Analysis of Dither in PWM Control on Electro-hydraulic Proportional Valve

    Guoping LIU


    Full Text Available Plus with modulation (PWM is widely used in proporational control systems for it is efficient, flexible and anti-interference. Due to the friction and hysteresis of electromagnet, hysteresis exists when hydraulic valve in steady-state, and hysteresis influences the dynamic characteristics of the valve seriously,the hysteresis can be improved by superimposing dithers with certain frequency and amplitude to the valve coil. Aiming at the character of anti-unloading power driver circuit ,this paper analyzed the parasitic dither which exists in ±24V PWM control,besides,the experiment shows that in a high frequency PWM, dither with independent frequency and amplitude can be generated by changing the frequency of the PWM, in this way, the dithers  and average current of coil  can be adjusted separately by changing PWM frequency and PWM duty cycle.  

  19. A Study on Power Quality Improvement in PWM Controlled AC Voltage Controller

    Ahmet ALTINTAŞ


    Full Text Available A lot of topologies of pulse-width modulated (PWM-AC controllers for single-phase and three-phase systems are proposed up to date. PWM-AC controllers have important advantages compared with the phase-controlled AC controllers using thyristors and triacs. The PWM-AC controller has sinusoidal current waveforms, smaller THD values, better power factor, faster dynamics, and smaller input/output filter. This article presents a novel control technique for application to PWM-AC controllers with ability of generating fewer harmonics. In the proposed control method, both the traditional AC voltage controllers and the PWM-AC controllers are combined; and smaller THD values are obtained. Thus, the harmonic pollution in the power system will be reduced; and consequently, the power quality will be increased. For this purpose, computer simulations are performed in order to investigate the proposed controller performance. The obtained results are compared with the conventional PWM-AC controller.

  20. Power electronic converters PWM strategies and current control techniques

    Monmasson, Eric


    A voltage converter changes the voltage of an electrical power source and is usually combined with other components to create a power supply. This title is devoted to the control of static converters, which deals with pulse-width modulation (PWM) techniques, and also discusses methods for current control. Various application cases are treated. The book is ideal for professionals in power engineering, power electronics, and electric drives industries, as well as practicing engineers, university professors, postdoctoral fellows, and graduate students.

  1. Implementation of Carrier-Based Simple Boost Pulse Width Modulation (PWM) for Z-Source Inverter (ZSI) using Field Programming Gate Array (FPGA)

    Muhammad, M.; Rasin, Z.; Jidin, A.


    In recent years, the research on the Z-source inverter (ZSI) has received a wide acceptance due to its attractive solution for example in the renewable energy interface that requires voltage boost capability. The conventional inverter circuit based on the SPWM technique for example does not able to fully utilize its DC input voltage to produce a greater output voltage. The ZSI shoot-through implementation in high switching frequency requires a processor with fast sampling and high precision. In simulation, this can be easily carried out with the available advanced engineering software. In the hardware implementation however, the processor used is not only handle the switching, but also needs to read the data obtained by the sensor, voltage and current control, information display etc. This limits the capacity that can be used to implement the switching fast sampling with high precision. The aims of this work are to implement high precision of carrier-based simple boost PWM for ZSI using FPGA and to verify its real time hardware implementation. The high precision of PWM control algorithm based on the FPGA platform is verified by comparing the simulation results with the experimental results for different modulation index and boost factor, and a good agreement is concluded. It is observed that the application of FPGA reduces complexity, increases speed and the design of the switching technique can be altered without having to modify the hardware implementation.

  2. Synthesis of Voltages of Multiple Uniform PWM, Generated by Trapezoidal and Sinusoidal Functions

    A. Ctryzhniou


    Full Text Available The problem of synthesis and qualitative estimation of the harmonic composition of voltages of multiple uniform PWM pulses generated by trapezoidal and sinusoidal functions is considered. Analytical expressions for PWM pulses parameters ai  and ti have been received and they can be used for program-based generation of multiple uniform PWM, determination of n-harmonic magnitude in pulse-width regulation and AC motor operation simulation.

  3. Analysis and Simulation of a High Performance Quasi Resonant PWM Inverter for Solar Power Generation

    Yun-Parn Lee; Yu-Huang Lin; Yu-Lun Lin


    A quasi resonant pulse width modulation (PWM) inverter is used in a solar power system to convert the solar panel and battery charger’s direct current (DC) output to alternating current (AC). Although much has been published about DC to AC PWM inverters, none of the previous work has shown modeling and simulation results for DC to AC inverters. In this study, we suggest a new topology for a quasi resonant PWM inverter. Experimental results are also presented.

  4. High-Frequency Link Inverter for Fuel Cells Based on Multiple-Carrier PWM (to continue)


    C. Operation of a PWM Cycloconverter The concepts in Section Ⅱ-B, present a progression of solutions to known design difficulties. To incorporate these benefits and eliminate the redundant conversion step shown in Fig. 6, we propose the PWM cycloconverter shown in Fig. 7. It will be shown in Section Ⅲ. that the conventional PWM inverter can be unified through a multiple-carrier PWM framework. The control concept introduced is extended to demonstrate that multiple-carrier PWM methods lead to HF link inverters that are nearly as simple to control as conventional PWM inverters.

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

    陈树君; 王军; 卢振洋; 殷树言


    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.

  6. Soft switching bidirectional DC-DC converter for ultracapacitor-batteries interface

    Adib, Ehsan; Farzanehfard, Hosein [Dept. of Electrical and Computer Engineering, Isfahan Univ. of Technology (Iran)


    In this paper a new soft switching bidirectional DC-DC converter is introduced which can be applied as the interface circuit between ultracapacitors and batteries or fuel cells. All semiconductor devices in the proposed converter are soft switched while the control circuit remains PWM. Due to achieved soft switching condition, the energy conversion through the proposed converter is highly efficient. The proposed converter is analyzed and a prototype converter is implemented. The presented experimental results confirm the theoretical analysis. (author)

  7. 三相电压型PWM整流器自抗扰控制%Active Disturbance Rejection Control of Three-Phase Voltage Source PWM Rectifiers

    刘子建; 吴敏; 王春生; 桂武鸣; 陈鑫


    Based on the nonlinear characteristic of three-phase voltage source PWM rectifiers, a nonlinear control strategy is proposed. The voltage and current controllers are designed by using active disturbance rejection control (ADRC) technique, and then, the controllers have the advantage of robustness. The load disturbance is compensated by the voltage controller, which effectively removes the static tracking error of the output direct current (DC) voltage, which is caused by the disturbance. The switching signals of the three-phase voltage source PWM rectifiers are generated by space vector pulse width modulation (PWM) method. Simulation results show the effectiveness of the presented control strategy.%针对三相电压型PWM整流器本身的非线性特点,提出一种非线性控制策略.采用自抗扰控制技术设计了电压和电流控制器,具有鲁棒性强的特点.通过电压控制器对负载扰动进行补偿,消除了负载扰动带来的输出直流电压稳态跟踪误差.三相电压型PWM整流器的开关信号利用空间矢量脉宽调制方法生成.仿真结果表明,本文所提控制策略是有效的,

  8. PV Power-Generation System with a Phase-Shift PWM Technique for High Step-Up Voltage Applications

    Cheng-Tao Tsai


    Full Text Available A PV power-generation system with a phase-shift pulse-width modulation (PWM technique for high step-up voltage applications is proposed. The proposed power-generation system consists of two stages. In the input stage, all power switches of the full-bridge converter with phase-shift technique can be operated with zero-current switching (ZCS at turn-on or turn-off transition. Hence, the switching losses of the power switches can be reduced. Then, in the DC output stage, a voltage-doubler circuit is used to boost a high dc-link bus voltage. To supply a utility power, a dc/ac inverter is connected to induce a sinusoidal source. In order to draw a maximum power from PV arrays source, a microcontroller is incorporated with the perturbation and observation method to implement maximum power point tracking (MPPT algorithm and power regulating scheme. In this study, a full load power of 300 W prototype has been built. Experimental results are presented to verify the performance and feasibility of the proposed PV power-generation system.

  9. Development of a PWM precision spraying controller for unmanned aerial vehicles

    This paper presents a new pulse width modulation (PWM) controller for unmanned aerial vehicle (UAV) precision sprayer for agriculture using a TL494 fix-frequency pulse width modulator together with a data acquisition board and developed software. The PWM controller was implemented through the guidan...

  10. High flexibility and low cost digital implementation for modern PWM strategies

    Mathe, Laszlo; Sera, Dezso; Kerekes, Tamas


    like AZSPWM, NSPWM, or ACRPWM. By using a conventional PWM unit from a microcontroller, these modern modulation techniques are often difficult, or even impossible, to implement. The proposed method can be used to implement PWM strategies even for those microcontrollers which are not equipped...

  11. Influence of PWM Modes on Commutation Torque Ripples in Sensorless Brushless DC Motor Control System

    ZHANGXiang-jun; CHENBo-shi; 等


    This paper introduces four PWM modes used in the sensorless brushless DC motor control system,analyzes their different influences on the commutation torque ripple in detail,and selects the best PWM mode in four given types to reduce commutation torque ripple of Brushless OC( BLDC) motors,Simulation and experimental results show that the selection is correct and practical.

  12. Integrated PWM converter/inverter system feeding three-phase induction motor

    Bayoumi, E.


    The integrated PWM converter/inverter system has the capability of unity power factor, sinusoidal supply current, bi-directional power capabilities and constant dc link voltage. Also, it has the ability to minimize the dc link capacitance. The integrated PWM converter/inverter fed three-phase induction motor consists of two identical PWM converters. One is used to serve as power regulator with unity power factor and constant dc voltage bus, while the other serve as inverter for the induction motor drive. By using the synchronous rotating-frame the current controllers in both the input and the output of the integrated system are characterized by fast current response and low harmonic distortion. The dc link is the intermediate stage between the PWM converter and the PWM inverter. It mainly consists of aluminium electrolytic capacitors, which are normally installed in the system as the energy storage element, but in some applications, such as high power voltage motor drives, the electrolytic capacitor has several drawbacks from the viewpoints of size, weight, cost and reliability. Due to continuous outgassing, the properties of the electrolytic capacitor deteriorate gradually (as time goes by). Hence, the capacitor is the major factor limiting the lifetime of the inverter systems. The aim of this work is to reduce the dc link capacitor size, as it means reduction of the cost and the volume of the converter/inverter systems. The work consists of 8 chapters: Chapter one illustrate the historical overview for the ac/dc/ac fed induction motor drive systems. It describes the benefits of the integrated PWM converter/inverter fed induction motor drive. It classified the integrated PWM converter/inverter systems into two types independent and dependent systems. It demonstrates some ideas for the control algorithms of these types of integrated systems. Chapter two introduces the mathematical model for the PWM converter. It explains the space vector PWM (SVPWM) method for

  13. High flexibility and low cost digital implementation for modern PWM strategies

    Mathe, Laszlo; Sera, Dezso; Kerekes, Tamas


    In this paper a new low cost technique for PWM strategy implementation is presented. The proposed technique does not require dedicated hardware PWM units, thus offering higher flexibility of use. Furthermore, the aforementioned method eases the digital implementation of modern modulation methods ...... with hardware PWM unit. The experimental results show that this new technique is suitable to replace traditional implementation methods with minimum computational overhead, with the benefit of high flexibility, lower cost and faster code development.......In this paper a new low cost technique for PWM strategy implementation is presented. The proposed technique does not require dedicated hardware PWM units, thus offering higher flexibility of use. Furthermore, the aforementioned method eases the digital implementation of modern modulation methods...

  14. Bifurcation boundary conditions for current programmed PWM DC-DC converters at light loading

    Fang, Chung-Chieh


    Three types of bifurcations (instabilities) in the PWM DC-DC converter at light loading under current mode control in continuous-conduction mode (CCM) or discontinuous-conduction mode (DCM) are analysed: saddle-node bifurcation (SNB) in CCM or DCM, border-collision bifurcation during the CCM-DCM transition, and period-doubling bifurcation in CCM. Different bifurcations occur in some particular loading ranges. Bifurcation boundary conditions separating stable regions from unstable regions in the parametric space are derived. A new methodology to analyse the SNB in the buck converter based on the peak inductor current is proposed. The same methodology is applied to analyse the other types of bifurcations and converters. In the buck converter, multiple stable/unstable CCM/DCM steady-state solutions may coexist. Possibility of multiple solutions deserves careful study, because an ignored solution may merge with a desired stable solution and make both disappear. Understanding of SNB can explain some sudden disappearances or jumps of steady-state solutions observed in switching converters.

  15. Minimization and identification of conducted emission bearing current in variable speed induction motor drives using PWM inverter

    A Ramachandran; M Channa Reddy; Ranjan Moodithaya


    The recent increase in the use of speed control of ac induction motor for variable speed drive using pulse width modulation (PWM) inverter is due to the advent of modern power electronic devices and introduction of microprocessors. There are many advantages of using ac induction motor for speed control applicatons in process and aerospace industries, but due to fast switching of the modern power electronic devices, the parasitic coupling produces undesirable effects. The undesirable effects include radiated and conducted electromagnetic interference (EMI) which adversely affect nearby computers, electronic/electrical instruments and give rise to the flow of bearing current in the induction motor. Due to the flow of bearing current in the induction motor, electrical discharge machining takes place in the inner race of the bearing which reduces the life of the bearing. In high power converters and inverters, the conducted and radiated emissions become a major concern. In this paper, identification of bearing current due to conducted emission, the measurement of bearing current in a modified induction motor and to minimize the bearing current are discussed. The standard current probe, the standard line impedance stabilization network (LISN)), the electronics interface circuits are used to measure high frequency common mode current, bearing current and to minimize the conducted noise from the system. The LISN will prevent the EMI noise entering the system from the supply source by conductive methods, at the same time prevents the EMI generated if any due to PWM, fast switching in the system, will not be allowed to enter the supply line. For comparing the results with Federal Communications Commission (FCC) and Special Committee on Radio Interference (CISPR) standards, the graphs are plotted with frequency Vs, line voltage in $dB{_\\mu} V$, common mode voltage in $dB{_\\mu} V$ and the bearing current in $dB_{\\mu} A$ with out and with minimizing circuits.

  16. Scalar Controlled Boost PWM Rectifier for Micro Wind Energy Systems

    J. Chelladurai


    Full Text Available Uses of Permanent Magnet Synchronous Generators (PMSG are increasing in variable speed micro-Wind Energy Conversion Systems (WECS. In stand-alone or grid-connected Micro-WECS, extraction of maximum power is vital. To extract maximum power output and to obtain a constant DC bus voltage from variable magnitude and variable frequency voltage output of PMSG and generally a two stage scheme namely i conventional diode bridge rectifier and ii DC-DC Boost/Buck/Buck-Boost converters are used. In this study, a single stage Scalar Controlled PWM (SCPWM Boost Rectifier is proposed in order to minimize the current harmonics and to improve the power factor on source side. The modeling and simulation of PMSG based wind generator and SCPWM Boost rectifier was developed in MATLAB. The harmonic content in the input current waveform of the proposed SCPWM rectifier is compared with the conventional three-phase bridge rectifier. The Simulation results show the effectiveness of the PWM Boost rectifier in terms of effective utilization of source, improved efficiency and harmonic mitigation for PMSG based Wind Generator. Simulation results demonstrate the effectiveness of the proposed system in reducing the current and voltage THD on source side.

  17. A New Hard Switching Bidirectional Converter With High Power Density

    Bahador Fani


    Full Text Available In this paper, a new isolated dc-dc bidirectional converter is proposed. This converter consists of two transformers (flyback and forward and only one switch in primary side and one switch in secondary side of transformers. In this converter energy transfers to the output in both on and off switch states so power density of this converter is high This converter controlled by PWM signal. Also this converter operates over a wide input voltage range. Theoretical analysis is presented and computer simulation and experimental results verify the converter analysis.

  18. Pengaruh Penambahan PWM (Pulse Width Modulation Pada Generator HHO Tipe Dry Cell

    Fungky Dyan Pertiwi


    Full Text Available Generator HHO memanfaatkan proses elektrolisis air agar mendapatkan gas H2. Namun, pada praktiknya pemakaian arus dari aki yang besar dan temperatur tinggi membuat bejana generator menjadi cepat rusak, sehingga dibutuhkan tambahan rangkaian elektronika PWM pada pengujian generator HHO guna mengatasi permasalahan tersebut. Penelitian menggunakan elektroda plat berjumlah 9 berdimensi 120mm 120mm, tebal 1mm dan dibatasi oleh o-ring dengan diameter 126mm, tebal 3mm. Pengujian dilakukan secara eksperimen dengan 2 kelompok yaitu kelompok control yang mana pengujian tanpa menggunakan PWM serta kelompok uji dimana pengujian menggunakan PWM dengan variasi duty cycle 30%, 50% dan 70%. Pengujian dilakukan hingga temperatur elektrolit 93oC. Hasil uji didapatkan bahwa arus, laju produksi dan efisiensi terbesar didapatkan pada pengujian tanpa PWM yang mencapai 60,6A, 6,033 10-6kg/s dan 25,69%. Namun, pada pengambilan data kedua efisiensi turun menjadi 19,74%. Penambahan PWM pada pengujian berpengaruh pada arus dan temperatur yang stabil meskipun laju produksi dan efisiensi lebih kecil daripada pengujian tanpa PWM. Pengujian dengan PWM pada duty cycle 70% menghasilkan laju produksi dan efisiensi terbesar yang mencapai 1,843 10-6 kg/s dan 15,19%.

  19. Design and test hardware for a solar array switching unit

    Patil, A. R.; Cho, B. H.; Sable, D.; Lee, F. C.


    This paper describes the control of a pulse width modulated (PWM) type sequential shunt switching unit (SSU) for spacecraft applications. It is found that the solar cell output capacitance has a significant impact on SSU design. Shorting of this cell capacitance by the PWM switch causes input current surges. These surges are minimized by the use of a series filter inductor. The system with a filter is analyzed for ripple and the control to output-voltage transfer function. Stable closed loop design considerations are discussed. The results are supported by modeling and measurements of loop gain and of closed-loop bus impedance on test hardware for NASA's 120 V Earth Observation System (EOS). The analysis and modeling are also applicable to NASA's 160 V Space Station power system.

  20. Synchronization of the distributed PWM carrier waves for modular multilevel converters

    Burlacu, Paul Dan; Mathe, Laszlo; Teodorescu, Remus


    The half-bridge modular multilevel converter has proven itself to be a suitable solution for HVDC application. In order to achieve high modularity and fault tolerance, distributed control strategy is one possible solution and is discussed in this paper. When distributed control strategy is used, ...... the PWM outputs of each sub-module increasing the total harmonic distortion of the output voltage. This paper presents a solution to synchronize the PWM outputs of the MMC submodules using EtherCAT communication protocol focusing on phase shifted PWM modulation technique....

  1. Parallel Interleaved VSCs: Influence of the PWM Scheme on the Design of the Coupled Inductor

    Gohil, Ghanshyamsinh Vijaysinh; Bede, Lorand; Maheshwari, Ram Krishan;


    -linkage in the CI is presented in this paper. The maximum flux density and the core losses, being the most important parameters for the CI design, are evaluated for continuous PWM and discontinuous pulsewidth modulation (DPWM) schemes. The effect of these PWM schemes on the design of the CI is discussed....... To limit the circulating current, magnetic coupling between the interleaved legs of the corresponding phase is provided by means of a Coupled Inductor (CI). The design of the CI is strongly influenced by the Pulsewidth Modulation (PWM) scheme used. The analytical model to evaluate the flux...

  2. Parametric algorithms for frequency estimation in PWM converter systems

    Lobos, T.; Hejke, I.; Rezmer, J.; Sikorski, T.; Kostyla, P. [Dept. of Electrical Engineering, Wroclaw University of Technology, Wyb. Wyspianskiego 27, 50-370 Wroclaw (Poland)


    Proper estimation of voltage parameters has a significant meaning for power converters control systems. One of the measured parameter, directly associated with control process, is frequency of the basic voltage component at the converter output. Unfortunately, power converters generate a wide spectrum of harmonics as well as interharmonics, that makes difficulties in estimation this frequency. Measurement carried out in industrial applications exhibits complex nature of investigated signals often corrupted by resonances or overvoltages phenomena. It entails searching a new digital algorithms for frequency measurement. This work presents algorithm using modification of high-resolution Prony method connected with digital filtering. The investigations was based on simulations and real measured signals recorded in two different commercial PWM converters. Obtained results indicate accuracy of the method as well as its fast response. (author)

  3. Single Phase Bidirectional PWM Converter for Microgrid System



    Full Text Available Smart grid is a newly flourishing research area because of its viable applications and expected to address the drawback of existing grid. Microgrids are the part of the Smart grid and they are designed to supply electricity for a small community such as residential areas, universities or industrial sites. Power electronics plays a vital role for connecting the renewable energy sources to Microgrid system. This paper deals the Microgrid connected single phase Bidirectional PWM converter which operates in Rectification and Inverting mode. This converter helps to connect renewable energy sources to loads as well as excess power are given to power grid. Double Loop PID control technique is used for controlling the converter for both modes. The designed Converter is simulated in MATLAB/Simulink software and results are verified using the Hardware.

  4. Stator insulation systems for medium voltage PWM drives fed motors

    Gao, G.; Chen, W. [TECO-Westinghouse Motor Co., Round Rock, TX (United States)


    Adjustable speed drives (ASD) are commonly used in power electronics and control systems. It is estimated that more than 15 per cent of medium voltage motors are currently fed by such drives worldwide. A research project was conducted to examine the influence of medium voltage pulse width modulated (PWM) ASD on motor stator insulation systems. The findings, based on accelerated laboratory tests, have helped designers to improve the capabilities of the insulation system used for ASD-fed motors. Repetitive, high magnitude voltage spikes with fast rise time create significant stress on insulation systems. Gradual deterioration and premature failure of the motor insulation can result from surge voltages which generate surface discharges between phase windings/end windings, or partial discharges between stator turns. However, there is no industrial standard to evaluate motor insulation life under ASD-cable-motor conditions. Several material manufacturers have developed their own version of corona resistant material. However, the insulation life of ASD-fed motors does not depend solely on the raw materials. Rather, it depends on the complete insulation system, including the stator manufacturing process. In order to address this problem, TECO-Westinghouse Motor Company has developed special design criteria and manufacturing practices in order to reduce winding insulation temperature and to compensate for the additional heat generated by high frequency contents in the PWM voltage waveform. A patent pending new cooling system should reduce winding temperature by 15 to 20 degrees C. This paper presented design considerations for turn insulation, groundwall insulation, and a voltage stress grading system. A new thermal class H insulation system was also described. 6 refs., 2 tabs., 5 figs.

  5. a microprocessor-based control, scheme for a pwm voltage-fed ...

    Dr Obe

    Department of Electrical Engineering ... integral controllers constitute the main control program while the application of thyristor gating ... PWM strategies depend on application .... Figure 3(a) shows the basic principle of gating signal.

  6. Semiconductor Light-Controlled Instrument Transducer with Direct PWM Output for Automatic Control Systems

    O. Malik


    The internal PWM signal conversion occurs by the use of non-equilibrium physical processes in the semiconductor substrate of the MOS-C. The 10-20 V amplitude limited square PWM output signal is obtained by the amplification of the sensor signal with a standard 60 dB transimpedance amplifier. The amplified output signal presents positive and negative PWM waveforms that can be easily separated using diodes. The duty of the positive part is proportional to the light intensity, whereas the negative part is inversely proportional to the intensity. The frequency operating range of this proposed instrument varies from 1 Hz to a few kilohertz. The duty cycle of the PWM output signal varies from 2% to 98% when the incident light intensity varies in the microwatts range. These new transducers or sensors could be useful for automatic control, robotic applications, dimmer systems, feedback electronic systems, and non-contact optical position sensing for nulling and centering measurements.

  7. Design of a High Performance Green-Mode PWM Controller IC with Smart Sensing Protection Circuits

    Shen-Li Chen; Shih-Hua Hsu


      A design of high performance green-mode pulse-width-modulation (PWM) controller IC with smart sensing protection circuits for the application of lithium-ion battery charger is investigated in this article...

  8. Analysis of VCO based noise shaping ADCs linearized by PWM modulation

    Hernandez, Luis; Prefasi, , Enrique; Paton , Susana; Rombouts, Pieter


    Nonlinearity is one of the main problems associated with VCO based noise shaping ADCs. Their open loop architecture does not permit correction of the nonlinear voltage to frequency response of the VCO by feedback. Recently, linearization of a VCO ADC by Pulse Width Modulation (PWM) precoding has been proposed. Here, the input signal is encoded by a PWM modulator to drive the VCO with a 2-level signal, thus eliminating the nonlinearity of the VCO. This paper analyzes the remaining inherent dis...

  9. Electrical Discharge Machining Flyback Converter using UC3842 Current Mode PWM Controller

    Nazriah Mahmud


    Full Text Available This paper presents a current mode Pulse Width Modulation (PWM controlled Flyback converter using UC3842 for Electrical Discharge Machining current generator control circuit. Circuit simplicity and high efficiency can be achieved by a Flyback converter with current mode PWM controller. The behaviors of the system's operation is analyzed and discussed by varying the load resistance. Matlab sofware is used to simulate the Flyback converter where a prototype has been built and tested to verify it's performance.

  10. Positioning Error of Optoelectronic Telescope Compensated by Bipolar PWM Driving Mode

    LI Xiao-yan; ZHOU Hui; FU Hong; HOU Yun-hai


    The optoelectronic telescope has two sets of control systems: azimuth one and elevation one, and both are driven by PWM power amplifier with high efficiency and wide speed regulation range. The diagram of the azimuth control system is demonstrated, the nonlinear factors is analyzed at low speed, and some related experiments are carried out. The results show that the positioning error with unipolar is 86 codes(106.21″),while 18 codes (22. 23″) is with bipolar PWM driver.

  11. Multi-frequency proportional-resonant (MFPR) current controller for PWM VSC under unbalanced supply conditions


    This letter presents a multi-frequency proportional-resonant (MFPR) current controller developed for PWM voltage source converter (VSC) under the unbalanced supply voltage conditions. The delta operator is used in place of the shift operator for the implementation of MFPR by using a low-cost fixed-point DSP. The experimental results with an alternative control strategy validated the feasibility of the proposed MFPR current controller for the PWM VSC during voltage unbalance.

  12. A New Method for Maintaining Constant Dither Amplitude in Low Frequency PWM

    KANG, H.


    Full Text Available Various controls for fluid flow and pressure are now required in related industries, and the pulse width modulation (PWM and dithering techniques have become essential for the proportional control of solenoids. However, there is a fatal drawback when the dither current signals are generated as a by-product of low frequency PWM. That is, the average current and the dither amplitude in low frequency PWM cannot be controlled independently. Therefore, a new method for maintaining constant dither amplitudes is proposed in this paper. Throughout the mathematical analysis, the effect of PWM frequency and duty cycle on the average current and dither amplitude was investigated, and the analysis result was validated by electrical experiments. Based on the mathematical analysis, a new method that properly varies both the duty cycle and the PWM frequency to obtain the desired average current and constant dither amplitude was established and verified. This method requires only the calculations for determining the proper PWM frequency and duty cycle, so it is possible to improve the performance of a proportional solenoid valve without additional devices or cost.

  13. 三电平PWM整流器网侧LCL滤波器设计%Design of grid side LCL filter for three-level PWM rectifier

    刘超; 赵争鸣; 鲁挺


    采用LCL滤波器代替L滤波器对入网电流进行滤波已成为变换器并网的趋势,相对于L滤波器,LCL滤波器具有成本低,体积小,整流器动态响应快等优点.然而,目前关于LCL滤波器的研究都是针对两电平变换器进行的,对多电平变换器鲜有涉及.本文以三电平PWM整流器为研究对象,提出了适用于三电平PWM整流器LCL滤波器的设计方法,并通过Simulink仿真和实验验证了滤波器的优良性能.%For high capacity PWM rectifier, large grid side inductor is required in order to reduce the grid current harmonics around the switching frequency. However, large inductor will increase not only the cost but also the vol ume of the rectifier. Furthermore, the dynamic response of the system would be depressed. In order to reduce the grid side inductance, LCL-filter can be used to replace the traditional L-filter. In this paper, the principle of LCL filter is investigated, a design method of parameters of grid side LCL-filter for three-level PWM rectifier is pro posed. For a lkW three-level PWM rectifier, a complete parameter scheme is put forward and verified by Simulink and experiment.

  14. OW式永磁直驱风电系统不连续脉宽调制∗%Open Winding PMSG for Discontinuous PWM

    殷杰; 向铁元; 杨瑶


    Permanent Magnet Synchronous Generator current ripple in the operation proposed an open winding type permanent magnet direct drive wind power system for discontinuous PWM modulation. Open winding pair was established equivalent switch model PMSG inverter drive system, clarify the decoupled nature of PWM modulation current ripple causes by introducing a“valid” by properly offset voltage vector time effectively solved PMSG machine side of the stator current ripple, realized the optimization of PMSG were converters power quality improvement. Finally, 110kW wind drag and experimental platform for the open winding PMSG continuous PWM modulation method for performance verification, verified the validity of the method in the optimization of PMSG on-grid power quality.%针对中压永磁直驱风电系统( PMSG)运行中存在的电流脉动问题,提出一种OW式永磁直驱风电系统不连续PWM调制方法。建立了OW双逆变器PMSG驱动系统等效开关模型,阐明了解耦PWM调制电流脉动问题的本质原因,引入“有效时间”概念,通过合理地偏移有效电压矢量作用时间,解决了PMSG机侧定子电流脉动问题,实现了PMSG变流器发电品质的优化提高。最后,基于110 kW风力发电对拖试验平台对所提OW PMSG不连续PWM调制方法进行性能验证,验证了该方法对优化PMSG并网电能品质的有效性。



    Since the early70s,many s mall-signal fre-quency-domain modeling technique have been de-veloped to study the dynamic perfor mances and sta-bilities ofPWMs witching converters around thestatic operating point.However,the accuracy of thederived models relies on accurate deter mination ofthe steady state operating point,and usually manyperfor mances of circuits are given based on steady-state,so it is very essential to analyze the steadystate of circuits.Analysis methods for steadystate ofnonlinear circuits ca...

  16. Current Controlled PWM Switching Mode Power Supply%电流控制PWM开关电源




  17. 双PWM变换器一体化控制策略%Integrated control strategy for dual-PWM converter

    李昆鹏; 万健如; 宫成; 李世群


    针对双PWM变换器依赖附加协调控制策略解决一体化的问题,研究PWM整流器及逆变器独立控制策略对协调性能的影响,借助瞬时功率中间变量,提出一种不外加其他协调方法的双PWM变换器一体化控制策略.整流器侧建立在离散化数学模型基础上,在固定时间周期内,以满足指标函数最小为原则预测下一时刻电网电流,借助空间矢量调制技术获得整流器期望开关状态.逆变器侧采用基于空间矢量调制技术的直接转矩控制.理论分析表明,由负载参数变化直接引起的直流母线电压波动通过电压环调节以瞬时功率形式作用于整流器电网电流预测环节.仿真和实验结果表明,双PWM变换器能快速响应负载变化情况并恢复稳态,对负载及系统参数扰动具有鲁棒性,验证了所提策略的有效性.%Aiming at the problem that dual pulse width modulation (PWM) converter relys on additional coordination control strategy to realize integrative control, the influences of PWM rectifier and inverter to coordination are studied. An integrated control strategy for dual PWM converter that not depends on the other harmonious methods is presented by use of the middle variable of instantaneous power. The control strategy for rectifier was built on the discrete mathematical model, and a cost function was chosen for pre dicting ac input current through minimizing itself in fixed cyclical time. Meanwhile, the state of switches for rectifier was determined with the help of space vector pulse width modulation technology. The control strategy for inverter adopted direct torque control method based on the space vector pulse width modula tion technique. A theoretical analysis shows that load parameter variation causes fluctuation of DC-bus voltage, and the fluctuation in instantaneous power shape acts on the predictive current for rectifier by voltage loop. The experiment and simulation results show quick response to the

  18. Analysis of Single Phase PWM Rectifier for Different Applications

    Mitra, Arkendu; Chowdhuri, Sumana


    This research work investigates the various applications of a PWM rectifier based on its input power factor. Most of the cases, the papers describe the operation of the rectifier used for unity power factor (UPF) operation. Beside this mode of operation, this paper compiles the application of the rectifier as STATCOM also, where the rectifier deals only with reactive power exchange. In this work, the controller is implemented by inserting a loop for reference input of phase angle which will be compared with the actual one, so that user can operate the rectifier at any power factor. Some basic formulae are derived for the input current, active power and reactive power based on which the control circuit is to be designed. Here two Proportional-Integral (PI) controllers are used. A brief description of tuning these two PI controllers is incorporated in this paper. Also some calculations are given to determine the harmonic factors of the input line current from which it is found that the rectifier when operated in each mode operation, the order of the harmonics are very low.

  19. Analysis of Single Phase PWM Rectifier for Different Applications

    Mitra, Arkendu; Chowdhuri, Sumana


    This research work investigates the various applications of a PWM rectifier based on its input power factor. Most of the cases, the papers describe the operation of the rectifier used for unity power factor (UPF) operation. Beside this mode of operation, this paper compiles the application of the rectifier as STATCOM also, where the rectifier deals only with reactive power exchange. In this work, the controller is implemented by inserting a loop for reference input of phase angle which will be compared with the actual one, so that user can operate the rectifier at any power factor. Some basic formulae are derived for the input current, active power and reactive power based on which the control circuit is to be designed. Here two Proportional-Integral (PI) controllers are used. A brief description of tuning these two PI controllers is incorporated in this paper. Also some calculations are given to determine the harmonic factors of the input line current from which it is found that the rectifier when operated in each mode operation, the order of the harmonics are very low.

  20. PWM SPWM的应用与PSIM仿真

    张伟龙; 谢新胜; 李帅


    With the continuous development of power electronics technology and mature, As the importance of power electronics technology and simulation applications. PWM and SPWM technology and PSIM software will certainly be with the power electronics technology development is recognized by more and more people. This paper simply introduces the technology of the most basic concepts, with PSIM software to deepen the understanding of them, Let us in the future life and work have a basic understanding of and cognition, also make a foundation for future learning.%随着电力电子技术的不断发展与成熟,电力电子在各个方面都得到了广泛的应用。而作为电力电子技术的重要技术和仿真应用软件,PWM与SPWM技术及PSIM软件必然会随着电力电子技术的发展被越来越多的人所认识。本文通过简单地介绍这项技术的最基本概念,并用PSIM软件来加深对它们的理解,让大家在日后的生活和工作有一个基本的了解和认识,也为今后的学习打一个基础。

  1. Assessment of an Average Controller for a DC/DC Converter via Either a PWM or a Sigma-Delta-Modulator

    R. Silva-Ortigoza


    Full Text Available Sliding mode control is a discontinuous control technique that is, by its nature, appropriate for controlling variable structure systems, such as the switch regulated systems employed in power electronics. However, when designing control laws based on the average models of these systems a modulator is necessary for their experimental implementation. Among the most widely used modulators in power electronics are the pulse width modulation (PWM and, more recently, the sigma-delta-modulator (Σ-Δ-modulator. Based on the importance of achieving an appropriate implementation of average control laws and the relevance of the trajectory tracking task in DC/DC power converters, for the first time, this research presents the assessment of the experimental results obtained when one of these controllers is implemented through either a PWM or a Σ-Δ-modulator to perform such a task. A comparative assessment based on the integral square error (ISE index shows that, at frequencies with similar efficiency, the Σ-Δ-modulator provides a better tracking performance for the DC/DC Buck converter. In this paper, an average control based on differential flatness was used to perform the experiments. It is worth mentioning that a different trajectory tracking controller could have been selected for this research.

  2. Semiconductor Light-Controlled Instrument Transducer with Direct PWM Output for Automatic Control Systems

    F. J. De la Hidalga-W


    Full Text Available This work shows that the direct PWM output electric signal, with a duty cycle controlled by light intensity, can beobtained using a circuit containing a saw-tooth voltage generator connected in series with a dc voltage source and ametal (semitransparent gate oxide semiconductor capacitor (MOS-C.The internal PWM signal conversion occurs by the use of non-equilibrium physical processes in the semiconductorsubstrate of the MOS-C. The 10-20 V amplitude limited square PWM output signal is obtained by the amplification ofthe sensor signal with a standard 60 dB transimpedance amplifier. The amplified output signal presents positive andnegative PWM waveforms that can be easily separated using diodes. The duty of the positive part is proportional tothe light intensity, whereas the negative part is inversely proportional to the intensity. The frequency operating rangeof this proposed instrument varies from 1 Hz to a few kilohertz. The duty cycle of the PWM output signal varies from2% to 98% when the incident light intensity varies in the microwatts range. These new transducers or sensors couldbe useful for automatic control, robotic applications, dimmer systems, feedback electronic systems, and non-contactoptical position sensing for nulling and centering measurements.

  3. XMEGA-Based Implementation of Four-Switch, Three-Phase Voltage Source Inverter-Fed Induction Motor Drive

    Abolfazl Halavei Niasar; Ehsan Boloor Kashani


    Induction motors offer many advantages tools, and therefore are becoming very popular industrially and commercially. This paper presents the implementation of Xmega microcontroller based PWM inverter controlled of four-switch three phase voltage source inverter (FSTPI) fed induction motor drive. The reduction of the number of power switches from six to four improves the cost effectiveness, volume-compactness and reliability of the three phase inverters in addition to less complexity of contro...

  4. Isolated PDM and PWM DC-AC SICAMs[Pulse Density Modulated; Pulse Width Modulated

    Ljusev, P.


    In this report a class of isolated PDM and PWM DC-AC SICAMs is described, which introduce the audio reference only in the output stage. AC-DC power supply is implemented in its simplest form: diode rectifier followed by a medium-size charge-storage capacitor. Isolation from the AC mains is achieved using a high frequency (HF) transformer, receiving the HF voltage pulses from the input 'inverter' stage and transferring them to the output 'rectifier+inverter' stage, which can use either PDM or PWM. The latter stage is then interfaced to the load using an output low-pass filter. Each of the dedicated stages is discussed in detail. Measurements on the master/slave PWM DC-AC SICAM prototype are presented to help benchmarking the performance of this class of SICAMs and identify the advantages and drawbacks. (au)

  5. A novel PWM scheme to eliminate the diode freewheeling In the Inactive phase in BLDC motor

    WEI Kun; HU Chang-sheng; ZHANG Zhong-chao


    The brushless DC motor (BLDCM) with trapezoidal electromotive force (back-EMF) waveform is used widely.In principle,when the motor runs in the 120°conduction mode,two of the three phases are active while the other phase is inactive at all times.However,a ripple current occurs in the inactive phase due to the diode freewheeling during the non-commutation period in the traditional pulse width modulation (PWM) methods,which aggravates the torque ripples.A new PWM method is proposed in this paper to eliminate the diode freewheeling during the non-commutation period in the inactive phase.As a result,the torque ripple is suppressed using the proposed method.The simulation and experimental results are demonstrated to verify the validity of the proposed PWM method.

  6. Design hardware calculator in PWM peripherals of nios Ⅱ with verilog HDL

    XU Yang; XIANG Min


    The Plus Width Module (PWM) in microprocessors is commonly used in motor control field. If the ordinary PWM peripherals output PWM waveform, the software must calculate the period and duty cycle number based on the microprocessor's system clock cycle first, and then write them into the registers. As all known, the microprocessor without hardware calculator consume very long time in multiplication and division. In order to reduce the CPU's running time, a calculation hardware unit was designed to calculate the waveform parameters. The software only need to write the period (Hz units) to the period register and the duty cycle (% units)to its register. This hardware unit was designed with Verilog HDL and running in the Nios II system successfully.

  7. Implementation strategy for soft switching PFC with low output voltage


    This paper proposes a novel implementation strategy for soft switching PFC whose circuit is simple and can achieve low voltage output directly. The main circuit adopts current mode full-bridge converter and all the power switches can realize ZCS or ZVS in the way of phase-shifted control, using the leakage inductance of the transformer, the junction capacitor of the switches and the stored energy of the output capacitor. The problems such as the function of phase-shifted link in control circuit, the implementation conditions of soft switching and bias restrained are analyzed. The adoption of constant frequency PWM control makes the design of the input and output filter link and the high frequency transformer simple. The transformation ratio regulation so as to achieve low voltage output and electrical insulation can be realized by using high frequency transformer.

  8. Control Strategy for Three Phase Voltage Source PWM Rectifier Based on the Space Vector Modulation

    MILOUD, Y.


    Full Text Available This paper proposes the space vector pulse width modulation (SVPWM control scheme for three-phase voltage source PWM rectifier. The control system based on SVPWM includes two PI controllers which are used to regulate the AC currents and DC-link voltage. The proposed control can stabilize the minimum of the systems storage function at the desired equilibrium point determined by unity power factor and sinusoidal current on the AC side, and constant output voltage on the DC side. So the stable state performance and robustness against the load�s disturbance of PWM rectifiers are both improved. The simulation result shows feasibility of this strategy.

  9. Led spectral and power characteristics under hybrid PWM/AM dimming strategy

    Beczkowski, Szymon; Munk-Nielsen, Stig


    In order to dim LEDs the pulse width modulation (PWM) or amplitude modulation (AM) dimming scheme is typically used. Previous studies show that these dimming schemes can have opposite effects on diodes peak wavelength shift. An experimental study was conducted to test the behavior of InGaN diodes...... and phosphor-converted white diodes under hybrid PWM/AM modulation. Feed forward control schemes that provide stable peak wavelength position during dimming and the ability to compensate the thermally induced color shifts and the decrease of the luminous flux are investigated....

  10. 电流谐波最优PWM开关角计算及数字实现%The Current Harmonic Optimal PWM (CHOPWM) Method and Its Digital Implementation

    王从刚; 何凤有; 邓庆伟; 刘战; 曹晓冬


    介绍了三电平变频器在低开关频率运行下的电流谐波最优PWM(CHOPWM)方法,对其基本原理及开关角的求解进行了深入分析和研究.对三电平变频器输出电压、电流进行傅里叶级数分析,求出电流畸变率的表达式;令电流总畸变率作为目标函数,令电压基波幅值等于参考电压幅值作为非线性约束条件,进而利用MATLAB优化工具箱中的ga函数和fmincon函数求解出CHOPWM开关角.用MATLAB软件搭建了仿真模型,对开关频率为250Hz时的开关角求解结果进行仿真验证.对基于TMS320F2812的CHOPWM数字实现进行分析.最后,通过实验验证了开关角求解方法的有效性.%The current harmonic Optimal PWM (CHOPWM) method for three level converters operating at low switching frequency is introduced. Its basic principle and the solution of the switching angle is researched. The three -level inverter output voltage and current is analyzed using fourier series and the expression of current distortion rate is calculated. The expression of current distortion rate is regarded as a nonlinear transcendental equation and the voltage fundamental amplitude is equal to the reference voltage amplitude seen as nonlinear constraints. Then the switching angle of CHOPWM is solved by using the function of ga and fmincon function in MATLAB optimization toolbox. A simulation model was built using MATLAB software. Results of the switching angle at 250Hz switching frequency are verified. CHOPWM digital implementation is analyzed based on the TMS320F2812. The experimental results verify the availability of the scheme.

  11. Isolated PWM DC-AC SICAM with an active capacitive voltage clamp[Pulse Density Modulated; Pulse Width Modulation

    Ljusev, P.


    In this report an isolated PWM DC-AC SICAM with an active capacitive voltage clamp is presented. AC-DC power supply is implemented in its simplest form: diode rectifier followed by a medium-size charge-storage capacitors and possibly with an EMC filter on the mains entrance. Isolation from the AC mains is achieved using a high frequency (HF) transformer, whose voltages are not audio-modulated. The latter simplifies the design and is expected to have many advantages over the approach where the transformer voltages are modulated in regards to the audio signal reference. Input stage is built as a DC-AC inverter (push-pull, half-bridge or a full-bridge) and operated with 50% duty cycle, with all the challenges to avoid transformer saturation and obtain symmetrical operation. On the secondary side the output section is implemented as rectifier+inverter AC-AC stage, i.e. a true bidirectional bridge, which operation is aimed towards amplification of the audio signal. In order to solve the problem with the commutation of the load current, a dead time between the incoming and outgoing bidirectional switch is implemented, while a capacitive voltage clamp is used to keep the induced overvoltage to reasonable levels. The energy stored in the clamping capacitor is not wasted as in the dissipative clamps, but is rather transferred back to the primary side for further processing using an auxiliary isolated single-switch converter, i.e. an active clamping technique is used. (au)

  12. Feedforward Synchronised PWM for Adjustable Speed AC Drives with Different Control Modes

    Oleschuk, Valentin; Blaabjerg, Frede; Jensen, Flemming Buus


    This paper presents a novel method of direct synchronised pulswidth modulation (PWM) for three-phase voltage source inverters, feeding induction motors with different control regimes. It is based on the universal algorithm with either simplified algebraic or accurate trigonometric control functions...

  13. Active and reactive power control of a current-source PWM-rectifier using space vectors

    Salo, M.; Tuusa, H. [Tampere University of Technology (Finland). Department of Electrical Engineering, Power Electronics


    In this paper the current-source PWM-rectifier with active and reactive power control is presented. The control system is realized using space vector methods. Also, compensation of the reactive power drawn by the line filter is discussed. Some simulation results are shown. (orig.) 8 refs.

  14. Unified analytical equation for theoretical determination of the harmonic components of modern PWM strategies

    Mathe, Laszlo; Cornean, Horia; Sera, Dezso


    of the transfer ratio. The difference between most of the proposed modulation methods like sine-triangular, SVM, and 120 - 60 - 30 Discontinuous PWM consists in the redistribution of the time-length applied for the zero voltage vectors during a fundamental frequency period. This paper presents a unified...

  15. PWM Flow Rate Control of ER Valve and its Application to ER Actuator Control

    Nakano, Masami; Minagawa, Shuji; Hagino, Katsuya

    The PWM (Pulse Width Modulation) control of ER valve consisting of two parallel electrodes has been investigated to continuously control the flow rate of an electrorheological (ER) suspension containing sulfonated polymer particles in silicone oil. PWM wave voltages are applied to the electrodes of the ER valve. It is possible to control continuously the flow rate by changing the duty ratio of the PWM wave from 1 to 0, where the duty ratio of 1 corresponds to the state to stop the flow. A miniature bellows actuator driven by a pair of PWM controlled ER valves has been developed, and the control characteristics of the actuator have been investigated. The duty ratios of both ER valves have been proposed to be changed alternately in proportion to the control voltage V to control the flow rate into and out of the bellows chamber, and also an overlap duty ratio Dov at V=0V has been introduced. The introduction of the overlap duty ratio Dov was found to be very important to smoothly control the actuator and to improve the control performance.

  16. Design of High-Voltage Switch-Mode Power Amplifier Based on Digital-Controlled Hybrid Multilevel Converter

    Yanbin Hou


    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.

  17. Exciter switch

    Mcpeak, W. L.


    A new exciter switch assembly has been installed at the three DSN 64-m deep space stations. This assembly provides for switching Block III and Block IV exciters to either the high-power or 20-kW transmitters in either dual-carrier or single-carrier mode. In the dual-carrier mode, it provides for balancing the two drive signals from a single control panel located in the transmitter local control and remote control consoles. In addition to the improved switching capabilities, extensive monitoring of both the exciter switch assembly and Transmitter Subsystem is provided by the exciter switch monitor and display assemblies.

  18. Switch wear leveling

    Wu, Hunter; Sealy, Kylee; Gilchrist, Aaron


    An apparatus for switch wear leveling includes a switching module that controls switching for two or more pairs of switches in a switching power converter. The switching module controls switches based on a duty cycle control technique and closes and opens each switch in a switching sequence. The pairs of switches connect to a positive and negative terminal of a DC voltage source. For a first switching sequence a first switch of a pair of switches has a higher switching power loss than a second switch of the pair of switches. The apparatus includes a switch rotation module that changes the switching sequence of the two or more pairs of switches from the first switching sequence to a second switching sequence. The second switch of a pair of switches has a higher switching power loss than the first switch of the pair of switches during the second switching sequence.

  19. A New Zero Voltage Switching Buck-Boost Type DC-DC Converter

    Majid Delshad


    Full Text Available In this paper, a new zero voltage switching isolated buck-boost DC-DC converter with active clamp circuit is proposed. The active clamp circuit in this converter not only absorbs voltage spikes across the main switch but also provides soft switching conditions for all switches. All switches are PWM controlled which simplifies the control implementation. One of the main advantages of this converter is the that it operating can operate at high power levels while soft switching conditions exist in both buck and boost modes of converter operation. Since this converter can operate over a wide input voltage range, it can be employed in power factor correction. The experimental results obtained from a 150W prototype circuit operating at 100KHz are presented to confirm the integrity of the proposed circuit.

  20. A Novel Four-Step Commutation for Bidirectional Switch Cells of AC-AC Matrix Converter

    Guo, Yougui; Zeng, Ping; Blaabjerg, Frede


    sector ones and active switching time PWM ones synchronize. Second, the required switching states are flexibly realized in the form of the look-up table by programming in VHDL language for 36 switching combinations of input sectors with output ones. Third, the obtained switching states are judged whether...... on or off of output current happens on the second and third steps. Here the second step is equal to the third one. This method is implemented with four steps by programming in VHDL language. First, the special flip-flop, 74AHC16373, is obtained by programming so as to make input sector signals, output......A novel four-step commutation is proposed with unequal step for each bidirectional switch cell on the basis on analysis of many proposed commutation methods of matrix converter in this paper. The first and fourth step can be shorter than the second or third one because the actual switching...

  1. Optimal feed-forward compensation for PWM dc/dc converters with 'linear' and 'quadratic' conversion ratio

    Calderone, Luigi; Pinola, Licia; Varoli, Vincenzo


    The paper describes an analytical procedure to optimize the feed-forward compensation for any PWM dc/dc converters. The aims of achieving zero dc audiosusceptibility was found to be possible for the buck, buck-boost, Cuk, and SEPIC cells; for the boost converter, however, only nonoptimal compensation is feasible. Rules for the design of PWM controllers and procedures for the evaluation of the hardware-introduced errors are discussed. A PWM controller implementing the optimal feed-forward compensation for buck-boost, Cuk, and SEPIC cells is described and fully experimentally characterized.

  2. Discontinuous PWM Modulation Strategy with Circuit-Level Decoupling Concept of Three-Level Neutral-Point Clamped (NPC) Inverter

    Zhang, Zhe; Thomsen, Ole Cornelius; Andersen, Michael A. E.


    A new pulse width modulation (PWM) strategy which is an alternative approach of discontinuous PWM (DPWM) for a three-level neutral point clamped (NPC) inverter is developed and presented in this paper. The proposed PWM scheme not only takes advantage of the special properties available in NPC...... can be simplified. The salient features of the proposed scheme, as compared with the existing carrier-based DPWM strategies, are: 1) its reduced computational processing time, 2) its capability to balance the DC-link voltage without any additional control and 3) its reduced complexity e.g. only one...

  3. Realization of PWM Velocity Modulation in Hydraulic Elevator%PWM调速在液压电梯中的实现

    唐国兴; 恽源世; 徐鸣谦


    This paper introduces the realization of velocity modulation control in hydraulic elevator by using PWM technology. It mainly includes two parts, one is about how to send out PWM signal via computer to perform the velocity modulation, and the other is about the design of manual PWM velocity modulation device.%介绍了运用PWM技术实现液压电梯的调速控制,主要包括两部分,一是用工控机发送PWM信号进行调速,二是手动PWM调速装置的设计。

  4. Comparison of Simple Self-Oscillating PWM Modulators

    Dahl, Nicolai J.; Iversen, Niels Elkjær; Knott, Arnold


    Switch-mode power amplifiers has become the conventional choice for audio applications due to their superior efficiency and excellent audio performance. These amplifiers rely on high frequency modulation of the audio input. Conventional modulators use a fixed high frequency for modulation. Self......-oscillating modulators do not have a fixed modulation frequency and can provide good audio performance with very simple circuitry. This paper proposes a new type of self-oscillating modulator. The proposed modulator is compared to an already existing modulator of similar type and their performances are compared both...

  5. Closed Loop Control of Soft Switched Interleaved Buck Converter

    R. Shenbagalakshmi


    Full Text Available Design, Modeling and Simulation of a closed loop control is presented for Interleaved Buck Converter with Soft Switching. The features of the closed loop system are to reduce the switching losses and load current sharing among the parallel connected converters. The control system of the converter is designed using PWM technique. In order to improve the transient response and dynamic stability of the converters, the controller parameters are designed based on current mode control. Resonant components thus designed enable the application of zero current switching for both the converters connected in parallel thereby maintaining greater efficiency and minimizing voltage and current oscillations. The system analysis, design and performance are verified through simulation using MATLAB/Simulink environment. The simulation approach reveals the high speed dynamic performance of the closed loop system designed using robust PID controller. The laboratory prototype of the Buck converter is developed to verify the controller platform using PIC16F877A microcontroller.

  6. Large-signal transient response of a switching regulator

    Harada, K.; Nabeshima, T.

    Analytical and experimental considerations on the large-signal transient-responses of the buck-type switching regulator are described. The behaviour under the large-signal operation is different from the case of small signal because of the saturation characteristics of the PWM feedback controller. The effect of this nonlinearity is analyzed by dividing its operation into three modes. As a result, the maximum peak values of the inrush current and output voltage are obtained analytically both for the start-up and for the step change of the load current.

  7. Carrier Phase Error Detection Method and Synchronization Control of Parallel-Connected PWM Inverters without Signal Line

    Kohara, Tatsuya; Noguchi, Toshihiko; Kondo, Seiji

    In recent years, parallel-operation of inverters is employed to increase reliability and capacity in an uninterruptible power supply (UPS) system. A phase error in PWM carrier-signals of each inverter causes high frequency loop current between inverters. Therefore, the PWM carrier-signal of each inverter should be adjusted in phase. This paper proposes a detection method of phase error in PWM carrier-signal and its application to synchronization control for parallel-connected inverters. A simple definite-integral circuit achieves the detection of carrier phase error from high frequency loop current using no signal line between inverters. The detected carrier phase error is applied to synchronize the PWM carrier-signal through a PI-compensator, and then the high frequency loop current can be suppressed. Several experimental test-results show the validity of the proposed detection method and synchronization control.

  8. Four-quadrant PWM rectifier design and simulation%四象限PWM整流器的设计与仿真



    A simplified mathematical model of four-quadrant PWM rectifier in dq coordinate system was given. The fixed switching frequency of pairs of closed-loop direct current control strategy was used in this paper. The method to determine the voltage and current PI regulator parameters was analyzed, the selection of the AC-side inductance and DC side capacitor on the entire main circuit was proposed, the design method was given, and the simulation model was built with Matlab/simulink. The simulation results show that the given regulator design method and circuit parameter design method is correct, and allows two-way flow of energy to achieve the energy feedback;the simulink has an important theoretical guide to four-quadrant PWM rectifier-style development.%给出了四象限电压型PWM整流器(VSR)在dq坐标系中的简化数学模型.采用固定开关频率的双闭环直接电流控制策略,分析了电压和电流PI调节器参数的确定方法,指出交流侧电感和直流侧电容的选取对整个系统的影响,给出了设计方法,在Matlab/simulink下建立仿真模型.仿真表明:给出的调节器设计方法和电路参数设计方法正确,且可使能量双向流动,实现了能量回馈,对四象限PWM整流器的研制有重要的理论指导意义.

  9. A AC-DC Inversion Power Design Based on PWM IC Controller%基于PWM IC芯片控制的开关电源设计

    王玉德; 韩翠玲; 陈春廷; 孙洪海


    介绍了SG3525 PWM IC芯片的内部结构,基于该芯片设计了15V/36V的开关电源.设计中给出具体的设计电路和参数.经过实验验证该系统控制可靠,稳定性好,纹波系数低,能够很好地适应电源电压10%和负载20%的变化,具有一定的实际应用价值.

  10. Space vector-based analysis of overmodulation in triangle-comparison based PWM for voltage source inverter

    Manoj Kumar Modi; S Venugopal; G Narayanan


    The equivalence of triangle-comparison-based pulse width modulation (TCPWM) and space vector based PWM (SVPWM) during linear modulation is well-known. This paper analyses triangle-comparison based PWM techniques (TCPWM) such as sine-triangle PWM (SPWM) and common-mode voltage injection PWM during overmodulation from a space vector point of view. The average voltage vector produced by TCPWM during overmodulation is studied in the stationary (a–b) reference frame. This is compared and contrasted with the average voltage vector corresponding to the well-known standard two-zone algorithm for space vector modulated inverters. It is shown that the two-zone overmodulation algorithm itself can be derived from the variation of average voltage vector with TCPWM. The average voltage vector is further studied in a synchronously revolving (d-q) reference frame. The RMS value of low-order voltage ripple can be estimated, and can be used to compare harmonic distortion due to different PWM methods during overmodulation. The measured values of the total harmonic distortion (THD) in the line currents are presented at various fundamental frequencies. The relative values of measured current THD pertaining to different PWM methods tally with those of analytically evaluated RMS voltage ripple.

  11. Output filter simplification based on random PWM for medium frequency power supply%基于随机脉宽调制技术简化中频电源输出滤波器

    李辉; 吴正国; 欧阳华


    Based on the analysis of electric inverter control model,the single-pole double-frequency PWM and the random PWM are used to modulate the inverter waveform,which improves the equivalent switching frequency of inverter and reduces the amplitude of discrete harmonics at switching frequency. The influence of random signals on the power spectral density characteristic of switching function is studied and a practical design of randomized PWM is proposed. The cut-off frequency of improved inverter output filter can be set higher to ensure the bandwidth of control system and improve the waveform quality of inverter output voltage. Simulation and experiment show that,the discrete harmonics with higher amplitude at switching frequency extend as the continuous harmonics with lower amplitude within a certain bandwidth, which verifies its effectiveness.%在分析逆变器控制模型的基础上,将单极倍频和随机脉宽调制技术用于逆变器波形调制,有效提高逆变器等效开关频率,并明显降低开关频率处的离散谐波幅值.分析了随机信号对开关函数功率谱密度特性的影响,据此提出随机脉宽调制技术的实用化设计方法.改进后逆变器输出滤波器的截止频率可以取较高值,保证足够的控制系统带宽,有效提高逆变器输出电压波形质量.仿真和实验表明,开关频率处幅值较大的离散谐波扩展为一定带宽内幅值较小的连续谐波,谐波幅值大幅降低,结果验证理论分析的有效性.

  12. Moment Stability of the Critical Case of PWM Feedback Systems with Stochastic Perturbations

    Zhong Zhang


    Full Text Available This paper further studies the moment stability of pulse-width-modulated (PWM feedback system which is subjected to multiplicative and additive random disturbance modeled by the derivative of Wiener process. Different from the existing investigation, we focus on its critical case. The linear plant considered herein is assumed to be critically stable; that is, the plant has one and only one pole at the origin, and the rest of the poles are left half of complex plane. We establish several globally asymptotically stability criteria for such PWM feedback systems and then propose an algorithm to calculate the stability bound effectively. Furthermore, we present two numerical examples to show the effectiveness of the theoretical results.

  13. Shunt PWM advanced var compensators based on voltage source inverters for Facts applications

    Barbosa, Pedro G.; Misaka, Isamu; Watanabe, Edson H. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Coordenacao dos Programas de Pos-graduacao de Engenharia


    Increased attention has been given to improving power system operation. This paper presents modeling, analysis and design of reactive shunt power compensators based on PWM-Voltage Source Inverters (Pulse Width Modulation -Voltage Source Inverters). (Pulse Width Modulation - Voltage Source Inverters). The control algorithm is based on new concepts of instantaneous active and reactive power theory. The objective is to show that with a small capacitor in the side of a 3-phase PWM-VSI it is possible to synthesize a variable reactive (capacitive or inductive) device. Design procedures and experimental results are presented. The feasibility of this method was verified by digital simulations and measurements on a small scale model. (author) 9 refs., 12 figs.

  14. Conversor Boost PWM Entrelaçado com Comutação Suave

    Lúcio dos Reis Barbosa


    Full Text Available Este artigo apresenta uma topologia aprimorada de um conversor Boost PWM com comutação suave. O circuito proposto, tendo duas chaves ativas entrelaçadas, opera com chaveamento suave, sob odulação PWM (pulse-width-modulation. Além disso, este conversor fornece alta rendimento sob as condições de operação, para uma larga variação de carga, e operando à altas freqüências. Para ilustrar o princípio de operação deste novo conversor apresenta-se um estudo pormenorizado, incluindo simulações e resultados. A validade deste novo conversor é confirmada por meio dos resultados obtidos.

  15. A 6-switch single-phase 5-level current-source inverter

    BAO Jian-yu; LI Yu-ling; ZHANG Zhong-chao


    The new 6-switch single-phase 5-level current-source inverter proposed in this paper was developed by properly simplifying the traditional 8-switch single-phase 5-level current-source inverter, and its operational principle was analyzed. Just like the problem of voltage-unbalance between different levels existing in voltage-source multilevel inverters, a similar problem of current-unbalance between different levels whether for the 8-switch single-phase 5-level current-source inverter, or for the new 6-switch 5-level current-source inverter also exists. A simple current-balance control method via DC current feedback is presented here to implement the current-balance control between different levels. And to reduce the output current harmonics, PWM control technique was used. Simulation and experimental results showed that this new 6-switch topology operates correctly and that the balance-inductor can almost equally distribute the total DC current.

  16. Nongrounded Common-Mode Equivalent Circuit for Brushless DC Motor Driven by PWM Inverter

    Maetani, Tatsuo; Isomura, Yoshinori; Watanabe, Akihiko; Iimori, Kenichi; Morimoto, Shigeo

    This paper describes nongrounded common-mode equivalent circuit for a motor driven by a voltage-source PWM inverter. When the capacitance of the rotor was small, the phenomenon that polarity of the common mode voltage and shaft voltage reversed was observed. In order to model this phenomenon, the bridge type equivalent circuit is proposed. It is verified with the calculation and experiment that shaft voltage values and polarity are accurately calculated with the proposed equivalent circuit.

  17. Modelling of a double star induction motor for space vector PWM control

    Hadiouche, D.; Razik, H.; Rezzoug, A. [Groupe de Recherche en Electrotechnique et Electronique de Nancy, G.R.E.E.N. - CNRS UPRES, University H. Poincare, Vandoeuvre-les-Nancy (France)


    In this paper, we present the analysis and the modelling of a Double-Star Induction Motor (DSIM). A steady-state model is first established in order to analyse its harmonic behaviour. Then, a new transformation matrix is proposed in order to develop a suitable dynamic model. In both cases, the study is made using an arbitrary shift angle between the two stars. At last, a space vector Pulse Width Modulation (PWM) control or the DSIM is simulated. (orig.)

  18. A New PWM Modifying Technique for Reconstructing Three-phase Currents from DC Bus Current

    Aoyagi, Shigehisa; Iwaji, Yoshitaka; Tobari, Kazuaki; Sakamoto, Kiyoshi

    Vector control is used to drive a DC brushless motor and generally needs current information. DC bus current detection is often adopted as a low cost method for reconstructing three-phase currents. PWM modifying techniques increase the DC pulse duration, thereby enabling easy detection of the DC bus current. However, these techniques have two problems: reducing a noise frequency and making the reconstructed current waveforms distorted by current ripple. In the techniques, modification signals are added to the three-phase voltage commands; the sum of the signals over a single cycle is zero. The authors examined several PWM modifying techniques from the points of view of noise and current distortion performance. One of the techniques had a good noise performance, and the frequency component of the noise was the same as the carrier frequency (fc). However, the reconstructed current waveforms were distorted. The total harmonic distortion (THD) varied from 1.7% to 4.1%. Another technique had a very poor noise performance, and the frequency component on the noise was one-fourth of fc. The authors developed a new PWM modifying method called “Half Pulse Shift”, which achieves the optimum noise and current distortion performance. The frequency component of the new method was two-thirds of fc, and the current waveforms were not distorted; the THD in the simulations and experiments was 0.5%-1.4% and 3.4%-3.6%, respectively.

  19. Non-Sinusoidal PWM Method for Cascaded Multilevel Inverter

    Abdul Halim M. Yatim


    Full Text Available This paper presents a new switching method for Cascaded Multilevel Inverter (CMI.  The new method uses multiple non-sinusoidal signals as the modulating signal.  The main advantage of using non-sinusoidal modulating signal is that it provides higher fundamental component but at the cost of having a numbers of low-order harmonics in its unfiltered output voltage; naturally contributed by the non-sinusoidal modulating signal. In this paper, the Trapezoidal waveform is employed as the non-sinusoidal modulating signal for the CMI.  Its harmonics profile of different slope angles is analysed.  From the analysis, it was found that the trapezoidal with the slope angle of 36o eliminates the third and fifth harmonics yet yields a high fundamental magnitude.  To verify, a single-phase CMI prototype is constructed and an ALTERA FPGA is deployed to implement the proposed method’s algorithm.  From the results, it was shown that analysis is validated

  20. 基于PWM_ON_PWM调制方式的控制力矩陀螺框架电机驱动控制%Control Moment Gyro Gimbal Motor Drive Control Based on PWM_ON_PWM Mode

    胡跃伟; 鲁明; 田利梅; 武登云


    控制力矩陀螺框架电机驱动电路采用的脉宽调制方式不同,所产生的电机转矩脉动也会不同.针对无刷直流电机驱动的控制力矩陀螺框架系统,从换相期间转矩脉动、非换相期间转矩脉动及脉宽调制方式的应用改进3个方面对不同脉宽调制方式进行分析,得出采用PWM_ON PWM方式的转矩脉动最小,适用于控制力矩陀螺框架系统的高精度控制要求.通过仿真验证了分析的正确性.

  1. High-Frequency Resonant Matrix Converter using IGBT-Based Bidirectional Switches for Induction Heating

    Jami Rajesh


    Full Text Available This paper deals with a novel type soft switching utility frequency AC- high frequency AC converter using asymmetrical PWM bidirectional active switches which can be defined as high frequency resonant matrix converter.This power frequency changer can directly convert utility frequency AC power to high frequency AC power ranging more than 20kHz up to 100kHz. Only one active edge resonant capacitor-assisted soft switching high frequency load resonant cyclo-converter is based on asymmetrical duty cycle PWM strategy. This high frequency cyclo-converter uses bidirectional IGBTs composed of anti-parallel one-chip reverse blocking IGBTs. This high frequency cycloconverter has some remarkable features as electrolytic capacitorless DC busline link, unity power factor correction and sinewave line current shaping, simple configuration with minimum circuit components and low cost, high efficiency and downsizing. This series load resonant cycloconverter incorporating bidirectional active power switches is developed and implemented for high efficiency consumer induction heated food cooking appliances. Its operating principle is described by using equivalent circuits. Its operating performances as soft switching operating ranges and high frequency effective power regulation characteristics are discussed on the basis of simulation and experimental results.

  2. Nucleosome switches.

    Schwab, David J; Bruinsma, Robijn F; Rudnick, Joseph; Widom, Jonathan


    We present a statistical-mechanical model for the positioning of nucleosomes along genomic DNA molecules as a function of the strength of the binding potential and the chemical potential of the nucleosomes. We show that a significant section of the DNA is composed of two-level nucleosome switching regions where the nucleosome distribution undergoes a localized, first-order transition. The location of the nucleosome switches shows a strong correlation with the location of gene-regulation regions.

  3. 汽车 ABS 电机 PWM 控制方法研究%Research on ABS motor PWM control

    初亮; 祁富伟; 王彦波; 蔡健伟


    通过对ABS工作过程中制动液流量的分析,确定了ABS电机的基本工作要求。结合ABS电机的工作特性,采用基于逻辑门限值的PWM控制方法控制电机。运用DSpace搭建快速原型试验台,对比在不同电机工作转速、PWM控制频率下的噪声和制动踏板感觉,优化逻辑门限值大小,得出合理的工作方式,使电机既能满足控制要求,又有较长的寿命。通过在不同路面的试验结果对该控制方法的两个关键参数进行了优化。最后进行不同工况的试验,结果表明:通过优化控制参数的PWM 控制方法,具有较强的鲁棒性,能够满足ABS在任何工作条件下对电机的要求。%T hrough the characteristics of the flow of brake fluid during ABS (anti-lock braking sys-tem) working process ,the basic requirements of ABS motor was determined and the PWM (pulse width modulation) control based logic threshold was adapted .A rapid prototyping test bench with DSpace was built .The logic threshold values were optimized by comparing the noise and the pedal stroke when various motor speed and PWM frequency were used .Then a much more reasonable con-trol method can be got w hich makes the motor to meet the control requirements and also has a longer life .After a lot of tests on different test track ,the key control parameters were optimized .Finally , the control method was tested under different road conditions and various load conditions .The results show that the control method is robust and meet the ABS requirements to the motor under any work conditions .

  4. Highly Sensitive and Wide-Dynamic-Range Multichannel Optical-Fiber pH Sensor Based on PWM Technique.

    Khan, Md Rajibur Rahaman; Kang, Shin-Won


    In this study, we propose a highly sensitive multichannel pH sensor that is based on an optical-fiber pulse width modulation (PWM) technique. According to the optical-fiber PWM method, the received sensing signal's pulse width changes when the optical-fiber pH sensing-element of the array comes into contact with pH buffer solutions. The proposed optical-fiber PWM pH-sensing system offers a linear sensing response over a wide range of pH values from 2 to 12, with a high pH-sensing ability. The sensitivity of the proposed pH sensor is 0.46 µs/pH, and the correlation coefficient R² is approximately 0.997. Additional advantages of the proposed optical-fiber PWM pH sensor include a short/fast response-time of about 8 s, good reproducibility properties with a relative standard deviation (RSD) of about 0.019, easy fabrication, low cost, small size, reusability of the optical-fiber sensing-element, and the capability of remote sensing. Finally, the performance of the proposed PWM pH sensor was compared with that of potentiometric, optical-fiber modal interferometer, and optical-fiber Fabry-Perot interferometer pH sensors with respect to dynamic range width, linearity as well as response and recovery times. We observed that the proposed sensing systems have better sensing abilities than the above-mentioned pH sensors.

  5. A PWM Buck Converter with High-efficiency under Light-load%一种具有高轻载效率的PWM Buck变换器

    刘南; 梁亮


    本文提出了一种在轻载工作环境下依然高效的PWM DC/DC buck变换器.该变换器由TSMC 1.8/3.3 V 0.18 μmCMOS技术设计而成.通过DCM操作,不仅能在满载时达到高效率,而且在不利用任何PFM技术的情况下大大提升轻载下的效率.这种变换器轻载时的输出精确性和输出纹波都优于PFM变换器,而在满载时与普通的PWM变换器同样稳定、高效,通过Saber仿真与电路实验验证了变换器的可行性.


    Eduardo Pérez Lobato


    Full Text Available This paper presents the use of a microcontroller to demodulate two Pulse Width Modulated (PWM signals which are being generated by a digital accelerometer, to obtain their pulse widths and transmit them serially to a parallel port of a general purpose computer.Esta publicación presenta el uso de un microcontrolador para demodular dos señales PWM que están siendo generadas por un acelerómetro digital, obtener sus anchos y enviarlas en forma serial al puerto paralelo de un computador de propósitos generales.

  7. A Novel Method of Suppressing the Inrush Current of Transformers Using a Series-Connected Voltage-Source PWM Converter

    Yamada, Hiroaki; Tanaka, Toshihiko; Funabiki, Shigeyuki

    This paper proposes a novel method of suppressing the inrush current of transformers. A small-rated voltage-source PWM converter is connected in series to the transformers through a matching transformer. As the connected PWM converter performs a resistor for the source current, no inrush phenomena occurs. The required-ratings of the PWM converter, which performs the damping resistor for the inrush phenomena, is one-four-hundredth as compared to that of the main transformers in single-phase circuits. In three-phase circuits, it is one-nine-hundredth. The basic principle of the proposed method is discussed. Digital computer simulation is implemented to confirm the validity and excellent practicability of the proposed method using the PSCAD/EMTDC. A prototype experimental-model is constructed and tested. The experimental results demonstrate that the proposed method can perfectly suppress the inrush phenomena.

  8. Filtro paso bajo discreto de operación directa sobre señales PWM

    López Batres, Sergio


    Este proyecto aborda la construcción y diseño de un filtro de paso bajo que opera sobre señales moduladas en anchura de impulsos (PWM). Utiliza componentes analógicos y un microprocesador que efectúa el control del sistema. Su función es servir de atenuador de los armónicos en amplificadores de clase D que podrían usarse en sistemas de audio, sin necesidad de un filtro paso bajo analógico de orden elevado. Ingeniería Técnica en Electrónica




    Full Text Available In this paper, the effect of placement of zero-space vector for the implementation of space vector based Pulse Width Modulation techniques for 3-phase Voltage Source Inverter is presented. Several pulse width modulation (PWM control strategies have been proposed for 3-phase voltage source inverter (VSI in the past. It is known that space vector modulation (SVM offers a degree of freedom in its implementation with regard to the placement of the zero-space vector. Apart from constructing a consistent theoretical framework, simulation results with conventional continuous SVM and various discontinuous SVM techniques are presented and all the cases are compared in this paper.

  10. Comparison of Performance of VSI and Z-Source Inverter for Space Vector PWM

    E. Sai Prateek


    Full Text Available Z-Source Inverters have the ability to boost the dc link voltage, thus increasing the output ac voltage beyond the values reached by conventional inverters. The enhanced ratio from ac output voltage to dc link voltage is possible due to an impedance network connected between the dc power supply and the main converter. The space vector pulse width modulation techniques gives more dc bus utilisation and low harmonics than other pulse width modulation techniques. In this paper space vector pwm is implemented for conventional VSI and Zsource inverter. The results are supported by SIMULINK simulation

  11. Control of a PWM Rectifier with Extended Functions in a Signal Digital Processor

    C. Núñez–Gutiérrez


    Full Text Available This work presents the application of a digital signal processor (DSP for the control of a three–phase PWM rectifier for industrial applications, to which are extended their functions to have capacity to compensate voltage sags. The study stands out the advantages that the DSP offers to control, based on the system transformation from fix reference frame to synchronous reference frame (D–Q theory and classical controllers. The analysis of the system is presented, as well as simulation and experimental results to validate the operation of the DSP as system element controller.

  12. The PWM strategies of grid-connected distributed generation active NPC inverters

    Ma, Lin; Xinmin, Jin; Kerekes, Tamas


    The Neutral Point Clamped topology due to high efficiency, low leakage current and EMI, its integration is widely used in the distributed generation (DG) systems. However the main disadvantage of the NPC inverter is given by an unequal distribution of the losses in the semiconductor devices, which...... leads to an unequal distribution of temperature. By using the Active NPC topology, the power losses distribution problem is alleviated. The modulation strategy is a key issue for losses distribution in this topology. In this paper two known strategies are discussed and a new proposed PWM strategy...

  13. A Matching Transformer-less Inrush Current Suppressor for Transformers Using a Series-Connected Small-Rated Voltage-Source PWM Converter

    Yamada, Hiroaki; Tanaka, Toshihiko; Funabiki, Shigeyuki

    This paper proposes a new inrush current suppressor using a series-connected small-rated PWM converter for a transformer. The PWM converter is directly connected in series between the source and transformer without a matching transformer. The inrush phenomena of the matching transformer, thus, can be avoided. The control gain and required-ratings of the series-connected small-rated PWM converter is discussed in detail. The capacity of the dc capacitor of the PWM converter is also discussed considering the active power flows into the PWM converter. The PSCAD/EMTDC is used to verify the validity of the proposed inrush current suppressor. A prototype experimental model is constructed and tested. The experimental results demonstrate that the proposed suppressor can perfectly overcome the inrush phenomena of transformers.

  14. 三相软开关PWM变流器电流极性检测与电流补偿方法%Current Polarity Detection and Current Compensation Strategy for PAC Based Three-Phase ZVS PWM Converter

    屈克庆; 陈国呈; 孙承波


    A novel software implementation for current polarity detection and current compensation is presented. For a three-phase zero-voltage soft-switching (ZVS) PWM converter based on phase and amplitude control (PAC), when saw-tooth carriers with alternate positive and negative slopes are adopted, the positive or negative slopes are chosen according to the phase current polarity. Since polarity reversal causes current distortion, current at the instant of reversal should be compensated for. Based on the characteristic of unity power factor converter in rectification and regeneration modes, a software implementation for current polarity detection is proposed.Distortion of current zero-crossing caused by using saw-tooth carriers with alternate positive and negative slopes is analyzed, and the relevant compensation method is proposed. Experimental study with a 1.5 kW device shows that phase current has a small harmonic content and power factor is high both in rectification and regeneration modes.

  15. PWM模拟DAC的关键参数分析%Key parameters analysis of DAC using PWM



    PWM 模拟 DAC 技术由于其价格便宜、技术简单在低成本嵌入式系统中应用广泛,然而其性能指标却无法与集成的 DAC 相比。建模讨论了影响 PWM 模拟实现 DAC 系统的性能的主要因素。仿真发现,滤波器环节对于 PWM 模拟 DAC 的性能参数是至关重要的,在不考虑 PWM 的位数限制时,滤波级数越高 DAC 精度越高,然而 DAC 的建立时间也会显著增加。分析发现,这两个主要参数分别取决于滤波系统对于高频成分的频率响应和对于直流分量的阶跃响应。具体应用中应该权衡DAC 精度和转换速度,以确保应用 PWM 模拟 DAC 可以满足具体应用需求。%DAC (Digital-to-Analog Converter) using PWM (Pulse Width Modulation) technology is widely used in low cost embedded systems due to cheap price and simple to use, however its performance index cannot match the real DAC. In this paper, models are built to discuss the main factors which affect the performance of PWM imitated DAC system. Through simulation it finds that the filter plays a key role in the DAC, without considering the digits limit of PWM, the higher the filter series the more accurate the DAC is, however, the establishment time of the DAC will increase significantly. Through analysis it finds that the two main parameters depend on the high frequency response and DC step response of the filtering system respectively. In specific applications, the precision and transformation speed of the DAC should be carefully weighed to meet specific requirements.

  16. Switching antidepressants

    by this time.4. Next-step ... and the side-effects are minimal), switching to an alternative antidepressant (if .... the new SSRI initiated immediately at the former therapeutic equivalent dose ... weeks because of the long half-life of its active metabolite, .... interactions with second-generation antidepressants: an update. Clin Ther.

  17. Improvement of speed profile in induction motor drive using a new idea of PWM pulses generation base on artificial neural networks

    hojat moayedi rad


    Full Text Available Due to simplicity and low cost, induction motors are more useful than direct current motors. Hence the control of these motors is important. The pervious methods are fitted normally for a limited speed range and could not be used for high, low and very low speeds. The voltage model is suitable for high speed because the voltage drop of stator resistance is not small in low speed. The current model is suitable for low speed because of the problems of flux saturation at high speed. This research presents a new method of PWM pulse generating in induction motors based on artificial neural networks in which, the switching pulses are generated by a multilayer feed-forward neural network that is trained by the voltage and current references. Also, for the estimation of required torque and flux information a multilayer perceptron is used. By application of this new method, there is no problem of stability at low and high speeds. The simulation results by matlab-simulink verify the proposed method in transient and steady-state operating modes.

  18. Energy optimal control strategies for electro motors; low-cost and sensorless PWM-VSI based induction motor control. Vol. 1: Main report, appendix and annex

    Abrahamsen, F.


    When variable speed induction motor drives are used in applications that run at low load for long periods, energy can be saved by reducing the motor flux at low load. In this report the efficiency of 2.2 kW standard and high-efficiency motor drives are investigated experimentally with efficiency optimized and constant flux control, with sinusoidal and PWM voltage supply and with varying switching frequency. Steady-state motor models are developed and verified experimentally, and are used to analyze and develop efficiency optimizing control strategies. Four energy optimal control strategies are tested experimentally: cos({phi}) control, model-based control, off-line calculated airgap flux control and stator current/input power minimising search control. Their dynamical properties and their ability to reject load disturbances are analysed. Their ability to save energy is tested on a water pump system. For a typical predefined test-cycle the energy optimal control reduces the energy consumption with 10% compared with classical constant V/Hz control. (au)

  19. 不等比例PWM脉冲技术在顶部振打器上的应用%Application of inequality proportion PWM impulse in top magnetic shaker

    王涌; 郑博闻; 王威


    为解决顶部振打器中控制器的精度等问题,将不等比例脉冲技术应用于顶部振打器中.开展了不等比例PWM脉冲技术原理的分析,建立了占空比和波形之间的关系,提出了新型的采用不等比例插入技术产生的非均匀PWM脉冲的原理和实现方法.在数字式DC-DC基础开关电路上对通用的8位微处理器和场效应管开关器件进行了评价,并进行了不等比例PWM技术实验验证.研究结果表明,非均匀PWM脉冲具有明显降低输出平均电压稳态误差的作用,提高了输出平均电压的精度,考虑了实际应用中对提高输出精度存在的各种外部综合因素,给出了合理选择该技术方法的依据.%In order to solve the problems of the accuracy of pulse in top magnetic shaker,the inequality proportion PWM impulse was investigated. After the analysis of inequality proportion PWM impulse,the relationship between duty cycle and waveform was established.A method was presented to the fundament and implementation method of the non-uniform pulse width modulation impulse.The universal 8- bit microcontroller and FET switching device were evaluated on the basis of the block diagram of digital DC-DC switched circuit,the inequality proportion PWM impulse technique were tested.The experimental results show that the theory is correct.Lastly, to practical application, the different exterior composite factor is analyzed, and the ways to select the new technique with appropriately are supplied.

  20. New zero voltage switching DC converter with flying capacitors

    Lin, Bor-Ren; Shiau, Tung-Yuan


    A new soft switching converter is presented for medium power applications. Two full-bridge converters are connected in series at high voltage side in order to limit the voltage stress of power switches at Vin/2. Therefore, power metal-oxide-semiconductor field-effect transistors (MOSFETs) with 600 V voltage rating can be adopted for 1200 V input voltage applications. In order to balance two input split capacitor voltages in every switching cycle, two flying capacitors are connected on the AC side of two full-bridge converters. Phase-shift pulse-width modulation (PS-PWM) is adopted to regulate the output voltage. Based on the resonant behaviour by the output capacitance of MOSFETs and the resonant inductance, active MOSFETs can be turned on under zero voltage switching (ZVS) during the transition interval. Thus, the switching losses of power MOSFETs are reduced. Two full-bridge converters are used in the proposed circuit to share load current and reduce the current stress of passive and active components. The circuit analysis and design example of the prototype circuit are provided in detail and the performance of the proposed converter is verified by the experiments.

  1. Impact of Switching Harmonics on Capacitor Cells Balancing in Phase-Shifted PWM-Based Cascaded H-Bridge STATCOM

    Behrouzian, Ehsan; Bongiorno, Massimo; Teodorescu, Remus


    is investigated and the interaction between voltage and current harmonics is analyzed. It is shown that in both cases, this interaction results in an uneven power distribution among the cells in the same phase leg, leading to drifting of the dc-capacitor voltages and thereby the need for proper stabilization...... contributing to the capacitors balancing. A methodology for optimal selection of the frequency modulation ratio is given. Theoretical conclusions are validated through simulation and experimental results....

  2. Motion Sensorless Bidirectional PWM Converter Control with Seamless Switching from Power Grid to Stand Alone and Back

    Fatu, Marius; Tutelea, Lucian; Teodorescu, Remus


    This paper presents concepts and tests results on a flexible sensorless control strategy for a PMSG driven by a small wind turbine with back-to-back power converters capable to function in both stand alone and grid connection mode. A new automatic seamless transfer method, based on phase-locked-l......This paper presents concepts and tests results on a flexible sensorless control strategy for a PMSG driven by a small wind turbine with back-to-back power converters capable to function in both stand alone and grid connection mode. A new automatic seamless transfer method, based on phase......-locked-loop technique, from grid connected to stand alone and vice versa in the event of a fault on grid is proposed. Tests results show the proposed method works properly...

  3. Motion Sensorless Bidirectional PWM Converter Control with Seamless Switching from Power Grid to Stand Alone and Back

    Fatu, Marius; Tutelea, Lucian; Teodorescu, Remus;


    This paper presents concepts and tests results on a flexible sensorless control strategy for a PMSG driven by a small wind turbine with back-to-back power converters capable to function in both stand alone and grid connection mode. A new automatic seamless transfer method, based on phase...

  4. Transient analysis and control of bias magnetic state in the transformer of on-line pulse-width-modulation switching full bridge direct current-direct current converter

    Chen, Jiaxin; Guo, Youguang; Zhu, Jianguo; Wei Lin, Zhi


    This paper presents a finite element analysis (FEA) based method for analyzing and controlling the bias magnetic state of the transformer of a pulse-width-modulation (PWM) switching full bridge dc-dc converter. A field-circuit indirect coupling method for predicting the transient bias magnetic state is introduced first. To increase flexibility of the proposed method, a novel transformer model which can address not only its basic input-output characteristic, but also the nonlinear magnetizing inductance, is proposed. Both the asymmetric characteristic and the variable laws of the current flowing through the two secondary windings during the period of PWM switching-off state are highlighted. Finally, the peak magnetizing current controlled method based on the on-line magnetizing current computation is introduced. Analysis results show that this method can address the magnetic saturation at winding ends, and hence many previous difficulties, such as the start-up process and asymmetry of power electronics, can be easily controlled.

  5. New Technologies for Information and Communication, PWM Remote Experimenting and 3G Networks as Teaching Support

    Juarez B. Silva


    Full Text Available Remote experiments may be an important tool to implement new technologies in the teaching/learning process, since it enables experimenting with real plants, essential to consolidate the concepts acquired in the theoretical classes, especially in technical and scientific disciplines.This article presents the “modulator PWM” remote experiment, its operational architecture and construction. It seeks to demonstrate its integration with theory and the use of the 3G cellular network as a communications channel for remote experimenting. The PWM modulators are often used in disciplines of higher education courses in electrical engineering, telecommunications and electronics. This article shows that it is possible to perform the practical activity completely remotely, via 3G cellular networks or through the internet to access the experiment and perform the experiments needed to fully understand the theories of the PWM modulator.This article is a further initiative for remote experiments in the world of different engineering specialties, involving the cellular networks that are rapidly expanding at this time.

  6. Estimating return levels from maxima of non-stationary random sequences using the Generalized PWM method

    P. Ribereau


    Full Text Available Since the pioneering work of Landwehr et al. (1979, Hosking et al. (1985 and their collaborators, the Probability Weighted Moments (PWM method has been very popular, simple and efficient to estimate the parameters of the Generalized Extreme Value (GEV distribution when modeling the distribution of maxima (e.g., annual maxima of precipitations in the Identically and Independently Distributed (IID context. When the IID assumption is not satisfied, a flexible alternative, the Maximum Likelihood Estimation (MLE approach offers an elegant way to handle non-stationarities by letting the GEV parameters to be time dependent. Despite its qualities, the MLE applied to the GEV distribution does not always provide accurate return level estimates, especially for small sample sizes or heavy tails. These drawbacks are particularly true in some non-stationary situations. To reduce these negative effects, we propose to extend the PWM method to a more general framework that enables us to model temporal covariates and provide accurate GEV-based return levels. Theoretical properties of our estimators are discussed. Small and moderate sample sizes simulations in a non-stationary context are analyzed and two brief applications to annual maxima of CO2 and seasonal maxima of cumulated daily precipitations are presented.

  7. A high efficiency PWM CMOS class-D audio power amplifier

    朱樟明; 刘帘曦; 杨银堂; 雷晗


    Based on the difference close-loop feedback technique and the difference pre-amp, a high efficiency PWM CMOS class-D audio power amplifier is proposed. A rail-to-rail PWM comparator with window function has been embedded in the class-D audio power amplifier. Design results based on the CSMC 0.5 μm CMOS process show that the max efficiency is 90%, the PSRR is -75 dB, the power supply voltage range is 2.5-5.5 V, the THD+N in 1 kHz input frequency is less than 0.20%, the quiescent current in no load is 2.8 mA, and the shutdown current is 0.5 μA. The active area of the class-D audio power amplifier is about 1.47 × 1.52 mm2. With the good performance, the class-D audio power amplifier can be applied to several audio power systems.

  8. A high efficiency PWM CMOS class-D audio power amplifier

    Zhu Zhangming; Liu Lianxi; Yang Yintang [Institute of Microelectronics, Xidian University, Xi' an 710071 (China); Lei Han, E-mail: [Xi' an Power-Rail Micro Co., Ltd, Xi' an 710075 (China)


    Based on the difference close-loop feedback technique and the difference pre-amp, a high efficiency PWM CMOS class-D audio power amplifier is proposed. A rail-to-rail PWM comparator with window function has been embedded in the class-D audio power amplifier. Design results based on the CSMC 0.5 mum CMOS process show that the max efficiency is 90%, the PSRR is -75 dB, the power supply voltage range is 2.5-5.5 V, the THD+N in 1 kHz input frequency is less than 0.20%, the quiescent current in no load is 2.8 mA, and the shutdown current is 0.5 muA. The active area of the class-D audio power amplifier is about 1.47 x 1.52 mm{sup 2}. With the good performance, the class-D audio power amplifier can be applied to several audio power systems.

  9. A novel three-phase-bridge cascaded PWM converter%一种新型的三相桥级联型PWM变换器

    陆治国; 赵丽丽; 吴春军; 祝万平


    The traditional single-phase cascaded H-bridge converter (CHBC) can not be used for three-phase high-voltage applications directly, thus a novel topology of three-phase-bridge (3P-Bridge) cascaded PWM converter is proposed and its basic cell is a 3P-Bridge. Its construction idea is analyzed and the currents and power expressions are derived. The proposed topology in this paper can not only be operated as a rectifier but also an inverter. One-cycle control (OCC) and CPS-PWM are employed for their simulation research separately. Simulation results verify the feasibility of the proposed 3P-Bridge cascaded converter and show that the proposed topology can improve the voltage level, and comparing with the traditional single-phase CHBC, it can reduce the number of switches and DC capacitors (or separated DC sources), and the voltage ripple at DC side is smaller. So the proposed 3P-Bridge cascaded converter has better prospect in three-phase high-voltage applications.%传统的单相级联H桥变换器不易直接应用于三相高压场合,为此提出了三相桥级联型PWM变换器的拓扑结构,其子模块为电压源型三相桥式变换器.分析了该新型拓扑的构成思想,推导了二级和三级级联拓扑的电流和功率表达式,其可做整流器也可做逆变器,分别采用单周控制和载波相移控制对其进行仿真研究.仿真结果验证了该新型拓扑的可行性,表明其能够提升电压等级,与传统的单相级联H桥变换器构成的三相变换器相比,能够节省开关管和直流侧电容(独立电源)个数,且直流侧电压纹波较小,在三相高压场合具有较好的应用前景.

  10. A Novel Algorithm of PWM Using Virtual Flux Model Prediction%一种采用虚拟磁链模型预测的新型PWM算法

    杜少通; 伍小杰; 周娟; 王福均; 杨宇


    In allusion to pulse-width modulation (PWM), a novel algorithm of pulse width modulation (NPWM) was proposed based on virtual flux model prediction. The virtual flux models consisting of sinusoidal modulation voltage and converter output voltage were established. The cost function was built aiming at making the flux error minimum. And the optimal objective voltage vector was obtained by using model prediction. On the basis of single target predictive method, a type of multi-target predictive method was put forward whi’ch ensures that the device’s average switching frequency was reduced under the premise of certain range of flux errors . The algorithm flow was analyzed according to the established cost function. The control effect of NPWM and space vector pulse width modulation was compared by simulations and experiments, which verifies the effectiveness of NPWM in the two predictive methods.%针对变流器脉宽调制(pulse-width modulation,PWM),基于虚拟磁链的模型预测,提出一种新型脉宽调制算法(novel algorithm of pulse-width modulation,NPWM)。建立由正弦调制电压和变流器输出电压构成的虚拟磁链模型,以磁链误差最小为优化目标建立价值函数,采用模型预测获取最优目标电压矢量。基于单一目标预测方法,提出一种多目标预测方案,确保在磁链误差范围一定的前提下降低器件平均开关频率,依据建立的价值函数分析算法流程。仿真和实验比较两种预测算法下NPWM调制和空间矢量脉宽调制的控制效果,验证两种预测方法下NPWM算法的有效性。

  11. 矩阵变换器的谐波注入PWM控制策略%Harmonic injected PWM control strategy for matrix converter

    王汝田; 王秀云; 崔永恒


    The non-controlled rectification and HIPWM(Harmonic Injected PWM) are respectively applied to the virtual rectifier and virtual inverter of equivalent AC/DC/AC model for matrix converter.The virtual rectifier generates fluctuant DC voltage when symmetric or asymmetric three-phase voltages are supplied.The compensation function is deduced based on the concept of switching function for compensating the modulation wave to eliminate the effect of fluctuant DC voltage on the HIPWM output voltage of virtual inverter.Its hardware implementation is very simple.Results of simulation with MATLAB/Simulink show that,the voltage gain of matrix converter can reach to 0.866,the theoretical maximum,and there is no loworder harmonics in its output voltage,verifying the correctness and effectiveness of the proposed control strategy.%在矩阵变换器间接变换法等效的交直和直交2个虚拟的环节上,分别采用不控整流和谐波注入PWM(HIPWM)2种简单易实现的调制方式.在三相输入电压是对称或非对称的情况下,虚拟整流环节输出的是直流波动电压,为消除此直流波动电压对虚拟逆变环节HIPWM输出的电压波形的影响,利用开关函数概念推导了对HIPWM的调制波进行补偿的补偿函数,此控制策略的硬件实现电路非常简单.应用MATLAB/Simulink进行了仿真,仿真结果表明:应用HIPWM控制策略,矩阵变换器的电压增益能够达到理论最大值0.866,输出电压中不含低次谐波,验证了所提控制算法的正确性和有效性.

  12. Sector Switching

    Newman, Carol; Rand, John; Tarp, Finn

    Much of the literature on industry evolution has found firm dynamics to be an important source of sector-level productivity growth. In this paper, we ask whether the delineation of entry and exit firms matters in assessing the impact of firm turnover. Using detailed firm level data from Vietnam......-level determinants of firm exit and switching, which need to be carefully considered in the search for effective policy...

  13. Sector Switching

    Newman, Carol; Rand, John; Tarp, Finn

    Much of the literature on industry evolution has found firm dynamics to be an important source of sector-level productivity growth. In this paper, we ask whether the delineation of entry and exit firms matters in assessing the impact of firm turnover. Using detailed firm level data from Vietnam, ......-level determinants of firm exit and switching, which need to be carefully considered in the search for effective policy...

  14. The design and application of multi-channel PWM pulse generator based on OMAPL138+FPGA%基于 OMAPL138+FPGA 的多路 PWM 发生器设计及应用

    窦亚力; 乔海强; 钱帆; 李龙光; 李子久


    In order to meet the inverter of trigger requirements applied to the power electronic , this paper primarily presents a novel method of using OMAPL 138 and FPGA to implement multi-channel PWM pulse generator with three-level PWM inverters .The pulse generator receives the PWM pattern parameters and setting parameters from OMA-PL138 processor through a built-in parallel interface , and produces the three-phase PWM driven signals by FPGA without the OMAPL138 intervention .The hardware architecture , basic principles , implementation method of the pulse generator described in this paper is verified by simulation and experiment .Three phase PWM generators have the fea-tures of simplifying circuit-design, improving reliability of system and guaranteeing concurrent triggering of power de-vices.%为了满足一种新能源发电领域的电力电子变换装置上逆变器触发的要求,研制了利用OMAPL138和FP-GA实现的多路PWM脉冲发生器。该脉冲发生器利用接口单元接收OMAPL138写入的PWM脉冲占空比和设置参数等数据,利用FPGA产生PWM波形,达到其工作不受OMAPL138影响的效果。同时介绍了脉冲发生器的硬件架构、基本原理和实现方法,并通过仿真和实验得到验证。该PWM发生器既简化了电路的设计,提高了系统的可靠性,又可保证逆变器功率元件触发的同步。

  15. Analysis of Peak-to-Peak Current Ripple Amplitude in Seven-Phase PWM Voltage Source Inverters

    Gabriele Grandi


    Full Text Available Multiphase systems are nowadays considered for various industrial applications. Numerous pulse width modulation (PWM schemes for multiphase voltage source inverters with sinusoidal outputs have been developed, but no detailed analysis of the impact of these modulation schemes on the output peak-to-peak current ripple amplitude has been reported. Determination of current ripple in multiphase PWM voltage source inverters is important for both design and control purposes. This paper gives the complete analysis of the peak-to-peak current ripple distribution over a fundamental period for multiphase inverters, with particular reference to seven-phase VSIs. In particular, peak-to-peak current ripple amplitude is analytically determined as a function of the modulation index, and a simplified expression to get its maximum value is carried out. Although reference is made to the centered symmetrical PWM, being the most simple and effective solution to maximize the DC bus utilization, leading to a nearly-optimal modulation to minimize the RMS of the current ripple, the analysis can be readily extended to either discontinuous or asymmetrical modulations, both carrier-based and space vector PWM. A similar approach can be usefully applied to any phase number. The analytical developments for all different sub-cases are verified by numerical simulations.

  16. A novel five-level optimized carrier multilevel PWM quad-inverter six-phase AC drive

    Sanjeevikumar, P.; Blaabjerg, F.; Wheeler, Pat


    A novel single carrier pulse-width modulation (PWM) for a new quad-inverter configuration for multilevel six-phase asymmetrical open-winding ac converter is proposed in this article. Modularity of the circuit consist of four standard two-level voltage source inverters (VSIs) with slight modificat...

  17. Suppression technology research of PWM inverter EMI%PWM 变频器的 EMI抑制技术研究

    郭攀锋; 李欣; 张红


    In view of the application of PWM inverter which commonly used in present market, we analyze the mecha-nism of electromagnetic interference ( EMI) from some aspects, including rectifier and inverter side and overvoltage. In this paper, the electromagnetic interference filter is introduced, and the parameters of the RLC filter are designed. The final LC-RLC cascade filter topology structure is put forward.Finally, simulation model is established by Matlab/Simulink, to verify the effectiveness of the electromagnetic interference suppression technique.%针对目前市场上常用的功率变频器———PWM变频器的应用,从几个方面分析了的其电磁干扰( EMI)产生机理,包括整流测、逆变侧和过电压产生。然后,介绍了几种常见滤波器,并对RLC滤波器参数进行设计,并提出了LC-RLC级联滤波器的拓扑结构。最后,利用Matlab/Simulink建立了相应的几种滤波器仿真模型,验证所设计的滤波器对了EMI抑制技术的有效性。

  18. 随机PWM CCM Boost变换器非脆弱H∞控制%Non-fragile H∞ control for random PWM CCM Boost converter

    冉华军; 张涛


    With two - state - Markov - chain random PWM scheme introduced into CCM Boost converter , the random discrete - time jumping model is established first. Then, non - fragile H∞ controller is derived on the basis of non - fragile H∞ control theory of stochastic jumping system. Finally, the simulation circuit is designed to check the validity of non - fragile H∞ controller on the Simulink platform. The results show that the controller designed in this paper has improved the EMI level of Boost converter with non - fragility to its parameters uncertainty, and the whole converter system is robust.%对CCM Boost变换器引入两模态马尔科夫链稳态期望平均脉宽固定的随机PWM策略,首先推导建立变换器的离散随机跳变模型,然后基于随机跳变系统非脆弱H∞控制理论为Boost变换器设计了非脆弱H∞控制器,最后在Simulink仿真平台上设计仿真电路进行验证.仿真结果表明,设计的控制器改善了Boost变换器的EMI品质,对控制器参数摄动表现出非脆弱性,整个变换器系统具有较好的鲁棒性.

  19. Highly Sensitive and Wide-Dynamic-Range Multichannel Optical-Fiber pH Sensor Based on PWM Technique

    Md. Rajibur Rahaman Khan


    Full Text Available In this study, we propose a highly sensitive multichannel pH sensor that is based on an optical-fiber pulse width modulation (PWM technique. According to the optical-fiber PWM method, the received sensing signal’s pulse width changes when the optical-fiber pH sensing-element of the array comes into contact with pH buffer solutions. The proposed optical-fiber PWM pH-sensing system offers a linear sensing response over a wide range of pH values from 2 to 12, with a high pH-sensing ability. The sensitivity of the proposed pH sensor is 0.46 µs/pH, and the correlation coefficient R2 is approximately 0.997. Additional advantages of the proposed optical-fiber PWM pH sensor include a short/fast response-time of about 8 s, good reproducibility properties with a relative standard deviation (RSD of about 0.019, easy fabrication, low cost, small size, reusability of the optical-fiber sensing-element, and the capability of remote sensing. Finally, the performance of the proposed PWM pH sensor was compared with that of potentiometric, optical-fiber modal interferometer, and optical-fiber Fabry–Perot interferometer pH sensors with respect to dynamic range width, linearity as well as response and recovery times. We observed that the proposed sensing systems have better sensing abilities than the above-mentioned pH sensors.

  20. A new complete model of switch-mode plasma cutting power supply

    Abdolreza Esmaeli; SUN Li(孙力); NIE Jian-hong(聂剑红)


    A complete model of switch-mode plasma cutting power supply and its simulation are developed. The full bridge isolated pulse width modulation (PWM) buck converter in continuous conduction mode (CCM) for high watt plasma power supply is approached. Reduced ripple current and improved power factor are achieved in the plasma power supply. With a PID control strategy, circuit responses become more stable and faster with low overshoot during load and current changing. The converter achieved high efficiency under 3 to 15kW load conditions.

  1. Internal-Model-Principle-Based Specific Harmonics Repetitive Controller for Grid-Connected PWM Inverters

    Wenzhou Lu


    Full Text Available This paper analyzes the general properties of IMP-based controller and presents an internal-model-principle-based (IMP-based specific harmonics repetitive control (SHRC scheme. The proposed SHRC is effective for specific nk±m order harmonics, with n>m≥0 and k=0,1,2,…. Using the properties of exponential function, SHRC can also be rewritten into the format of multiple resonant controllers in parallel, where the control gain of SHRC is n/2 multiple of that of conventional RC (CRC. Therefore, including SHRC in a stable closed-loop feedback control system, asymptotic disturbance eliminating, or reference tracking for any periodic signal only including these specific harmonic components at n/2 times faster error convergence rate compared with CRC can be achieved. Application examples of SHRC controlled three-phase/single-phase grid-connected PWM inverters demonstrate the effectiveness and advantages of the proposed SHRC scheme.

  2. A PAC Based Current Feedforward Control for Three-Phase PWM Voltage-Type Converter

    屈克庆; 陈国呈; 孙承波


    This paper presents a novel current feedforward control strategy for a three-phase pulse-width modulation (PWM) DC voltage-type converter based on phase and amplitude control (PAC). With right-angle triangle relation of phasors and principle of conservation of energy, a phasor adjustment method and the relevant low-frequency mathematical model of the system are analyzed in detail, both in rectification and regeneration modes for the converter, are discussed. For improving the traditional PAC dynamic performance, variable load current is detected indirectly by the change of the DC voltage, which is fed to the control system as an additional control variable to generate modulation index and phase angle. Also, the algorithm is derived and the system principle is introduced. Experimental results from a 3 kw laboratory device are included to demonstrate the effectiveness of the proposed control strategy.

  3. Direct Vector Control of Induction Motor Based on Sinusoidal PWM Inverter with Fuzzy Logic Controller

    Nirban Chakraborty


    Full Text Available This paper presents the speed control scheme of direct vector control of Induction Motor drive (IM drive. The Fuzzy logic controller is (FLC used as the controller part here for the direct vector control of Induction Motor using Sinusoidal PWM Inverter (SPWM. Fuzzy logic controller has become a very popular controlling scheme in the field of Industrial application. The entire module of this IM is divided into several parts such as IM body module, Inverter module, coordinate transformation module and Sinusoidal pulse width modulation (SPWM production module and so on. With the help of this module we can analyze a variety of different simulation waveforms, which provide an effective means for the analysis and design of the IM control system using FLC technique.

  4. Advanced Control Strategy of Back-to-Back PWM Converters in PMSG Wind Power System

    Tan Luong Van


    Full Text Available This paper proposes a control scheme of back-to-back PWM converters for the permanent magnet synchronous generator (PMSG wind turbine system. The DC-link voltage can be controlled at the machine-side converter (MSC, while the grid-side converter (GSC controls the grid active power for a maximum power point tracking (MPPT. At the grid fault condition, the DC-link voltage controller is designed using a feedback linearization (FL theory. For the MPPT, a proportional control loop is added to the torque control to reduce the influence of the inertia moment in the wind turbines, which can improve its dynamic performance. The validity of this control algorithm has been verified by the simulation of the 2-MW PMSG wind turbine system.

  5. Microcontroller based PWM Inverter for Speed Control of a Three Phase Induction Motor

    M. A. Latif


    Full Text Available Three phase induction motor has proven to be an extremely reliable electromechanical energy conversion device for over 100 years. The speed control of induction motor is a crying need for the real world industrial applications. However, there are so many options available for the precise speed control of induction motor except by changingthe frequency. Therefore to achieve the goal of speed control of induction motor, there is no alternative of inverters. With the availability of high speed power semiconductor devices, the three phase inverters play the key role for variable speed ac motor drives. In addition to the speed control, the inverter can also provide some unique features, like voltage control, torque control, power factor correction, auto breaking, built in protection system and so forth.In this paper, a three phases PWM inverter using MC3PHAC microcontroller with computer interface is proposed to run a squirrel case induction motor. Some results of the proposed inverter are presented.

  6. Superconducting switch pack

    Srivastava, V.C.; Wollan, J.J.


    This patent describes a superconducting switch pack at least one switch element. The switch element including a length of superconductive wire having a switching portion and two lead portions, the switching portion being between the lead portions; means for supporting the switching portion in a plane in a common mold; hardened resin means encapsulating the switching portion in the plane in a solid body; wherein the solid body has an exterior surface which is planar and substantially parallel with and spaced apart from the plane in which the switching portion is positioned. The exterior surface being exposed to the exterior of the switch pack and the resin means filling the space between the exterior surface and the plane of the switching portion so as to provide uninterrupted thermal communication between the plane of the switching portion and the exterior of the switch pack; and a heater element in thermal contact with the switching portion.




    Full Text Available The emergence of multilevel inverters has been in increase since the last decade. These new types of converters are suitable for high voltage and high power application due to their ability to synthesize waveforms with better harmonic spectrum. Numerous topologies have been introduced and widely studied for utility and drive applications. Amongst these topologies, the multilevel cascaded inverter was introduced in Static VAR compensation and drive systems. This project presents a new technique for getting a multilevel output and also uses PWM control techniques. In this technique, the number of switches used for the dc to ac conversion is reduced. So this dc to ac conversion significantly reduces the initial cost. This technique exhibits some attractive features which suits industrial applications. MATLAB simulink environment is used to simulate the results. The hardware results are also presented for the proposed technique.

  8. Magnetic switching

    Birx, D.; Cook, E.; Hawkins, S.; Poor, S.; Reginato, L.; Schmidt, J.; Smith, M.


    The paper discusses the development program in magnetic switching which was aimed at solving the rep-rate and reliability limitations of the ATA spark gaps. The end result has been a prototype physically very similar to the present Advanced Test Accelerator (ATA) pulse power unit but vastly superior in performance. This prototype, which is easily adaptable to the existing systems, has achieved a burst rep-rate of 20 kHz and an output voltage of 500 kV. A one-on-one substitution of the existing pulse power module would result in a 100 MeV accelerator. Furthermore, the high efficiency of the magnetic pulse compression stages has allowed CW operation of the prototype at one kilohertz opening up other applications for the pulse power. Performance and design details will be described.

  9. 基于FPGA的空间矢量PWM的实现%A Realization of FPGA-based Space-vector PWM

    孙文焕; 程善美; 秦忆


    本文详述了空间矢量SVPWM的算法,并提出用FPGA实现SVPWM的方法,最后分析了使用FPGA的优点。%This paper reviews an arithmetic of the space-vector PWM in detail,and advances a realization of FPGA-based space-vector PWM ,finally analyses the merit of FPGA-based strategy.

  10. Modeling and simulation of induction motor drive system to investigate and mitigate of PWM inverter' s adverse effects

    ESMAELI Abdolreza; SUN Li


    Modeling and simulation of induction motor drive system to investigate and mitigate the adverse effects of PWM inverter based on analysis, modeling and simulation are presented. The estimation of conducted disturbances and other adverse effects of PWM inverter by simulation offer a considerable gain from the economic point of view. For an accurate model of the motor drive system including mains, rectifier, inverter, motor and its long cables, the high frequency parasitic current paths are taken into account. The novel model and its parasitic values for three-phase induction motor system are presented. Finally a new solution for suppressing EMI, common mode voltage, leakage current, bearing current and shaft voltages is proposed and the results show the excellent performances of proposed solution including active and passive filters.

  11. A Fuzzy-Logic-Based Controller for Three-Phase PWM Rectifier With Unity Power Factor Operation

    A. Bouafia


    Full Text Available In this paper, direct power control (DPC of three-phase PWM rectifiers based on fuzzy logic controller is presented, without line voltage sensors. The control technique is built upon the ideas of the well known direct torque control (DTC for induction motors. The instantaneous active and reactive powers, directly controlled by selecting the optimum state of the converter, are used as the PWM control variables instead of the phase line currents being used. The proposed fuzzy logic controller presents the advantage to be based on linguistic description and does not require a mathematical model of the system. The controller ensures a good regulation of the output voltage, and guarantees the power factor close to one. The simulation results show that the designed fuzzy controller has a good dynamic behavior, a good rejection of impact load disturbance, and is very robust.

  12. Simple digital PWM and PSM controlled DC-DC boost converter for luminance-regulated WLED driver

    LIU Xin; GUO Shu-xu; CHANG Yu-chun; ZHU Shun-dong; WANG Shuai


    This article presents a control strategy based on simple digital pulse-width modulation (DPWM) and pulse-skip modulation (PSM) for a DC-DC boost converter, to drive a luminance-regulated white light emitting diodes (WLEDs). The presented control strategy not only retains most of the advantages and flexibilities of traditional digital PWM, but also reduces complexity and cost. Based on analyzing the principle of the presented control strategy, the white light emitting diode (WLED) driver is designed and simulated using the 0.6 (m CMOS process. Simulation results of the boost converter show that the power efficiency is above 76% for a full load, with a peak efficiency of 88% when supply voltage varies from 2.7 V to 5.5 V. The control strategy overcomes low efficiency for PWM mode with light load.

  13. A Novel Electronically Controllable of Current-mode Level Shifted Multicarrier PWM Based on MO-CFTA

    W. Kongnun


    Full Text Available This paper proposes the application of an electronically controlled current-mode for a level shifted multicarrier PWM generator. The proposed circuit consists of two multiple-output current follower transconductance amplifiers (MO-CFTAs for the multiple-output triangular generator and four current follower transconductance amplifiers (CFTAs for the signal comparator. The characteristics of the circuit are as follows: the current output can be controlled by bias current, the maximum amplitude deviation due to temperature variation is less than 1.37% and the power consumption is approximately 0.744 microwatt, at ±1.5V supply voltages. The proposed PWM has been verified through PSpice simulation results which are in consistent with the theoretical analysis.

  14. A PWM Buck Converter With Load-Adaptive Power Transistor Scaling Scheme Using Analog-Digital Hybrid Control for High Energy Efficiency in Implantable Biomedical Systems.

    Park, Sung-Yun; Cho, Jihyun; Lee, Kyuseok; Yoon, Euisik


    We report a pulse width modulation (PWM) buck converter that is able to achieve a power conversion efficiency (PCE) of > 80% in light loads 100 μA) for implantable biomedical systems. In order to achieve a high PCE for the given light loads, the buck converter adaptively reconfigures the size of power PMOS and NMOS transistors and their gate drivers in accordance with load currents, while operating at a fixed frequency of 1 MHz. The buck converter employs the analog-digital hybrid control scheme for coarse/fine adjustment of power transistors. The coarse digital control generates an approximate duty cycle necessary for driving a given load and selects an appropriate width of power transistors to minimize redundant power dissipation. The fine analog control provides the final tuning of the duty cycle to compensate for the error from the coarse digital control. The mode switching between the analog and digital controls is accomplished by a mode arbiter which estimates the average of duty cycles for the given load condition from limit cycle oscillations (LCO) induced by coarse adjustment. The fabricated buck converter achieved a peak efficiency of 86.3% at 1.4 mA and > 80% efficiency for a wide range of load conditions from 45 μA to 4.1 mA, while generating 1 V output from 2.5-3.3 V supply. The converter occupies 0.375 mm(2) in 0.18 μm CMOS processes and requires two external components: 1.2 μF capacitor and 6.8 μH inductor.

  15. Switched on!


    Like a star arriving on stage, impatiently followed by each member of CERN personnel and by millions of eyes around the world, the first beam of protons has circulated in the LHC. After years in the making and months of increasing anticipation, today the work of hundreds of people has borne fruit. WELL DONE to all! Successfully steered around the 27 kilometres of the world’s most powerful particle accelerator at 10:28 this morning, this first beam of protons circulating in the ring marks a key moment in the transition from over two decades of preparation to a new era of scientific discovery. "It’s a fantastic moment," said the LHC project leader Lyn Evans, "we can now look forward to a new era of understanding about the origins and evolution of the universe". Starting up a major new particle accelerator takes much more than flipping a switch. Thousands of individual elements have to work in harmony, timings have to be synchronize...

  16. Highly Sensitive Temperature Sensors Based on Fiber-Optic PWM and Capacitance Variation Using Thermochromic Sensing Membrane.

    Khan, Md Rajibur Rahaman; Kang, Shin-Won


    In this paper, we propose a temperature/thermal sensor that contains a Rhodamine-B sensing membrane. We applied two different sensing methods, namely, fiber-optic pulse width modulation (PWM) and an interdigitated capacitor (IDC)-based temperature sensor to measure the temperature from 5 °C to 100 °C. To the best of our knowledge, the fiber-optic PWM-based temperature sensor is reported for the first time in this study. The proposed fiber-optic PWM temperature sensor has good sensing ability; its sensitivity is ~3.733 mV/°C. The designed temperature-sensing system offers stable sensing responses over a wide dynamic range, good reproducibility properties with a relative standard deviation (RSD) of ~0.021, and the capacity for a linear sensing response with a correlation coefficient of R² ≈ 0.992 over a wide sensing range. In our study, we also developed an IDC temperature sensor that is based on the capacitance variation principle as the IDC sensing element is heated. We compared the performance of the proposed temperature-sensing systems with different fiber-optic temperature sensors (which are based on the fiber-optic wavelength shift method, the long grating fiber-optic Sagnac loop, and probe type fiber-optics) in terms of sensitivity, dynamic range, and linearity. We observed that the proposed sensing systems have better sensing performance than the above-mentioned sensing system.

  17. 一种PWM/LDO双模同步降压型稳压器的设计%Design of a PWM/LDO Dual-Mode Synchronous Buck Regulator

    常昌远; 郑烁锐; 王青


    A PWM/LDO dual-mode system controlled by external synchronous signal was designed, which improved the system performance at light load. Architecture of the entire system and its functions were described, and a detailed analysis was made on the switchover circuit The circuit was simulated based on CSMC 0. 5 μm CMOS process. Results showed that the system had an input voltage ranging from 3. 5 V to 6 V, an output voltage of 3. 3 V,and an operating frequency of 1. 2 MHz. The ripple of the output voltage was less than 30 mV in PWM mode, while the ripple voltage was less than 10 μV and the max load current was 50 mA in LEX) mode. The circuit had a conversion efficiency above 80% over the load range from 20 mA to 1. 2 A, and the PWM/LDO switchover time was less than 60 μs.%设计了一种新颖的外部同步信号控制PWM/LDO双模系统,用来提高系统在轻载下的性能.介绍了整个系统的整体框架和功能,并对切换电路进行了详细的分析与设计.在此基础上,基于华润上华0.5 μm CMOS工艺,使用Cadence对整体电路进行仿真验证.结果表明,系统输入电压Vin的范围为3.6~6 V,输出电压Vo为3.3V,PWM信号工作频率为1.2 MHz,PWM模式下纹波小于30 mV,LDO模式下最大负载电流为50 mA、纹波电压小于10μV,在20 mA~l.2 A负载范围内,系统效率保持在80%以上,PWM/LDO双模切换稳定时间小于60μs.

  18. Reactive power compensation capacity tuning method based on PWM rectifier%基于 PWM 整流器的无功补偿容量整定方法

    甘伟; 冀红超; 杨兴武


    为了充分利用PWM整流器的容量,实现对电网无功功率的调节及电网电压的稳定控制,深入分析了一种基于PWM整流器的无功补偿容量整定方法。重载情况下,PWM整流器在其容量范围内向电网不补偿或少量补偿无功功率,无功功率补偿量由PWM整流器的额定容量和直流负载功率共同决定;轻载情况下,PWM整流器能够补偿电网所缺的所有无功功率。文章还详细分析了直流电容参数的选取方法。最后通过MATLAB/Simulink仿真进行了验证,仿真结果表明该整定方法能够实现无功功率的动态补偿。%In order to fully employ the capacity of the PWM rectifier , and realize the regulation of reactive power and the stable control of voltage in the grid , a deep analysis of a reactive power compensation capacity tuning method based on PWM rectifier has been presented in this paper .In heavy load situations , the PWM rectifier does not com-pensate or compensate a small amount of reactive power , that is to say , the reactive power compensation amount is de-termined by the rated capacity of the PWM rectifier and the DC load power;in light load situations , the PWM rectifier can compensate the whole reactive power in the grid .This paper also analyzes the selection method of the DC capaci-tor parameter in detail.At last, it validates the system through the MATLAB/Simulink, the simulation results show that the tuning method can realize dynamic reactive power compensation .

  19. 最小开关损耗VSVPWM技术的研究与仿真%Study and Simulation of Minimum Switching Losses VSVPWM Technique

    张桂斌; 徐政


    The basic principle of Voltage Space Vector PWM is analyzed. It is shown that the switch status may not change in 120° sectors at most for each phase in a cycle, and the positions of the non-switching sectors can be adjusted continuously by allocating the duty time of the two zero vectors properly. Furthermore, a method is proposed to choose the zero vectors dynamically according to the power factor angle of the load, and the concept of the lag angle of non-switching sectors is proposed and defined. Using this method, the minimum switching losses can be reached, and the maximum switching current can be reduced effectively. This has been shown in the simulation results. In addition, the realization of the above method by the Harmonic Injection PWM method is also presented.%分析了电压空间矢量PWM(VSVPWM)的基本原理,指出在VSVPWM中每相每周期最多可有120°的扇区不开关,通过零矢量作用时间的适当分配可以连续调整不开关扇区的位置。在此基础上提出了一种根据负荷功率因数角动态分配零矢量的方法,并引入了不开关扇区滞后角的概念。这种方法开关损耗最小,并可有效降低开关器件的最大开关电流,仿真结果证明了其可行性。同时还给出了与此等效的谐波注入PWM方法。

  20. Modeling and Simulation of DSP Controlled SV PWM Three Phase VSI

    Saadoun, A.; Yousfi, A.; Amirat, Y.

    The present research is concerned with the development of two space vector pulse width modulated VSI models using the software package Matlab. The theoretical principles underlying the space vector modulation technique are presented but have been limited to the few relations needed for the model implementation. The first model, the formulation of which is based on the concept of switching function associated with the semiconductor power switches, is a switched mode inverter while the second model, the sine mode inverter, is formulated in terms of the duty times cycles of the pole switches is a nearly perfect sine wave space vector controlled generator. By comparison to the switched mode inverter, the sine mode inverter exhibits a larger bandwidth to frequency demand. The reliability of the sine mode model has been checked against the experimental results available in the literature provided by Analog Device Corporation.

  1. Performance optimization of a photovoltaic chain conversion by the PWM control

    Rezoug, M. R.; Chenni, R.


    The interest of the research technique of maximum power point tracking, exposed by this article, lays in the fact of work instantly on the real characteristic of the photovoltaic module. This work is based on instantaneous measurements of its terminals' current & voltage as well as the exploitation of the characteristic "Power - Duty Cycle" to define rapidly the Duty cycle in which power reaches its maximum value. To ensure instantaneous tracking of the point of maximum power, we use "DC/DC Converter" based on "Pulse Wave Modulation's (PWM) Command" controlled by an algorithm implanted in a microcontroller's memory. This algorithm responds to the quick changes in climate (sunlight and temperature). To identify the control parameters "VPV & IPV" at any change in operating conditions, sensors are projected. this algorithm applied to the Duty cycle of the static converter enables the control of power supplied by the photovoltaic generator thanks to oscillatory movement around the MPP. Our article highlights the importance of this technique which lays in its simplicity and performance in changing climatic conditions. This efficiency is confirmed by experimental tests and this technique will improve its predecessors.

  2. Dual Z-Source Inverter With Three-Level Reduced Common-Mode Switching

    Gao, Feng; Loh, Poh Chiang; Blaabjerg, Frede


    This paper presents the design of a dual Z-source inverter that can be used with either a single dc source or two isolated dc sources. Unlike traditional inverters, the integration of a properly designed Z-source network and semiconductor switches to the proposed dual inverter allows buck......-boost power conversion to be performed over a wide modulation range, with three-level output waveforms generated. The connection of an additional transformer to the inverter ac output also allows all generic wye-or delta-connected loads with three-wire or four-wire configuration to be supplied by the inverter....... Modulationwise, the dual inverter can be controlled using a carefully designed carrier-based pulsewidth-modulation (PWM) scheme that will always ensure balanced voltage boosting of the Z-source network while simultaneously achieving reduced common-mode switching. Because of the omission of dead-time delays...

  3. A novel space vector hysteresis control for three-phase voltage source PWM rectifier%一种新型三相电压型PWM整流器滞环空间矢量控制



    The improved space vector hysteresis control was introduced for the disadvantage of poor current tracking caused by the traditional control strategy in the three-phase voltage source PWM rectifier. The improved strategy choose the hysteresis loop width and the switch state through the judgment of the AC error current vector modulus, and the selection principle of the switch state was provided in order to reduce the switching losses. Final y, the simulation model was established under matlab/simulink to compare AC current quality between the traditional and the improved control strategies, the simulation results further demonstrated the superiority of the improved control scheme.%提出了一种改进的滞环空间矢量控制,用于解决三相电压型PWM整流器采用传统滞环空间矢量控制时,电流跟踪效果不佳的问题。改进后的控制策略通过对交流侧误差电流矢量模值大小判断后,选择滞环环宽和对应的开关状态,同时总结出最佳的开关状态选择原则,以最大限度地低开关损耗,提高系统响应速度。最后在matlab/simulink下建立系统的仿真模型,通过对改进前后两种控制策略下交流侧电流质量的对比,进一步验证了改进后控制策略的优越性。

  4. 基于PSIM的PWM逆变器通用仿真模型%The General Simulation Model of PWM Inverter on PSIM



    PWM(Pusle Width Modulation,PWM)逆变器的应用越来越广泛,而PWM逆变器的控制模式又多种多样,因此对于系统仿真而言,建立PWM逆变器的通用仿真模型就尤为重要。该文建立三相全桥PWM逆变器的仿真模型,通过仿真表明该模型具有结构简单、通用性好和仿真效率高的特点。%Application of PWM(Pusle Width Modulation,PWM)inverter is more and more extensive, and there are all kinds of control method of PWM inverter, so the establishment of general simulation model of PWM inverter is very important when sys?tem simulation is needed. A simualtion model of three-phase full bridge PWM converter is established in this paper, it is proved that the configuration of simulation model is simple, the generality of this model is good and the simulation efficiency is high.

  5. Latching micro optical switch

    Garcia, Ernest J; Polosky, Marc A


    An optical switch reliably maintains its on or off state even when subjected to environments where the switch is bumped or otherwise moved. In addition, the optical switch maintains its on or off state indefinitely without requiring external power. External power is used only to transition the switch from one state to the other. The optical switch is configured with a fixed optical fiber and a movable optical fiber. The movable optical fiber is guided by various actuators in conjunction with a latching mechanism that configure the switch in one position that corresponds to the on state and in another position that corresponds to the off state.

  6. 电流型 PWM 变流器在串级调速中的应用%Application of the Current Mode PWM Converter to the Cascade Speed Regulation System

    冯阳; 王奔; 王亚芳; 马明智


    Using the current mode PWM rectifier technology in the cascade speed regulation system for motor can e-liminate the need for the dc Boost chopper of the voltage - type converter cascade speed regulation system,thus,sim-plify the topology of the system,and improve the power factor of the regulation system and reduce the content of the transformer network side harmonic. But thecurrent mode PWM inverter under the dq coordinate system is a nonlinear coupling system,which is not conducive to the controller design,so This paper proposed precise linearization to line-arize and decouple the original system,constructed its pseudo linear system model,and designed a closed loop con-troller of the pseudo linear system by usingthe sliding mode variable structure control theory. At the same time,in the Matlab / Simulink software,a simulation model was established based on this control strategy. The simulation results showed that the control strategy could achieve rapidand effective regulation of the motor speed,and meanwhile could improve th epower factor of the system and reduce the harmonic content.%采用电流型 PWM 整流技术的串级调速系统,省去了电压型斩波串级调速系统中的直流 Boost 斩波环节,简化了系统的拓扑结构,同时也能够实现系统功率因数的提高和变压器网侧谐波含量的减少。考虑到电流型PWM 逆变器在 dq 坐标系下是一个非线性耦合系统,不利于控制器的设计,采用精确线性化方法对原系统进行线性化并解耦,构造其伪线性系统模型,运用滑模变结构控制理论设计该伪线性系统的闭环控制器。同时,在Matlab/ Simulink 软件下,建立了基于此控制策略的模型并进行仿真。结果表明,该控制策略可实现电动机转速的快速、有效调节,同时可提高系统的功率因数,减少谐波含量。

  7. 基于Boost变换器的ZVT软开关三相APFC仿真研究%Simulation research on 3-phase APFC with ZVT soft-switching based on boost converter

    朱志明; 陈俊杰


    As the increasingly strict requirements to the power quality of electric grid,they,to increase the input power factor and to reduce the pollution of harmonic currents,have become significant performance index to the inverter type switching power supply.In this paper,the feasibility and superiority of single-phase Active Power Factor Correction (APFC) technology,which being applied in the three-phase rectifier and capacitor filter circuit of the inverter type plasma arc cutting power supply,was theoretically analyzed firstly,and then,the load adaptability of the APFC circuit with Zero Voltage Transition (ZVT) soft-switching was researched on account of the switching loss of power semiconductors in the APFC circuit.The application environment and operational modes of the Boost converter based three-phase APFC circuit with ZVT soft-switching were analyzed in details, pointing out the rationality of adopting discontinuous conduction mode.By using PSpice software,the simulation investigation was carried through to the APFC circuit,giving out the simulation waveforms of voltage and current in supply input and power semiconductors under different output power.The research results show that,the ZVT soft-switching of power semiconductor in the APFC circuit has been achieved in the total load ranges by adopting discontinuous conduction mode,the input power factor of supply can be raised to above 0.94,the waveform of input current is improved effectively and the pollution of harmonic currents is reduced substantially.%随着对电网电能质量的要求日益严格,提高输入功率因数、减少谐波电流污染已成为逆变式开关电源的重要性能指标.首先从理论上分析了将单相有源功率因数校正(APFC)技术应用于逆变式等离子孤切割电源三相整流、电容滤波电路的可行性和优势;然后针对APFC电路的功率器件开关损耗,研究了零压过渡(ZVT)软开关APFC电路的负载适应

  8. Optical packet switched networks

    Hansen, Peter Bukhave


    Optical packet switched networks are investigated with emphasis on the performance of the packet switch blocks. Initially, the network context of the optical packet switched network is described showing that a packet network will provide transparency, flexibility and bridge the granularity gap...... between the electrical switched layer and the WDM transport layer. Analytical models are implemented to determine the signal quality ghrough the switch blocks in terms of power penalty and to assess the traffic performance of different switch block architectures. Further, a computer simulation model...... is used to investigate the influence on the traffic performance of asynchronous operation of the switch blocks. The signal quality investigation illustrates some of the component requirements in respect to gain saturation in SOA gates and crosstalk in order to obtain high cascadability of the switch...




    Full Text Available A space vector PWM method for a two level inverter is proposed in this paper. A two level inverter using space vector modulation strategy has been modeled and simulated with a passive R-L load. Photovoltaic cells are used as DC source for input of two-level inverter. Simulation results are presented for various operation conditions to verify the system model. In this paper, MATLAB/Simulink package program has been used for modeling and simulation of PV cells and two-level space vector pulse width modulation (SVPWM inverter.

  10. Convertidor Matricial CA-CA Trifásico PWM: Simulación e Implementación

    Ortega Gutiérrez, Daniel


    En el presente trabajo se estudian los principios básicos de un Convertidor Matricial (CM). Para ello se implementó un prototipo y se realizaron simulaciones previas en Matlab-Simulink. Se estudian los conceptos básicos para su operación así como las diferentes técnicas de modulación PWM utilizadas para su control. El CM es un convertidor CA-CA trifásico que se considera de la nueva generación de variadores de velocidad integrados, dado que no requiere de componentes qu...

  11. Remote switch actuator

    Haas, Edwin Gerard; Beauman, Ronald; Palo, Jr., Stefan


    The invention provides a device and method for actuating electrical switches remotely. The device is removably attached to the switch and is actuated through the transfer of a user's force. The user is able to remain physically removed from the switch site obviating need for protective equipment. The device and method allow rapid, safe actuation of high-voltage or high-current carrying electrical switches or circuit breakers.

  12. Perancangan Switch Matrik Besar Menggunakan Array Switch Analog Zarlink


    Secara tradisional, perancangan sebuah switch matrik yang besar dilakukan dengan menggunakan switch-switch elektromekanik. Dengan demikian, banyak bagian yang bergerak yang digunakan untuk membangun switch matrik ini. Dengan kemajuan bidang elektronik, switch elektromekanik saat ini dapat digantikan dengan switch-switch semikonduktor yang ekivalen yang menawarkan solusi yang lebih ekonomis dan memiliki keandalan yang lebih baik. Rumpun switch crosspoint analog Zarlink dapat disusun dengan mud...

  13. Position-Sensorless Rotor Position Detection of Brushless DC Motor Based on H_PWM-L_PWM Modulation Model%基于H_PWM-L_PWM调制的无感无刷直流电机转子位置的检测

    王宝忠; 孙健涛; 要丹


    Exactly detecting of rotor position was required during the control of brushless DC motor, and back EMF detecting method was a simple, effective way to detect the position-sensorless rotor position of brushless DC motor. A back EMF detecting method based on the H_PWM-L_PWM modulation model by analyzing the freewheeling condition of a non-conducted phase of this model was raised. This back EMF detecting method needed not to detect the center voltage of the three-phase winding, and gained a two times of the back EMF of a non-conducted phase. The simulation under MATLAB software environment and experimental results showed that this method had good performance in low speed control of brushless DC motor.%无刷电机的控制需要准确检测到转子的位置,反电动势法是检测无位置传感器无刷直流电机转子位置的一种简单、有效的方法.采用二相导通星形三相六状态的控制模式,通过分析在H_PWM-L PWM调制方式下不导通相的续流情况,提出了基于该调制方式的反电动势检测方法.该反电动势检测法不需要检测三相绕组中点电压,所获得的是不导通相的两倍的反电动势.MATLAB仿真和试验结果证明,该检测方法具有良好的低速控制性能.

  14. DC Bus Control of Back-to-Back Connected Two-Level PWM Rectifier-Five-Level NPC Voltage Source Inverter to Torque Ripple Reduction in Induction Motor

    Abdelkrim Thameur


    Full Text Available This paper proposes a regulation method of back-to-back connected two-level PWM rectifier-five-level Voltage Source Inverter (VSI in order to reduce the torque ripple in induction motor. First part is dedicated to the presentation of the feedback control of two-level PWM rectifier. In the second part, five-level Neutral Point Clamped (NPC voltage source inverter balancing DC bus algorithm is presented. A theoretical analysis with a complete simulation of the system is presented to prove the excellent performance of the proposed technique.

  15. PWM调制下无刷直流电机的转矩脉动抑制%Torque Ripple Reduction of Brushless DC Motors by PWM Modes

    孟光伟; 李槐树; 熊浩


    分析无刷直流电机在PWM调制下稳态时的换相过程,通过在换相期间的PWM调制来实现高、低速条件下的换相转矩脉动补偿控制,确定了保持换相期间非换相相电流幅值不变的换相时间.分析PWM调制方式对三相六状态二二导通无刷直流电机控制系统的影响,提出了在PWM-ON-PWM调制方式下的换相转矩脉动补偿控制,不但能够完全消除非换相期间由于关断相出现电流而引起的电磁转矩脉动,而且能够完全补偿由于换相而引起的转矩脉动,实现电机在低速和高速时的无转矩脉动控制.%The steady commutation process of brushless DC motor by PWM modes was analyzed, and realized phase conversion torque ripple compensation control under both low speed and high speed operation by PWM control in commutation period,and confirmed commutation time to hold amplitude of current in commutation period. The effect by PWM modes on a three-phase six-state 120°conduction brushless DC motor was analyzed,and proposed torque ripple compensation control in PWM_ON_PWM mode, which can not only entirely eliminate torque ripple resulted from the current emerging in the turn-off phase during non-commutation period but also compensate torque ripple caused by the commutation current during commutation period. The torque ripple can be effectively reduced under both low speed and high speed operation using torque ripple compensation control in PWM ON PWM mode.

  16. Hybrid Voltage-Multipliers Based Switching Power Converters

    Rosas-Caro, Julio C.; Mayo-Maldonado, Jonathan C.; Vazquez-Bautista, Rene Fabian; Valderrabano-Gonzalez, Antonio; Salas-Cabrera, Ruben; Valdez-Resendiz, Jesus Elias


    This work presents a derivation of PWM DC-DC hybrid converters by combining traditional converters with the Cockcroft-Walton voltage multiplier, the voltage multiplier of each converter is driven with the same transistor of the basic topology; this fact makes the structure of the new converters very simple and provides high-voltage gain. The traditional topologies discussed are the boost, buck-boost, Cuk and SEPIC. They main features of the discussed family are: (i) high-voltage gain without using extreme duty cycles or transformers, which allow high switching frequency and (ii) low voltage stress in switching devices, along with modular structures, and more output levels can be added without modifying the main circuit, which is highly desirable in some applications such as renewable energy generation systems. It is shown how a multiplier converter can become a generalized topology and how some of the traditional converters and several state-of-the-art converters can be derived from the generalized topologies and vice-versa. All the discussed converters were simulated, additionally experimental results are provided with an interleaved multiplier converter.

  17. 基于直接功率控制的电压型PWM整流器的电动汽车充电器研究%Research on Electric Vehicle Charger Based on Voltage Source PWM Rectifier with Direct Power Control

    高洋; 尹忠东


    For Electric Vehicle (EV) chargers, the modified strategy of Direct Power Control based on voltage source PWM rectifier is proposed. First, the topological structure of PWM rectifier is introduced. Then the basic principle and control characteristic of traditional Direct Power Control (DPC) system with six interval divisions is analyzed, based on which a control method with twelve interval divisions is proposed to improve the control characteristics. Then this new method is deduced in detail, and the switch table which is defined by this method is proposed. Finally, the modified Direct Power Control method is validated by PSCAD, and simulation on the switch table is implemented by using of QuartusII9.0, which shows that each data can reach its predefined index.%针对电动汽车充电器,提出了基于电压型PwM整流器的改进的直接功率控制策略.首先,介绍了PWM整流器的拓扑结构;然后分析了传统的六区间直接功率控制系统的基本原理和控制特性;为了改善控制特性,在传统六区间的控制方法的基础上,提出了十二区间的控制方法,并对该方法进行了详细推导和阐述,给出了在该方法定义下的开关表;最后用PSCAD对改进的直接功率控制方法进行了可行性验证,用QuartusII9.0对开关表进行了仿真,发现各项数据都可以达到预期指标.

  18. Design of two-layer switching rule for stabilization of switched linear systems with mismatched switching

    Dan MA


    A two-layer switching architecture and a two-layer switching rule for stabilization of switched linear control systems are proposed, under which the mismatched switching between switched systems and their candidate hybrid controllers can be allowed. In the low layer, a state-dependent switching rule with a dwell time constraint to exponentially stabilize switched linear systems is given;in the high layer, supervisory conditions on the mismatched switching frequency and the mismatched switching ratio are presented, under which the closed-loop switched system is still exponentially stable in case of the candidate controller switches delay with respect to the subsystems. Different from the traditional switching rule, the two-layer switching architecture and switching rule have robustness, which in some extend permit mismatched switching between switched subsystems and their candidate controllers.

  19. Apparatus and method for heat-run test on high-power PWM converters with low energy expenditure

    J S Siva Prasad; G Narayanan


    Before installation, a voltage source converter is usually subjected to heat-run test to verify its thermal design and performance under load. For heat-run test, the converter needs to be operated at rated voltage and rated current for a substantial length of time. Hence, such tests consume huge amount of energy in case of high-power converters. Also, the capacities of the source and loads available in the research and development (R & D) centre or the production facility could be inadequate to conduct such tests. This paper proposes a method to conduct heat-run tests on highpower, pulse width modulated (PWM) converters with low energy consumption. The experimental set-up consists of the converter under test and another converter (of similar or higher rating), both connected in parallel on the ac side and open on the dc side. Vector-control or synchronous reference frame control is employed to control the converters such that one draws certain amount of reactive power and the other supplies the same; only the system losses are drawn from the mains. The performance of the controller is validated through simulation and experiments. Experimental results, pertaining to heat-run tests on a high-power PWM converter, are presented at power levels of 25 kVA to 150 kVA.

  20. Control strategy for three-phase four-wire PWM converter of integrated voltage compensation type active SFCL

    Chen, Lei; Tang, Yuejin; Shi, Jing; Li, Zhi; Ren, Li; Cheng, Shijie


    The integrated voltage compensation type active superconducting fault current limiter (SFCL) is composed of three air-core superconducting transformers and a three-phase four-wire PWM converter. In order to realize the current-limiting characteristics of the integrated active SFCL, it is needed to control the three-phase four-wire PWM converter flexibly and reasonably. Thereby, the control strategy for the converter is analyzed in this paper. In dq0 reference frame, the mathematical model of the converter is founded. The double-loop control strategy, consisting of voltage outer loop and current inner loop, is presented. Moreover, the voltage balance control for the split DC link capacitors is also considered. Using MATLAB, the simulation model of the integrated active SFCL is built. According to the simulation results, it is known that, the presented control strategy is feasible and valid, and the converter can work well under unsymmetrical and symmetrical fault conditions, and then the fault current can be limited quickly and effectively.

  1. A new measurement method for color discrimination thresholds of human eyes based on PWM light-mixing technology

    Zhang, Jiyan; Dong, Jinxin


    The color discrimination is a powerful tool for detection of eye diseases, and it is is necessary to produce different kinds of color rapidly and precisely for testing color discrimination thresholds of human eyes. Three channels' pulse-width modulation (PWM) and light-mixing technology is a new way to mixing color, and a new measurement method for color discrimination thresholds of human eyes based on PWM light-mix technology can generate kinds of color stimuli. In this study, 5 youth volunteers were measured via this equipment after the test for the stability of the device's illumination and chrominance. Though the theory of Macadam ellipses and the interleaved staircase method, a psychophysical experiment was made to study the color discrimination threshold of the human eyes around a basic color center. By analyzing the data of the chromatic ellipse and the color discrimination threshold, the result shows that each color is not uniform in a single color region and the color difference threshold of normal human is around the third Macadam ellipses. The experimental results show that the repeatability and accuracy of the observer can meet the accuracy requirements of the relevant experiments, and the data is reliable and effective, which means the measurement method is an effective way to measure the color discrimination thresholds of human visual system.

  2. Phase Opposition Disposition PWM Strategy and Hardware in the Loop Validation for a 3-SM Modular Multilevel Converter

    Imen Ouerdani


    Full Text Available This paper focuses on the carrier disposition Pulse Width Modulation (PWM strategies for Modular Multilevel Converters (MMC. The authors propose a new Phase Opposition Disposition PWM (PODPWM scheme applicable regardless of the converter’s sub-modules number. Moreover, a capacitor voltage sorting algorithm is synthesized aiming to ensure the converter’s balanced operation. Simulation results of a 3.6 MVA, 3-SM-MMC are presented and discussed. In addition, a Hardware In the Loop (HIL validation of the proposed PODPWM has been made using Field Programmable Gate Array (FPGA target. The actual power system (the 3-SM-MMC and the 3-phase RL load is then replaced by its real-time emulator. The latter is interfaced to the PODPWM control under test and both are implemented and run altogether in the same Xilinx XC7Z020 Zynq FPGA device. The obtained real-time HIL emulation results are presented and compared to the offline simulation results.

  3. Numerical Analysis of Harmonic Influence for Selected Harmonic Elimination PWM%消谐法SHEPWM的谐波影响数值分析

    王榕生; 吴汉光


    为了研究特定谐波消除脉宽调制技术(SHEPWM)的谐波影响,采用数值法计算了SHEPWM线电压波形特征及全电压范围的谐波分布、THD、转矩脉动。并与不对称规则采样正弦波脉宽调制(SPWM)进行了数值对比。结果表明,相同开关频率下,在M〉0.54区间,SHEPWM的转矩与转速脉动优于SPWM的对应值;而在M〈0.54区间,SHEPWM不具有优势。在M∈[0,1]区间,SPWM的THD优于SHEPWM。因此,不同PWM的转矩脉动比值与相应的THD比值之间不具有对应关系。所得结果为客观评估SHEPWM技术性能及其谐波影响提供了新依据。%In order to study SHEPWM's harmonic influence,the numerical analysis is applied to calculate SHEPWM line-voltage waveform characteristics,harmonics distribution,THD,and torque pulsation over the complete fundamental voltage range.Further,numeric comparisons are performed on above-mentioned parameters but with an asymmetric regular sampled SPWM.The results show that,under the same switching frequency,SHEPWM is superior to SPWM in terms of torque and speed pulsation only if the modulation index M〉0.54;while SHEPWM has no superiority if M〈0.54.The THD of SPWM outperforms that of SHEPWM if M∈.Therefore,a correlation does not exist between the torque pulsation ratio and THD ratio for different PWM.The study results provide a new basis to fairly evaluate the SHEPWM performance and its harmonic influence.

  4. An analytical inductor design procedure for three-phase PWM converters in power factor correction applications

    Kouchaki, Alireza; Niroumand, Farideh Javidi; Haase, Frerk;


    circuit is used to provide the inductor current harmonic spectrum. Therefore, using the harmonic spectrum, the low and high frequency copper losses are calculated. The high frequency minor B-H loops in one switching cycle are also analyzed. Then, the loss map provided by the measurement setup is used...

  5. An Integrated Inductor for Parallel Interleaved VSCs and PWM Schemes for Flux Minimization

    Gohil, Ghanshyamsinh Vijaysinh; Bede, Lorand; Teodorescu, Remus;


    The interleaving of the carrier signals of the parallel Voltage Source Converters (VSCs) can reduce the harmonic content in the resultant switched output voltages. As a result, the size of the line filter inductor can be reduced. However, in addition to the line filter, an inductive filter is oft...

  6. XMEGA-Based Implementation of Four-Switch, Three-Phase Voltage Source Inverter-Fed Induction Motor Drive

    Abolfazl Halavei Niasar


    Full Text Available Induction motors offer many advantages tools, and therefore are becoming very popular industrially and commercially. This paper presents the implementation of Xmega microcontroller based PWM inverter controlled of four-switch three phase voltage source inverter (FSTPI fed induction motor drive. The reduction of the number of power switches from six to four improves the cost effectiveness, volume-compactness and reliability of the three phase inverters in addition to less complexity of control algorithms and reduced interface circuits. Simulation and experimental work are carried out and results presented to demonstrate the feasibility of the proposed approach. Simulation is carried out using SIMULINK and in experimental work, a prototype model is built to verify the simulation results. XMEGA microcontroller (XMEGA64A3 is used to generate the PWM pulses with a new algorithm for FSTPI to drive a 5 hp, 3-phase induction motor. Experimental and simulation results show that the proposed drive system provides a fast speed response and good disturbance rejection capability.

  7. A Double Modulation Wave Carrier-Based PWM Strategy for Three-Level Neutral Point Clamped Converter%基于双调制波的三电平NPC变流器载波调制策略

    李宁; 王跃; 王兆安


    In modulation strategies for three-level neutral point clamped (NPC) converters the double modulation wave carrier-based PWM (DMWPWM) strategy is such a modulation strategy, by which the neutral point voltage control under the entire modulation index and full power factor can be achieved. Firstly, the basic principle of existing DMWPWM strategies are analyzed and the relation between modulation wave in DMWPWM and that in traditional sinusoidal pulse width modulation (SPWM) is analyzed, and on this basis a DMWPWM strategy for three-level NPC converter is proposed;secondly, in the aspects of total harmonic distortion (THD) characteristic of output phase voltage, DC voltage utilization and switching loss of the device the proposed DMWPWM strategy is compared with traditional SPWM strategy to further expound the features of the proposed method. The correctness of theoretical analysis is validated by results from simulation and experiments.%三电平NPC变流器的调制策略中,双调制波载波调制策略(double modulation wave carrier-based PWM , DMWPWM)是一种可以实现全调制度和全功率因数中点电压无波动的调制策略。首先分析了已有DMWPWM策略的基本原理,推导了DMWPWM策略调制波与传统SPWM策略调制波的关系,在此基础上提出了应用于三电平NPC变流器的DMWPWM策略。然后,从输出相电压总谐波畸变率(total harmonic distortion,THD)特性、直流电压利用率以及器件开关损耗三方面对新型DMWPWM策略与传统正弦脉冲宽度调制(sinusoidal pulse width modulation,SPWM)策略进行对比,进一步阐明了所提方法特点。仿真和实验结果验证了理论分析的正确性。


    罗建武; 詹琼华; 邓琼


    为了实现开关磁阻电机(SRM)绕组电流或磁链的精确控制,必须提高SRM功率变换器的工作频率以提高系统的动态响应速度.然而,较高的工作频率会引起严重的电磁干扰(EMI)和开关损耗从而导致系统整体效率降低,文中结合谐振开关(RS)、直流谐振环(RDCL)和脉冲宽度调制(PWM)的优点,提出了一种新型的软开关SRM功率变换器,基工作原理为通过在非对称桥式电路的基础上增加一套换流电路,以此实现功率器件的软开关.在对变换器工作原理详细分析的基础上,导出了实现软开关的条件并给出了设计实例.仿真和实验研究证实了新型软开关SRM变换器的可行性.%To achieve the precision control of phase current or phase flux linkage in switched reluctance motor (SRM), the higher switching frequency of converter is required to increase dynamic response speed. However, higher switching frequency may cause higher switching losses, higher Electro-Magnetic Interference (EMI) and lower overall efficiency. The use of soft-switching techniques in converter can resolve these issues.A brand new soft-switching converter for SRM is presented,which has advantages of all Resonant Switch converter (RS),Resonant dc Link converter (RDCL) and Pulse Width Modulation (PWM). The addition of external commutating devices to conventional asymmetric bridge converter for SRM achieves the soft- switching of power devices. The conditions of soft switching are deduced and a practical design consideration is given. Finally, detailed simulation study of the complete system is presented and is validated with experimental results.

  9. Saturated Switching Systems

    Benzaouia, Abdellah


    Saturated Switching Systems treats the problem of actuator saturation, inherent in all dynamical systems by using two approaches: positive invariance in which the controller is designed to work within a region of non-saturating linear behaviour; and saturation technique which allows saturation but guarantees asymptotic stability. The results obtained are extended from the linear systems in which they were first developed to switching systems with uncertainties, 2D switching systems, switching systems with Markovian jumping and switching systems of the Takagi-Sugeno type. The text represents a thoroughly referenced distillation of results obtained in this field during the last decade. The selected tool for analysis and design of stabilizing controllers is based on multiple Lyapunov functions and linear matrix inequalities. All the results are illustrated with numerical examples and figures many of them being modelled using MATLAB®. Saturated Switching Systems will be of interest to academic researchers in con...

  10. 基于功率变换器脉宽调制和电流检测的通信方法%A Communication Method Based on PWM Technology and Current Detection of Power Converter

    杨博; 杜海江; 吕剑刚; 孙航


    基于功率变换器脉宽调制(pulse width modulation PWM)技术实现通信功能,就是在保证对功率变换器输出功率进行控制的同时,实现设备间的有效通信。文章以光伏阵列发电系统为应用对象,设计了相应的通信方法实现系统中设备之间的通信:改变载波频率对信源信号进行调制,生成PWM开关驱动信号作为信源信号的调制信号,同时驱动开关管控制功率传输;解调时,提出以电流信号作为检测对象,设计了幅值阈值判定法和能量值阈值判定法确定信源信号的起始码元及后续码元,最终实现同一光伏组串内的不同光伏组件之间、以及组件与阵列通信终端之间的有效通信。仿真设计相应的系统参数和工况来模拟光伏阵列系统的通信过程,并在通信的同时改变占空比实现功率调节,结果表明了所提方法的有效性。%The essence of communication function based on pulse width modulation (PWM) technology of power converter is to implement effective communication among devices while the output power control of power inverter is ensured. Taking the generation system composed of photovoltaic cell arrays as the object to apply the proposed communication method, a corresponding method for the communication among devices in PV array generation system is designed, that is, the source signal is modulated by changing carrier frequency to generate the driving signal of PWM switch, which is taken as the modulation signal of source signal;for the demodulation, it is proposed to take the current signal as the detected object, and the amplitude threshold based judgment method and the energy threshold based judgment method are designed to determine the initial code element and subsequent code elements, eventually the effective communication among different PV modules in the same PV module string and that among modules and array communication terminals are realized. Corresponding

  11. Single Atom Plasmonic Switch

    Emboras, Alexandros; Niegemann, Jens; Ma, Ping; Haffner, Christian; Luisier, Mathieu; Hafner, Christian; Schimmel, Thomas; Leuthold, Juerg


    The atom sets an ultimate scaling limit to Moores law in the electronics industry. And while electronics research already explores atomic scales devices, photonics research still deals with devices at the micrometer scale. Here we demonstrate that photonic scaling-similar to electronics-is only limited by the atom. More precisely, we introduce an electrically controlled single atom plasmonic switch. The switch allows for fast and reproducible switching by means of the relocation of an individ...

  12. Atomic Scale Plasmonic Switch

    Emboras, A.; Niegemann, J.; Ma, P.; Haffner, C; Pedersen, A.; Luisier, M.; Hafner, C.; Schimmel, T.; Leuthold, J.


    The atom sets an ultimate scaling limit to Moore’s law in the electronics industry. While electronics research already explores atomic scales devices, photonics research still deals with devices at the micrometer scale. Here we demonstrate that photonic scaling, similar to electronics, is only limited by the atom. More precisely, we introduce an electrically controlled plasmonic switch operating at the atomic scale. The switch allows for fast and reproducible switching by means of the relocat...

  13. FreeSWITCH Cookbook

    Minessale, Anthony


    This is a problem-solution approach to take your FreeSWITCH skills to the next level, where everything is explained in a practical way. If you are a system administrator, hobbyist, or someone who uses FreeSWITCH on a regular basis, this book is for you. Whether you are a FreeSWITCH expert or just getting started, this book will take your skills to the next level.

  14. Encryption Switching Protocols

    Couteau, Geoffroy; Peters, Thomas; Pointcheval, David


    International audience; We formally define the primitive of encryption switching protocol (ESP), allowing to switch between two encryption schemes. Intuitively, this two-party protocol converts given ciphertexts from one scheme into ciphertexts of the same messages under the other scheme, for any polynomial number of switches, in any direction. Although ESP is a special kind of two-party computation protocol, it turns out that ESP implies general two-party computation (2-PC) under natural con...

  15. Platform switching and bone platform switching.

    Carinci, Francesco; Brunelli, Giorgio; Danza, Matteo


    Bone platform switching involves an inward bone ring in the coronal part of the implant that is in continuity with the alveolar bone crest. Bone platform switching is obtained by using a dental fixture with a reverse conical neck. A retrospective study was performed to evaluate the effectiveness of conventional vs reverse conical neck implants. In the period between May 2004 and November 2007, 86 patients (55 females and 31 males; median age, 53 years) were operated and 234 implants were inserted: 40 and 194 were conventional vs reverse conical neck implants, respectively. Kaplan-Meier algorithm and Cox regression were used to detect those variables associated with the clinical outcome. No differences in survival and success rates were detected between conventional vs reverse conical neck implants alone or in combination with any of the studied variables. Although bone platform switching leads to several advantages, no statistical difference in alveolar crest resorption is detected in comparison with reverse conical neck implants. We suppose that the proximity of the implant abutment junction to the alveolar crestal bone gives no protection against the microflora contained in the micrograph. Additional studies on larger series and a combination of platform switching and bone platform switching could lead to improved clinical outcomes.

  16. Advantages and Disadvantages of the Traditional DAC and High Performance PWM-DAC's Basic Design%传统数模转换器的优缺点分析及高性能PWM-DAC的基本设计思想



    分析了基于零阶保持器( ZOH)原理的传统数模转换器(DAC)和线性功率放大器的优点和缺点,以及基于脉冲宽度调制( PWM)技术的D类功率放大器在节能方面的优势和性能上的不足.详细分析了数字PWM调制器( PWM- DAC)的基本原理并推导其算法,进行了性能仿真分析计算,证明了用PWM-DAC同时完成数模转换和PWM调制的可行性,结果表明,这种转换性能优良.

  17. Optimal switching using coherent control

    Kristensen, Philip Trøst; Heuck, Mikkel; Mørk, Jesper


    that the switching time, in general, is not limited by the cavity lifetime. Therefore, the total energy required for switching is a more relevant figure of merit than the switching speed, and for a particular two-pulse switching scheme we use calculus of variations to optimize the switching in terms of input energy....

  18. PWM Regulation of Grid-Tied PV System on the Base of Photovoltaic-Fed Diode-Clamped Inverters

    Oleschuk V.I.


    Full Text Available Investigation of grid-tied photovoltaic system on the base of two diode-clamped inverters, controlled by specific algorithms of pulse-width modulation (PWM, has been done. This system includes two strings of photovoltaic panels feeding two diode-clamped inverters. The outputs of inverters are connected with the corresponding windings on the primary side of three-phase transformer, connected with a grid. In order to reduce phase voltage distortion and to increase efficiency of operation of the system, special scheme of control and modulation of inverters has been used, providing minimization of common-mode voltages and voltage waveforms symmetries under different operating conditions. Detailed simulation of processes in this photovoltaic-fed power conversion system has been executed. The results of simulations verify good performance of photovoltaic system regulated in accordance with specific strategy of control and modulation.

  19. Integrated modeling and control of a PEM fuel cell power system with a PWM DC/DC converter

    Choe, Song-Yul; Ahn, Jong-Woo [Mechanical Engineering Department, Auburn University, Auburn, AL 36848 (United States); Lee, Jung-Gi [Electrical Engineering Department, Pohang University of Science and Technology, Pohang (Korea); Baek, Soo-Hyun [Electrical Engineering Department, Dong-guk University, Seoul (Korea)


    A fuel cell powered system is regarded as a high current and low voltage source. To boost the output voltage of a fuel cell, a DC/DC converter is employed. Since these two systems show different dynamics, they need to be coordinated to meet the demand of a load. This paper proposes models for the two systems with associated controls, which take into account a PEM fuel cell stack with air supply and thermal systems, and a PWM DC/DC converter. The integrated simulation facilitates optimization of the power control strategy, and analyses of interrelated effects between the electric load and the temperature of cell components. In addition, the results show that the proposed power control can coordinate the two sources with improved dynamics and efficiency at a given dynamic load. (author)

  20. Transfer function-based modelling for voltage oscillation phenomena in PWM motor drives with long feeding cables

    Lee, Sang-Choel; Park, Ju H.


    In this article, a transfer function-based modelling is proposed to investigate voltage oscillation phenomena, i.e. over-voltage at the motor terminal, associated with pulse-width modulation (PWM) inverter-fed motor drives with long feeding cables. As such, the long feeding cable is assumed to be a distortionless transmission line; then, a bounce diagram and time-harmonic method are utilised to derive a simple model with a minimum computational burden that is easy to realise using the Matlab/Simulink software package. Furthermore, the model takes account of the inverter output and the motor terminal filters, which are commonly used to suppress the motor terminal over-voltage. The model accuracy is verified by a comparison with the circuit-oriented software, OrCAD/PSpice, simulation results.

  1. Multi Channels PWM Controller for Thermoelectric Cooler Using a Programmable Logic Device and Lab-Windows CVI

    Eli FLAXER


    Full Text Available We present a complete design of a multi channels PID controller for Thermoelectric Cooler (TEC using a pulse width modulation (PWM technique implemented by a dedicated programmable logic device (PLD programmed by VHDL. The PID control loop is implemented by software written by National Instrument Lab-Windows CVI. Due to the fact that the implementation is by a VHDL and PLD the design is modular, as a result, the circuit is very compact in size and very low cost as compared to any commercial product. In addition, since the control loop is implemented by software running on a personal computer (PC using a C language, it is easy to adjust the controller to various environmental conditions and for a width range of sensors like: a thermo couple (TC, thermistor, resistance temperature detectors (RTD etc. We demonstrate the performance of this circuit as a controller for a small incubator using thermistor as the temperature sensor.

  2. Analysis on Photovoltaic Assisted Three Phase five level Unipolar PWM Inverter for Induction Motor Driven Water Pumping System

    Ajay Kumar Maurya, Kishore Chahar, Y. K. Chauhan


    Full Text Available This paper presents the analysis of a photovoltaicbases three-phase five level voltage source inverter(VSI supplying induction motor driven waterpump. The VSI uses a unipolar PWM technique forproducing three phase 5 level voltage output andthis output is used to drive three-phase inductionmotor driving a pump load. Multilevel inverters areused for generating AC voltage from several levelsof DC voltages and enhance the performance of thesystem. The proposed system is used to reduce thefiltering requirements and reduce the amplitude ofall harmonics at the output of the inverter. ThePower quality improves by reducing the harmonicslevel. The complete simulation model is simulatedin MATLAB/SIMULINK and validates thetheoretical considerations

  3. Optical switching device

    Broeder, F.J.A. den; Hanzen, R.M.N.; Duine, P.A.; Jungblut, R.M.; Draijer, C.; Roozeboom, F.; Sluis, P. van der


    A description is given of an optical switching device (1) comprising a transparent substrate (3), a switching film (5) of a hydride compound of a trivalent transition or rare earth metal having a thickness of 300 nm, and a palladium capping layer (7) having a thickness of 30 nm. The capping layer is

  4. Quantum cryptography without switching.

    Weedbrook, Christian; Lance, Andrew M; Bowen, Warwick P; Symul, Thomas; Ralph, Timothy C; Lam, Ping Koy


    We propose a new coherent state quantum key distribution protocol that eliminates the need to randomly switch between measurement bases. This protocol provides significantly higher secret key rates with increased bandwidths than previous schemes that only make single quadrature measurements. It also offers the further advantage of simplicity compared to all previous protocols which, to date, have relied on switching.

  5. Switch on, switch off: stiction in nanoelectromechanical switches

    Wagner, Till J W


    We present a theoretical investigation of stiction in nanoscale electromechanical contact switches. We develop a mathematical model to describe the deflection of a cantilever beam in response to both electrostatic and van der Waals forces. Particular focus is given to the question of whether adhesive van der Waals forces cause the cantilever to remain in the \\'ON\\' state even when the electrostatic forces are removed. In contrast to previous studies, our theory accounts for deflections with large slopes (i.e. geometrically nonlinear). We solve the resulting equations numerically to study how a cantilever beam adheres to a rigid electrode: transitions between \\'free\\', \\'pinned\\' and \\'clamped\\' states are shown to be discontinuous and to exhibit significant hysteresis. Our findings are compared to previous results from linearized models and the implications for nanoelectromechanical cantilever switch design are discussed. © 2013 IOP Publishing Ltd.

  6. Single Atom Plasmonic Switch

    Emboras, Alexandros; Ma, Ping; Haffner, Christian; Luisier, Mathieu; Hafner, Christian; Schimmel, Thomas; Leuthold, Juerg


    The atom sets an ultimate scaling limit to Moores law in the electronics industry. And while electronics research already explores atomic scales devices, photonics research still deals with devices at the micrometer scale. Here we demonstrate that photonic scaling-similar to electronics-is only limited by the atom. More precisely, we introduce an electrically controlled single atom plasmonic switch. The switch allows for fast and reproducible switching by means of the relocation of an individual or at most - a few atoms in a plasmonic cavity. Depending on the location of the atom either of two distinct plasmonic cavity resonance states are supported. Experimental results show reversible digital optical switching with an extinction ration of 10 dB and operation at room temperature with femtojoule (fJ) power consumption for a single switch operation. This demonstration of a CMOS compatible, integrated quantum device allowing to control photons at the single-atom level opens intriguing perspectives for a fully i...

  7. A Novel Molecular Switch

    Daber, Robert; Lewis, Mitchell


    Transcriptional regulation is a fundamental process for regulating the flux of all metabolic pathways. For the last several decades, the lac operon has served as a valuable model for studying transcription. More recently, the switch that controls the operon has also been successfully adapted to function in mammalian cells. Here we describe how, using directed evolution, we have created a novel switch that recognizes an asymmetric operator sequence. The new switch has a repressor with altered headpiece domains for operator recognition, and a redesigned dimer interface to create a heterodimeric repressor. Quite unexpectedly, the heterodimeric switch functions better than the natural system. It can repress more tightly than the naturally occurring switch of the lac operon; it is less leaky and can be induced more efficiently. Ultimately these novel repressors could be evolved to recognize eukaryotic promoters and used to regulate gene expression in mammalian systems. PMID:19540845

  8. A New Method to Implement Resampled Uniform PWM Suitable for Distributed Control of Modular Multilevel Converters

    Huang, Shaojun; Mathe, Laszlo; Teodorescu, Remus


    of inaccuracy in terms of switching instant, while the latter is inflexible with higher cost. In order to overcome these drawbacks, this paper proposes an alternative solution, which uses high frequency saw-tooth carrier and two independent comparators, usually available in microcontrollers, to create......Two existing methods to implement resampling modulation technique for modular multilevel converter (MMC) (the sampling frequency is a multiple of the carrier frequency) are: the software solution (using a microcontroller) and the hardware solution (using FPGA). The former has a certain level...

  9. A New Generalized Discontinuous-PWM Strategy for Active Power Filters

    Asiminoaei, Lucian; Rodriguez, Pedro; Blaabjerg, Frede


    losses in any operating point. This paper proposes a new discontinuous pulse width modulation strategy applied to shunt active power filters. The proposed modulation strategy detects the current vector position relative to the inverter voltage reference and determines instantaneously the optimum clamped...... duration on each phase. It achieves a clamped voltage pattern, with variable lengths depending on the magnitude of the inverter current. This property adaptively reduces the current stress and minimizes the inverter switching losses, regardless of its application. The proposed modulation strategy...... is described, analyzed and validated on a three-phase voltage source inverter, rated at 7 kVA, 400 V, controlled as an active power filter....

  10. Intelligent Optimize Design of LCL Filter for Three-Phase Voltage-Source PWM Rectifier

    Sun, Wei; Chen, Zhe; Wu, Xiaojie


    Compared to traditional L filter, a LCL filter is more effective on reducing harmonic distortion at switch frequency. So it is important to choose the LCL filter parameters to achieve good filtering effect. This paper introduces some traditional design methods. Design of a LCL filter by genetic...... algorithm (GA) and particle swam optimization (PSO) are presented in this paper and comparison of the two intelligent optimization. Simulation result and calculate data are provided to prove that intelligent optimization are more effective and simple than traditional methods....

  11. Optical packet switching

    Shekel, Eyal; Ruschin, Shlomo; Majer, Daniel; Levy, Jeff; Matmon, Guy; Koenigsberg, Lisa; Vecht, Jacob; Geron, Amir; Harlavan, Rotem; Shfaram, Harel; Arbel, Arnon; McDermott, Tom; Brewer, Tony


    We report here a scalable, multichassis, 6.3 terabit core router, which utilizes our proprietary optical switch. The router is commercially available and deployed in several customer sites. Our solution combines optical switching with electronic routing. An internal optical packet switching network interconnects the router"s electronic line cards, where routing and buffering functions take place electronically. The system architecture and performance will be described. The optical switch is based on Optical Phased Array (OPA) technology. It is a 64 x 64, fully non-blocking, optical crossbar switch, capable of switching in a fraction of a nanosecond. The basic principles of operation will be explained. Loss and crosstalk results will be presented, as well as the results of BER measurements of a 160 Gbps transmission through one channel. Basic principles of operation and measured results will be presented for the burst-mode-receivers, arbitration algorithm and synchronization. Finally, we will present some of our current research work on a next-generation optical switch. The technological issues we have solved in our internal optical packet network can have broad applicability to any global optical packet network.

  12. A Metabolic Switch

    Hjorth, Poul G.

    Our muscles are metabolically flexible, i.e., they are capable of `switching' between two types of oxidation: (1) when fasting, a predominantly lipid oxidation with high rates of fatty acid uptake, and (2) when fed, suppression of lipid oxidation in favour of increased glucose uptake, oxidation...... and storage, in response to insulin. One of the many manifestations of obesity and Type 2 diabetes is an insulin resistance of the skeletal muscles, which suppresses this metabolic switch. This talk describes recent development of a low-dimensional system of ODEs that model the metabolic switch, displaying...

  13. JUNOS Enterprise Switching

    Reynolds, Harry


    JUNOS Enterprise Switching is the only detailed technical book on Juniper Networks' new Ethernet-switching EX product platform. With this book, you'll learn all about the hardware and ASIC design prowess of the EX platform, as well as the JUNOS Software that powers it. Not only is this extremely practical book a useful, hands-on manual to the EX platform, it also makes an excellent study guide for certification exams in the JNTCP enterprise tracks. The authors have based JUNOS Enterprise Switching on their own Juniper training practices and programs, as well as the configuration, maintenanc

  14. Photoconductive switch package

    Ca[rasp, George J


    A photoconductive switch is formed of a substrate that has a central portion of SiC or other photoconductive material and an outer portion of cvd-diamond or other suitable material surrounding the central portion. Conducting electrodes are formed on opposed sides of the substrate, with the electrodes extending beyond the central portion and the edges of the electrodes lying over the outer portion. Thus any high electric fields produced at the edges of the electrodes lie outside of and do not affect the central portion, which is the active switching element. Light is transmitted through the outer portion to the central portion to actuate the switch.

  15. Electromechanical magnetization switching

    Chudnovsky, Eugene M. [Department of Physics and Astronomy, Lehman College and Graduate School, The City University of New York, 250 Bedford Park Boulevard West, Bronx, New York 10468-1589 (United States); Jaafar, Reem [Department of Mathematics, Engineering and Computer Science, LaGuardia Community College, The City University of New York, 31-10 Thomson Avenue, Long Island City, New York 11101 (United States)


    We show that the magnetization of a torsional oscillator that, in addition to the magnetic moment also possesses an electrical polarization, can be switched by the electric field that ignites mechanical oscillations at the frequency comparable to the frequency of the ferromagnetic resonance. The 180° switching arises from the spin-rotation coupling and is not prohibited by the different symmetry of the magnetic moment and the electric field as in the case of a stationary magnet. Analytical equations describing the system have been derived and investigated numerically. Phase diagrams showing the range of parameters required for the switching have been obtained.

  16. Harmonic Analysis of Seven and Nine Level Cascade Multilevel Inverter using Multi-Carrier PWM Technique

    Chetanya Gupta


    Full Text Available The use of multilevel inverters has become popular in recent years for high-power applications. Multilevel Inverters are power converter systems composed by an array of power semiconductor sources that when properly connected and controlled can generate a multistep voltage waveform with variable and controllable frequency, phase and amplitude. This study deals with the comparison of a 7-level inverter with a 9-level inverter system; the voltage source inverters (VSI are modelled and simulated using MATLAB Simulink and the results are presented. The test results verify the effectiveness of the proposed strategy in terms of computational efficiency as well as the capability of the inverter to produce very low distorted voltage with low-switching losses. This research aims to extend the knowledge about the performance of different clamped multilevel inverter through harmonic analysis. Simulations results validate up to the mark performance of the mentioned topologies.

  17. Stabilizing Randomly Switched Systems

    Chatterjee, Debasish


    This article is concerned with stability analysis and stabilization of randomly switched systems under a class of switching signals. The switching signal is modeled as a jump stochastic (not necessarily Markovian) process independent of the system state; it selects, at each instant of time, the active subsystem from a family of systems. Sufficient conditions for stochastic stability (almost sure, in the mean, and in probability) of the switched system are established when the subsystems do not possess control inputs, and not every subsystem is required to be stable. These conditions are employed to design stabilizing feedback controllers when the subsystems are affine in control. The analysis is carried out with the aid of multiple Lyapunov-like functions, and the analysis results together with universal formulae for feedback stabilization of nonlinear systems constitute our primary tools for control design

  18. Optical fiber crossbar switch

    Kilcoyne, Michael K.; Beccue, Stephen M.; Brar, Berinder; Robinson, G.; Pedrotti, Kenneth D.; Haber, William A.


    Advances in high performance computers and signal processing systems have led to parallel system architectures. The main limitation in achieving the performance expected of these parallel systems has been the realization of an efficient means to interconnect many processors into a effective parallel system. Electronic interconnections have proved cumbersome, costly and ineffective. The Optical Fiber Crossbar Switch (OFCS) is a compact low power, multi-gigahertz bandwidth multi-channel switch which can be used in large scale computer and telecommunication applications. The switch operates in the optical domain using GaAs semiconductor lasers to transmit wideband multiple channel optical data over fiber optic cables. Recently, a 32 X 32 crossbar switching system was completed and demonstrated. Error free performance was obtained at a data bandwidth of 410 MBPS, using a silicon switch IC. The switch can be completely reconfigured in less than 50 nanoseconds under computer control. The fully populated OFCS has the capability to handle 12.8 gigabits per second (GBPS) of data while switching this data over 32 channels without the loss of a single bit during switching. GaAs IC technology has now progressed to the point that 16 X 16 GaAs based crossbar switch Ics are available which have increased the data bandwidth capability to 2.4 GBPS. The present optical interfaces are integrated GaAs transmitter drivers, GaAs lasers, and integrated GaAs optical receivers with data bandwidths exceeding 2.4 GBPS. A system using all Ill-V switching and optoelectronic components is presently under development for both NASA and DoD programs. The overall system is designed to operate at 1.3 GBPS. It is expected that these systems will find wide application in high capacity computing systems based on parallel microprocessor architecture which require high data bandwidth communication between processors. The OFCS will also have application in commercial optical telecommunication systems

  19. High Power Switching Transistor

    Hower, P. L.; Kao, Y. C.; Carnahan, D. C.


    Improved switching transistors handle 400-A peak currents and up to 1,200 V. Using large diameter silicon wafers with twice effective area as D60T, form basis for D7 family of power switching transistors. Package includes npn wafer, emitter preform, and base-contact insert. Applications are: 25to 50-kilowatt high-frequency dc/dc inverters, VSCF converters, and motor controllers for electrical vehicles.

  20. Photonics in switching

    Midwinter, John E; Kelley, Paul


    Photonics in Switching provides a broad, balanced overview of the use of optics or photonics in switching, from materials and devices to system architecture. The chapters, each written by an expert in the field, survey the key technologies, setting them in context and highlighting their benefits and possible applications. This book is a valuable resource for those working in the communications industry, either at the professional or student level, who do not have extensive background knowledge or the underlying physics of the technology.

  1. 基于改进 PIDNN 滑模控制的电压型 PWM 整流器%Improved PID Neural Network Sliding-mode Controller for Voltage Source PWM Rectifier

    彭一芯; 魏建勋; 黄辉先; 方鑫; 陆建龙


    For the problem that the system input parameters exists disturbances when the traditional sliding-mode varia-ble-structure control(SMVSC)is applied to the three-phase voltage source PWM rectifier,an online solution that sliding-mode variable-structure control base on improved PID neural network design was presented in this paper,taking three pa-rameters of PID as neurons of neural network in the hidden layer and considering that PID algorithm is of fast response,no static error and the online self-learning ability of neural network,the PID algorithm and neural network is combined to modi-fy the sliding approaching rate parameter in real-time,thus the time of system state into the sliding surface and jitter is re-duced.Through improving the selected value function,the algorithm cannot fall into local minimum and the global optimal solution is approached;also,the overall stability of the system is analyzed.Finally into simulation and experimental valida-tion research,show that the method possesses smaller shake and preferable dynamic response.%针对传统滑模变结构控制在三相电压型 PWM 整流器中应用时参数摄动所引起的抖动现象,提出一种改进 PID 神经网络的滑模变结构在线控制方法,将 PID 三个参数作为神经网络隐藏层的神经元,利用 PID 算法响应快、无静差的特点以及神经网络的在线自学习能力,实时对滑模趋近律参数进行修改,从而缩短系统状态进入滑模面的时间并减小抖动。对选取的价值函数进行改进,使算法不会陷入局部最优而逼近全局最优解,并对系统的全局稳定性进行分析。通过仿真和实验验证,结果表明该方法能使系统全局稳定,抖动有明显削弱且具有更好的动态响应。

  2. Power Quality Enhancement in Wind Connected Grid System Interface Based On Static Switched Filter Compensator (SSFC

    Lakshmi Prasanna Vatti


    Full Text Available Wind energy has become one of the significant alternative renewable energy resources because of its abundance and the strong drive for its commercialization. Dynamic electric load variations and wind velocity excursions cause excessive changes in the prime mover kinetic energy and the corresponding electrical power injected into the AC grid utility system. In this paper, a scheme based on the low cost static switched filter compensator (SSFC is presented for voltage sag/swell compensation, power factor improvement in distribution grid networks with the dispersed wind energy interface. The SSFC scheme is based on an intermittent switching process between two shunt capacitor banks to be one of them in parallel with the capacitor of a tuned arm filter. Two regulators based on a tri- loop dynamic error driven inter-coupled weighted modified proportional-integralderivative (PID controller which is used to modulate the PWM. The Static Switched Filter Compensation (SSFC compensation scheme which enhances the system power quality has been fully validated using MATLAB–Simulink. The effectiveness of this compensation scheme approach is demonstrated using a study case of 3 bus system. Simulation results show that there is improvement in harmonics reduction, voltage sag/swell compensation, power factor improvement at generator bus, load bus, and infinite bus respectively

  3. Design of offline switch mode power based on FSL206MR%基于FSL206MR的离线式开关电源设计

    汤永科; 王勇; 王小亮; 秦磊


    The paper introduces a design of offline switch mode power based on the power supply chip FSL206MR which integrates pulse width modulator(PWM)and SenseFET. It analyzes the working process and design program of the feedback circuit and buck topology in detail. The feedback network is composed of NPN transistor MMBT222A and voltage regulator diode BZX84C13. This switch mode power performs well and has many advantages, such as the simple structure, a good result of voltage stabilization and easy encapsulation, so it has the very high value in application.%介绍了一种基于集成 PWM 和 SenseFET 的开关电源芯片 FSL206MR 的离线式开关电源设计,详细分析了反馈电路和降压拓扑的工作过程及设计方案。采用 NPN 晶体三极管 MMBT2222A 和稳压管 BZX84C13组成反馈网络。该开关电源性能优良,具有结构简单、稳压效果好、易封装等优点,具有很高的生产应用价值。

  4. Research of high-accurary PWM output in overfrequency based on MC9S12DG128B%基于MC9S12DG128B超频状态下高精度PWM输出的研究



    Based on Freescale MC9S12DG128 as the core control unit, designed and implemented the PWM output under over-clocking conditionso The higher precision of the PWM output is,the less of the PWM output value is. And the PWM output pulse amplitude decreases, overelocking can be applied to high precision PWM output system.%以MC9S12DG128作为核心控制单元,利用MC9S12DG128实现了超频条件下的高精度PWM输出。随着输出PWM精度的增加,PWM输出的幅值开始减小,同时PWM输出脉冲幅值减小,超频状态下可应用于高精度PWM输出系统中。

  5. The PWM by Controlling the PC Motor Achieved in C8051%电动机控制中的PWM在C8051中的实现



    在直流电动机的控制中,通过脉宽调制(PWM)技术,调节PWM信号的占空比来实现调速.应用C8051 PCA的PWM工作方式,我们可以很容易地得到8位PWM波.或者通过其它方式实现高分辨率的PWM波.

  6. PWM电机调速在专用打印机中的应用%The application in passport of the DC motor PWM speed control mode



    本文主要研究了单片机实现直流电机闭环控制的调速方式,阐述了直流电机的PWM调速控制的软硬件设计思路与实现。%This paper mainly studies the MCU DC motor closed-loop control mode, elaborated the DC motor PWM speed control hardware and software design and implementation.

  7. Tipe Dry Cell dan Wet Cell berdimensi 80 x 80 mm dengan Penambahan PWM E-3 FF (1 kHz

    Yanur Arzaqa Ghiffari


    Full Text Available Ketersediaan bahan bakar minyak semakin terbatas dan hasil pembakarannya berdampak pada pencemaran lingkungan, salah satu solusinya dengan memanfaatkan gas HHO pada kendaraan bermotor. Penelitian dengan sistem direct connection, temperatur mencapai lebih dari 90oC menyebabkan  generator HHO menjadi rusak dan meleleh, maka penelitian ini menambahan alat untuk mengkontrol besarnya arus, frekuensi, dan duty cycle. Pengembangan generator HHO menggunakan tipe kering (dry cell dan tipe basah (wet cell dengan penambahan PWM (Pulse Width Modulation E-3 Fixed Frequency 1 kHz divariasikan berupa duty cycle: 20%, 40%, 60%, 80%  dan direct connection. Pengujian dilakukan di Laboratorium Teknik Pembakaran dan Bahan Bakar - Teknik Mesin ITS.  Dari hasil penelitian didapatkan karakteristik unjuk kerja terbaik pada kedua tipe generator HHO dengan penambahan PWM. Nilai arus dan tegangan lebih stabil dibandingkan dengan tanpa penambahan PWM (direct connection, namun arus cenderung meningkat seiring dengan kenaikan temperatur mencapai 70oC. Efisiensi terbaik pada generator tipe wet dengan duty cycle 80%,  yaitu 27,7 %.

  8. 桥式直流PWM变换器的建模与仿真研究%Research on Modeling and Simulation of bridge DC PWM converter

    朱莉波; 荣军; 王峰; 刘正; 钟颖


    首先介绍了PWM控制技术的基本原理,然后结合无源逆变器,详细地阐述了桥式直流PWM变换器的工作原理。最后在MATLAB/Simulink建立了桥式直流PWM变换器的仿真模型,然后对仿真结果进行了分析,仿真结果表明通过调节占空比,可以改变电压和电流的大小和方向,与理论分析完全一致。%The paper firstly introduces the basic principle of PWM control technology, and then combines with passive inverter, and also expounds in detail the working principle of PWM bridge DC converter. Finally, the simulation model is built in the MATLAB/Simulink of bridge DC PWM converter, and then the simulation results have been carried on the analysis. The simulation results show that the size and the direction of the voltage and current can be changed by adjusting the duty ratio, and it is fully consistent with the theoretical analysis.

  9. The Application of PWM Control Technology in Bridge Inverter Circuit%PWM控制技术在逆变电路中的应用



    研究了PWM控制技术在单相桥式逆变电路中的应用,首先详细地阐述了PWM控制技术的基本原理,简要地介绍了单相桥式逆变电路的工作原理,然后将PWM控制技术应用到单相桥式逆变电路中,最后通过仿真结果验证了理论分析的正确性。%The paper studies the application of PWM control technology in single-phase bridge inverter circuit, and the basic principle of PWM control technology is firstly introduced, and the working principle of single-phase bridge inverter circuit is introduced briefly. Then the paper applies the PWM control technology to the single-phase bridge inverter circuit, and the correctness of theoretical analysis is verified by simulation results.

  10. Low inductance gas switching.

    Chavez, Ray; Harjes, Henry Charles III; Wallace, Zachariah; Elizondo, Juan E.


    The laser trigger switch (LTS) is a key component in ZR-type pulsed power systems. In ZR, the pulse rise time through the LTS is > 200 ns and additional stages of pulse compression are required to achieve the desired <100 ns rise time. The inductance of the LTS ({approx}500nH) in large part determines the energy transfer time through the switch and there is much to be gained in improving system performance and reducing system costs by reducing this inductance. The current path through the cascade section of the ZR LTS is at a diameter of {approx} 6-inches which is certainly not optimal from an inductance point of view. The LTS connects components of much greater diameter (typically 4-5 feet). In this LDRD the viability of switch concepts in which the diameter of cascade section is greatly increased have been investigated. The key technical question to be answered was, will the desired multi-channel behavior be maintained in a cascade section of larger diameter. This LDRD proceeded in 2 distinct phases. The original plan for the LDRD was to develop a promising switch concept and then design, build, and test a moderate scale switch which would demonstrate the key features of the concept. In phase I, a switch concept which meet all electrical design criteria and had a calculated inductance of 150 nH was developed. A 1.5 MV test switch was designed and fabrication was initiated. The LDRD was then redirected due to budgetary concerns. The fabrication of the switch was halted and the focus of the LDRD was shifted to small scale experiments designed to answer the key technical question concerning multi-channel behavior. In phase II, the Multi-channel switch test bed (MCST) was designed and constructed. The purpose of MCST was to provide a versatile, fast turn around facility for the study the multi-channel electrical breakdown behavior of a ZR type cascade switch gap in a parameter space near that of a ZR LTS. Parameter scans on source impedance, gap tilt, gap spacing and

  11. 基于PID及PWM的无线传能系统研究%Wireless energy transfer system based on PID and PWM

    倪晗悦; 丁嘉毅; 曹婷; 张胜


    近年来,无线传能技术在无线充电等领域得到逐步应用,但其在谐振频率准确性、输出功率调整及传输效率等方面还不尽人意。本文基于LC谐振耦合无线传能原理,采用数字PID控制和PWM调制技术,实现了谐振频率自动跟踪及输出功率的精确控制。系统发送部分由MSP430单片机、IR2111高频驱动、桥式大功率MOS开关管CSD19535及串联谐振LC组成;接收电路由并联谐振LC、高频整流滤波电路、高边电流检测INA282、ADS1115电压采样及LCD系统参数显示等部分组成。在传输距离为10厘米时,其传输效率达到65%;通过跟踪检测,发现由于谐振电容和线圈发热等影响,在系统启动至稳定过程中,系统效率和工作频率会有所下降;此外,得到工作波形在占空比为50%时,系统效率最高的结论。%During recent years, there is an increasing need in wireless energy transfer technology for wireless charging, etc., but the transmission efficiency, automatic power control and some other aspects are still unsatisfying. The paper presents a design which can automatically track resonant frequency and control output power. It is based on digital PID control, PWM and the principle of LC resonant coupling-based wireless energy transfer theory. The sender part of the system consists of a MSP430 microcontroller, an IR2111 high-frequency driver, high-power MOS switch CSD19535 bridge and series resonant LC. The receiver part consists of a parallel resonant receiving circuit LC, high-frequency rectifier filter circuit, a high-side current sensor INA282, ADS1115 voltage sampler and a LCD for displaying system parameters. When transmission distance is 10cm, the efficiency is up to 65%. However, the efficiency and working frequency decrease slightly during the startup of the system. It is due to the heating of the resonant capacitor and wire. In addition, the system achieves its highest efficiency when duty

  12. Energy losses in switches

    Martin, T.H.; Seamen, J.F.; Jobe, D.O.


    The authors experiments show energy losses between 2 and 10 times that of the resistive time predictions. The experiments used hydrogen, helium, air, nitrogen, SF{sub 6} polyethylene, and water for the switching dielectric. Previously underestimated switch losses have caused over predicting the accelerator outputs. Accurate estimation of these losses is now necessary for new high-efficiency pulsed power devices where the switching losses constitute the major portion of the total energy loss. They found that the switch energy losses scale as (V{sub peak}I{sub peak}){sup 1.1846}. When using this scaling, the energy losses in any of the tested dielectrics are almost the same. This relationship is valid for several orders of magnitude and suggested a theoretical basis for these results. Currents up to .65 MA, with voltages to 3 MV were applied to various gaps during these experiments. The authors data and the developed theory indicates that the switch power loss continues for a much longer time than the resistive time, with peak power loss generally occurring at peak current in a ranging discharge instead of the early current time. All of the experiments were circuit code modeled after developing a new switch loss version based on the theory. The circuit code predicts switch energy loss and peak currents as a function of time. During analysis of the data they noticed slight constant offsets between the theory and data that depended on the dielectric. They modified the plasma conductivity for each tested dielectric to lessen this offset.

  13. Transformerless Topology for Grid-Conected Inverters With Unipolar PWM Control



    Full Text Available Most of the PV systems are designed with transformer for safety purpose with galvanic isolation. However, the transformer is big, heavy and expensive. Also, it reduces the overall frequency of the conversion stage. Generally PV inverter with transformer is having good efficiency. To overcome these problems, transformer less PV system is introduced. It is smaller, lighter, cheaper and higher in efficiency. However, dangerous leakage current will flow between PV array and the grid due to the stray capacitance. There are different types of configurations available for transformer less inverters like H5, H6, HERIC, and Dual paralleled buck inverter. But each configuration is suffering from its own disadvantages like high conduction losses, shoot-through issues of switches, dead-time requirements at zero crossing instants of grid voltage to avoid grid shoot-through faults and MOSFET reverse recovery issues. The main objective of the proposed transformer less inverter is to address two key issues: One key issue for a transformer less inverter is that it is necessary to achieve high efficiency compared to other existing inverter topologies. Another key issue is that the inverter configuration should not have any shoot-through issues for higher reliability.

  14. Target-optimum-oriented PWM Algorithm Based on SPWM and SVPWM%基于SPWM与SVPWM的目标随优PWM算法

    李涛; 张晓锋; 张侨; 乔鸣忠


    通过对总谐波畸变率(total harmonic distortion,THD)的分析,证明基于最小THD的多电平脉宽调制(pulse width modulation,PWM)电平选择策略的存在.进一步对多相多电平PWM进行THD最优化分析,建立与相数、电平数及单相目标波形的具体形式无关的目标随优PWM算法.将所得结论应用于正圆形目标轨迹,论证空间矢量脉宽调制最优算法和零矢量对称分配方案的本质,揭示多相PWM中谐波注入应遵循的普遍规律.从理论推导、数值仿真和实验3个方面对算法进行检验,检验结果证明了所做结论的理论正确性和应用广泛性.%In the paper, the existence of the minimal total harmonic distortion (THD) based multi-level pulse width modulation (PWM) chosen strategies was proved through THD theoretical analysis. Furthermore, the novel target-optimum-oriented PWM algorithm, which is independent of number of inverter phases or level numbers, and with no relation with the form of curves on any phase, was proposed the first time through the multi-phase-multi-level PWM with minimal THD analysis. Then, this algorithm was applied in circular track case, the essence of optimized space vector pulse width modulation (SVPWM) and equal-distribution policy of zero-vectors was discovered, the universal rules for the harmonic injection in multi-phase PWM was revealed. Finally, the conclusion of this paper was verified by theory, simulation and experiment, which was proved to be correct in both theoretical and application aspects.

  15. Atomic Scale Plasmonic Switch.

    Emboras, Alexandros; Niegemann, Jens; Ma, Ping; Haffner, Christian; Pedersen, Andreas; Luisier, Mathieu; Hafner, Christian; Schimmel, Thomas; Leuthold, Juerg


    The atom sets an ultimate scaling limit to Moore's law in the electronics industry. While electronics research already explores atomic scales devices, photonics research still deals with devices at the micrometer scale. Here we demonstrate that photonic scaling, similar to electronics, is only limited by the atom. More precisely, we introduce an electrically controlled plasmonic switch operating at the atomic scale. The switch allows for fast and reproducible switching by means of the relocation of an individual or, at most, a few atoms in a plasmonic cavity. Depending on the location of the atom either of two distinct plasmonic cavity resonance states are supported. Experimental results show reversible digital optical switching with an extinction ratio of 9.2 dB and operation at room temperature up to MHz with femtojoule (fJ) power consumption for a single switch operation. This demonstration of an integrated quantum device allowing to control photons at the atomic level opens intriguing perspectives for a fully integrated and highly scalable chip platform, a platform where optics, electronics, and memory may be controlled at the single-atom level.

  16. On stability of switched linear systems with perturbed switching paths


    This paper addresses the stability issue of switched linear systems with perturbed switching paths. First,by introducing thenotions of child-path and parent-path, we are able to define the distance between two switching paths by means of their switching matrices chains. Next, we present the nice properties of the defined distance. Then, a stability criterion is presented for a class of switched linear systems with perturbed switching paths. Finally, an illustrative example is presented to verify the effectiveness of the approach.

  17. Energy reversible switching from amorphous metal based nanoelectromechanical switch

    Mayet, Abdulilah M.


    We report observation of energy reversible switching from amorphous metal based nanoelectromechanical (NEM) switch. For ultra-low power electronics, NEM switches can be used as a complementary switching element in many nanoelectronic system applications. Its inherent zero power consumption because of mechanical detachment is an attractive feature. However, its operating voltage needs to be in the realm of 1 volt or lower. Appropriate design and lower Young\\'s modulus can contribute achieving lower operating voltage. Therefore, we have developed amorphous metal with low Young\\'s modulus and in this paper reporting the energy reversible switching from a laterally actuated double electrode NEM switch. © 2013 IEEE.

  18. A new type of accelerator power supply based on voltage-type space vector PWM rectification technology

    Wu, Fengjun, E-mail: [Institute of Modern Physics, CAS, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Gao, Daqing; Shi, Chunfeng; Huang, Yuzhen [Institute of Modern Physics, CAS, Lanzhou 730000 (China); Cui, Yuan [Institute of Modern Physics, CAS, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Yan, Hongbin [Institute of Modern Physics, CAS, Lanzhou 730000 (China); Zhang, Huajian [Institute of Modern Physics, CAS, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Wang, Bin [University of Chinese Academy of Sciences, Beijing 100049 (China); Li, Xiaohui [Institute of Modern Physics, CAS, Lanzhou 730000 (China)


    To solve the problems such as low input power factor, a large number of AC current harmonics and instable DC bus voltage due to the diode or thyristor rectifier used in an accelerator power supply, particularly in the Heavy Ion Research Facility in Lanzhou-Cooler Storage Ring (HIRFL-CSR), we designed and built up a new type of accelerator power supply prototype base on voltage-type space vector PWM (SVPWM) rectification technology. All the control strategies are developed in TMS320C28346, which is a digital signal processor from TI. The experimental results indicate that an accelerator power supply with a SVPWM rectifier can solve the problems above well, and the output performance such as stability, tracking error and ripple current meet the requirements of the design. The achievement of prototype confirms that applying voltage-type SVPWM rectification technology in an accelerator power supply is feasible; and it provides a good reference for design and build of this new type of power supply. - Highlights: • Applying SVPWM rectification technology in an accelerator power supply improves its grid-side performance. • New Topology and its control strategies make an accelerator power supply have bidirectional power flow ability. • Hardware and software of controller provide a good reference for design of this new type of power supply.

  19. A new type of accelerator power supply based on voltage-type space vector PWM rectification technology

    Wu, Fengjun; Gao, Daqing; Shi, Chunfeng; Huang, Yuzhen; Cui, Yuan; Yan, Hongbin; Zhang, Huajian; Wang, Bin; Li, Xiaohui


    To solve the problems such as low input power factor, a large number of AC current harmonics and instable DC bus voltage due to the diode or thyristor rectifier used in an accelerator power supply, particularly in the Heavy Ion Research Facility in Lanzhou-Cooler Storage Ring (HIRFL-CSR), we designed and built up a new type of accelerator power supply prototype base on voltage-type space vector PWM (SVPWM) rectification technology. All the control strategies are developed in TMS320C28346, which is a digital signal processor from TI. The experimental results indicate that an accelerator power supply with a SVPWM rectifier can solve the problems above well, and the output performance such as stability, tracking error and ripple current meet the requirements of the design. The achievement of prototype confirms that applying voltage-type SVPWM rectification technology in an accelerator power supply is feasible; and it provides a good reference for design and build of this new type of power supply.

  20. Research on Space Vector PWM Based on RBF Neural Network%基于RBF神经网络的SVPWM研究

    宣光银; 胡丹; 车畅


    论述了电压空间矢量脉宽调制( SVPWM)的基本原理,提出利用径向基(RBF)网络实现SVPWM的方法;并在Matlab下结合神经网络工具箱进了仿真研究.仿真结果表明,RBF-SVPWM收敛速度快、误差精度高,使用该方法建立的异步电动机控制系统具有更小的定子电流谐波和转矩脉动.%The basic principle of space voltage vector PWM was discussed,and a new algorithm for SVPWM based on radial basis function neural network( RBF-SVPWM) was proposed. The emulation of RBF-SVPWM was carried out in Mat-lab together with Nntoolbox. The results indicate that RBF-SVPWM has a fast convergence and high accurate error,and the induction motor control system using RBF-SVPWM also has less stator current harmonics and torque pulsation.

  1. Enhanced control of DFIG-used back-to-back PWM VSC under unbalanced grid voltage conditions


    This paper presents a unified positive- and negative-sequence dual-dq dynamic model of wind-turbine driven doublyfed induction generator (DFIG) under unbalanced grid voltage conditions. Strategies for enhanced control and operation of a DFIG-used back-to-back (BTB) PWM voltage source converter (VSC) are proposed. The modified control design for the grid-side converter in the stationary αβ frames diminishes the amplitude of DC-link voltage ripples of twice the grid frequency, and the two proposed control targets for the rotor-side converter are alternatively achieved, which, as a result, improve the fault-ride through (FRT) capability of the DFIG based wind power generation systems during unbalanced network supply. A complete unbalanced control scheme with both grid- and rotor-side converters included is designed. Finally, simulation was carried out on a 1.5 MW wind-turbine driven DFIG system and the validity of the developed unified model and the feasibility of the proposed control strategies are all confirmed by the simulated results.

  2. Design of New Physiotherapy Instrument Based on PWM%基于PWM的新型理疗仪设计

    陈海军; 温志浩


    STM32 as the main chip, we design a novel electrical pulse physiotherapy instrument which realize pulse width modulation (PWM) by timer set ing, then get the needed treatment waveform after signal conditioning, power ampliifer, and output control. The experimental results show that, physiotherapy instrument is stable and reliable, physical strength large adjustable range, which can be suitable for the vast majority of the crowd;and the output waveform is smooth, without burr, there were no obvious pain, obvious physical therapy effect.%利用S T M32作为主控芯片,设计了一种新型中频电脉冲理疗仪,通过微秒级定时器设置实现高精度脉宽调制(P W M)功能,经过信号调理、功率放大以及输出控制得到所需要的治疗波形。实验结果表明,理疗仪工作稳定可靠,理疗强度可调幅度大,可适合绝大多数人群;输出波形光滑、无毛刺、病人无明显刺痛感,理疗效果明显。

  3. 一种基于FAN6754A的PWM反激式开关电源的设计%Design of PWM Flyback Power Supply by Using FAN6754A

    陈建萍; 张文; 钟晨东; 魏仲华


    The working characteristics and principles of a novel peak current-mode PWM IC FAN6754A are described. The analysis is put forward of design principles in operating process of flyback switching power supplies. A novel flyback switching power supply is provided to meet the needs of the secondary circuit, with emphasis on its transformer design including inductance current, transformer type, windings and gap length etc. The voltage control and stable output are realized by using three-terminal voltage regulator TL431, input/output isolation and feedback with opti-coupler. Its design principle, module functions and working process are analyzed. And in the circuit there exists thermistors, over-voltage, and over-current protection etc. Experimental results show that the designed converter has the characteristics of efficiency of near 89%, steady, low voltage ripples, high load regulation rate and voltage adjustment rate etc.%介绍了新款峰值电流型PWM控制芯片FAN6754A的工作特性和原理,分析了反激式开关电源的设计原理以及工作过程.针对次级电路结构,设计了一种新型反激式开关稳压电源.着重介绍了反激式开关电源的变压器设计过程,包括电感值的计算、磁芯的选择、绕组匝数的确定以及气隙等.利用三端稳压器TL431配合FAN6754A实现了对电源电压的控制和稳压输出,采用光耦器件实现了输入/输出的隔离和反馈.并在电源电路中加入了热敏电阻以及过压、过流保护等保护措施.实验测试结果表明:所设计的电源效率接近89%、稳压性能优良、纹波小、电压调整率、负载调整率高等优点.

  4. Microfabricated triggered vacuum switch

    Roesler, Alexander W.; Schare, Joshua M.; Bunch, Kyle


    A microfabricated vacuum switch is disclosed which includes a substrate upon which an anode, cathode and trigger electrode are located. A cover is sealed over the substrate under vacuum to complete the vacuum switch. In some embodiments of the present invention, a metal cover can be used in place of the trigger electrode on the substrate. Materials used for the vacuum switch are compatible with high vacuum, relatively high temperature processing. These materials include molybdenum, niobium, copper, tungsten, aluminum and alloys thereof for the anode and cathode. Carbon in the form of graphitic carbon, a diamond-like material, or carbon nanotubes can be used in the trigger electrode. Channels can be optionally formed in the substrate to mitigate against surface breakdown.

  5. Beyond the switch

    Aliakseyeu, Dzmitry; Meerbeek, Bernt; Mason, Jon


    and established lighting network, and with the advent of the LED, new types of lighting output are now possible. However, the current approach for controlling such systems is to simply replace the light switch with a somewhat more sophisticated smartphone-based remote control. The focus of this workshop...... is to explore new ways of interacting with light where lighting can not only be switched on or off, but is an intelligent system embedded in the environment capable of creating a variety of effects. The connectivity between multiple systems and other ecosystems, for example when transitioning from your home...

  6. Optical Packet Switching Demostrator

    Mortensen, Brian Bach; Berger, Michael Stübert


    In the IST project DAVID (data and voice integration over DWDM) work is carried out defining possible architectures of future optical packet switched networks. The feasibility of the architecture is to be verified in a demonstration set-up. This article describes the demonstrator set-up and the m......In the IST project DAVID (data and voice integration over DWDM) work is carried out defining possible architectures of future optical packet switched networks. The feasibility of the architecture is to be verified in a demonstration set-up. This article describes the demonstrator set...


    P. Karpagavalli


    Full Text Available This study presents the performance of a new four quadrant single phase DC drive closed loop system controlled by proportional integral and derivative controller with Pulse Width Modulation (PWM full bridge DC-DC converter using bipolar voltage switching. The proposed method is found to be more efficient in improving the step response characteristics such as reducing the settling time, rise time, steady state error and maximum overshoot in speed response of the closed loop DC motor drive and also reduced total harmonics distortion in the AC line current when compared to open loop system. The proposed topologies were simulated using MATLAB/Simulink software package and the results were obtained.

  8. A Switched Capacitor Harmonic Compensation Part for Switching Supplies


    A new approach based on switched capacitor network to harmonic compensation for switching supplies is presented in the paper,The basic principle is discussed.SPICE simulation is applied to analyze the behaviour of the switched capacitor harmonic compensation part.

  9. The Octopus switch

    Havinga, Paul Johannes Mattheus


    This chapter1 discusses the interconnection architecture of the Mobile Digital Companion. The approach to build a low-power handheld multimedia computer presented here is to have autonomous, reconfigurable modules such as network, video and audio devices, interconnected by a switch rather than by a


    J. G. Viveros Talavera


    Full Text Available This paper describes the design of the program of control for a Digital Phone Switch (PBAX with a maximumcapacity of one hundred and twenty-eight lines (extensions and trunks. The control program was designedusing object-oriented programming and concurrent programming techniques.

  11. Kiowa Creek Switching Station


    The Western Area Power Administration (Western) proposes to construct, operate, and maintain a new Kiowa Creek Switching Station near Orchard in Morgan County, Colorado. Kiowa Creek Switching Station would consist of a fenced area of approximately 300 by 300 feet and contain various electrical equipment typical for a switching station. As part of this new construction, approximately one mile of an existing 115-kilovolt (kV) transmission line will be removed and replaced with a double circuit overhead line. The project will also include a short (one-third mile) realignment of an existing line to permit connection with the new switching station. In accordance with the Council on Environmental Quality (CEQ) regulations for implementing the procedural provisions of the National Environmental Policy Act of 1969 (NEPA), 40 CFR Parts 1500--1508, the Department of Energy (DOE) has determined that an environmental impact statement (EIS) is not required for the proposed project. This determination is based on the information contained in this environmental assessment (EA) prepared by Western. The EA identifies and evaluates the environmental and socioeconomic effects of the proposed action, and concludes that the advance impacts on the human environment resulting from the proposed project would not be significant. 8 refs., 3 figs., 1 tab.

  12. Photonic MEMS switch applications

    Husain, Anis


    As carriers and service providers continue their quest for profitable network solutions, they have shifted their focus from raw bandwidth to rapid provisioning, delivery and management of revenue generating services. Inherently transparent to data rate the transmission wavelength and data format, MEMS add scalability, reliability, low power and compact size providing flexible solutions to the management and/or fiber channels in long haul, metro, and access networks. MEMS based photonic switches have gone from the lab to commercial availability and are now currently in carrier trials and volume production. 2D MEMS switches offer low up-front deployment costs while remaining scalable to large arrays. They allow for transparent, native protocol transmission. 2D switches enable rapid service turn-up and management for many existing and emerging revenue rich services such as storage connectivity, optical Ethernet, wavelength leasing and optical VPN. As the network services evolve, the larger 3D MEMS switches, which provide greater scalability and flexibility, will become economically viable to serve the ever-increasing needs.

  13. Safe LPV Controller Switching

    Trangbæk, K


    Before switching to a new controller it is crucial to assure that the new closed loop will be stable. In this paper it is demonstrated how stability can be checked with limited measurement data available from the current closed loop. The paper extends an existing method to linear parameter varying...

  14. Switching Between Multivariable Controllers

    Niemann, Hans Henrik; Stoustrup, Jakob; Abrahamsen, Rune


    it is possible to smoothly switch between multivariable controllers with guaranteed closed-loop stability. This includes also the case where one or more controllers are unstable. The concept for smooth online changes of multivariable controllers based on the YJBK architecture can also handle the start up...

  15. Kiowa Creek Switching Station


    The Western Area Power Administration (Western) proposes to construct, operate, and maintain a new Kiowa Creek Switching Station near Orchard in Morgan County, Colorado. Kiowa Creek Switching Station would consist of a fenced area of approximately 300 by 300 feet and contain various electrical equipment typical for a switching station. As part of this new construction, approximately one mile of an existing 115-kilovolt (kV) transmission line will be removed and replaced with a double circuit overhead line. The project will also include a short (one-third mile) realignment of an existing line to permit connection with the new switching station. In accordance with the Council on Environmental Quality (CEQ) regulations for implementing the procedural provisions of the National Environmental Policy Act of 1969 (NEPA), 40 CFR Parts 1500--1508, the Department of Energy (DOE) has determined that an environmental impact statement (EIS) is not required for the proposed project. This determination is based on the information contained in this environmental assessment (EA) prepared by Western. The EA identifies and evaluates the environmental and socioeconomic effects of the proposed action, and concludes that the advance impacts on the human environment resulting from the proposed project would not be significant. 8 refs., 3 figs., 1 tab.

  16. Implementation Method of High-Resolution DAC Using the MCU's PWM Interfaces%微控制器PWM接口实现高分辨率D/A 转换器方法研究

    吴桂清; 李泓霖; 戴瑜兴; 郑宗伟


    本文针对嵌入式应用中PWM (Pulse-Width Modulation)方式DAC(Digital-to-Analog Converter)和独立DAC芯片选择问题,提出了通过插值方式和多PWM组合方式提高PWM方式DAC分辨率的方法;分析了PWM信号频谱,提出了模拟滤波器设计原则与方法.以MCU(Micro Control Unit)的PWM通道方式实现DAC,经过数据分析证明此方法稳定可靠.%A method that improving the resolution of PWM(Pulse-Width Modulation) mode DAC(Digital-To-Analog Converter) by interpolator was proposed for the problem that PWM mode DAC in embedded applications and how to choose DAC chip. The PWM signal spectrum was analyzed. The design principle and method of analog filter was proposed. The design of High-Resolution DAC using MCU' s(Micro Control Unit) PWM proved that this method is stable and reliable by analysis of experiments.

  17. Molecular Rotors as Switches

    Kang L. Wang


    Full Text Available The use of a functional molecular unit acting as a state variable provides an attractive alternative for the next generations of nanoscale electronics. It may help overcome the limits of conventional MOSFETd due to their potential scalability, low-cost, low variability, and highly integratable characteristics as well as the capability to exploit bottom-up self-assembly processes. This bottom-up construction and the operation of nanoscale machines/devices, in which the molecular motion can be controlled to perform functions, have been studied for their functionalities. Being triggered by external stimuli such as light, electricity or chemical reagents, these devices have shown various functions including those of diodes, rectifiers, memories, resonant tunnel junctions and single settable molecular switches that can be electronically configured for logic gates. Molecule-specific electronic switching has also been reported for several of these device structures, including nanopores containing oligo(phenylene ethynylene monolayers, and planar junctions incorporating rotaxane and catenane monolayers for the construction and operation of complex molecular machines. A specific electrically driven surface mounted molecular rotor is described in detail in this review. The rotor is comprised of a monolayer of redox-active ligated copper compounds sandwiched between a gold electrode and a highly-doped P+ Si. This electrically driven sandwich-type monolayer molecular rotor device showed an on/off ratio of approximately 104, a read window of about 2.5 V, and a retention time of greater than 104 s. The rotation speed of this type of molecular rotor has been reported to be in the picosecond timescale, which provides a potential of high switching speed applications. Current-voltage spectroscopy (I-V revealed a temperature-dependent negative differential resistance (NDR associated with the device. The analysis of the device

  18. Closing photoconductive semiconductor switches

    Loubriel, G.M.; Zutavern, F.J.; Hjalmarson, H.P.; O' Malley, M.W.


    One of the most important limitations of Photoconductive Semiconductor Switches (PCSS) for pulsed power applications is the high laser powers required to activate the switches. In this paper, we discuss recent developments on two different aspects of GaAs PCSS that result in reductions in laser power by a factor of nearly 1000. The advantages of using GaAs over Si are many. First of all, the resistivity of GaAs can be orders of magnitude higher than that of the highest resistivity Si material, thus allowing GaAs switches to withstand dc voltages without thermal runaway. Secondly, GaAs has a higher carrier mobility than Si and, thus, is more efficient (per carrier). Finally, GaAs switches can have naturally fast (ns) opening times at room temperature and low fields, microsecond opening times at liquid nitrogen temperature of 77 K, or, on demand, closing and opening at high fields and room temperature by a mechanism called lock-on (see Ref. 1). By contrast, Si switches typically opening times of milliseconds. The amount of laser light required to trigger GaAs for lock-on, or at 77 K, is about three orders of magnitude lower than at room temperature. In this paper we describe the study of lock-on in GaAs and InP, as well as switching of GaAs at 77 K. We shall show that when GaAs is switched at 77 K, the carrier lifetime is about three orders of magnitude longer than it is at room temperature. We shall explain the change in lifetime in terms of the change in electron capture cross section of the deep levels in GaAs (these are defect or impurity levels in the band gap). In the second section, we describe the lock-on effect, now seen in GaAs and InP, and at fields as high as 70 kV/cm. We show how lock-on can be tailored by changing the GaAs temperature or by neutron bombardment. In the third section, we discuss possible lock-on mechanisms. 5 refs., 5 figs.

  19. Heat-transfer thermal switch

    Friedell, M. V.; Anderson, A. J.


    Thermal switch maintains temperature of planetary lander, within definite range, by transferring heat. Switch produces relatively large stroke and force, uses minimum electrical power, is lightweight, is vapor pressure actuated, and withstands sterilization temperatures without damage.

  20. Control synthesis of switched systems

    Zhao, Xudong; Niu, Ben; Wu, Tingting


    This book offers its readers a detailed overview of the synthesis of switched systems, with a focus on switching stabilization and intelligent control. The problems investigated are not only previously unsolved theoretically but also of practical importance in many applications: voltage conversion, naval piloting and navigation and robotics, for example. The book considers general switched-system models and provides more efficient design methods to bring together theory and application more closely than was possible using classical methods. It also discusses several different classes of switched systems. For general switched linear systems and switched nonlinear systems comprising unstable subsystems, it introduces novel ideas such as invariant subspace theory and the time-scheduled Lyapunov function method of designing switching signals to stabilize the underlying systems. For some typical switched nonlinear systems affected by various complex dynamics, the book proposes novel design approaches based on inte...

  1. Illuminated push-button switch

    Iwagiri, T.


    An illuminated push-button switch is described. It is characterized by the fact that is consists of a switch group, an operator button opening and closing the switch group, and a light-emitting element which illuminates the face of the operator button.

  2. Cytokine and immunoglobulin production by PWM-stimulated peripheral and tumor-infiltrating lymphocytes of undifferentiated nasopharyngeal carcinoma (NPC patients

    Bouzouita Kamel


    Full Text Available Abstract Background Undifferentiated Nasopharyngeal Carcinoma (NPC patients show a characteristic pattern of antibody responses to the Epstein-Barr virus (EBV which is regularly associated with this tumor. However, no EBV-specific cytotoxic activity is detectable by the standard chromium-release assay at both peripheral and intratumoral levels. The mechanisms underlying this discrepancy between the humoral and cellular immune responses in NPC are still unknown, but might be related to an imbalance in immunoregulatory interleukin production. In this report, we investigated the ability of peripheral (PBL and tumor- infiltrating (TIL lymphocytes of undifferentiated NPC patients to produce in vitro three interleukins (IL-2, IL-6, IL-10 and three immunoglobulin isotypes (IgM, IgG, IgA. Methods Lymphocytes from 17 patients and 17 controls were cultured in the presence of Pokeweed mitogen (PWM for 12 days and their culture supernatants were tested for interleukins and immunoglobulins by specific enzyme-linked immunosorbent assays (ELISA. Data were analysed using Student's t-test and probability values below 5% were considered significant. Results The data obtained indicated that TIL of NPC patients produced significantly more IL-2 (p = 0,0002, IL-10 (p = 0,020, IgM (p= 0,0003 and IgG (p Conclusion Taken together, our data reinforce the possibility of an imbalance in immunoregulatory interleukin production in NPC patients. An increased ability to produce cytokines such as IL-10 may underlie the discrepancy between humoral and cellular immune responses characteristic of NPC.

  3. Abacus switch: a new scalable multicast ATM switch

    Chao, H. Jonathan; Park, Jin-Soo; Choe, Byeong-Seog


    This paper describes a new architecture for a scalable multicast ATM switch from a few tens to thousands of input ports. The switch, called Abacus switch, has a nonblocking memoryless switch fabric followed by small switch modules at the output ports; the switch has input and output buffers. Cell replication, cell routing, output contention resolution, and cell addressing are all performed distributedly in the Abacus switch so that it can be scaled up to thousnads input and output ports. A novel algorithm has been proposed to resolve output port contention while achieving input and output ports. A novel algorithm has been proposed to reolve output port contention while achieving input buffers sharing, fairness among the input ports, and multicast call splitting. The channel grouping concept is also adopted in the switch to reduce the hardware complexity and improve the switch's throughput. The Abacus switch has a regular structure and thus has the advantages of: 1) easy expansion, 2) relaxed synchronization for data and clock signals, and 3) building the switch fabric using existing CMOS technology.

  4. 四程脉宽调制模型对无传感器无电刷直流电机控制系统中换向力矩波动的影响%Influence of PWM Modes on Commutation Torque Ripples in Sensorless Brushless DC Motor Control System

    张相军; 陈伯时


    This paper introduces four PWM modes used in the sensorless brushless DC motor control system, analyzes their different influences on the commutation torque ripple in detail, and selects the best PWM mode in four given types to reduce commutation torque ripple of Brushless OC(BLDC) motors. Simulation and experimental results show that the selection is correct and practical.

  5. A Novel Topology of Soft Switching Three-level Inverters for Highest Efficiency Rates%一种达到最高效率的新型软切换三电平逆变器拓扑结构

    Manfred W. Gekeler


    The Soft Switching Three Level Inverter (S3L) was first presented in 2011. It represents a novel topology for pulse width modulation (PWM) inverters that are used in electrical drives, in grid supply inverters for photovoltaic and wind power plants and for power supplies. It has a rather simple structure and is thus economically priced. It is completely operated in soft switching mode and consequently only displays very low switching losses. As a result, the efficiency rate is very high and particularly high switching frequency values can be achieved. In the present paper, the functionality is described, prototypes with output power from 20 kVA to 90 kVA are presented and results are specified.%  软开关三电平逆变器(soft switching three-level inverter,S3L)于2011年首次推出。它代表了脉宽调制(pulse width modulation,PWM)逆变器的一种新的拓扑结构,应用于电力驱动,光伏和风力发电厂的并网逆变器,以及用于供电领域。因其结构非常简单,所以价格相当低廉。它完全在软切换模式下运行,并且持续表现出极低的切换损耗。其结果是,效率非常高,而且可以实现特别高的切换频率。该论文对其功能进行描述,还展示一部输出电源为20~90 kVA 的逆变器样品,并对测试结果作详细说明。

  6. Implementation of Discrete Hopfield Neural Network Using PWM Mode Pulse Stream Technique%离散Hopfield神经网络的PWM型脉冲流技术实现

    姚剑敏; 林明秀; 宋建中



  7. Diseño de un conversor A/D empleando una modulador PWM y un circuito de decodificación mediante una FPGA

    Martín Ruiz, Manuel


    El presente proyecto muestra el diseño de un convertidor A/D (Analógico/Digital), basado en un modulador PWM cuya señal es capturada y decodificada por una FPGA. El convertidor A/D será implementando en un circuito de prueba analógico mediante componentes discretos (resistencias, condensadores, etc.) y amplificadores operacionales. La captura de la señal digital y su posterior decodificación, se realizará, empleando un dispositivo FPGA (del inglés Field Programmable Gate Arr...

  8. Features and Application of TOPSwitch- GX Series%复合PWM/MOSFET单片电路TOPSwitch-GX系列的特性及应用

    刘胜利; 严仰光



  9. A Novel PWM Generator Based on the Theory of Harmonic Elimination%基于谐波消去原理的新型PWM发生器

    朱其新; 张培建; 迟磊


    A novel PWM generator based on the theory of harmonicelimination is proposed in this paper, which has the following ad-vantages such as sheer digitizing, not occupying the time of the mi-croproessor and simpler circuit.%介绍了一种基于谐波消去原理的新型PWM发生器,该系统具有全数字控制、电路简单、不占用微机资源等优点。

  10. Neurotransmitter Switching? No Surprise.

    Spitzer, Nicholas C


    Among the many forms of brain plasticity, changes in synaptic strength and changes in synapse number are particularly prominent. However, evidence for neurotransmitter respecification or switching has been accumulating steadily, both in the developing nervous system and in the adult brain, with observations of transmitter addition, loss, or replacement of one transmitter with another. Natural stimuli can drive these changes in transmitter identity, with matching changes in postsynaptic transmitter receptors. Strikingly, they often convert the synapse from excitatory to inhibitory or vice versa, providing a basis for changes in behavior in those cases in which it has been examined. Progress has been made in identifying the factors that induce transmitter switching and in understanding the molecular mechanisms by which it is achieved. There are many intriguing questions to be addressed.

  11. Python Switch Statement


    Full Text Available The Python programming language does not have a built in switch/case control structure as found in many other high level programming languages. It is thought by some that this is a deficiency in the language, and the control structure should be added. This paper demonstrates that not only is the control structure not needed, but that the methods available in Python are more expressive than built in case statements in other high level languages.

  12. "Platform switching": Serendipity

    N Kalavathy


    Full Text Available Implant dentistry is the latest developing field in terms of clinical techniques, research, material science and oral rehabilitation. Extensive work is being done to improve the designing of implants in order to achieve better esthetics and function. The main drawback with respect to implant restoration is achieving good osseointegration along with satisfactory stress distribution, which in turn will improve the prognosis of implant prosthesis by reducing the crestal bone loss. Many concepts have been developed with reference to surface coating of implants, surgical techniques for implant placement, immediate and delayed loading, platform switching concept, etc. This article has made an attempt to review the concept of platform switching was in fact revealed accidentally due to the nonavailability of the abutment appropriate to the size of the implant placed. A few aspect of platform switching, an upcoming idea to reduce crestal bone loss have been covered. The various methods used for locating and preparing the data were done through textbooks, Google search and related articles.

  13. "Platform switching": serendipity.

    Kalavathy, N; Sridevi, J; Gehlot, Roshni; Kumar, Santosh


    Implant dentistry is the latest developing field in terms of clinical techniques, research, material science and oral rehabilitation. Extensive work is being done to improve the designing of implants in order to achieve better esthetics and function. The main drawback with respect to implant restoration is achieving good osseointegration along with satisfactory stress distribution, which in turn will improve the prognosis of implant prosthesis by reducing the crestal bone loss. Many concepts have been developed with reference to surface coating of implants, surgical techniques for implant placement, immediate and delayed loading, platform switching concept, etc. This article has made an attempt to review the concept of platform switching was in fact revealed accidentally due to the nonavailability of the abutment appropriate to the size of the implant placed. A few aspect of platform switching, an upcoming idea to reduce crestal bone loss have been covered. The various methods used for locating and preparing the data were done through textbooks, Google search and related articles.

  14. 非对称优化PWM串联型有源滤波器的研究及设计%Asymmetric Research and Design Optimization the PWM Series Active Filter



    This article first describes the basic principle and optimization of asymmetric filter characteristic and mathe-matical model of PWM, and then discussed the unsymmetrical optimal PWM series active filter design of hardware and software. Finally, system simulation using Matlab.%  首先介绍了有源滤波器基本原理和非对称优化PWM的特点及数学模型;然后讨论了非对称优化PWM串联型有源滤波的硬件及软件设计;最后使用Matlab对系统进行了仿真。

  15. Design of a High Switching Power Supply Based on UC3846%基于UC3846的大功率开关电源的设计

    吴军; 李长华; 刘平


    本文介绍并比较了电压控制型和电流控制型PWM变换器的基本原理.设计出基于电流型控制芯片UC3846的大功率全桥开关电源的实用电路。给出了各部分相应的原理图。并进行了详细的介绍。实践表明。该电路具有良好的性能。%The basic principles of voltage-mode control and current-mode control PWM converters are introduced and compared .An applied circuit of a high power Full-Bridge switching power supply is designed based on the PWM IC UC3846 for current mode control.The every circuit diagram with corresponding part is provide and detailed.The experiment result shows that the circuit has better performance.

  16. Feedback Solution to Optimal Switching Problems With Switching Cost.

    Heydari, Ali


    The problem of optimal switching between nonlinear autonomous subsystems is investigated in this paper where the objective is not only bringing the states to close to the desired point, but also adjusting the switching pattern, in the sense of penalizing switching occurrences and assigning different preferences to utilization of different modes. The mode sequence is unspecified and a switching cost term is used in the cost function for penalizing each switching. It is shown that once a switching cost is incorporated, the optimal cost-to-go function depends on the subsystem which was active at the previous time step. Afterward, an approximate dynamic programming-based method is developed, which provides an approximation of the optimal solution to the problem in a feedback form and for different initial conditions. Finally, the performance of the method is analyzed through numerical examples.

  17. PWM控制器UC2637的工作方式及应用%Working modes and applications of PWM chip UC2637



    Modern motor control technology has developed fast and made rapid progress these days. Actuators driven by DC motors are widely used in R&D processes of series projects in which the author participated. In these projects,the pulse width modulation(PWM)mode has played an important role in DC motor control. In this article,several working conditions of PWM driver chip UC2637 used in electrical actuator are discussed. Its flexible application in similar occasions is expected .%  现代电机控制技术日新月异,发展很快。在从事研制开发的多个型号课题中应用了直流电动舵机,而其核心部分直流电机控制方式又多采用脉冲调宽方式,对电动舵机脉冲调宽驱动芯片UC2637工作方式中的几种情况给予讨论,希望对其能够灵活运用,并可推广到其他的使用情况中去。

  18. Design on Anti-disturbance for Three-phase PWM Rectifier%三相电压型PWM整流器抗扰动设计

    郑征; 周文斌


    分析了三相电压型PWM整流器的基本原理并进行了建模.针对传统的双闭环控制下,直流母线电压受负载扰动和电网波动影响较大的问题,根据整流器功率平衡的原则,提出了电压外环采用前馈补偿(负载电流和电网电压)和输出电压反馈的控制方法,该方法有效地改善PWM整流器的抗扰动能力,仿真结果验证了控制策略的有效性和正确性.%The basic principle of the three-phase PWM rectifier was analyzed and the model was established. With the traditional double-loop control. The load disturbance and grid voltage fluctuations have a great influence on the DC bus voltage. According to the principle of power balance for rectifier, the outer control loop which is based on feed-forward compensation (load current and power voltage) and output voltage feedback control were proposed. This method effectively improves the anti-disturbance ability of PWM rectifier. Simulation results show the effectiveness and validity of control strategies.

  19. 电压型PWM逆变器控制技术的改进%The Improvement of Control Technology for Voltage Source PWM Inverter

    李雪龙; 周渊深; 李少鹏


    For the purpose of enhancing PWM inverter’s dynamic decoupling effects in current control loop, this paper apply IMC method to PWM inverter which is based on double (voltage and current) close-loop control. In addition, a kind of AC current regulator is designed, and its compensation signal as well as DC correction signal are together to determine the output of control, which reduces fluctuations at the DC side. In this paper, the waveforms via Simulink of the advanced scheme are presented, and the simulation results confirm the validity of the mentioned strategy.%基于电压型PWM逆变器电压电流双闭环控制框架,针对电流环的交叉耦合问题,采用内模解耦(IMC)方法以提高PWM逆变器动态过程中的解耦效果。除此以外,设计了交流电流调节器,其补偿信号与直流电流调节器的校正信号相加共同产生控制量的输出,以降低直流侧电压的波动性。给出了整体改进方案的Simulink仿真波形,结果证明了改进方案的可行性和有效性。

  20. A Study of MPLS Hybrid Switch Based on ATM Switch


    MPLS is the most successful integrating model of IP over ATM. The paper discusses some problems and their possible solutions when MPLS is supported by ATM switch. How to design the hardware, software and network management systems of such a switch device that has only one switching platform and one NMS but two sets of control planes at the same time, ATM and MPLS, is studied in details. The application of such a hybrid switch is presented in the last part of the paper.

  1. Composite Thermal Switch

    McDonald, Robert; Brawn, Shelly; Harrison, Katherine; O'Toole, Shannon; Moeller, Michael


    Lithium primary and lithium ion secondary batteries provide high specific energy and energy density. The use of these batteries also helps to reduce launch weight. Both primary and secondary cells can be packaged as high-rate cells, which can present a threat to crew and equipment in the event of external or internal short circuits. Overheating of the cell interior from high current flows induced by short circuits can result in exothermic reactions in lithium primary cells and fully charged lithium ion secondary cells. Venting of the cell case, ejection of cell components, and fire have been reported in both types of cells, resulting from abuse, cell imperfections, or faulty electronic control design. A switch has been developed that consists of a thin layer of composite material made from nanoscale particles of nickel and Teflon that conducts electrons at room temperature and switches to an insulator at an elevated temperature, thus interrupting current flow to prevent thermal runaway caused by internal short circuits. The material is placed within the cell, as a thin layer incorporated within the anode and/or the cathode, to control excess currents from metal-to-metal or metal-to-carbon shorts that might result from cell crush or a manufacturing defect. The safety of high-rate cells is thus improved, preventing serious injury to personnel and sensitive equipment located near the battery. The use of recently available nanoscale particles of nickel and Teflon permits an improved, homogeneous material with the potential to be fine-tuned to a unique switch temperature, sufficiently below the onset of a catastrophic chemical reaction. The smaller particles also permit the formation of a thinner control film layer (switch (CTS(TradeMark)) coating can be incorporated in either the anode or cathode or both. The coating can be applied in a variety of different processes that permits incorporation in the cell and electrode manufacturing processes. The CTS responds quickly

  2. Research Progress on Multimode Interference Switches

    GAO Qing; SHENG Zhi-rui; JIANG Xiao-qing; WANG Ming-hua


    Optical switches are key components for constructing optical communication networks, so it is necessary to design optical switches and optical switch arrays with high performance and low cost. As one type of optical switches, the multimode interference(MMI) switches have received considerable attention due to their unique merits. The structures and operation principles of various types of MMI switches are introduced,and the recent progresses of MMI switches are also discussed.


    马运东; 阮新波; 严仰光


    The application areas of conventional push-pull converters are limited because of high voltage stress of switches (twice of input voltage). This paper presents a novel zero-voltage and zero-current-switching (ZCS) PWM push-pull three-level converter in which the voltage stress of switches is input voltage. With phase-shifted modulation strategy, the leading switches can only realize zero-voltage-switching (ZVS), and the lagging switches can realize ZCS when block capacitor and block diodes are added. Using the strategy, the converter overcomes the drawbacks presented by the conventional push-pull converter, such as magnetic aberration, large switch loss, and voltage spike on switches, so it can get higher efficiency, and a wider application area. The operating principle of the new converter is analyzed and verified on a 600 W, 50 kHz experimental prototype. Several zero-voltage and zero-current-switching PWM push-pull three-level converters are proposed.%由于传统推挽直流变换器中开关管的电压应力高(输入电压的两倍),故该变换器的应用范围受到限制.本文提出了一种新型的零电压零电流开关PWM推挽三电平直流变换器,其中开关管的电压应力为输入电压.对该变换器采用移相控制,可以发现超前管只能实现零电压开关;加入阻断电容和阻断二极管可以使滞后管实现零电流开关.在这种控制方式下该变换器克服了传统推挽变换器存在的偏磁现象、开关损耗大、开关管有电压尖峰等缺点,使得其变换效率更高,有更广的应用范围.该变换器的工作原理在一个600 W,50 kHz的实验样机上得以分析和验证.最后,本文还提出了另外几种零电压零电流开关PWM推挽三电平直流变换器.

  4. Recent developments in switching theory

    Mukhopadhyay, Amar


    Electrical Science Series: Recent Developments in Switching Theory covers the progress in the study of the switching theory. The book discusses the simplified proof of Post's theorem on completeness of logic primitives; the role of feedback in combinational switching circuits; and the systematic procedure for the design of Lupanov decoding networks. The text also describes the classical results on counting theorems and their application to the classification of switching functions under different notions of equivalence, including linear and affine equivalences. The development of abstract har

  5. Software Switching for Data Acquisition

    CERN. Geneva; Malone, David


    In this talk we discuss the feasibility of replacing telecom-class routers with a topology of commodity servers acting as software switches in data acquisition. We extend the popular software switch, Open vSwitch, with a dedicated, throughput-oriented buffering mechanism. We compare the performance under heavy many-to-one congestion to typical Ethernet switches and evaluate the scalability when building larger topologies, exploiting the integration with software-defined networking technologies. Please note that David Malone will speak on behalf of Grzegorz Jereczek.

  6. Noise-induced coherent switch


    Taking the famous genetic toggle switch as an example,we numerically investigated the effect of noise on bistability.We found that extrinsic noise resulting from stochastic fluctuations in synthesis and degradation rates and from the environmental fluctuation in gene regulatory processes can induce coherent switch,and that there is an optimal noise intensity such that the noise not only can induce this switch,but also can amplify a weak input signal.In addition,we found that the intrinsic noise introduced through the Poisson τ-leap algorithm cannot induce such a switch.

  7. Low power all optical switches

    Alireza Bananej; LI Chun-fei 李淳飞


    In this paper, we propose a new design of all fiber optical switches by using a high finesse ring resonator (RR) side coupled Mach-Zehnder interferometer. We will show that by compensating the total loss in the RR the switching power can be decreased greatly and by loss, compensating the bistability effect in RR can be cancelled and the switching performance can be improved. In addition, we will show that by using Erbium doped fiber for fabricating the RR we can obtain switching power threshold in mW range.

  8. Neuromorphic atomic switch networks.

    Audrius V Avizienis

    Full Text Available Efforts to emulate the formidable information processing capabilities of the brain through neuromorphic engineering have been bolstered by recent progress in the fabrication of nonlinear, nanoscale circuit elements that exhibit synapse-like operational characteristics. However, conventional fabrication techniques are unable to efficiently generate structures with the highly complex interconnectivity found in biological neuronal networks. Here we demonstrate the physical realization of a self-assembled neuromorphic device which implements basic concepts of systems neuroscience through a hardware-based platform comprised of over a billion interconnected atomic-switch inorganic synapses embedded in a complex network of silver nanowires. Observations of network activation and passive harmonic generation demonstrate a collective response to input stimulus in agreement with recent theoretical predictions. Further, emergent behaviors unique to the complex network of atomic switches and akin to brain function are observed, namely spatially distributed memory, recurrent dynamics and the activation of feedforward subnetworks. These devices display the functional characteristics required for implementing unconventional, biologically and neurally inspired computational methodologies in a synthetic experimental system.

  9. Data center coolant switch

    Iyengar, Madhusudan K.; Parida, Pritish R.; Schultz, Mark D.


    A data center cooling system is operated in a first mode; it has an indoor portion wherein heat is absorbed from components in the data center, and an outdoor heat exchanger portion wherein outside air is used to cool a first heat transfer fluid (e.g., water) present in at least the outdoor heat exchanger portion of the cooling system during the first mode. The first heat transfer fluid is a relatively high performance heat transfer fluid (as compared to the second fluid), and has a first heat transfer fluid freezing point. A determination is made that an appropriate time has been reached to switch from the first mode to a second mode. Based on this determination, the outdoor heat exchanger portion of the data cooling system is switched to a second heat transfer fluid, which is a relatively low performance heat transfer fluid, as compared to the first heat transfer fluid. It has a second heat transfer fluid freezing point lower than the first heat transfer fluid freezing point, and the second heat transfer fluid freezing point is sufficiently low to operate without freezing when the outdoor air temperature drops below a first predetermined relationship with the first heat transfer fluid freezing point.

  10. Tuning the temperature dependence for switching in dithienylethene photochromic switches.

    Kudernac, Tibor; Kobayashi, Takao; Uyama, Ayaka; Uchida, Kingo; Nakamura, Shinichiro; Feringa, Ben L


    Diarylethene photochromic switches use light to drive structural changes through reversible electrocyclization reactions. High efficiency in dynamic photoswitching is a prerequisite for applications, as is thermal stability and the selective addressability of both isomers ring-opened and -closed diarylethenes. These properties can be optimized readily through rational variation in molecular structure. The efficiency with regard to switching as a function of structural variation is much less understood, with the exception of geometric requirements placed on the reacting atoms. Ultimately, increasing the quantum efficiency of photochemical switching in diarylethenes requires a detailed understanding of the excited-state potential energy surface(s) and the mechanisms involved in switching. Through studies of the temperature dependence, photoswitching and theoretical studies demonstrate the occurrence or absence of thermal activation barriers in three constitutional isomers that bear distinct π-conjugated systems. We found that a decrease in the thermal barriers correlates with an increase in switching efficiency. The origin of the barriers is assigned to the decrease in π-conjugation that is concomitant with the progress of the photoreaction. Furthermore, we show that balanced molecular design can minimize the change in the extent of π-conjugation during switching and lead to optimal bidirectional switching efficiencies. Our findings hold implications for future structural design of diarylethene photochromic switches.

  11. Research on Torque Ripple of Non-Commutation State in Brushless De Motor Affected by Different Types of PWM%调制方式对无刷直流电动机非换相状态转矩脉动的影响

    潘前华; 危韧勇


    The torque ripple caused by diode freewheeling of the inactive phase during non-commutation state of PM brushless DC motor (BLDCM) when using the PWM_ON type of pulse width modulation was analyzed. And the characteris-tics of PWM_ON_PWM type of pulse width modulation was also discussed. Simulation with Matlab indicates that PWM_ON _PWM type is better than other traditional types of PWM in reducing torque ripple during non-commutation state of BLD-CM.%分析了传统的FWM_ON调制方式对无刷直流电动机在非换相期间由于截止相的反并联二极管续流而导致转矩脉动的原因.还分析了PWM_ON_PWM调制方式的运行特性.Matlab仿真表明此种调制方式应用在无刷直流电动机非换相转矩脉动抑制上比传统调制方式具有更好的效果.

  12. A continuous switching model for piezoelectric state switching methods

    Lopp, Garrett K.; Kauffman, Jeffrey L.


    Piezoelectric-based, semi-active vibration reduction approaches have been studied for over a decade due to their potential in controlling vibration over a large frequency range. Previous studies have relied on a discrete model when switching between the stiffness states of the system. In such a modeling approach, the energy dissipation of the stored potential energy and the transient dynamics, in general, are not well understood. In this paper, a switching model is presented using a variable capacitance in the attached shunt circuit. When the switch duration is small in comparison to the period of vibration, the vibration reduction performance approaches that of the discrete model with an instantaneous switch, whereas longer switch durations lead to less vibration reduction. An energy analysis is then performed that results in the appearance of an energy dissipation term due to the varying capacitance in the shunt circuit.

  13. Hybrid switch for resonant power converters

    Lai, Jih-Sheng; Yu, Wensong


    A hybrid switch comprising two semiconductor switches connected in parallel but having different voltage drop characteristics as a function of current facilitates attainment of zero voltage switching and reduces conduction losses to complement reduction of switching losses achieved through zero voltage switching in power converters such as high-current inverters.

  14. EDITORIAL: Molecular switches at surfaces Molecular switches at surfaces

    Weinelt, Martin; von Oppen, Felix


    In nature, molecules exploit interaction with their environment to realize complex functionalities on the nanometer length scale. Physical, chemical and/or biological specificity is frequently achieved by the switching of molecules between microscopically different states. Paradigmatic examples are the energy production in proton pumps of bacteria or the signal conversion in human vision, which rely on switching molecules between different configurations or conformations by external stimuli. The remarkable reproducibility and unparalleled fatigue resistance of these natural processes makes it highly desirable to emulate nature and develop artificial systems with molecular functionalities. A promising avenue towards this goal is to anchor the molecular switches at surfaces, offering new pathways to control their functional properties, to apply electrical contacts, or to integrate switches into larger systems. Anchoring at surfaces allows one to access the full range from individual molecular switches to self-assembled monolayers of well-defined geometry and to customize the coupling between molecules and substrate or between adsorbed molecules. Progress in this field requires both synthesis and preparation of appropriate molecular systems and control over suitable external stimuli, such as light, heat, or electrical currents. To optimize switching and generate function, it is essential to unravel the geometric structure, the electronic properties and the dynamic interactions of the molecular switches on surfaces. This special section, Molecular Switches at Surfaces, collects 17 contributions describing different aspects of this research field. They analyze elementary processes, both in single molecules and in ensembles of molecules, which involve molecular switching and concomitant changes of optical, electronic, or magnetic properties. Two topical reviews summarize the current status, including both challenges and achievements in the field of molecular switches on

  15. A CMOS Switched Transconductor Mixer

    Klumperink, Eric A.M.; Louwsma, S.M.; Wienk, Gerhardus J.M.; Nauta, Bram

    A new CMOS active mixer topology can operate at low supply voltages by the use of switches exclusively connected to the supply voltages. Such switches require less voltage headroom and avoid gate-oxide reliability problems. Mixing is achieved by exploiting two transconductors with cross-coupled

  16. Seidel Switching and Graph Energy

    Haemers, W.H.


    Abstract: The energy of a graph Γ is the sum of the absolute values of the eigenvalues of the adjacency matrix of Γ. Seidel switching is an operation on the edge set of Γ. In some special cases Seidel switching does not change the spectrum, and therefore the energy. Here we investigate when Seidel s

  17. Molecule-Based Rheology Switching

    Paulusse, Jos M.J.; Sijbesma, Rint P.


    Sound-activated switching: The rheological behavior of fluids can be affected by external stimuli, as demonstrated by electrochemically and photochemically induced changes in viscosity and sol–gel transitions. Recently, ultrasound has emerged as a novel rheology switch for supramolecular polymers an

  18. Improved switch-resistor packaging

    Redmerski, R. E.


    Packaging approach makes resistors more accessible and easily identified with specific switches. Failures are repaired more quickly because of improved accessibility. Typical board includes one resistor that acts as circuit breaker, and others are positioned so that their values can be easily measured when switch is operated. Approach saves weight by using less wire and saves valuable panel space.

  19. Battery switch for downhole tools

    Boling, Brian E.


    An electrical circuit for a downhole tool may include a battery, a load electrically connected to the battery, and at least one switch electrically connected in series with the battery and to the load. The at least one switch may be configured to close when a tool temperature exceeds a selected temperature.

  20. Optimized scalable network switch

    Blumrich, Matthias A.; Chen, Dong; Coteus, Paul W.


    In a massively parallel computing system having a plurality of nodes configured in m multi-dimensions, each node including a computing device, a method for routing packets towards their destination nodes is provided which includes generating at least one of a 2m plurality of compact bit vectors containing information derived from downstream nodes. A multilevel arbitration process in which downstream information stored in the compact vectors, such as link status information and fullness of downstream buffers, is used to determine a preferred direction and virtual channel for packet transmission. Preferred direction ranges are encoded and virtual channels are selected by examining the plurality of compact bit vectors. This dynamic routing method eliminates the necessity of routing tables, thus enhancing scalability of the switch.

  1. Amorphous metal based nanoelectromechanical switch

    Mayet, Abdulilah M.


    Nanoelectromechanical (NEM) switch is an interesting ultra-low power option which can operate in the harsh environment and can be a complementary element in complex digital circuitry. Although significant advancement is happening in this field, report on ultra-low voltage (pull-in) switch which offers high switching speed and area efficiency is yet to be made. One key challenge to achieve such characteristics is to fabricate nano-scale switches with amorphous metal so the shape and dimensional integrity are maintained to achieve the desired performance. Therefore, we report a tungsten alloy based amorphous metal with fabrication process development of laterally actuated dual gated NEM switches with 100 nm width and 200 nm air-gap to result in <5 volts of actuation voltage (Vpull-in). © 2013 IEEE.

  2. Static spray deposition distribution characteristics of PWM-based intermittently spraying system%脉宽调制间歇喷雾变量喷施系统的静态雾量分布特性

    魏新华; 于达志; 白敬; 蒋杉


    Owing to its intermittently spraying characteristics, spray deposition distribution uniformity of PWM-based variable rate application system is hard to control. A PWM-based variable rate application testing system was constructed by integration of a modified commercial boom sprayer and an IPC-based measurement and control system to study its static deposition distribution characteristics. The sprayer consisted of a fluid tank, a filter, a diaphragm pump, a proportional relief valve, 12 high speed on-off solenoid valves, 12 TR80-05 hollow-cone nozzles and various pipelines, mounted on a tractor, and was driven by the tractor via its power take-off shaft. The IPC-based measurement and control system was composed of a pressure sensor, 4 flow sensors, a signal conditioning module, an IPC, an analog input data acquisition card、a PWM signal output card、an analog output card, and 2 driving modules. Real-time monitoring of subgroup flow and boom pressure, feedback stable control of average boom pressure, setting of the average boom pressure, and setting of frequency and duty cycle of the PWM signal were performed by the measurement and control software which was developed with Labview. Droplets were collected with a matrix-styled droplet collection device, it had a horizontal collection dimention of 1000 mm×1000 mm and was divided evenly into 20×20 grids. Putting a paper cup in each grid, weighting the cups before and after each spraying test, droplet deposition of each grid could be deduced, and two-dimentional deposition distribution was obtained. Static deposition distributions of the PWM controlled nozzle were tested under various spray conditions of different spray pressures, different frequencies and duty cycles of PWM signal with the tractor holding still and the tested nozzle 0.5 m distance above the droplet collection area. And nonlinear regression analyses were performed on static deposition distribution specimens acquired under spray conditions of 0.3MPa

  3. grammatical constraints on intrasentential code switching


    characterise another approach to code switching, namely a Minimalist ... la Virgen (God and the Virgin willing), as well as code switching involving set phrases .... switching is possible where the placement of adjectives and nouns obey both ...

  4. 三电平空间矢量与载波调制策略统一理论的研究%Research of the Unity Theory Between Three-level Space Vector and Carrier-based PWM Modulation Strategy

    陈娟; 何英杰; 王新宇; 刘进军


    There is an inherent correlation between the carrier-based PWM and SVPWM in two level inverters.Some researchers have proved that this inherent relationship also exists between those two modulation strategies in three level inverters.In the former researches,the unity correlation was focused on the traditional 8 segments SVPWM switching sequences,but it couldn't be applied to some switching sequences more than 8 segments obtained by using redundancy vectors in the practical SVPWM modulation strategy.So far,seldom researchers have the unity test of SVPWM and SPWM under these conditions,so the existing unity theory between SVPWM and SPWM contains some shortage.In this paper,a technique of decomposing the original modulation wave into two sub-modulation waves has been proposed which is utilized to discuss the unity relations between SPWM and SVPWM with more than 8 segments.The strict theoretical derivation and simulation result effectively evolves the unity theory of SPWM and SVPWM successfully.%两电平空间矢量脉宽调制(space vector pulse width modulation,SVPWM)与正弦脉宽调制(sinusoidal pulse width modulation,SPWM)存有一定的本质关系,对于三电平,在常见的8段式SVPWM序列中可以证明,SVPWM与SPWM本质上也存在某种统一.实际的SVPWM调制中,由于要考虑中点电压平衡、减少谐波等其它性能问题,一般会利用开关冗余状态得到8段以上的开关调制序列.目前的文献中还未曾有对这些情况进行统一性地验证,因此三电平SVPWM与SPWM的统一理论存在一定的不足.研究发现,可通过严格地理论推导将传统意义上的调制波分解为2个子调制波,再进行SPWM调制,可以得到与SVPWM完全吻合的序列.该文在此方法基础上深入研究了8段以上(10、12、14段)的SVPWM调制序列与SPWM的统一.经过严格地理论推导,成功实现了含任意段数的SVPWM序列与SPWM的统一.仿真结果证明了该理论的正确性.

  5. Keep flexible - Keep switching! The influence of forced task switching on voluntary task switching.

    Fröber, Kerstin; Dreisbach, Gesine


    Goal directed behavior depends on a dynamic balance between cognitive flexibility and stability. Identifying factors that modulate the balance between these control states is therefore of major interest for the understanding of human action control. In two experiments we used a hybrid paradigm combining forced- and free-choice task switching and measured spontaneous voluntary switch rate (VSR) as an indicator of cognitive flexibility. In Experiment 1 participants were free to choose a given task on 75%, 50%, or 25% of all trials. In the remaining forced-choice trials task repetitions and switches were roughly equally distributed. Results showed that VSR increases with increasing proportion of forced choices. To clarify whether the frequency of forced choices per se or the frequency of forced task switches in particular drives this effect we conducted Experiment 2. In a fully orthogonal between design participants were free to choose a given task on 75% or 25% of all trials with a predetermined switch rate in the remaining forced-choice trials of 75% or 25%, respectively. Results revealed an interaction of both manipulations: The highest VSR was found for the combination of 75% forced-choice trials with 75% forced switch rate, while VSR for 75% forced-choice trials with 25% forced switch rate was still higher than VSRs in both conditions with 25% forced-choice trials. This suggests that a context of frequent forced task switching changes global control parameters towards more flexible behavior. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Model Reduction of Switched Systems Based on Switching Generalized Gramians

    Shaker, Hamid Reza; Wisniewski, Rafal


    In this paper, a general method for model order reduction of discrete-time switched linear systems is presented. The proposed technique uses switching generalized gramians. It is shown that several classical reduction methods can be developed into the generalized gramian framework for the model r......-Galerkin projection is constructed instead of the similarity transform approach for reduction. It is proven that the proposed reduction framework preserves the stability of the original switched system. The performance of the method is illustrated by numerical examples....

  7. An Induction Motor Drive System Based on the Back-To-Back Connection of Two Five-Level Diode-Clamped PWM Converters

    Kondo, Yosuke; Natchpong, Hatti; Akagi, Hirofumi

    This paper discusses a 6.6-kV transformerless motor drive system based on the back-to-back connection of two five-level diode-clamped PWM converters. In addition, this paper designs, constructs and experimentally tests a down-scaled model rated at 200V and 5.5kW. This system consist of the two five-level converters, a common dc-link, and voltage-balancing circuits using two bi-directional buck-boost choppers. Experimental results obtained from the down-scaled model verify the validity of the system design, giving promise of the viability of the 6.6-kV transformerless motor drive system.

  8. PWM脉宽调制实现电机的恒速驱动%The Driver of Constant Speed Motor Based on PWM Pulse Width Modulation



    现在许多单片机具有PWM脉宽调制功能,结合单片机的定时器、计数器,我们可以很方便的实现电机的恒速驱动。本文以编码器为反馈信号,构成了电机恒速转动的闭环系统。%Now many Single Chip Microcomputer with PWM pulse width modulation,combined with Single Chip Microcomputer timer and counter,we can easily achieve the constant speed drive motor.In this paper,encoder acts as feedback signal,constitutes a constant speed motor rotating closed-loop system.

  9. Approaches to Suppressing Shaft Voltage in Brushless DC Motor Driven by PWM Inverter Based on Ungrounded Common-Mode Equivalent Circuit

    Maetani, Tatsuo; Isomura, Yoshinori; Watanabe, Akihiko; Iimori, Kenichi; Morimoto, Shigeo

    This paper describes an ungrounded common-mode equivalent circuit for a motor driven by a voltage-source PWM inverter. When the capacitance of the rotor was is small, the reversal of the polarities of the common-mode voltage and shaft voltage is observed. In order to model this reversal, a bridge-type equivalent circuit is proposed. On the basis of calculations and experiment, it is found the values and polarity of the shaft voltage can be are accurately determined with the proposed equivalent circuit. Furthermore, the capacitance value of the insulated rotor required to make the shaft voltage equal to or less than the dielectric breakdown voltage of the bearing grease is obtained.

  10. Rectify output of PWM power amplifier transmitted through long cable%PWM型功率放大器长线传输波形整型

    王刚; 柳秋兴; 宋晓明; 柳井莉


    为解决PWM功率放大器输出长线传输引发的波形畸变,可能伤及力矩电动机的问题,对实际系统结构进行了理论分析,找出了可能引发波形畸变的原因,并给出了3种解决方法.实际试验结果证实所给方法的有效性.%When transmitted through long cable, the output of PWM power amplifier may be distorted. The distorted wave may damage torque motor. By analyzing system at work, the factors caused distortion are found, and three solutions are presented. Experiment result shows that these solutions are valid.

  11. Simulation and experimental control of a 3-RPR parallel robot using optimal fuzzy controller and fast on/off solenoid valves based on the PWM wave.

    Moezi, Seyed Alireza; Rafeeyan, Mansour; Zakeri, Ehsan; Zare, Amin


    In this paper, a robust optimal fuzzy controller based on the Pulse Width Modulation (PWM) technique is proposed to control a laboratory parallel robot using inexpensive on/off solenoid valves. The controller coefficients are determined using Modified Cuckoo Optimization Algorithm. The objective function of this method is considered such that the results show the position tracking by the robot with less force and more efficiency. Regarding the results of experimental tests, the control strategy with on/off valves indicates good performance such that the maximum value of RMS of error for a circular path with increasing force on the system is 3.1mm. Furthermore, the results show the superiority of the optimal fuzzy controller compared with optimal PID controller in tracking paths with different conditions and uncertainties.

  12. 基于脉冲宽度调制技术的超声波测风系统研究%Ultrasonic Anemometer System Based on PWM Techniques

    吴宗玲; 闫连山; 曾德兵; 陈娟子


    The ultrasonic anemometer system design based on time-difference-method was presented, and the ways to improve the arriving time of ultrasonic signals were analyzed and that to achieve ultrasonic driving signal basing upon pulse width modulation ( PWM) proposed. Having the schemes with or without modulation techniques compared shows that the driving pulse with modulation techniques can greatly benefit the right judgment of the arriving time of the ultrasonic echo signal, the designed ultrasonic pulse driving scheme provides the good reference for the ultrasonic anemometer based on time-difference-method.%给出了时差法超声波测风系统的总体设计,分析了几种改善超声波信号到达时刻的方法.重点提出了一种基于脉冲宽度调制技术( PWM)的超声波驱动信号的具体实现方法.同时对采用和不采用调制技术两种方案进行了详细的对比分析,结果表明采用调制技术的驱动脉冲更有利于正确判决超声波回波信号的到达时刻.所设计的超声波脉冲驱动方案对基于时差法的超声波风速仪具有重要的参考价值.

  13. Dual PWM Wind Power Grid System Based on DSP%基于DSP双PWM风力发电并网系统的研究

    吕振; 孟祥海; 林振杨; 高爽


    The double PWM wind power grid systems theory was analyzed. The basic theory of the wind power generator system was elaborated based on DSP TMS320LF2407, while the system machine-side converter and the network-side converter were analyzed. And by controlling the inverter output, the parallel running with the grid is realized under the premise of ensuring the quality of the output power. And to ensure that the harmonic content fed into the grid should be as small as possible while still meet the power requirements. Finally, the whole system was verified by experiment, experiment results show that the dual PWM wind power grid system has good stability and reliability.%详细分析了风力发电双PWM并网系统的原理,阐述了基于DSP TMS320LF2407风力发电并网系统的基本理论,同时对系统的机侧变流器和网侧变流器进行了分析,并通过控制逆变器的输出,在保证输出电能质量的前提下实现与电网的并行运行;并且保证馈入电网的谐波含量要尽可能小的同时还要符合功率要求.最后,对整个系统进行了实验验证,实验结果表明,双PWM风力发电并网系统具有良好的稳定性和可靠性.

  14. PWM的整流器无交流电压传感器控制%Vector Control of PWM Rectifier without AC Voltage sensors



      针对采用虚拟磁链定向控制策略的PWM整流器无交流电压传感器控制中存在的由积分环节带来的一系列问题,将滑模观测器(SMO)应用于估测电网电压角度,利用饱和函数代替传统滑模观测器中的符号函数以削弱系统抖振,并对比分析了两种情况下等效控制信号的频谱图,仿真和实验结果表明,基于滑模观测器的PWM整流器具有良好的动静态响应和输入输出特性,验证了所提出的无交流电压传感器控制策略的有效性和准确性。%  To solve the problems caused by integer which were used in virtual flux oriented control of PWM rec⁃tifier without AC voltage sensors, a sliding mode observer (SMO) was designed to estimate grid voltage angle. This paper analyzes the principle, designs steps of SMO .and uses saturated function instead of symbols function in traditional sliding mode observer to weaken the system chattering. The paper also analyzes the equivalent con⁃trol signal spectrum diagram in the two cases. Simulation and experimental results show that PWM rectifier has a good dynamic/static response and input/output characteristics and verifies the validity and feasibility of the pro⁃posed AC voltage sensorless control strategy.

  15. 高频变压器


    Double two switch forward soft switching PWM DC-DC converter, Double two-switch forward transformer linked soft-switching PWM DC-DC power converter using IGBTs,Experimental Determination of Stray Capacitances in High Frequency Transformers,Full Bridge Soft-Switching Phase-Shifted PWM DC-DC Converter using Tapped Inductor Filter

  16. A novel passive soft switch converter%新型无源软开关变换器

    胡浩; 闫英敏; 陈永利


    普通的PWM变换器具有结构简洁、控制简单、频率恒定、输出特性好等优点,故广泛应用于社会生活的各个领域中.本文以boost基本电路为基础,采用简单的无源谐振网络,设计实现了开关管的软开关.这种新型的无源软开关解决了输出二极管反向恢复问题,具有结构简单、高频率、高效率、易于控制等优点.该设计可用于以IGBT为开关器件的高压场合.分析了该变换器的工作原理、实现条件、设计谐振网络的参数、并进行了仿真.%Ordinary PWM converters have advantages of concise structure, simple control, constant frequency, perfect output characteristics, so it is widely used in the fields of social life. The converter based on the basic boost circuit, simple passive resonant network, designed and realized the soft switch of the switch tube. The improved passive soft switch solved the problem of output diode reverse recovery and has simple structure, high frequency and high efficiency. This design can be used for switching device with IGBT in high-pressure occasion. The operational principle of the converter and realizing condition is analyzed, design parameters of resonant network, and simulate itself.

  17. Adaptive switching frequency buck DC—DC converter with high-accuracy on-chip current sensor

    Jinguang, Jiang; Fei, Huang; Zhihui, Xiong


    A current-mode PWM buck DC—DC converter is proposed. With the high-accuracy on-chip current sensor, the switching frequency can be selected automatically according to load requirements. This method improves efficiency and obtains an excellent transient response. The high accuracy of the current sensor is achieved by a simple switch technique without an amplifier. This has the direct benefit of reducing power dissipation and die size. Additionally, a novel soft-start circuit is presented to avoid the inrush current at the starting up state. Finally, this DC—DC converter is fabricated with the 0.5 μm standard CMOS process. The chip occupies 3.38 mm2. The accuracy of the proposed current sensor can achieve 99.5% @ 200 mA. Experimental results show that the peak efficiency is 91.8%. The input voltage ranges from 5 to 18 V, while a 2 A load current can be obtained. Project supported by the National Natural Science Foundation of China (No. 41274047), the Natural Science Foundation of Jiangsu Province (No. BK2012639), the Science and Technology Enterprises in Jiangsu Province Technology Innovation Fund (No. BC2012121), and the Changzhou Science and Technology Support (Industrial) Project (No. CE20120074).

  18. Three-Phase High-Power and Zero-Current-Switching OBC for Plug-In Electric Vehicles

    Cheng-Shan Wang


    Full Text Available In this paper, an interleaved high-power zero-current-switching (ZCS onboard charger (OBC based on the three-phase single-switch buck rectifier is proposed for application to plug-in electric vehicles (EVs. The multi-resonant structure is used to achieve high efficiency and high power density, which are necessary to reduce the volume and weight of the OBC. This study focuses on the border conditions of ZCS converting with a battery load, which means the variation ranges of the output voltage and current are very large. Furthermore, a novel hybrid control method combining pulse frequency modulation (PFM and pulse width modulation (PWM together is presented to ensure a driving frequency higher than 10 kHz, and this will reduce the unexpected inner resonant power flow and decrease the total harmonic distortion (THD of the input current under a light load at the end of the charging process. Finally, a prototype is established, and experiments are carried out. According to the experimental results, the conversion efficiency is higher than 93.5%, the THD about 4.3% and power factor (PF 0.98 under the maximum power output condition. Besides, a three-stage charging process is also carried out the experimental platform.

  19. Tuning the Temperature Dependence for Switching in Dithienylethene Photochromic Switches

    Kudernac, Tibor; Kobayashi, Takao; Uyama, Ayaka; Uchida, Kingo; Nakamura, Shinichiro; Feringa, Ben L.


    Diarylethene photochromic switches use light to drive structural changes through reversible electrocyclization reactions. High efficiency in dynamic photoswitching is a prerequisite for applications, as is thermal stability and the selective addressability of both isomers ring-opened and -closed dia

  20. Switching Processes in Queueing Models

    Anisimov, Vladimir V


    Switching processes, invented by the author in 1977, is the main tool used in the investigation of traffic problems from automotive to telecommunications. The title provides a new approach to low traffic problems based on the analysis of flows of rare events and queuing models. In the case of fast switching, averaging principle and diffusion approximation results are proved and applied to the investigation of transient phenomena for wide classes of overloading queuing networks.  The book is devoted to developing the asymptotic theory for the class of switching queuing models which covers  mode

  1. DC Injection Elimination Using Modified Resonant Controller in Unipolar Switched Transformerless H-Bridge PV Inverter

    Anjali Varghese C


    Full Text Available The necessity of efficient topologies for photovoltaic (PV inverters is a concern presently. With the advent of transformerless inverters, the size, volume and cost of PV inverters can be decreased. Efficiency can be increased nearly by 2% by avoiding the galvanic connection. With no galvanic isolation comes the problem of dc injection which pauses serious problems to core saturation of distribution transformers and cable corrosion and has to be limited as per IEEE, IEC standards. This paper presents a proportional resonant controller and is used along with a modelled series capacitance to limit DC injection. This avoids the use of a real capacitor in the output of the inverter used conventionally toprevent dc injection and hence overcomes the drawbacks of series voltage drops and reverse polarity effects. The topology of inverter chosen is the H-Bridge and switching scheme used is unipolar PWMconsidering the advantages of the same . A comparison of the dc injection values with and without the controller is presented for unipolar pulse width modulated (PWM inverters.

  2. Electrically switched ion exchange

    Lilga, M.A. [Pacific Northwest National Lab., Richland, WA (United States); Schwartz, D.T.; Genders, D.


    A variety of waste types containing radioactive {sup 137}Cs are found throughout the DOE complex. These waste types include water in reactor cooling basins, radioactive high-level waste (HLW) in underground storage tanks, and groundwater. Safety and regulatory requirements and economics require the removal of radiocesium before these wastes can be permanently disposed of. Electrically Switched Ion Exchange (ESIX) is an approach for radioactive cesium separation that combines IX and electrochemistry to provide a selective, reversible, and economic separation method that also produces little or no secondary waste. In the ESIX process, an electroactive IX film is deposited electrochemically onto a high-surface area electrode, and ion uptake and elution are controlled directly by modulating the potential of the film. For cesium, the electroactive films under investigation are ferrocyanides, which are well known to have high selectivities for cesium in concentrated sodium solutions. When a cathode potential is applied to the film, Fe{sup +3} is reduced to the Fe{sup +2} state, and a cation must be intercalated into the film to maintain charge neutrality (i.e., Cs{sup +} is loaded). Conversely, if an anodic potential is applied, a cation must be released from the film (i.e., Cs{sup +} is unloaded). Therefore, to load the film with cesium, the film is simply reduced; to unload cesium, the film is oxidized.

  3. Wide Bandgap Extrinsic Photoconductive Switches

    Sullivan, James S. [State Univ. of New York (SUNY), Plattsburgh, NY (United States); Univ. of California, Davis, CA (United States)


    Photoconductive semiconductor switches (PCSS) have been investigated since the late 1970s. Some devices have been developed that withstand tens of kilovolts and others that switch hundreds of amperes. However, no single device has been developed that can reliably withstand both high voltage and switch high current. Yet, photoconductive switches still hold the promise of reliable high voltage and high current operation with subnanosecond risetimes. Particularly since good quality, bulk, single crystal, wide bandgap semiconductor materials have recently become available. In this chapter we will review the basic operation of PCSS devices, status of PCSS devices and properties of the wide bandgap semiconductors 4H-SiC, 6H-SiC and 2H-GaN.

  4. Industry switching in developing countries

    Newman, Carol; Rand, John; Tarp, Finn


    established entrants and exiting firms that are closing down operations. In this study, we develop an empirical model that examines switching behavior using data from Vietnamese manufacturing firms during the 2001–2008 period. The diagnostic shows that switching firms exhibit different characteristics......Firm turnover (i.e., firm entry and exit) is a well-recognized source of sector-level productivity growth. In contrast, the role and importance of firms that switch activities from one sector to another is not well understood. Firm switchers are likely to be unique, differing from both newly...... and behavior than do entry and exit firms. Switchers tend to be labor intensive and to seek competitive opportunities in labor-intensive sectors in response to changes in market environments. Moreover, resource reallocation resulting from switching forms an important component of productivity growth. The topic...

  5. A Piezoelectric Cryogenic Heat Switch

    Jahromi, Amir E.; Sullivan, Dan F.


    We have measured the thermal conductance of a mechanical heat switch actuated by a piezoelectric positioner, the PZHS (PieZo electric Heat Switch), at cryogenic temperatures. The thermal conductance of the PZHS was measured between 4 K and 10 K, and on/off conductance ratios greater than 100 were achieved when the positioner applied its maximum force of 8 N. We discuss the advantages of using this system in cryogenic applications, and estimate the ultimate performance of an optimized PZHS.

  6. High PRF high current switch

    Moran, Stuart L.; Hutcherson, R. Kenneth


    A triggerable, high voltage, high current, spark gap switch for use in pu power systems. The device comprises a pair of electrodes in a high pressure hydrogen environment that is triggered by introducing an arc between one electrode and a trigger pin. Unusually high repetition rates may be obtained by undervolting the switch, i.e., operating the trigger at voltages much below the self-breakdown voltage of the device.

  7. Magnetically insulated opening switch research

    McGeoch, M. W.; Kraft, R.


    We examine the feasibility of an opening switch concept based on magnetic insulation in a coaxial thermionic diode. It is found that the impedance ratio between closed and open states of the diode is marginal for efficient energy transfer via this type of switch. The open, or insulated state of the diode is characterized by current leakage across the magnetic field which is associated with the presence of plasma waves.

  8. K-Band Latching Switches

    Piotrowski, W. S.; Raue, J. E.


    Design, development, and tests are described for two single-pole-double-throw latching waveguide ferrite switches: a K-band switch in WR-42 waveguide and a Ka-band switch in WR-28 waveguide. Both switches have structurally simple junctions, mechanically interlocked without the use of bonding materials; they are impervious to the effects of thermal, shock, and vibration stresses. Ferrite material for the Ka-band switch with a proper combination of magnetic and dielectric properties was available and resulted in excellent low loss, wideband performance. The high power handling requirement of the K-band switch limited the choice of ferrite to nickel-zinc compositions with adequate magnetic properties, but with too low relative dielectric constant. The relative dielectric constant determines the junction dimensions for given frequency responses. In this case the too low value unavoidably leads to a larger than optimum junction volume, increasing the insertion loss and restricting the operating bandwidth. Efforts to overcome the materials-related difficulties through the design of a composite junction with increased effective dielectric properties efforts to modify the relative dielectric constant of nickel-zinc ferrite are examined.

  9. K-band latching switches

    Piotrowski, W. S.; Raue, J. E.


    Design, development, and tests are described for two single-pole-double-throw latching waveguide ferrite switches: a K-band switch in WR-42 waveguide and a Ka-band switch in WR-28 waveguide. Both switches have structurally simple junctions, mechanically interlocked without the use of bonding materials; they are impervious to the effects of thermal, shock, and vibration stresses. Ferrite material for the Ka-band switch with a proper combination of magnetic and dielectric properties was available and resulted in excellent low loss, wideband performance. The high power handling requirement of the K-band switch limited the choice of ferrite to nickel-zinc compositions with adequate magnetic properties, but with too low relative dielectric constant. The relative dielectric constant determines the junction dimensions for given frequency responses. In this case the too low value unavoidably leads to a larger than optimum junction volume, increasing the insertion loss and restricting the operating bandwidth. Efforts to overcome the materials-related difficulties through the design of a composite junction with increased effective dielectric properties efforts to modify the relative dielectric constant of nickel-zinc ferrite are examined.

  10. Quadratic stabilization of switched nonlinear systems

    DONG YaLi; FAN JiaoJiao; MEI ShengWei


    In this paper, the problem of quadratic stabilization of multi-input multi-output switched nonlinear systems under an arbitrary switching law is investigated. When switched nonlinear systems have uniform normal form and the zero dynamics of uniform normal form is asymptotically stable under an arbitrary switching law, state feedbacks are designed and a common quadratic Lyapunov function of all the closed-loop subsystems is constructed to realize quadratic stabilizability of the class of switched nonlinear systems under an arbitrary switching law. The results of this paper are also applied to switched linear systems.

  11. Switching at the nanoscale: chiroptical molecular switches and motors. : Section Title: Optical, Electron, and Mass Spectroscopy and Other Related Properties

    Browne, Wesley R.; Pijper, Dirk; Pollard, Michael M.; Feringa, Bernard; Amabilino, David B.


    A review on the recent developments in the field of chiroptical switches and nanomotors. Topics discussed include switching of mol. state, azobenzene-based chiroptical photoswitching, electrochiroptical switching, diarylethene-based chiroptical switches, mol. switching with circularly polarized

  12. A Novel Technique on Simulation of A Space Vector PWM Controller for a Three Level Inverter FED Induction Motor

    S. Radha Krishna Reddy


    Full Text Available Multilevel inverters are increasingly being used in high-power medium voltage applications due to their superior performance compared to two-level inverters. Among various modulation techniques for a multilevel inverter, the space vector pulse width modulation (SVPWM is widely used. This paper deals with the three-phase three-level inverter fed induction motor drive. The proposed scheme deals with the development and implementation of three phase three level inverter to improve the efficiency and reliability of the inverter. Simulation tests have been carried out to examine the operating characteristics of the completed three-phase three-level inverter driving induction motor and an RL load with different switching devices and are compared

  13. Principles of broadband switching and networking

    Liew, Soung C


    An authoritative introduction to the roles of switching and transmission in broadband integrated services networks Principles of Broadband Switching and Networking explains the design and analysis of switch architectures suitable for broadband integrated services networks, emphasizing packet-switched interconnection networks with distributed routing algorithms. The text examines the mathematical properties of these networks, rather than specific implementation technologies. Although the pedagogical explanations in this book are in the context of switches, many of the fundamenta

  14. Influence of Bipolar PWM Method on Commutation Torque Ripple of BLDCM%双极型PWM调制方式对无刷直流电机换相转矩脉动的影响

    杨新龙; 窦满峰; 张振华


    针对脉冲宽度调制方式对无刷直流电机换相过程中电磁转矩脉动影响的问题,对双极性PWM调制方式与上斩下不斩PWM调制方式进行了对比研究.理论分析表明双极性PWM调制方式可以通过消除截止相上的二极管续流现象,消除因二极管续流引起的电磁转矩脉动,仿真结果中,两者的截止相电流脉动最大分别为0.12A和0,试验结果两者的截止相最大电流脉动分别为额定电流的20%和5%,表明双极性PWM调制方式可以减小换相期间的转矩脉动.%A comparative study on bipolar PWM method and PWM-ON method for the pulse width modulation on the impact of the electromagnetic torque ripple in brushless DC motor commutation process.Theoretical analysis shows that the ripple current caused by the diode freewheeling in the non-commutation zone can be eliminated,and so the torque ripples can also be decreased by the bipolar PWM method.Simulation results between the two non-commutation phases maximum current ripple,were respectively 0.12A and 0,Test results between the two non-commutation phases maximum current ripple,were respectively 20% and 5% of the rated current,indicating that the bipolar PWM method can reduce the torque ripple during commutation.

  15. 电机控制中的16位PWM在C8051单片机中的实现%In electrical machinery control 16 PWM in C8051 monolithic integrated circuit reality

    何曦光; 阮祥发; 赵燕



  16. High power solid state switches

    Gundersen, Martin


    We have successfully produced an optically triggered thyristor based in Gallium Arsenide, developed a model for breakdown, and are developing two related devices, including a Gallium Arsenide based static inductor thyristor. We are getting at the basic limitations of Gallium Arsenide for these applications, and are developing models for the physical processes that will determine device limitations. The previously supported gas phase work - resulting in the back-lighted thyratron (BLT) - has actually resulted in a very changed view of how switching can be accomplished, and this is impacting the design of important machines. The BLT is being studied internationally: in Japan for laser fusion and laser isotope separation. ITT has built a BLT that has switched 30 kA at 60 kV in testing at NSWC Dahlgren and the device is being commercialized by another American company. Versions of the switch are now being tested for excimer laser and other applications. Basically, the switch, which arose from pulse power physics studies at USC, can switch more current faster (higher di/dt), with less housekeeping, and with other advantageous properties. There are a large number of other new applications, include kinetic energy weapons, pulsed microwave sources and R.F. accelerators.

  17. Research on PWM-based Variable Frequency Speed Control System%基于脉冲宽度调制技术的变频调速系统研究

    王建清; 吕晶; 王建平


    介绍了交流变频调速类型、基本原理和脉冲宽度调制技术,分析了基于脉冲宽度调制技术变频调速的优点以及发展趋势,并对其性能进行了探讨,研究了脉冲宽度调制技术变频调速的工作原理和性能表现,论述了其克服谐波严重危害的基本方法。%The paper introduced the types and basic principle of AC variable frequency speed control system,and PWM technique. The advantages of PWM-based variable frequency speed control technique and its application prospect were analysed. The working principle and performance of PWM-based technique were studied,and the method to overcome the hazards caused by harmonic waves was elaborated.

  18. A Novel Simulation Research on Double Closed-loop of Three-phase PWM Rectifier%一种新型双闭环三相PWM整流器的仿真研究

    雷美艳; 欧阳昌华; 朱俊杰


    采用一种基于输入输出电流解耦反馈的控制策略和PI调节方法,以三相整流器在d-q同步旋转坐标系中的模型为基础,建立电流内环和电压外环的PWM整流器简化数学模型,并且运用MATLABR2009a建立系统仿真模型,保证输出电压的稳定性。%The basic principle of three-phase PWM rectifier is introduced in this paper. A control strategies of decoupling of input and output current based on feedback and methods for regulation of PI is used, and the simplified mathematical model of the PWM rectifier of the current inner loop and outer voltage is established, which is based on the model of the d-q synchronous rotating coordinate system in three-phase rectifier, and a simulation model of the PWM rectifier, which can achieve the stability of the output voltage, is established by the MATLAB R2009a.

  19. 一种新型的双闭环三相PWM整流器仿真分析%Novel Simulation Research on Double Closed-Loop of Three-Phase PWM Rectifier

    雷美艳; 欧阳昌华; 朱俊杰


    The basic principle of three-phase PWM rectifier is introduced.The control strategies of decoupling of input and output current based on feedback and the methods of PI regulation are used,and the simplified mathematical model of the PWM rectifier of the current inner loop and outer voltage is established,which is based on the model of the d-q synchronous rotating coordinate system in three-phase rectifier.A simulation model of the PWM rectifier,which can achieve the stability of the output voltage,is established by the MATLAB R2009a.The simulation results verify that the proposed method is effective and practical.%介绍了三相PWM整流的基本原理,并以三相整流器在d-q同步旋转坐标系中的模型为基础,采用基于输入输出电流解耦反馈控制策略和PI调节方法,建立了电流内环和电压外环的PWM整流器简化数学模型.运用MatlabR2009a建立了系统仿真模型,实现了输出电压的稳定性,仿真结果验证了该方法的有效性和实用性.

  20. Design and realization of the Variable period PWM control circuit of the electro-hydraulic proportional valve%变周期PWM电液比例阀控制电路的设计与实现

    王朋; 李文魁


    This paper analyses the basic principle of PWM control the electro-hydraulic ,proportional valve. The PWM control circuit is designed based on C8051F340 single chip microcomputer. Variable period PWM signal is generated by programmed PCA module and power is amplified by darlington transistor arrays chip. The experiment shows that the circuit can be configured flexibly and fast responsible and high precision which Satisfies the demand of electro-hydraulic proportional valve control.%分析了脉冲宽度调制(PWM)控制电液比例阀的基本原理,采用C8051F340单片机设计控制电路,通过可编程计数器阵列(PCA)模块编程实现了变周期PWM信号的产生,通过达林顿晶体管阵列芯片实现功率放大。实验表明,该电路具有配置灵活、响应快、精度高等优点,满足电液比例阀控制要求。

  1. Switching Systems: Active Mode Recognition, Identification of the Switching Law

    Elom Ayih Domlan; José Ragot; Didier Maquin

    2007-01-01; International audience; The problem of the estimation of the discrete state of a switching system is studied. The knowledge of the switching law is essential for this kind of system as it simplifies their manipulation for control purposes. This paper investigates the use of a model-based disgnosis method for the determination of the active mode at each timepoint based on the system input/output data. The issue of the parametric identificati...

  2. PWM整流器的欠驱动特性与非线性控制%Underactuated Property and Nonlinear Control for PWM Rectifier

    张晓华; 郭源博; 周鑫; 陈宏钧


    针对三相电压型脉宽调制(pulsewidthmodulation,PWM)整流器级联式双闭环控制系统结构的选择成因尚缺乏理论阐释的问题,基于欠驱动系统理论对此结构进行理论研究。建立PWM整流器在砌同步旋转坐标系下的数学模型,并对其欠驱动特性进行分析。给出PWM整流器驱动变量与欠驱动变量的选择方法,利用零动态分析理论与部分反馈线性化控制策略,设计电流内环控制器。为增强PWM整流器抵抗电网电压和负载扰动的能力,提出白抗扰比例积分电压外环非线性控制方案。所设计的PWM整流器控制系统具有较好的稳态和动态性能,特别是对电网电压/负载扰动具有很强的鲁棒性。仿真与实物实验结果证明了所提理论的正确性和控制策略的有效性。%Based on the underactuated system theory, the cascaded double-closed-loop control system structure of the three-phase voltage-type pulse width modulation (PWM) rectifier was studied theoretically for lack of effective interpretation for choosing this specific structure. The underactuated property of PWM rectifier was analyzed with its model in the dq synchronous reference frame. The choosing method for actuated and underactuated variables was given. Consequently, the current inner-loop controller was designed, based on the zero dynamics theory and partial feedback linearization control method. Moreover, auto-disturbance- rejection proportional integral (ADR-PI) voltage outer-loop controller was presented to reinforce the rejection ability for the AC voltage and DC load disturbances. The proposed PWM rectifier control system has better steady and dynamic performances, as well as strong robustness for the disturbances especially. Simulation and practical experiment results validate the correctness of the proposed theory and the effectiveness of the control strategy.

  3. One-cycle-controlled Single-phase Half-bridge PWM Converter%单相半桥PWM变换器单周期控制研究

    黄刚; 王友阳; 徐镭; 夏泽中


    在基本单周期控制基础上,提出一种单相半桥脉冲宽度调制变换器改进单周期控制算法,引进桥臂电容电压差值变量,构建桥臂电容电压闭环控制,明显改善了基本单周期控制算法应用在单相半桥脉冲宽度调制变换器中桥臂电容电压严重不平衡的问题,限制了桥臂电容中心点电压波动范围,使变换器系统稳定性增强,增强了带载能力,同时实现交流侧高功率。在理论分析的基础上,对控制算法进行了系统的建模仿真,仿真结果表明单相半桥变换器能改进单周期控制算法的有效性。%An improved one -cycle control algorithm was applied in single -phase half -bridge PWM converter .It was based on the basic one -cycle-controlled algorithm .The difference between the variable capacitor voltage arms was introduced to build the bridge arm capacitor voltage closed -loop control .This algorithm can improve the imbalance of the arm capacitor voltage in single-phase half-bridge PWM converter , and limit the fluctuation range of the center of the bridge capacitor volt-age.So the stability and the load capacity of the system could be enhanced .The high power factor in the AC side was achieved . Based on the theoretical analysis of this algorithm , system simulation was realized to demonstrate the effectiveness of this algo-rithm.



    With the increase of link rate, the arbitrator of centralized switch fabric becomes too complicated to implement. A parallel switch fabric based on crossbar, named as PSFBC (Parallel Switch Fabric Based on Crossbar), has been proposed in this paper. PSFBC is composed of k switches whose rate is 1/k of link', these switches exchange cells in parallel; this increases the arbitrator's period and make it easy to implement. Load is evenly distributed to each switch with FCFS (First Come First Serve) rule, it can keep the order of cells in one stream. A multi-class queue scheduling policy is used in PSFBC to ensure the quality of realtime streams. Experiments show that the load on each switch in PSFBC is well balanced, its average delay of cells is little and its performance is very close to centralized switch; and with the increase of number of parallel switches, the loss of PSFBC's performance keeps very small, it becomes easier to implement.

  5. Critical dwell time of switched linear systems

    Lijun ZHANG; Chunwen LI


    In this paper, we consider the relation between the switching dwell time and the stabilization of switched linear control systems. First of all, a concept of critical dwell time is given for switched linear systems without control inputs, and the critical dwell time is taken as an arbitrary given positive constant for a switched linear control systems with controllable switching models. Secondly, when a switched linear system has many stabilizable switching models, the problem of stabilization of the overall system is considered. An on-line feedback control is designed such that the overall system is asymptotically stabilizable under switching laws which depend only on those of uncontrollable subsystems of the switching models. Finally, when a switched system is partially controllable (While some switching models are probably unstabilizable), an on-line feedback control and a cyclic switching strategy are designed such that the overall system is asymptotically stabilizable if all switching models of this uncontrollable subsystems are asymptotically stable. In addition,algorithms for designing switching laws and controls are presented.

  6. Portable Userspace Virtual Filesystem Switch

    Łukasz Faber


    Full Text Available Multiple different filesystems — including disk-based, network, distributed, abstract — arean integral part of every operating system. They are usually written as kernel modules and abstracted to the user via a virtual filesystem switch. In this paper we analyse the feasibility of reimplementing the virtual filesystem switch as a userspace daemon and applicability of this approach in real-life usage. Such reimplementation will require a way to virtualise processes behaviour related to filesystem operations. The problem is non-trivial, as we assume limited capabilities of the VFS switch implemented in userspace. We present a layered architecture comprising of a monitoring process, the VFS abstraction and real filesystem implementations. All working in userspace. Then, we evaluate this solution in four areas: portability, feasibility, usability and performance. Our results demonstrate possible gains in using the userspace-based approach with monolithic kernels, but also underline problems that are encountered in this approach.

  7. Finite-time quantised feedback asynchronously switched control of sampled-data switched linear systems

    Wang, Ronghao; Xing, Jianchun; Li, Juelong; Xiang, Zhengrong


    This paper studies the problem of stabilising a sampled-data switched linear system by quantised feedback asynchronously switched controllers. The idea of a quantised feedback asynchronously switched control strategy originates in earlier work reflecting actual system characteristic of switching and quantising, respectively. A quantised scheme is designed depending on switching time using dynamic quantiser. When sampling time, system switching time and controller switching time are all not uniform, the proposed switching controllers guarantee the system to be finite-time stable by a piecewise Lyapunov function and the average dwell-time method. Simulation examples are provided to show the effectiveness of the developed results.

  8. Topology optimized RF MEMS switches

    Philippine, M. A.; Zareie, H.; Sigmund, Ole


    Topology optimization is a rigorous and powerful method that should become a standard MEMS design tool - it can produce unique and non-intuitive designs that meet complex objectives and can dramatically improve the performance and reliability of MEMS devices. We present successful uses of topology...... optimization for an RF MEM capacitive switch. Extensive experimental data confirms that the switches perform as designed by the optimizations, and that our simulation models are accurate. A subset of measurements are presented here. Broader results have been submitted in full journal format....

  9. CMOS integrated switching power converters

    Villar-Pique, Gerard


    This book describes the structured design and optimization of efficient, energy processing integrated circuits. The approach is multidisciplinary, covering the monolithic integration of IC design techniques, power electronics and control theory. In particular, this book enables readers to conceive, synthesize, design and implement integrated circuits with high-density high-efficiency on-chip switching power regulators. Topics covered encompass the structured design of the on-chip power supply, efficiency optimization, IC-compatible power inductors and capacitors, power MOSFET switches and effi

  10. Long Life MEM Switch Technology


    switched capacitors. It proves that by decreasing the size, miniature switched capacitors with Con/ Coff =2.8 for a single bridge and Con/ Coff =1.9 for a 3...TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, 2006 top covershielding housing fabricated filterb i a s p r o b e a p e r t u r e r e f e r e n c...e p l a n e s 2 m m Fig. 16. The fabricated filter in the shielding housing (cover removed). Frequency (GHz) 2 3 4 5 6 7 S -p a ra m e te rs ( d B


    Zhiqiang LI; Yupeng QIAO; Hongsheng QI; Daizhan CHENG


    This paper investigates the stability of (switched) polynomial systems. Using semi-tensor product of matrices, the paper develops two tools for testing the stability of a (switched) polynomial system. One is to convert a product of multi-variable polynomials into a canonical form, and the other is an easily verifiable sufficient condition to justify whether a multi-variable polynomial is positive definite. Using these two tools, the authors construct a polynomial function as a candidate Lyapunov function and via testing its derivative the authors provide some sufficient conditions for the global stability of polynomial systems.

  12. Switch Using Radio Frequency Identification

    Fink, Patrick W. (Inventor); Lin, Gregory Y. (Inventor); Kennedy, Timothy F. (Inventor); Ngo, Phong H. (Inventor)


    Disclosed is an apparatus for use as a switch. In one embodiment, the switch comprises at least one RFID tag, each RFID tag comprising an antenna element and an RFID integrated circuit, at least one source element, and at least one lever arm. Each lever arm is connected to one of the RFID tags, and each lever arm is capable of two positions. One of the positions places the lever arm and the RFID tag connected thereto into alignment with the source element. Other embodiments are also described.

  13. Practical Aspects of Broken Rotor Bars Detection in PWM Voltage-Source-Inverter-Fed Squirrel-Cage Induction Motors

    Hong-yu Zhu


    Full Text Available Broken rotor bars fault detection in inverter-fed squirrel cage induction motors is still as difficult as the dynamics introduced by the control system or the dynamically changing excitation (stator frequency. This paper introduces a novel fault diagnosis techniques using motor current signature analysis (MCSA to solve the problems. Switching function concept and frequency modulation theory are firstly used to model fault current signal. The competency of the amplitude of the sideband components at frequencies (1±2sfs as indices for broken bars recognition is subsequently studied in the controlled motor via open-loop constant voltage/frequency control method. The proposed techniques are composed of five modules of anti-aliasing signal acquisition, optimal-slip-estimation based on torque-speed characteristic curve of squirrel cage motor with different load types, fault characteristic frequency determination, nonparametric spectrum estimation, and fault identification for achieving MCSA efficiently. Experimental and simulation results obtained on 3 kW three-phase squirrel-cage induction motors show that the model and the proposed techniques are effective and accurate.

  14. Bumpless switching control for switched systems with partial actuator failures

    Qi, Yiwen; Bao, Wen; Zhang, Qingxin; Chang, Juntao


    This study is concerned with the bumpless transfer problem for switched systems with partial actuator failures, in order to obtain smooth system performance output transition. Taking into account that the system requires a controller switching from current sub-controller to a fault-tolerant sub-controller after actuator fault. And bumpless transfer for control input cannot be traditionally designed when the actuator fault occurs, while performance smoothing can be considered and it is actually the ultimate goal of bumpless transfer. Specifically, the actuator fault model is firstly established and partial actuator fault is considered. Then, the system performance output signal is deemed as the main design variable of bumpless transfer, and closed-loop control systems both previous and after controller switching are constructed. Moreover, by using model matching thought and the adaptive sliding mode control technique, a bumpless transfer compensator design strategy is given to drive the performance output variable (after controller switching) to track the one of reference model. At last, simulation results of numeric and application examples demonstrate the effectiveness of the proposed bumpless transfer strategy.

  15. Molecular DNA switches and DNA chips

    Sabanayagam, Chandran R.; Berkey, Cristin; Lavi, Uri; Cantor, Charles R.; Smith, Cassandra L.


    We present an assay to detect single-nucleotide polymorphisms on a chip using molecular DNA switches and isothermal rolling- circle amplification. The basic principle behind the switch is an allele-specific oligonucleotide circularization, mediated by DNA ligase. A DNA switch is closed when perfect hybridization between the probe oligonucleotide and target DNA allows ligase to covalently circularize the probe. Mismatches around the ligation site prevent probe circularization, resulting in an open switch. DNA polymerase is then used to preferentially amplify the closed switches, via rolling-circle amplification. The stringency of the molecular switches yields 102 - 103 fold discrimination between matched and mismatched sequences.

  16. Switching in electrical transmission and distribution systems

    Smeets, René; Kapetanovic, Mirsad; Peelo, David F; Janssen, Anton


    Switching in Electrical Transmission and Distribution Systems presents the issues and technological solutions associated with switching in power systems, from medium to ultra-high voltage. The book systematically discusses the electrical aspects of switching, details the way load and fault currents are interrupted, the impact of fault currents, and compares switching equipment in particular circuit-breakers. The authors also explain all examples of practical switching phenomena by examining real measurements from switching tests. Other highlights include: up to date commentary on new develo

  17. Research on the Core Loss Model Under PWM Wave and DC Bias Excitations%PWM波及直流偏磁励磁下磁芯损耗模型研究

    叶建盈; 陈为; 汪晶慧


    In order to evaluate and predict the core losses of magnetics in power converters, by equivalently replacing the dynamic B-H loop which surrounding area reflects the core losses in a magnetizing cycle period with an elliptical loop, the model of magnetics core losses under the PWM excitation without DC bias was derived. The core losses of magnetics under both DC bias and PWM excitations using a DC/AC inverter as the test circuit were measured by differential loss test idea. By the analysis of the core loss test results and their characteristics, a new core loss model considering the effects of both DC bias and PWM excitations was conceived based on the basic B-H curve. Finally, the test results were compared with the proposed model and the model accuracy was verified.%为了有效地评估和预测功率变换器中磁元件的磁芯损耗,将反映磁芯一个励磁周期内损耗的动态磁滞回线以椭圆回线等效,推导出了无直流偏磁工况下脉宽调制(pulse width modulation,PWM)波形励磁的磁芯损耗模型。采用差值损耗测量思想,以DC/AC逆变电路作为测试电路,测量了直流偏磁及PWM波励磁下的磁芯损耗。进一步根据直流偏磁下磁芯损耗的测量结果及其特征的分析,构思了以磁芯基本磁化曲线模型为基础的直流偏磁和 PWM 波励磁下的磁芯损耗模型。最后,对比了测试数据和所提出的模型的计算结果,验证了模型的正确性。

  18. Introduction to the reliability study of IGBT switching cells under strong constraints; Introduction a l'etude de la fiabilite des cellules de commutation a IGBT sous fortes contraintes

    Vallon, J.


    The reliability approach in power electronics is a complex problem including the coupling of current / voltage surges, physical and technological imperfections, from the die to the power circuit. First of all, we define a methodology based on the monitoring of a great number of components, during a long time campaign. Components are 600 V-50 A-20 kHz IGBT-diodes modules working in PWM inverter cells owing to an original opposition method. An exhaustive study of cell-switching failure modes allowed us to design a suitable and efficient protection. Afterwards, a complete reliability test bench was carried out with electrical and thermal monitoring. A preliminary screening protocol was also applied. The first results are presented in this thesis. (author)

  19. Reduction of Common-Mode Conducted Noise Emissions in PWM Inverter-fed AC Motor Drive Systems using Optimized Passive EMI Filter

    Jettanasen, C.; Ngaopitakkul, A.


    Conducted electromagnetic interference (EMI) generated by PWM inverter-fed induction motor drive systems, which are currently widely used in many industrial and/or avionic applications, causes severe parasitic current problems, especially at high frequencies (HF). These restrict power electronic drive's evolution. In order to reduce or minimize these EMI problems, several techniques can be applied. In this paper, insertion of an optimized passive EMI filter is proposed. This filter is optimized by taking into account real impedances of each part of a considered AC motor drive system contrarily to commercial EMI filters designed by considering internal impedance of disturbance source and load, equal to 50Ω. Employing the latter EMI filter would make EMI minimization less effective. The proposed EMI filter optimization is mainly dedicated to minimize common mode (CM) currents due to its most dominant effects in this kind of system. The efficiency of the proposed optimization method using two-port network approach is deduced by comparing the minimized CM current spectra to an applied normative level (ex. DO-160D in aeronautics).

  20. Constant Resistance Is Not Constant Termperature Anemometry - A Lesson From the PWM-CTA Simulation and Its Impact on All CTA Frequency Responce Evaluations.

    Morris, Scott; Foss, John


    The transient response of a hot-wire sensor has been simulated numerically ala Perry(Perry, A., (1982), Hotwire Anemometry, Oxford Press.). The recently developed Pulse-Width-Modulated Constant Temperature Anemometer (PWM-CTA(J.F.Foss,D.G. Bohl, and T.J. Hicks (1996) ``The Pulse Width Modulated-Constant Temperature Anemometer,'' Meas. Sci. and Tech., vol. 7, pp. 1388-1395.)) was the power source for the sensor. The simplicity of this electrical circuit has permitted the simulation to reveal a distinctive feature of the sensor's response. A typical sensor was "calibrated" in the model for 3t_0) = 25m/sec. The indicated velocity did not equal the established Q(t>t_o) value albeit the proper overheat resistance was achieved in one time step. The discrepancy is a result of transient effects in the temperature distribution: T(z) and the non-linear coupling between the velocity and the heat transfer. This effect will be present in all CTA operations. The ``effective frequency response'' will be discussed.

  1. 三电平PWM整流器控制研究%Research on the Control Strategy of Three-level PWM Rectifier

    刘毅; 谭国俊; 洪书娟; 徐世周


    针对高压、大功率三电平PWM整流器进行了分析研究.提出一种优化三电平SVPWM算法,建立了三电平整流器的高频数学模型,采用虚拟磁链定向的定频直接功率控制,实现了整流器高动态性能控制.基于Matlab/Simulink搭建了仿真模型,并采用DSP2812进行了三电平整流器样机控制实验,仿真与实验结果验证了所述控制策略的正确性及有效性.%Based on the high voltage and high power considerations, the three-level PWM rectifier is analyzed. An optimized space vector pulse width modulation(SVPWM) algorithm of a three-level rectifier is proposed,and the highfrequency mathematical model is constructed. Based on the virtual flux orientation, fixed -frequency direct power control using space vector modulation (SVM-DPC) is proposed to achieve high dynamic performance control.The simulation model is built to study the strategy .The control strategy is verified correctly and validly via simulation and experimental results of prototype based upon DSP2812.

  2. Comparative Analysis of Different PWM Techniques to Reduce the Common Mode Voltage in Three-Level Neutral-Point-Clamped Inverters for Variable Speed Induction Drives

    Bharati Raja


    Full Text Available This work presents the comparative study of the different PWM techniques to reduce the common-mode voltage (CMV at the output of neutral point diode clamped inverter for variable speed drives. Here the comparative study is done by the phase opposition disposed (POD, sinusoidal pulse width modulation (SPWM, phase disposition (PD, phase shift (PS space vector modulation (SVM techniques are proposed. A good trade-off between the quality of the output voltage and the partial magnitude of the CMV is achieved in this work. The scheme is proposed for three-level inverter. This work realizes the implementation of Three-level diode clamped MLI for three-phase (Y-Δ induction motor with the implementation of a space vector modulation technique without any additional control algorithm to reduce CMV within the range + Vdc/6. The Simulation with a 1HP induction motor drive system is setup in Matlab-2011b  and the same results validated effectively by hardware – FPGA-SPARTEN III processor and its shows that the CM voltage is effectively reduced and the maximum output voltage is not affected.  

  3. Development of microheaters for gas sensor with an AT-Mega 8535 temperature controller using a PWM (pulse width modulation) method

    Megayanti, Meti; Panatarani, Camellia; Joni, I. Made


    Microheater is the main component in gas sensor characterized by their sensitivity, selectivity, and time response of gas sensor which is depend on the microheater temperature stability. A Cu microheater was developed and utilized AT-Mega 8535 controller using a PWM (pulse width modulation) method. This control system is interfaced to the PC to observe the real time temperature response of the microheater. Three initial resistance (R0) variations of microheater were developed in an open loop control system. The power characteristic of designed microheater depends on the specified microheater initial resistance. The smaller R0, the less power required to reach a temperature setting value. The developed microheater was designed to reach a temperature setting value of 250°C having resistance 0.531 Ω for 1.979 Watt and 0.265 Ω for 1.072 Watt respectively. The results of the investigation on the control performances shows microheater-control system achieved operating temperature up to 250°C. The response of the temperature control shows smallest R0 resulted in a high stability with short settling time, short delay time and small ripple for temperature setting values higher than 150°C. The obtained error of microheater temperature with R0 = 0.265 is 8.596 %. It is concluded that the developed microheater can be utilized as a component of a gas sensor.

  4. A Dimming Method for RGB LED Based on Three Channels' PWM%基于PWM的三基色LED的调光调色方法

    宋鹏程; 文尚胜; 尚俊; 史晨阳; 陈颖聪


    提出了一种基于脉冲宽度调制(PWM)的三基色发光二极管(LED)调光调色计算模型,建立了混合光的色品坐标与占空比、相关色温与占空比、最大光通量与色品坐标的函数关系.采用红绿蓝(RGB)三基色LED进行实验验证,实验结果表明:计算模型能较好的指导LED光色调节,混合光色品坐标的理论值和测量值之间的误差小于2.5%,模拟太阳光的色温变化误差仅为50 K.该计算模型可应用于各种三通道LED的调光调色,其高精度的优点能更精确地实现智能照明,极具实用价值.

  5. Research on Pneumatic Position Control Using on/off Valves Based on PWM%高速开关阀的气缸定位控制

    胡杰; 许昌


    首先分析了基于PWM高速开关阀的气缸定位控制系统的工作原理,在此基础上建立阀控缸定位系统的数学模型.应用脉宽调制方式以及常规PID控制算法和模糊PID控制算法,在MATLAB/SIMULINK上对基于高速开关阀的气缸定位系统进行了仿真.仿真结果表明,用模糊PID控制算法控制阀控缸定位系统,可以实现更快速、更精确的气动执行器位置伺服控制.%Firstly,this paper analyses the working principle of cylinder postton controlling system based on PWM with on/off solenoid valves and then establishs the pneumatic system model. Moreover, using conventional General PID and Fuzzy -PID control algorithm, the established model is simulated by MATLAB/SIMULINK. The results show that controlling the system with Fuzzy - PID algorithm can achieve a more fast, more precise pneumatic actuator positon.

  6. Multiuser switched diversity scheduling schemes

    Shaqfeh, Mohammad


    Multiuser switched-diversity scheduling schemes were recently proposed in order to overcome the heavy feedback requirements of conventional opportunistic scheduling schemes by applying a threshold-based, distributed, and ordered scheduling mechanism. The main idea behind these schemes is that slight reduction in the prospected multiuser diversity gains is an acceptable trade-off for great savings in terms of required channel-state-information feedback messages. In this work, we characterize the achievable rate region of multiuser switched diversity systems and compare it with the rate region of full feedback multiuser diversity systems. We propose also a novel proportional fair multiuser switched-based scheduling scheme and we demonstrate that it can be optimized using a practical and distributed method to obtain the feedback thresholds. We finally demonstrate by numerical examples that switched-diversity scheduling schemes operate within 0.3 bits/sec/Hz from the ultimate network capacity of full feedback systems in Rayleigh fading conditions. © 2012 IEEE.

  7. Magnetically Insulated Opening Switch Research.


    this research is to investigate the validity of the magneti- cally insulated opening switch concept proposed by Eninger (Ref. 5, Appendix 1). The...1973). 3. Y. Carmel, and J. Nation, Phys, Rev. Lett. 31, 286 (1973). 4. T.J. Orzechowski, and G. Bekefi, Phys. Fluids 19, 43 (1976). U 5. 3. Eninger

  8. The Atlas load protection switch

    Davis, H A; Dorr, G; Martínez, M; Gribble, R F; Nielsen, K E; Pierce, D; Parsons, W M


    Atlas is a high-energy pulsed-power facility under development to study materials properties and hydrodynamics experiments under extreme conditions. Atlas will implode heavy liner loads (m~45 gm) with a peak current of 27-32 MA delivered in 4 mu s, and is energized by 96, 240 kV Marx generators storing a total of 23 MJ. A key design requirement for Atlas is obtaining useful data for 95601130f all loads installed on the machine. Materials response calculations show current from a prefire can damage the load requiring expensive and time consuming replacement. Therefore, we have incorporated a set of fast-acting mechanical switches in the Atlas design to reduce the probability of a prefire damaging the load. These switches, referred to as the load protection switches, short the load through a very low inductance path during system charge. Once the capacitors have reached full charge, the switches open on a time scale short compared to the bank charge time, allowing current to flow to the load when the trigger pu...

  9. Industry Switching in Developing Countries

    Newman, Carol; Rand, John; Tarp, Finn

    as compared to entry and exit firms. They tend, inter alia, to be labour-intensive and seek out competitive opportunities in labour-intensive sectors in response to changes in the market environment. We also show that resource reallocations resulting from switching form an important component of productivity...

  10. Wide Bandgap Extrinsic Photoconductive Switches

    Sullivan, James S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)


    Semi-insulating Gallium Nitride, 4H and 6H Silicon Carbide are attractive materials for compact, high voltage, extrinsic, photoconductive switches due to their wide bandgap, high dark resistance, high critical electric field strength and high electron saturation velocity. These wide bandgap semiconductors are made semi-insulating by the addition of vanadium (4H and 6HSiC) and iron (2H-GaN) impurities that form deep acceptors. These deep acceptors trap electrons donated from shallow donor impurities. The electrons can be optically excited from these deep acceptor levels into the conduction band to transition the wide bandgap semiconductor materials from a semi-insulating to a conducting state. Extrinsic photoconductive switches with opposing electrodes have been constructed using vanadium compensated 6H-SiC and iron compensated 2H-GaN. These extrinsic photoconductive switches were tested at high voltage and high power to determine if they could be successfully used as the closing switch in compact medical accelerators.

  11. Switching Costs in Accounting Services

    Fatih Koç


    Full Text Available Switching cost is defined as possible costs that customers may encounter when they want to change the firm they buy service, and an important subject in terms of accounting services. Particularly, small business entrepreneurs’ not having knowledge about accounting procedures, and sharing private information with accounting firms make switching costs more important for accounting services. Thus, the aim of this study is to investigate the concept of switching costs (relational cost, procedural cost and financial cost, its determinants (perceived service quality, service importance, and service failures, and consequences (re-purchasing, and recommen ding to others. Theresearch was conducted on small business entrepreneurs in down-town of Balıkesir in Turkey. Total 405 small business entrepreneur owners were interviewed. According to results of the study, perceived service quality positively affects all dimensions of switching costs, significance of service positively affects procedural and relational costs, and service failures negatively affect procedural and relational costs. The results showed that while procedural and relational costs positively affect re-purchasing and recommending to others variables, financial cost did not have any effect on these variables.

  12. Intrinsic nanofilamentation in resistive switching

    Wu, Xing


    Resistive switching materials are promising candidates for nonvolatile data storage and reconfiguration of electronic applications. Intensive studies have been carried out on sandwiched metal-insulator-metal structures to achieve high density on-chip circuitry and non-volatile memory storage. Here, we provide insight into the mechanisms that govern highly reproducible controlled resistive switching via a nanofilament by using an asymmetric metal-insulator-semiconductor structure. In-situ transmission electron microscopy is used to study in real-time the physical structure and analyze the chemical composition of the nanofilament dynamically during resistive switching. Electrical stressing using an external voltage was applied by a tungsten tip to the nanosized devices having hafnium oxide (HfO2) as the insulator layer. The formation and rupture of the nanofilaments result in up to three orders of magnitude change in the current flowing through the dielectric during the switching event. Oxygen vacancies and metal atoms from the anode constitute the chemistry of the nanofilament.

  13. Industry Switching in Developing Countries

    Newman, Carol; Rand, John; Tarp, Finn

    Firm turnover (i.e. firm entry and exit) is a well-recognized source of sectorlevel productivity growth across developing and developed countries. In contrast, the role and importance of firms switching activities from one sector to another is little understood. Firm switchers are likely to be un...

  14. CSR Pulsed Switching Power Supplies


    In 2001, CSR power supply system made a great progress. Three prototypes were designed for CSR quadruple and correct magnet. Three different companies provided the three prototypes, but the same circuit-chopper were employed. The simplified diagram is showed in Fig.1. All pulsed switching power supply prototypes were tested successfully before the end of 2001.

  15. Soliton switching in directional couplers

    Valkering, T.P.; Hoekstra, Hugo; de Boer, Pieter-Tjerk


    The mechanism of pulse switching is investigated analytically and numerically for a family of initial conditions with a solitonlike pulse in one channel and no signal on the other channel of the coupler. This investigation is performed directly in the coupled nonlinear Schroedinger equations that

  16. Digital Switching in the Quantum Domain

    Tsai, I M


    In this paper, we present an architecture and implementation algorithm such that digital data can be switched in the quantum domain. First we define the connection digraph which can be used to describe the behavior of a switch at a given time, then we show how a connection digraph can be implemented using elementary quantum gates. The proposed mechanism supports unicasting as well as multicasting, and is strict-sense non-blocking. It can be applied to perform either circuit switching or packet switching. Compared with a traditional space or time domain switch, the proposed switching mechanism is more scalable. Assuming an n-by-n quantum switch, the space consumption grows linearly, i.e. O(n), while the time complexity is O(1) for unicasting, and O(log n) for multicasting. Based on these advantages, a high throughput switching device can be built simply by increasing the number of I/O ports.

  17. Key Technologies for Optical Packet Switching

    Akira; Okada


    The paper describes our recent progress on key technologies and components for realizing optical packet switching, including an out-of-band optical label switching technique, an optical packet synchronizer and a burst-mode optical receiver.

  18. Key Technologies for Optical Packet Switching

    Akira Okada


    The paper describes our recent progress on key technologies and components for realizing optical packet switching,including an out-of-band optical label switching technique, an optical packet synchronizer and a burst-mode optical receiver.

  19. A Demonstration of Automatically Switched Optical Network


    We build an automatically switched optical network (ASON) testbed with four optical cross-connect nodes. Many fundamental ASON features are demonstrated, which is implemented by control protocols based on generalized multi-protocol label switching (GMPLS) framework.

  20. The increased importance of sector switching

    Frederiksen, Anders; Hansen, Jesper Rosenberg


    Sector switching is an important phenomenon that casts light on public–private differences. Yet our knowledge about its prevalence and trends is limited. We study sector switching using unique Danish register-based employer–employee data covering more than 25 years. We find that sector switching...

  1. Caffeine improves anticipatory processes in task switching

    Tieges, Zoe; Snel, Jan; Kok, Albert; Wijnen, Jasper G.; Lorist, Monicque M.; Ridderinkhof, K. Richard

    We studied the effects of moderate amounts of caffeine on task switching and task maintenance using mixed-task (AABB) blocks, in which participants alternated predictably between two tasks, and single-task (AAAA, BBBB) blocks. Switch costs refer to longer reaction times (RT) on task switch trials

  2. A gain-coefficient switched Alexandrite laser

    Lee, Chris J.; Slot, van der Peter J.M.; Boller, Klaus-J.


    We report on a gain-coefficient switched Alexandrite laser. An electro-optic modulator is used to switch between high and low gain states by making use of the polarization dependent gain of Alexandrite. In gain-coefficient switched mode, the laser produces 85 ns pulses with a pulse energy of 240 mJ

  3. A Bilingual Advantage in Task Switching

    Prior, Anat; MacWhinney, Brian


    This study investigated the possibility that lifelong bilingualism may lead to enhanced efficiency in the ability to shift between mental sets. We compared the performance of monolingual and fluent bilingual college students in a task-switching paradigm. Bilinguals incurred reduced switching costs in the task-switching paradigm when compared with…

  4. Bootstrapped Low-Voltage Analog Switches

    Steensgaard-Madsen, Jesper


    Novel low-voltage constant-impedance analog switch circuits are proposed. The switch element is a single MOSFET, and constant-impedance operation is obtained using simple circuits to adjust the gate and bulk voltages relative to the switched signal. Low-voltage (1-volt) operation is made feasible...

  5. A gain-coefficient switched Alexandrite laser

    Lee, Chris J; Boller, Klaus-J


    We report on a gain-coefficient switched Alexandrite laser. An electro-optic modulator is used to switch between high and low gain states by making use of the polarization dependent gain of Alexandrite. In gain-coefficient switched mode, the laser produces 85 ns pulses with a pulse energy of 240 mJ at a repetition rate of 5 Hz.

  6. A CW Gunn Diode Switching Element.

    Hurtado, Marco; Rosenbaum, Fred J.

    As part of a study of the application of communication satellites to educational development, certain technical aspects of such a system were examined. A current controlled bistable switching element using a CW Gunn diode is reported on here. With modest circuits switching rates of the order of 10 MHz have been obtained. Switching is initiated by…

  7. A CW Gunn diode bistable switching element.

    Hurtado, M.; Rosenbaum, F. J.


    Experiments with a current-controlled bistable switching element using a CW Gunn diode are reported. Switching rates of the order of 10 MHz have been obtained. Switching is initiated by current pulses of short duration (5-10 ns). Rise times of the order of several nanoseconds could be obtained.

  8. Caffeine improves anticipatory processes in task switching

    Tieges, Zoe; Snel, Jan; Kok, Albert; Wijnen, Jasper G.; Lorist, Monicque M.; Ridderinkhof, K. Richard


    We studied the effects of moderate amounts of caffeine on task switching and task maintenance using mixed-task (AABB) blocks, in which participants alternated predictably between two tasks, and single-task (AAAA, BBBB) blocks. Switch costs refer to longer reaction times (RT) on task switch trials (e

  9. Mechanism of single atom switch on silicon

    Quaade, Ulrich; Stokbro, Kurt; Thirstrup, C.


    We demonstrate single atom switch on silicon which operates by displacement of a hydrogen atom on the silicon (100) surface at room temperature. We find two principal effects by which the switch is controlled: a pronounced maximum of the switching probability as function of sample bias...

  10. 30 CFR 56.9308 - Switch throws.


    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Switch throws. 56.9308 Section 56.9308 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Switch throws. Switch throws shall be installed to provide clearance to protect switchmen from...

  11. Switch Detection in Preschoolers' Cognitive Flexibility

    Chevalier, Nicolas; Wiebe, Sandra A.; Huber, Kristina L.; Espy, Kimberly Andrews


    The current study addressed the role of switch detection in cognitive flexibility by testing the effect of transition cues (i.e., cues that directly signal the need to switch or maintain a given task goal) in a cued set-shifting paradigm at 5 years of age. Children performed better, especially on switch trials, when transition cues were combined…

  12. 49 CFR 236.822 - Switch, spring.


    ... 49 Transportation 4 2010-10-01 2010-10-01 false Switch, spring. 236.822 Section 236.822 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Switch, spring. A switch equipped with a spring device which forces the points to their original...

  13. 14 CFR 27.1361 - Master switch.


    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Master switch. 27.1361 Section 27.1361... STANDARDS: NORMAL CATEGORY ROTORCRAFT Equipment Electrical Systems and Equipment § 27.1361 Master switch. (a) There must be a master switch arrangement to allow ready disconnection of each electric power...

  14. 基于MCU控制的开关电源稳压电路设计%Design for voltage regulator circuit of switching power supply based on MCU control

    李淑红; 邢军


    A voltage regulator circuit of the switching power supply based on MCU control was designed,which is com-posed of rectification filtering circuit,push-pull power conversion circuit and control circuit. In this circuit,the output voltage of the switching power supply is controlled by regulating PWM via the MCU. The digital signal output by MCU is converted into analog signal through the DAC0832. The analog signal is taken as the reference voltage of the second pin of the switching con-trol chip SG3525. SG3525 generates PWM control pulse automatically according to the variation of reference voltage to regulate the output pulse width of the switching tube,so the purpose of regulating the output voltage is achieved. The experimental re-sults show that the output voltage adjustable range is 28~36 V,the maximum output current is 15 A,and the efficiency of the switching power supply is 89%.%设计了一款基于MCU控制的开关电源稳压电路,该系统主要由整流滤波电路、推挽式功率变换电路和控制电路组成,并通过MCU调节PWM控制开关电源输出电压.MCU输出的数字信号通过DAC0832转换为模拟信号,该模拟信号作为开关控制芯片SG3525第二管脚的基准电压,SG3525根据基准电压的变化自动产生PWM控制脉冲,调节开关管的输出脉宽,从而达到调节输出电压的目的.实验表明,输出电压可调范围为28~36 V,最大输出电流Imax=15 A,开关电源的效率为η=89%.

  15. Stabilization and tracking for switching linear systems under unknown switching sequences

    Baglietto, M.; Battistelli, G.; Tesi, P.


    This paper describes recent progress in the study of switching linear systems i.e. linear systems whose dynamics can switch among a family of possible configurations/modes. The attention is focused on those classes of switching systems governed by unknown switching sequences. For this case, we addre

  16. Degree of Conversational Code-Switching Enhances Verbal Task Switching in Cantonese-English Bilinguals

    Yim, Odilia; Bialystok, Ellen


    The study examined individual differences in code-switching to determine the relationship between code-switching frequency and performance in verbal and non-verbal task switching. Seventy-eight Cantonese-English bilinguals completed a semi-structured conversation to quantify natural code-switching, a verbal fluency task requiring language…


    Prema Kannan; Senthil Kumar Natarajan; Subhransu Sekar Dash


    .... A fuzzy logic controller is designed to change the pulse width of switching signal applied to the converter and thereby the voltage fed to the armature of the separately excited DC motor to regulate the speed...

  18. Nonlinear interface optical switch structure for dual mode switching revisited

    Bussjager, Rebecca J.; Osman, Joseph M.; Chaiken, Joseph


    There is a need for devices which will allow integration of photonic/optical computing subsystems into electronic computing architectures. This presentation reviews the nonlinear interface optical switch (NIOS) concept and then describes a new effect, the erasable optical memory (EOM) effect. We evaluate an extension of the NIOS device to allow simultaneous optical/electronic, i.e. dual mode, switching of light utilizing the EOM effect. Specific devices involve the fabrication of thin film tungsten (VI) oxide (WO3) and tungsten (V) oxide (W2O5) on the hypotenuse of glass (BK-7), fused silica (SiO2) and zinc selenide (ZnSe) right angle prisms. Chemical reactions and temporal response tests were performed and are discussed.

  19. Research on DC-Link Capacitor Voltage Harmonics Reduction of PWM Rectifier Based on Carrier Phase-Shifting%基于载波移相控制的脉冲整流器直流侧支撑电容电压谐波抑制研究

    王娜; 宋文胜; 冯晓云


    In the paper, to reduce the DC-link capacitor voltage harmonics of dual-cascading PWM rectifier in electric traction AC drive system, firstly, the theoretical design method of DC-link capacitor was introduced, then, the characteristic of high order harmonics of DC-link voltage in the steady-state was derived, and DC link voltage ripple of the dual-cascading PWM with carrier phase-shifting technology was analyzed in detail. The theoretical analysis showed that the high order ripples of DC-link voltage were mainly distributed around the twice switching frequency, and the carrier phase-shifting technology could reduce these high order ripples to suppress the DC voltage ripple coefficient. Therefore, the DC-link capacitor could be minimized based on traditional design method in combination with carrier phase-shifting technology, Control methods with and without carrier phase-shifting technology were compared in computer simulation and hardware-in-the-loop(HIL) experiment system respectively, which showed the validity and effectiveness of theoretical analysis.%以电力牵引交流传动系统中两重化脉冲整流器拓扑为研究对象,以实现其直流侧支撑电容电压谐波抑制为目标,首先从理论上分析了直流侧支撑电容容量的设计方法;然后分析了稳态运行时直流侧电压高次谐波的产生机理,并重点分析了两重化脉冲整流器载波移相控制方法对直流侧脉动的影响.理论分析表明直流侧电压高次纹波主要分布在2倍开关频率附近,载波移相控制技术可以有效地抑制直流侧2倍开关频率附近的纹波电压,从而减小直流侧电压纹波系数.因此在传统直流侧支撑电容容量设计方法的基础上,加入载波移相控制可以进一步减小所设计的支撑电容大小.最后对未添加载波移相控制和添加载波移相控制的方法分别进行了计算机仿真和半实物试验测试.Matlab仿真和dSPACE半实物测试结果都验证了理

  20. On the stabilization of switched linear stochastic systems with unobservable switching laws


    This paper is concerned with the stabilization problem of switched linear stochastic systems with unobservable switching laws. In this paper the system switches among a finite family of linear stochastic systems. Since there are noise perturbations, the switching laws can not be identified in any finite time horizon. We prove that if each individual subsystem is controllable and the switching duration uniformly has a strict positive lower bound, then the system can be stabilized by using a controller that uses online state estimation.