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Sample records for digital inverter based

  1. Inverter-based successive approximation capacitance-to-digital converter

    KAUST Repository

    Omran, Hesham

    2017-03-23

    An energy-efficient capacitance-to-digital converter (CDC) is provided that utilizes a capacitance-domain successive approximation (SAR) technique. Unlike SAR analog- to-digital converters (ADCs), analysis shows that for SAR CDCs, the comparator offset voltage will result in signal-dependent and parasitic-dependent conversion errors, which necessitates an op-amp-based implementation. The inverter-based SAR CDC contemplated herein provides robust, energy-efficient, and fast operation. The inverter- based SAR CDC may include a hybrid coarse-fine programmable capacitor array. The design of example embodiments is insensitive to analog references, and thus achieves very low temperature sensitivity without the need for calibration. Moreover, this design achieves improved energy efficiency.

  2. Inverter-based successive approximation capacitance-to-digital converter

    KAUST Repository

    Omran, Hesham; Alhoshany, Abdulaziz; Salama, Khaled N.

    2017-01-01

    offset voltage will result in signal-dependent and parasitic-dependent conversion errors, which necessitates an op-amp-based implementation. The inverter-based SAR CDC contemplated herein provides robust, energy-efficient, and fast operation. The inverter

  3. Analysis of the Measurement and Modeling of a Digital Inverter Based on a Ferroelectric Transistor

    Science.gov (United States)

    MacLeod, Todd C.; Phillips, Thomas A.; Sayyah, Rana; Ho, Fat D.

    2009-01-01

    The use of ferroelectric materials for digital memory devices is widely researched and implemented, but ferroelectric devices also possess unique characteristics that make them have interesting and useful properties in digital circuits. Because ferroelectric transistors possess the properties of hysteresis and nonlinearity, a digital inverter containing a FeFET has very different characteristics than one with a traditional FET. This paper characterizes the properties of the measurement and modeling of a FeFET based digital inverter. The circuit was set up using discrete FeFETs. The purpose of this circuit was not to produce a practical integrated circuit that could be inserted directly into existing digital circuits, but to explore the properties and characteristics of such a device and to look at possible future uses. Input and output characteristics are presented, as well as timing measurements. Comparisons are made between the ferroelectric device and the properties of a standard digital inverter. Potential benefits and possible uses of such a device are presented.

  4. A digital output accelerometer using MEMS-based piezoelectric accelerometers and arrayed CMOS inverters with satellite capacitors

    International Nuclear Information System (INIS)

    Kobayashi, T; Okada, H; Maeda, R; Itoh, T; Masuda, T

    2011-01-01

    The present paper describes the development of a digital output accelerometer composed of microelectromechanical systems (MEMS)-based piezoelectric accelerometers and arrayed complementary metal–oxide–semiconductor (CMOS) inverters accompanied by capacitors. The piezoelectric accelerometers were fabricated from multilayers of Pt/Ti/PZT/Pt/Ti/SiO 2 deposited on silicon-on-insulator (SOI) wafers. The fabricated piezoelectric accelerometers were connected to arrayed CMOS inverters. Each of the CMOS inverters was accompanied by a capacitor with a different capacitance called a 'satellite capacitor'. We have confirmed that the output voltage generated from the piezoelectric accelerometers can vary the output of the CMOS inverters from a high to a low level; the state of the CMOS inverters has turned from the 'off-state' into the 'on-state' when the output voltage of the piezoelectric accelerometers is larger than the threshold voltage of the CMOS inverters. We have also confirmed that the CMOS inverters accompanied by the larger satellite capacitor have become 'on-state' at a lower acceleration. On increasing the acceleration, the number of on-state CMOS inverters has increased. Assuming that the on-state and off-state of CMOS inverters correspond to logic '0' and '1', the present digital output accelerometers have expressed the accelerations of 2.0, 3.0, 5.0, and 5.5 m s −2 as digital outputs of 111, 110, 100, and 000, respectively

  5. Digital Control Techniques Based on Voltage Source Inverters in Renewable Energy Applications: A Review

    Directory of Open Access Journals (Sweden)

    Sohaib Tahir

    2018-02-01

    Full Text Available In the modern era, distributed generation is considered as an alternative source for power generation. Especially, need of the time is to provide the three-phase loads with smooth sinusoidal voltages having fixed frequency and amplitude. A common solution is the integration of power electronics converters in the systems for connecting distributed generation systems to the stand-alone loads. Thus, the presence of suitable control techniques, in the power electronic converters, for robust stability, abrupt response, optimal tracking ability and error eradication are inevitable. A comprehensive review based on design, analysis, validation of the most suitable digital control techniques and the options available for the researchers for improving the power quality is presented in this paper with their pros and cons. Comparisons based on the cost, schemes, performance, modulation techniques and coordinates system are also presented. Finally, the paper describes the performance evaluation of the control schemes on a voltage source inverter (VSI and proposes the different aspects to be considered for selecting a power electronics inverter topology, reference frames, filters, as well as control strategy.

  6. Measurements of simulated periodontal bone defects in inverted digital image and film-based radiograph: an in vitro study

    International Nuclear Information System (INIS)

    Molon, Rafael Scaf; Morais Camillo, Juliana Aparecida Najarro Dearo; Ferreira, Mauricio Goncalves; Loffredo, Leonor Castro Monteiro; Scaf, Gulnara; Sakakura, Celso Eduardo

    2012-01-01

    This study was performed to compare the inverted digital images and film-based images of dry pig mandibles to measure the periodontal bone defect depth. Forty 2-wall bone defects were made in the proximal region of the premolar in the dry pig mandibles. The digital and conventional radiographs were taken using a Schick sensor and Kodak F-speed intraoral film. Image manipulation (inversion) was performed using Adobe Photoshop 7.0 software. Four trained examiners made all of the radiographic measurements in millimeters a total of three times from the cementoenamel junction to the most apical extension of the bone loss with both types of images: inverted digital and film. The measurements were also made in dry mandibles using a periodontal probe and digital caliper. The Student's t-test was used to compare the depth measurements obtained from the two types of images and direct visual measurement in the dry mandibles. A significance level of 0.05 for a 95% confidence interval was used for each comparison. There was a significant difference between depth measurements in the inverted digital images and direct visual measurements (p>|t|=0.0039), with means of 6.29 mm (IC 95% :6.04-6.54) and 6.79 mm (IC 95% :6.45-7.11), respectively. There was a non-significant difference between the film-based radiographs and direct visual measurements (p>|t|=0.4950), with means of 6.64 mm(IC 95% :6.40-6.89) and 6.79 mm(IC 95% :6.45-7.11), respectively. The periodontal bone defect measurements in the inverted digital images were inferior to film-based radiographs, underestimating the amount of bone loss.

  7. Measurements of simulated periodontal bone defects in inverted digital image and film-based radiograph: an in vitro study

    Energy Technology Data Exchange (ETDEWEB)

    Molon, Rafael Scaf; Morais Camillo, Juliana Aparecida Najarro Dearo; Ferreira, Mauricio Goncalves; Loffredo, Leonor Castro Monteiro; Scaf, Gulnara [Araraquara Dental School, Universidade Estadual Paulista, Sao Paulo (Brazil); Sakakura, Celso Eduardo [Barretos Dental School, Barretos Educational Fundation, Sao Paulo (Brazil)

    2012-09-15

    This study was performed to compare the inverted digital images and film-based images of dry pig mandibles to measure the periodontal bone defect depth. Forty 2-wall bone defects were made in the proximal region of the premolar in the dry pig mandibles. The digital and conventional radiographs were taken using a Schick sensor and Kodak F-speed intraoral film. Image manipulation (inversion) was performed using Adobe Photoshop 7.0 software. Four trained examiners made all of the radiographic measurements in millimeters a total of three times from the cementoenamel junction to the most apical extension of the bone loss with both types of images: inverted digital and film. The measurements were also made in dry mandibles using a periodontal probe and digital caliper. The Student's t-test was used to compare the depth measurements obtained from the two types of images and direct visual measurement in the dry mandibles. A significance level of 0.05 for a 95% confidence interval was used for each comparison. There was a significant difference between depth measurements in the inverted digital images and direct visual measurements (p>|t|=0.0039), with means of 6.29 mm (IC{sub 95%}:6.04-6.54) and 6.79 mm (IC{sub 95%}:6.45-7.11), respectively. There was a non-significant difference between the film-based radiographs and direct visual measurements (p>|t|=0.4950), with means of 6.64 mm(IC{sub 95%}:6.40-6.89) and 6.79 mm(IC{sub 95%}:6.45-7.11), respectively. The periodontal bone defect measurements in the inverted digital images were inferior to film-based radiographs, underestimating the amount of bone loss.

  8. A 33fJ/Step SAR Capacitance-to-Digital Converter Using a Chain of Inverter-Based Amplifiers

    KAUST Repository

    Omran, Hesham

    2016-11-16

    A 12 - bit energy-efficient capacitive sensor interface circuit that fully relies on capacitance-domain successive approximation (SAR) technique is presented. Analysis shows that for SAR capacitance-to-digital converter (CDC) comparator offset voltage will result in parasitic-dependent conversion errors, which necessitates using an offset cancellation technique. Based on the presented analysis, a SAR CDC that uses a chain of cascode inverter-based amplifiers with near-threshold biasing is proposed to provide robust, energy-efficient, and fast operation. A hybrid coarse-fine capacitive digital-to-analog converter (CapDAC) achieves 11.7 - bit effective resolution, and provides 83% area saving compared to a conventional binary weighted implementation. The prototype fabricated in a 0.18μm CMOS technology is experimentally verified using MEMS capacitive pressure sensor. Experimental results show an energy efficiency figure-of-merit (FoM) of 33 f J/Step which outperforms the state-of-the-art. The CDC output is insensitive to analog references; thus, a very low temperature sensitivity of 2.3 ppm/°C is achieved without the need for calibration.

  9. A 33fJ/Step SAR Capacitance-to-Digital Converter Using a Chain of Inverter-Based Amplifiers

    KAUST Repository

    Omran, Hesham; Alhoshany, Abdulaziz; Alahmadi, Hamzah; Salama, Khaled N.

    2016-01-01

    A 12 - bit energy-efficient capacitive sensor interface circuit that fully relies on capacitance-domain successive approximation (SAR) technique is presented. Analysis shows that for SAR capacitance-to-digital converter (CDC) comparator offset voltage will result in parasitic-dependent conversion errors, which necessitates using an offset cancellation technique. Based on the presented analysis, a SAR CDC that uses a chain of cascode inverter-based amplifiers with near-threshold biasing is proposed to provide robust, energy-efficient, and fast operation. A hybrid coarse-fine capacitive digital-to-analog converter (CapDAC) achieves 11.7 - bit effective resolution, and provides 83% area saving compared to a conventional binary weighted implementation. The prototype fabricated in a 0.18μm CMOS technology is experimentally verified using MEMS capacitive pressure sensor. Experimental results show an energy efficiency figure-of-merit (FoM) of 33 f J/Step which outperforms the state-of-the-art. The CDC output is insensitive to analog references; thus, a very low temperature sensitivity of 2.3 ppm/°C is achieved without the need for calibration.

  10. An active damping method based on biquad digital filter for parallel grid-interfacing inverters with LCL filters

    DEFF Research Database (Denmark)

    Lu, Xiaonan; Sun, Kai; Huang, Lipei

    2014-01-01

    around the switching frequency and its multiples. Although the LCL-filters have several advantages compared to single inductance filter, its resonance problem should be noticed. Conventionally, the resonance analysis is mainly focused on the single inverter system, whereas in a renewable energy system...... to the conventional active damping approaches, the biquad filter based active damping method does not require additional sensors and control loops. Meanwhile, the multiple instable closed-loop poles of the parallel inverter system can be moved to the stable region simultaneously. Real-time simulations based on d...

  11. Capacitor Current Feedback-Based Active Resonance Damping Strategies for Digitally-Controlled Inductive-Capacitive-Inductive-Filtered Grid-Connected Inverters

    Directory of Open Access Journals (Sweden)

    Iman Lorzadeh

    2016-08-01

    Full Text Available Inductive-capacitive-inductive (LCL-type line filters are widely used in grid-connected voltage source inverters (VSIs, since they can provide substantially improved attenuation of switching harmonics in currents injected into the grid with lower cost, weight and power losses than their L-type counterparts. However, the inclusion of third order LCL network complicates the current control design regarding the system stability issues because of an inherent resonance peak which appears in the open-loop transfer function of the inverter control system near the control stability boundary. To avoid passive (resistive resonance damping solutions, due to their additional power losses, active damping (AD techniques are often applied with proper control algorithms in order to damp the LCL filter resonance and stabilize the system. Among these techniques, the capacitor current feedback (CCF AD has attracted considerable attention due to its effective damping performance and simple implementation. This paper thus presents a state-of-the-art review of resonance and stability characteristics of CCF-based AD approaches for a digitally-controlled LCL filter-based grid-connected inverter taking into account the effect of computation and pulse width modulation (PWM delays along with a detailed analysis on proper design and implementation.

  12. A hybrid damping method for LLCL-filter based grid-tied inverter with a digital filter and an RC parallel passive damper

    DEFF Research Database (Denmark)

    Wu, Weimin; Lin, Zhe; Sun, Yunjie

    2013-01-01

    Grid-tied inverters have been widely used to inject the renewable energies into the distributed power generation systems. However, a large variation of the grid impedance challenges the stability of the high-order power filter based grid-tied inverter. Many passive and active damping methods have...... been proposed to overcome this issue. Recently, a composite passive damping method for a high-order power filter based grid-tied inverter with an RC parallel damper and an RL series damper was presented to eliminate this problem, but at the cost of more material and power losses. In this paper...

  13. Inverted base pavements: construction and performance

    KAUST Repository

    Papadopoulos, Efthymios

    2017-05-11

    Inverted base pavements involve a well-compacted granular aggregate base built between a thin asphalt concrete layer and a cement-treated base. Inverted base pavements can be constructed using conventional equipment and procedures but require proper quality control. This study reviews the extensive South African experience and case histories in the USA. Accumulating evidence suggests that inverted base pavements are a viable alternative and can outperform conventional pavements at a lower cost. Inverted base pavements rely on the complementary interaction between layers. The cement-treated base provides a stiff foundation for efficient compaction and constrains the deformation of the stress-sensitive granular aggregate base. The thin asphalt surface layer deforms as a membrane and develops low tensile stress. Additional large-scale field tests should be conducted to assess the performance of inverted base pavement designs in a wide range of conditions relevant to the USA.

  14. Inverted base pavements: construction and performance

    KAUST Repository

    Papadopoulos, Efthymios; Santamarina, Carlos

    2017-01-01

    quality control. This study reviews the extensive South African experience and case histories in the USA. Accumulating evidence suggests that inverted base pavements are a viable alternative and can outperform conventional pavements at a lower cost

  15. Base drive for paralleled inverter systems

    Science.gov (United States)

    Nagano, S. (Inventor)

    1980-01-01

    In a paralleled inverter system, a positive feedback current derived from the total current from all of the modules of the inverter system is applied to the base drive of each of the power transistors of all modules, thereby to provide all modules protection against open or short circuit faults occurring in any of the modules, and force equal current sharing among the modules during turn on of the power transistors.

  16. Disturbance estimator based predictive current control of grid-connected inverters

    OpenAIRE

    Al-Khafaji, Ahmed Samawi Ghthwan

    2013-01-01

    ABSTRACT: The work presented in my thesis considers one of the modern discrete-time control approaches based on digital signal processing methods, that have been developed to improve the performance control of grid-connected three-phase inverters. Disturbance estimator based predictive current control of grid-connected inverters is proposed. For inverter modeling with respect to the design of current controllers, we choose the d-q synchronous reference frame to make it easier to understand an...

  17. Control strategy based on SPWM switching patterns for grid connected photovoltaic inverter

    Science.gov (United States)

    Hassaine, L.; Mraoui, A.

    2017-02-01

    Generally, for lower installation of photovoltaic systems connected to the grid, pulse width modulation (PWM) is a widely used technique for controlling the voltage source inverters injects currents into the grid. The current injected must be sinusoidal with reduced harmonic distortion. In this paper, a digital implementation of a control strategy based on PWM switching patterns for an inverter for photovoltaic system connected to the grid is presented. This strategy synchronize a sinusoidal inverter output current with a grid voltage The digital implementation of the proposed PWM switching pattern when is compared with the conventional one exhibit the advantage: Simplicity, reduction of the memory requirements and power calculation for the control

  18. Capacitor Current Feedback-Based Active Resonance Damping Strategies for Digitally-Controlled Inductive-Capacitive-Inductive-Filtered Grid-Connected Inverters

    DEFF Research Database (Denmark)

    Lorzadeh, Iman; Askarian Abyaneh, Hossein; Savaghebi, Mehdi

    2016-01-01

    Inductive-capacitive-inductive (LCL)-type line filters are widely used in grid-connected voltage source inverters (VSIs), since they can provide substantially improved attenuation of switching harmonics in currents injected into the grid with lower cost, weight and power losses than their L......-type counterparts. However, the inclusion of third order LCL network complicates the current control design regarding the system stability issues because of an inherent resonance peak which appears in the open-loop transfer function of the inverter control system near the control stability boundary. To avoid...... passive (resistive) resonance damping solutions, due to their additional power losses, active damping (AD) techniques are often applied with proper control algorithms in order to damp the LCL filter resonance and stabilize the system. Among these techniques, the capacitor current feedback (CCF) AD has...

  19. Motion Analysis Based on Invertible Rapid Transform

    Directory of Open Access Journals (Sweden)

    J. Turan

    1999-06-01

    Full Text Available This paper presents the results of a study on the use of invertible rapid transform (IRT for the motion estimation in a sequence of images. Motion estimation algorithms based on the analysis of the matrix of states (produced in the IRT calculation are described. The new method was used experimentally to estimate crowd and traffic motion from the image data sequences captured at railway stations and at high ways in large cities. The motion vectors may be used to devise a polar plot (showing velocity magnitude and direction for moving objects where the dominant motion tendency can be seen. The experimental results of comparison of the new motion estimation methods with other well known block matching methods (full search, 2D-log, method based on conventional (cross correlation (CC function or phase correlation (PC function for application of crowd motion estimation are also presented.

  20. Solar-Based Boost Differential Single Phase Inverter | Eya | Nigerian ...

    African Journals Online (AJOL)

    Solar-Based Boost Differential Single Phase Inverter. ... Solar-based boost differential inverter is reduced down to 22.37% in closed loop system with the aid of Proportional –integral-Differential (PID) ... The dc power source is photovoltaic cell.

  1. A digital controlled PV-inverter with grid impedance estimation for ENS detection

    DEFF Research Database (Denmark)

    Asiminoaei, Lucian; Teodorescu, Remus; Blaabjerg, Frede

    2005-01-01

    in dispersed power generation networks. For instance, the knowledge of the utility impedance at the fundamental frequency can be used to detect a utility failure. A PV-inverter with this feature can anticipate a possible network problem and decouple it in time. This paper describes the digital implementation...

  2. InvertNet: a new paradigm for digital access to invertebrate collections

    Directory of Open Access Journals (Sweden)

    Chris Dietrich

    2012-07-01

    Full Text Available InvertNet, one of the three Thematic Collection Networks (TCNs funded in the first round of the U.S. National Science Foundation’s Advancing Digitization of Biological Collections (ADBC program, is tasked with providing digital access to ~60 million specimens housed in 22 arthropod (primarily insect collections at institutions distributed throughout the upper midwestern USA. The traditional workflow for insect collection digitization involves manually keying information from specimen labels into a database and attaching a unique identifier label to each specimen. This remains the dominant paradigm, despite some recent attempts to automate various steps in the process using more advanced technologies. InvertNet aims to develop improved semi-automated, high-throughput workflows for digitizing and providing access to invertebrate collections that balance the need for speed and cost-effectiveness with long-term preservation of specimens and accuracy of data capture. The proposed workflows build on recent methods for digitizing and providing access to high-quality images of multiple specimens (e.g., entire drawers of pinned insects simultaneously. Limitations of previous approaches are discussed and possible solutions are proposed that incorporate advanced imaging and 3-D reconstruction technologies. InvertNet couples efficient digitization workflows with a highly robust network infrastructure capable of managing massive amounts of image data and related metadata and delivering high-quality images, including interactive 3-D reconstructions in real time via the Internet.

  3. Closed Loop Fuzzy Logic Controlled PV Based Cascaded Boost Five-Level Inverter System

    Science.gov (United States)

    Revana, Guruswamy; Kota, Venkata Reddy

    2018-04-01

    Recent developments in intelligent control methods and power electronics have produced PV based DC to AC converters related to AC drives. Cascaded boost converter and inverter find their way in interconnecting PV and Induction Motor. This paper deals with digital simulation and implementation of closed loop controlled five-level inverter based Photo-Voltaic (PV) system. The objective of this work is to reduce the harmonics using Multi Level Inverter based system. The DC output from the PV panel is boosted using cascaded-boost-converters. The DC output of these cascaded boost converters is applied to the bridges of the cascaded inverter. The AC output voltage is obtained by the series cascading of the output voltage of the two inverters. The investigations are done with Induction motor load. Cascaded boost-converter is proposed in the present work to produce the required DC Voltage at the input of the bridge inverter. A simple FLC is applied to CBFLIIM system. The FLC is proposed to reduce the steady state error. The simulation results are compared with the hardware results. The results of the comparison are made to show the improvement in dynamic response in terms of settling time and steady state error. Design procedure and control strategy are presented in detail.

  4. Inverted base pavements : new field test and design catalogue.

    Science.gov (United States)

    2014-01-01

    The current economic situation has severely affected the US road infrastructure and funding has become : inadequate for either maintenance or future growth. : The inverted base pavement structure is a promising alternative to achieve high quality roa...

  5. Six transformer based asymmetrical embedded Z-source inverters

    DEFF Research Database (Denmark)

    Wei, Mo; Poh Chiang, Loh; Chi, Jin

    2013-01-01

    Embedded/Asymmetrical embedded Z-source inverters were proposed to maintain smooth input current/voltage across the dc source and within the impedance network, remain the shoot-through feature used to boost up the dc-link voltage without adding bulky filter at input side. This paper introduces a ...... a class of transformer based asymmetrical embedded Z-source inverters which keep the smooth input current and voltage while achieving enhanced voltage boost capability. The presented inverters are verified by laboratory prototypes experimentally....

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1994-12-31

    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.

  7. High performance Si nanowire field-effect-transistors based on a CMOS inverter with tunable threshold voltage.

    Science.gov (United States)

    Van, Ngoc Huynh; Lee, Jae-Hyun; Sohn, Jung Inn; Cha, Seung Nam; Whang, Dongmok; Kim, Jong Min; Kang, Dae Joon

    2014-05-21

    We successfully fabricated nanowire-based complementary metal-oxide semiconductor (NWCMOS) inverter devices by utilizing n- and p-type Si nanowire field-effect-transistors (NWFETs) via a low-temperature fabrication processing technique. We demonstrate that NWCMOS inverter devices can be operated at less than 1 V, a significantly lower voltage than that of typical thin-film based complementary metal-oxide semiconductor (CMOS) inverter devices. This low-voltage operation was accomplished by controlling the threshold voltage of the n-type Si NWFETs through effective management of the nanowire (NW) doping concentration, while realizing high voltage gain (>10) and ultra-low static power dissipation (≤3 pW) for high-performance digital inverter devices. This result offers a viable means of fabricating high-performance, low-operation voltage, and high-density digital logic circuits using a low-temperature fabrication processing technique suitable for next-generation flexible electronics.

  8. A Digital Hysteresis Current Control for Half-Bridge Inverters with Constrained Switching Frequency

    Directory of Open Access Journals (Sweden)

    Triet Nguyen-Van

    2017-10-01

    Full Text Available This paper proposes a new robustly adaptive hysteresis current digital control algorithm for half-bridge inverters, which plays an important role in electric power, and in various applications in electronic systems. The proposed control algorithm is assumed to be implemented on a high-speed Field Programmable Gate Array (FPGA circuit, using measured data with high sampling frequency. The hysteresis current band is computed in each switching modulation period based on both the current error and the negative half switching period during the previous modulation period, in addition to the conventionally used voltages measured at computation instants. The proposed control algorithm is derived by solving the optimization problem—where the switching frequency is always constrained at below the desired constant frequency—which is not guaranteed by the conventional method. The optimization problem also keeps the output current stable around the reference, and minimizes power loss. Simulation results show good performances of the proposed algorithm compared with the conventional one.

  9. Real-time digital simulation of power electronics systems with Neutral Point Piloted multilevel inverter using FPGA

    Energy Technology Data Exchange (ETDEWEB)

    Rakotozafy, Mamianja [Groupe de Recherches en Electrotechnique et Electronique de Nancy (GREEN), Faculte des Sciences et Techniques, BP 70239, 54506 Vandoeuvre Cedex (France); CONVERTEAM SAS, Parc d' activites Techn' hom, 24 avenue du Marechal Juin, BP 40437, 90008 Belfort Cedex (France); Poure, Philippe [Laboratoire d' Instrumentation Electronique de Nancy (LIEN), Faculte des Sciences et Techniques, BP 70239, 54506 Vandoeuvre Cedex (France); Saadate, Shahrokh [Groupe de Recherches en Electrotechnique et Electronique de Nancy (GREEN), Faculte des Sciences et Techniques, BP 70239, 54506 Vandoeuvre Cedex (France); Bordas, Cedric; Leclere, Loic [CONVERTEAM SAS, Parc d' activites Techn' hom, 24 avenue du Marechal Juin, BP 40437, 90008 Belfort Cedex (France)

    2011-02-15

    Most of actual real time simulation platforms have practically about ten microseconds as minimum calculation time step, mainly due to computation limits such as processing speed, architecture adequacy and modeling complexities. Therefore, simulation of fast switching converters' instantaneous models requires smaller computing time step. The approach presented in this paper proposes an answer to such limited modeling accuracies and computational bandwidth of the currently available digital simulators.As an example, the authors present a low cost, flexible and high performance FPGA-based real-time digital simulator for a complete complex power system with Neutral Point Piloted (NPP) three-level inverter. The proposed real-time simulator can model accurately and efficiently the complete power system, reducing costs, physical space and avoiding any damage to the actual equipment in the case of any dysfunction of the digital controller prototype. The converter model is computed at a small fixed time step as low as 100 ns. Such a computation time step allows high precision account of the gating signals and thus avoids averaging methods and event compensations. Moreover, a novel high performance model of the NPP three-level inverter has also been proposed for FPGA implementation. The proposed FPGA-based simulator models the environment of the NPP converter: the dc link, the RLE load and the digital controller and gating signals. FPGA-based real time simulation results are presented and compared with offline results obtained using PLECS software. They validate the efficiency and accuracy of the modeling for the proposed high performance FPGA-based real-time simulation approach. This paper also introduces new potential FPGA-based applications such as low cost real time simulator for power systems by developing a library of flexible and portable models for power converters, electrical machines and drives. (author)

  10. Large-Signal Lyapunov-Based Stability Analysis of DC/AC Inverters and Inverter-Based Microgrids

    Science.gov (United States)

    Kabalan, Mahmoud

    Microgrid stability studies have been largely based on small-signal linearization techniques. However, the validity and magnitude of the linearization domain is limited to small perturbations. Thus, there is a need to examine microgrids with large-signal nonlinear techniques to fully understand and examine their stability. Large-signal stability analysis can be accomplished by Lyapunov-based mathematical methods. These Lyapunov methods estimate the domain of asymptotic stability of the studied system. A survey of Lyapunov-based large-signal stability studies showed that few large-signal studies have been completed on either individual systems (dc/ac inverters, dc/dc rectifiers, etc.) or microgrids. The research presented in this thesis addresses the large-signal stability of droop-controlled dc/ac inverters and inverter-based microgrids. Dc/ac power electronic inverters allow microgrids to be technically feasible. Thus, as a prelude to examining the stability of microgrids, the research presented in Chapter 3 analyzes the stability of inverters. First, the 13 th order large-signal nonlinear model of a droop-controlled dc/ac inverter connected to an infinite bus is presented. The singular perturbation method is used to decompose the nonlinear model into 11th, 9th, 7th, 5th, 3rd and 1st order models. Each model ignores certain control or structural components of the full order model. The aim of the study is to understand the accuracy and validity of the reduced order models in replicating the performance of the full order nonlinear model. The performance of each model is studied in three different areas: time domain simulations, Lyapunov's indirect method and domain of attraction estimation. The work aims to present the best model to use in each of the three domains of study. Results show that certain reduced order models are capable of accurately reproducing the performance of the full order model while others can be used to gain insights into those three areas of

  11. Adaptive robust pole-placement control of 4-leg voltage-source inverters for standalone photovoltaic systems: Considering digital delays

    International Nuclear Information System (INIS)

    Nasiri, Reza; Radan, Ahmad

    2011-01-01

    Three leg inverters for photovoltaic systems have a lot of disadvantages, especially when the load is unbalanced. These disadvantages are for example, small utilization of the DC link voltage, the dependency of the modulation factor of the load current and the superposition of a DC component with the output AC voltage. A solution for these problems is the 4-leg inverter. Most papers dealing with 4-leg inverters ignore the effect of digital delays in control loop and suggest classic controllers, such as PI controller. However, the transient performance of the system does not become adjustable by applying classic control techniques. Additionally, adaptive control techniques have not yet been discussed for 4-leg inverters. This paper proposes the pole-placement control strategy via state feedback with integral state, which is a modern control technique, to control the system. Consequently, resulted system becomes highly robust. In addition, it suggests a Self-Tuner Regulator to guarantee the adaptive performance of the final system. Moreover, it proposes a novel model, considering digital delays, for 4-leg inverters. Simulation results show that transient performance of the system becomes accurately adjustable and the 4-leg inverter generates balanced voltage, with sinusoidal waveform, in spite of the presence of RL time variant loads.

  12. Inverting the diastereoselectivity of the mukaiyama-michael addition with graphite-based catalysts

    KAUST Repository

    Acocella, Maria Rosaria; Mauro, Marco; Falivene, Laura; Cavallo, Luigi; Guerra, Gaetano

    2014-01-01

    , the graphite-based catalysts described here invert the diastereoselectivity relative to that observed with known catalysts, with the unprecedented large prevalence of the anti diastereoisomer. This inverted diastereoselectivity is increased when the catalyst

  13. Inverted Polarity Thunderstorms Linked with Elevated Cloud Base Height

    Science.gov (United States)

    Cummins, K. L.; Williams, E.

    2016-12-01

    The great majority of thunderstorms worldwide exhibit gross positive dipole structure, produce intracloud lightning that reduces this positive dipole (positive intracloud flashes), and produce negative cloud-to-ground lightning from the lower negative end of this dipole. During the STEPS experiment in 2000 much new evidence for thunderstorms (or cells within multi-cellular storms) with inverted polarity came to light, both from balloon soundings of electric field and from LMA analysis. Many of the storms with inverted polarity cells developed in eastern Colorado. Fleenor et al. (2009) followed up after STEPS to document a dominance of positive polarity CG lightning in many of these cases. In the present study, surface thermodynamic observations (temperature and dew point temperature) have been used to estimate the cloud base heights and temperatures at the time of the Fleenor et al. lightning observations. It was found that when more than 90% of the observed CG lightning polarity within a storm is negative, the cloud base heights were low (2000 m AGL or lower, and warmer, with T>10 C), and when more than 90% of the observed CG lightning within a storm was positive, the cloud base heights were high (3000 m AGL or higher, and colder, with Tmixed polarity were generally associated with intermediate cloud base heights. These findings on inverted polarity thunderstorms are remarkably consistent with results in other parts of the world where strong instability prevails in the presence of high cloud base height: the plateau regions of China (Liu et al., 1989; Qie et al., 2005), and in pre-monsoon India (Pawar et al., 2016), particularly when mixed polarity cases are excluded. Calculations of adiabatic cloud water content for lifting from near 0 oC cast some doubt on earlier speculation (Williams et al., 2005) that the graupel particles in these inverted polarity storms attain a wet growth condition, and so exhibit positive charging following laboratory experiments. This

  14. FPGA Based Compensation Method for Correcting Distortion in Voltage Inverters

    National Research Council Canada - National Science Library

    Williamson, Kenya D

    2007-01-01

    ...) voltage source inverters. Blanking time distortion is caused by the delay inserted to prevent the short circuit that would occur if the two transistors in the same inverter leg are both on at the same time...

  15. Wavy Channel TFT-Based Digital Circuits

    KAUST Repository

    Hanna, Amir; Hussain, Aftab M.; Hussain, Aftab M.; Hussain, Aftab M.; Omran, Hesham; Alsharif, Sarah M.; Salama, Khaled N.; Hussain, Muhammad Mustafa

    2016-01-01

    We report a wavy channel (WC) architecture thin-film transistor-based digital circuitry using ZnO as a channel material. The novel architecture allows for extending device width by integrating vertical finlike substrate corrugations giving rise to 50% larger device width, without occupying extra chip area. The enhancement in the output drive current is 100%, when compared with conventional planar architecture for devices occupying the same chip area. The current increase is attributed to both the extra device width and 50% enhancement in field-effect mobility due to electrostatic gating effects. Fabricated inverters show that WC inverters can achieve two times the peak-to-peak output voltage for the same input when compared with planar devices. In addition, WC inverters show 30% faster rise and fall times, and can operate up to around two times frequency of the planar inverters for the same peak-to-peak output voltage. WC NOR circuits have shown 70% higher peak-to-peak output voltage, over their planar counterparts, and WC pass transistor logic multiplexer circuit has shown more than five times faster high-to-low propagation delay compared with its planar counterpart at a similar peak-to-peak output voltage.

  16. Wavy Channel TFT-Based Digital Circuits

    KAUST Repository

    Hanna, Amir

    2016-02-23

    We report a wavy channel (WC) architecture thin-film transistor-based digital circuitry using ZnO as a channel material. The novel architecture allows for extending device width by integrating vertical finlike substrate corrugations giving rise to 50% larger device width, without occupying extra chip area. The enhancement in the output drive current is 100%, when compared with conventional planar architecture for devices occupying the same chip area. The current increase is attributed to both the extra device width and 50% enhancement in field-effect mobility due to electrostatic gating effects. Fabricated inverters show that WC inverters can achieve two times the peak-to-peak output voltage for the same input when compared with planar devices. In addition, WC inverters show 30% faster rise and fall times, and can operate up to around two times frequency of the planar inverters for the same peak-to-peak output voltage. WC NOR circuits have shown 70% higher peak-to-peak output voltage, over their planar counterparts, and WC pass transistor logic multiplexer circuit has shown more than five times faster high-to-low propagation delay compared with its planar counterpart at a similar peak-to-peak output voltage.

  17. Inverter Circuits Using ZnO Nanoparticle Based Thin-Film Transistors for Flexible Electronic Applications.

    Science.gov (United States)

    Vidor, Fábio F; Meyers, Thorsten; Hilleringmann, Ulrich

    2016-08-23

    Innovative systems exploring the flexibility and the transparency of modern semiconducting materials are being widely researched by the scientific community and by several companies. For a low-cost production and large surface area applications, thin-film transistors (TFTs) are the key elements driving the system currents. In order to maintain a cost efficient integration process, solution based materials are used as they show an outstanding tradeoff between cost and system complexity. In this paper, we discuss the integration process of ZnO nanoparticle TFTs using a high- k resin as gate dielectric. The performance in dependence on the transistor structure has been investigated, and inverted staggered setups depict an improved performance over the coplanar device increasing both the field-effect mobility and the I ON / I OFF ratio. Aiming at the evaluation of the TFT characteristics for digital circuit applications, inverter circuits using a load TFT in the pull-up network and an active TFT in the pull-down network were integrated. The inverters show reasonable switching characteristics and V / V gains. Conjointly, the influence of the geometry ratio and the supply voltage on the devices have been analyzed. Moreover, as all integration steps are suitable to polymeric templates, the fabrication process is fully compatible to flexible substrates.

  18. Inverter Circuits Using ZnO Nanoparticle Based Thin-Film Transistors for Flexible Electronic Applications

    Directory of Open Access Journals (Sweden)

    Fábio F. Vidor

    2016-08-01

    Full Text Available Innovative systems exploring the flexibility and the transparency of modern semiconducting materials are being widely researched by the scientific community and by several companies. For a low-cost production and large surface area applications, thin-film transistors (TFTs are the key elements driving the system currents. In order to maintain a cost efficient integration process, solution based materials are used as they show an outstanding tradeoff between cost and system complexity. In this paper, we discuss the integration process of ZnO nanoparticle TFTs using a high-k resin as gate dielectric. The performance in dependence on the transistor structure has been investigated, and inverted staggered setups depict an improved performance over the coplanar device increasing both the field-effect mobility and the ION/IOFF ratio. Aiming at the evaluation of the TFT characteristics for digital circuit applications, inverter circuits using a load TFT in the pull-up network and an active TFT in the pull-down network were integrated. The inverters show reasonable switching characteristics and V/V gains. Conjointly, the influence of the geometry ratio and the supply voltage on the devices have been analyzed. Moreover, as all integration steps are suitable to polymeric templates, the fabrication process is fully compatible to flexible substrates.

  19. Modelling of the modified-LLCL-filter-based single-phase grid-tied Aalborg inverter

    DEFF Research Database (Denmark)

    Liu, Zifa; Wu, Huiyun; Liu, Yuan

    2017-01-01

    Owing to less conduction and switching power losses, the recently proposed Aalborg inverter has high efficiency within a wide range of input DC voltage for single-phase DC/AC power conversion. In theory, the conduction power losses can be further decreased, if an LLCL-filter is adopted instead...... of an LCL-filter for a voltage source inverter, mainly due to the reduced inductance. The Aalborg inverter shows the characteristic of a current source inverter, when working in the `boost' state. Whether the LLCL-filter can meet the control requirement of this type inverter needs to be further explored....... In this study, the small signal analysis for the modified-LLCL-filter-based Aalborg inverter is addressed. Through the modelling, it can be proven that compared with the LCL-filter, the modified-LLCL-filter causes no extra control challenge for the Aalborg inverter, and therefore more inductance in the power...

  20. Simple and robust image-based autofocusing for digital microscopy.

    Science.gov (United States)

    Yazdanfar, Siavash; Kenny, Kevin B; Tasimi, Krenar; Corwin, Alex D; Dixon, Elizabeth L; Filkins, Robert J

    2008-06-09

    A simple image-based autofocusing scheme for digital microscopy is demonstrated that uses as few as two intermediate images to bring the sample into focus. The algorithm is adapted to a commercial inverted microscope and used to automate brightfield and fluorescence imaging of histopathology tissue sections.

  1. Single-Phase LLCL-Filter-based Grid-Tied Inverter with Low-Pass Filter Based Capacitor Current Feedback Active damper

    DEFF Research Database (Denmark)

    Liu, Yuan; Wu, Weimin; Li, Yun

    2016-01-01

    The capacitor-current-feedback active damping method is attractive for high-order-filter-based high power grid-tied inverter when the grid impedance varies within a wide range. In order to improve the system control bandwidth and attenuate the high order grid background harmonics by using the quasi....... In this paper, a low pass filter is proposed to be inserted in the capacitor current feedback loop op LLCL-filter based grid-tied inverter together with a digital proportional and differential compensator. The detailed theoretical analysis is given. For verification, simulations on a 2kW/220V/10kHz LLCL...

  2. Integrated Power Flow and Short Circuit Calculation Method for Distribution Network with Inverter Based Distributed Generation

    OpenAIRE

    Yang, Shan; Tong, Xiangqian

    2016-01-01

    Power flow calculation and short circuit calculation are the basis of theoretical research for distribution network with inverter based distributed generation. The similarity of equivalent model for inverter based distributed generation during normal and fault conditions of distribution network and the differences between power flow and short circuit calculation are analyzed in this paper. Then an integrated power flow and short circuit calculation method for distribution network with inverte...

  3. Fast Grid Frequency Support from Distributed Inverter-Based Resources

    Energy Technology Data Exchange (ETDEWEB)

    Hoke, Anderson F [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2018-05-04

    This presentation summarizes power hardware-in-the-loop testing performed to evaluate the ability of distributed inverter-coupled generation to support grid frequency on the fastest time scales. The research found that distributed PV inverters and other DERs can effectively support the grid on sub-second time scales.

  4. dSPACE based adaptive neuro-fuzzy controller of grid interactive inverter

    International Nuclear Information System (INIS)

    Altin, Necmi; Sefa, İbrahim

    2012-01-01

    Highlights: ► We propose a dSPACE based neuro-fuzzy controlled grid interactive inverter. ► The membership functions and rule base of fuzzy logic controller by using ANFIS. ► A LCL output filter is designed. ► A high performance controller is designed. - Abstract: In this study, design, simulation and implementation of a dSPACE based grid interactive voltage source inverter are proposed. This inverter has adaptive neuro-fuzzy controller and capable of importing electrical energy, generated from renewable energy sources such as the wind, the solar and the fuel cells to the grid. A line frequency transformer and a LCL filter are used at the output of the grid interactive inverter which is designed as current controlled to decrease the susceptibility to phase errors. Membership functions and rule base of the fuzzy logic controller, which control the inverter output current, are determined by using artificial neural networks. Both simulation and experimental results show that, the grid interactive inverter operates synchronously with the grid. The inverter output current which is imported to the grid is in sinusoidal waveform and the harmonic level of it meets the international standards (4.3 < 5.0%). In addition, simulation and experimental results of the neuro-fuzzy and the PI controlled inverter are given together and compared in detail. Simulation and experimental results show that the proposed inverter has faster response to the reference variations and lower steady state error than PI controller.

  5. Z-Source Inverter Based Power Quality Compensator with Enhanced Ride-Through Capability

    DEFF Research Database (Denmark)

    Gajanayake, C.J.; Vilathgamuwa, D.M.; Loh, P.C.

    2007-01-01

    Distributed generation has been gaining acceptance over the years and it has the potential to provide reliable power to sensitive loads. However, distributed networks are prone to unbalanced faults conditions. This makes single inverter DG systems unsuitable as UPS systems. This paper proposes...... a Zsource inverter based power quality compensator and a control structure that supplies high quality voltage to the connected sensitive load in the presence of other non linear loads. The proposed topology consists of combination of shunt and series inverters connected to a common Z-source impedance...... network. The shunt inverter is controlled to maintain a quality voltage waveform at the load bus. Whereas the series inverter enhances the ride-through capability during grid faults, protects the shunt inverter by limiting the current and also controls the power delivered to the grid. The performance...

  6. High-speed all-optical logic inverter based on stimulated Raman scattering in silicon nanocrystal.

    Science.gov (United States)

    Sen, Mrinal; Das, Mukul K

    2015-11-01

    In this paper, we propose a new device architecture for an all-optical logic inverter (NOT gate), which is cascadable with a similar device. The inverter is based on stimulated Raman scattering in silicon nanocrystal waveguides, which are embedded in a silicon photonic crystal structure. The Raman response function of silicon nanocrystal is evaluated to explore the transfer characteristic of the inverter. A maximum product criterion for the noise margin is taken to analyze the cascadability of the inverter. The time domain response of the inverter, which explores successful inversion operation at 100 Gb/s, is analyzed. Propagation delay of the inverter is on the order of 5 ps, which is less than the delay in most of the electronic logic families as of today. Overall dimension of the device is around 755  μm ×15  μm, which ensures integration compatibility with the matured silicon industry.

  7. Mode tunable p-type Si nanowire transistor based zero drive load logic inverter.

    Science.gov (United States)

    Moon, Kyeong-Ju; Lee, Tae-Il; Lee, Sang-Hoon; Han, Young-Uk; Ham, Moon-Ho; Myoung, Jae-Min

    2012-07-25

    A design platform for a zero drive load logic inverter consisting of p-channel Si nanowire based transistors, which controlled their operating mode through an implantation into a gate dielectric layer was demonstrated. As a result, a nanowire based class D inverter having a 4.6 gain value at V(DD) of -20 V was successfully fabricated on a substrate.

  8. LLCL-Filter Based Single-Phase Grid-Tied Aalborg Inverter

    DEFF Research Database (Denmark)

    Wu, Weimin; Feng, Shuangshuang; Ji, Junhao

    2014-01-01

    The Aalborg Inverter is a new type of high efficient DC/AC grid-tied inverter, where the input DC voltage can vary in a wide range. Compared with the LCL-filter, the LLCL-filter can save the total inductance for the conventional voltage source inverter. In this paper, an LLCL-filter based Aalborg...... Inverter is proposed and its character is illustrated through the small signal analysis in both “Buck” and “Buck-Boost” mode. From the modeling, it can be seen that the resonant inductor in the capacitor loop has not brought extra control difficulties, whereas more inductance in the power loop can be saved...

  9. A Decoupled Control of 5-Legs PWM Inverter Feeding a two Induction Motors-based Electric Vehicle Powertrain

    Directory of Open Access Journals (Sweden)

    Bekheïra Tabbache

    2016-06-01

    Full Text Available This paper proposes a traction drive system for electric vehicles (EVs with two separate induction motor drive-based wheels. In this context, two three-phase induction motors are associated to five legs power inverter which one leg is shared by two phases of the motors. The independent control of the two induction motors allows replacing the mechanical differential speeds by an equivalent electrical module called electric differential (ED. In the proposed EV powertrain based on 5-leg inverter, the challenge is to achieve a decoupled control of the induction motors to ensure the EV stability while cornering or under slippery road condition. For this, the proposed independent control uses Indirect Field Oriented Control to ensure speed and rotor flux control of each induction motor , a Pulse Width Modulation to provide the command sequences to the 5-leg inverter and electric differential to generate the an appropriate reference when the two induction motors should be controlled at different speeds. For this, a numerical implementation of the independent controls on an embedded board (TMS 320F2812 to ensure a separate control of induction motor fed by the 5-leg inverter. Moreover, the proposed control takes into account the EV context such as the EV dynamic and uses European and American normalized driving cycles. EV-specific experimental tests on a digital signal processor TMS320LF2812 are carried-out to show the effectiveness of the proposed independent control for ED in terms of robustness and stability.

  10. Fine Output Voltage Control Method considering Time-Delay of Digital Inverter System for X-ray Computed Tomography

    Science.gov (United States)

    Shibata, Junji; Kaneko, Kazuhide; Ohishi, Kiyoshi; Ando, Itaru; Ogawa, Mina; Takano, Hiroshi

    This paper proposes a new output voltage control for an inverter system, which has time-delay and nonlinear load. In the next generation X-ray computed tomography of a medical device (X-ray CT) that uses the contactless power transfer method, the feedback signal often contains time-delay due to AD/DA conversion and error detection/correction time. When the PID controller of the inverter system is received the adverse effects of the time-delay, the controller often has an overshoot and a oscillated response. In order to overcome this problem, this paper proposes a compensation method based on the Smith predictor for an inverter system having a time-delay and the nonlinear loads which are the diode bridge rectifier and X-ray tube. The proposed compensation method consists of the hybrid Smith predictor system based on an equivalent analog circuit and DSP. The experimental results confirm the validity of the proposed system.

  11. RTDS implementation of an improved sliding mode based inverter controller for PV system.

    Science.gov (United States)

    Islam, Gazi; Muyeen, S M; Al-Durra, Ahmed; Hasanien, Hany M

    2016-05-01

    This paper proposes a novel approach for testing dynamics and control aspects of a large scale photovoltaic (PV) system in real time along with resolving design hindrances of controller parameters using Real Time Digital Simulator (RTDS). In general, the harmonic profile of a fast controller has wide distribution due to the large bandwidth of the controller. The major contribution of this paper is that the proposed control strategy gives an improved voltage harmonic profile and distribute it more around the switching frequency along with fast transient response; filter design, thus, becomes easier. The implementation of a control strategy with high bandwidth in small time steps of Real Time Digital Simulator (RTDS) is not straight forward. This paper shows a good methodology for the practitioners to implement such control scheme in RTDS. As a part of the industrial process, the controller parameters are optimized using particle swarm optimization (PSO) technique to improve the low voltage ride through (LVRT) performance under network disturbance. The response surface methodology (RSM) is well adapted to build analytical models for recovery time (Rt), maximum percentage overshoot (MPOS), settling time (Ts), and steady state error (Ess) of the voltage profile immediate after inverter under disturbance. A systematic approach of controller parameter optimization is detailed. The transient performance of the PSO based optimization method applied to the proposed sliding mode controlled PV inverter is compared with the results from genetic algorithm (GA) based optimization technique. The reported real time implementation challenges and controller optimization procedure are applicable to other control applications in the field of renewable and distributed generation systems. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

  12. Optimization of SiC-based H5 and Conergy-NPC transformerless PV inverters

    DEFF Research Database (Denmark)

    Saridakis, Stefanos; Koutroulis, Eftichios; Blaabjerg, Frede

    2013-01-01

    effective in terms of energy production than their non-optimized and Si-based counterparts. Reducing the market price of SiC-type power semiconductors enables to design optimized PV inverters with a lower cost of energy than that of PV inverters employing Si technology, thus maximizing the economic...... profitability of the PV system....

  13. Coupled-Inductor-Based Aalborg Inverter With Input DC Energy Regulation

    DEFF Research Database (Denmark)

    Wang, Houqing; Wu, Weimin; Chung, Henry Shu-hung

    2018-01-01

    Due to the global environmental issues and energy crisis, the injection of renewable energy sources (RESs) into the power system is continuously increasing. As the interface between RESs and power grid, grid-tied inverters using MOSFET switches, without traditional line frequency transformers, show...... some potential advantages, in terms of low cost, high efficiency, and lightweight and small size. Among several proposed configurations, the Aalborg inverter was proposed as a new family of high efficiency MOSFET-switch-based hybrid source inverters. For a conventional “half bridge” type Aalborg...... inverter, due to the imbalance of two independent dc sources, the input dc energies may not be fully utilized, which may reduce the efficiency of whole system. In order to extract the maximum energy from two independent dc sources, a coupled-inductor-based “half bridge” type Aalborg inverter is proposed...

  14. State-space-based harmonic stability analysis for paralleled grid-connected inverters

    DEFF Research Database (Denmark)

    Wang, Yanbo; Wang, Xiongfei; Chen, Zhe

    2016-01-01

    This paper addresses a state-space-based harmonic stability analysis of paralleled grid-connected inverters system. A small signal model of individual inverter is developed, where LCL filter, the equivalent delay of control system, and current controller are modeled. Then, the overall small signal...... model of paralleled grid-connected inverters is built. Finally, the state space-based stability analysis approach is developed to explain the harmonic resonance phenomenon. The eigenvalue traces associated with time delay and coupled grid impedance are obtained, which accounts for how the unstable...... inverter produces the harmonic resonance and leads to the instability of whole paralleled system. The proposed approach reveals the contributions of the grid impedance as well as the coupled effect on other grid-connected inverters under different grid conditions. Simulation and experimental results...

  15. SiC MOSFETs based split output half bridge inverter

    DEFF Research Database (Denmark)

    Li, Helong; Munk-Nielsen, Stig; Beczkowski, Szymon

    2014-01-01

    output. The double pulse test shows the devices' current during commutation process and the reduced switching losses of SiC MOSFETs compared to that of the traditional half bridge. The efficiency comparison is presented with experimental results of half bridge power inverter with split output...... and traditional half bridge inverter, from switching frequency 10 kHz to 100 kHz. The experimental results comparison shows that the half bridge with split output has an efficiency improvement of more than 0.5% at 100 kHz switching frequency....

  16. Microcontroller Based SPWM Single-Phase Inverter For Wind Power Application

    Directory of Open Access Journals (Sweden)

    Khin Ohmar Lin

    2017-04-01

    Full Text Available In this paper microcontroller based sinusoidal pulse width modulation SPWM single-phase inverter is emphasized to constant frequency conversion scheme for wind power application. The wind-power generator output voltage and frequency are fluctuated due to the variation of wind velocity. Therefore the AC output voltage of wind-generator is converted into DC voltage by using rectifier circuit and this DC voltage is converted back to AC voltage by using inverter circuit. SPWM technique is used in inverter to get nearly sine wave and reduce harmonic content. The rating of inverter is 500W single-phase 220V 50 Hz. The required SPWM timing pulses for the inverter are generated from the PIC16F877A microcontroller. Circuit simulation was done by using Proteus 7 Professional and MATLABR 2008 software. The software for microcontroller is implemented by using MPASM assembler.

  17. 6 5KVA POWER INVERTER DESIGN AND SIMULATION BASED ...

    African Journals Online (AJOL)

    DR. AMINU

    increasing and conventional energy resources are diminishing and even threatened to be depleted. With the increasing popularity of alternative power sources, such as solar and wind, the need for static inverters to convert dc energy stored in batteries to conventional ac form has increased substantially. This conversion.

  18. Multilevel inverter based class D audio amplifier for capacitive transducers

    DEFF Research Database (Denmark)

    Nielsen, Dennis; Knott, Arnold; Andersen, Michael A. E.

    2014-01-01

    The reduced semiconductor voltage stress makes the multilevel inverters especially interesting, when driving capacitive transducers for audio applications. A ± 300 V flying capacitor class D audio amplifier driving a 100 nF load in the midrange region of 0.1-3.5 kHz with Total Harmonic Distortion...

  19. Modeling and Grid impedance Variation Analysis of Parallel Connected Grid Connected Inverter based on Impedance Based Harmonic Analysis

    DEFF Research Database (Denmark)

    Kwon, JunBum; Wang, Xiongfei; Bak, Claus Leth

    2014-01-01

    This paper addresses the harmonic compensation error problem existing with parallel connected inverter in the same grid interface conditions by means of impedance-based analysis and modeling. Unlike the single grid connected inverter, it is found that multiple parallel connected inverters and grid...... impedance can make influence to each other if they each have a harmonic compensation function. The analysis method proposed in this paper is based on the relationship between the overall output impedance and input impedance of parallel connected inverter, where controller gain design method, which can...

  20. Fully patterned and low temperature transparent ZnO-based inverters

    Energy Technology Data Exchange (ETDEWEB)

    Gutierrez-Heredia, G. [Centro de Investigación en Materiales Avanzados, Unidad Monterrey, México (Mexico); Department of Materials Science and Engineering, University of Texas at Dallas (United States); Mejia, I.; Rivas-Aguilar, M.E.; Hernandez-Como, N. [Department of Materials Science and Engineering, University of Texas at Dallas (United States); Martinez-Landeros, V.H. [Centro de Investigación en Materiales Avanzados, Unidad Monterrey, México (Mexico); Department of Materials Science and Engineering, University of Texas at Dallas (United States); Aguirre-Tostado, F.S. [Centro de Investigación en Materiales Avanzados, Unidad Monterrey, México (Mexico); Quevedo-Lopez, M.A., E-mail: mquevedo@utdallas.edu [Department of Materials Science and Engineering, University of Texas at Dallas (United States)

    2013-10-31

    The fabrication and characterization of transparent logic inverters based on zinc oxide (ZnO) thin film transistors (TFTs) is reported. The inverters are fabricated using standard photolithographic techniques on glass substrates, and the entire fabrication process temperature is maintained < 100 °C, which render the devices suitable for flexible and transparent electronics applications. Pulsed laser deposition is used to deposit aluminum-doped zinc oxide and ZnO as electrode and active semiconductor materials, respectively. Electrical characterization for individual TFTs demonstrate mobilities of ∼ 10 cm{sup 2}/V-s, threshold voltages of 6 V, sub-threshold slopes of 630 mV/decade and I{sub ON}/I{sub OFF} ratios of 5 × 10{sup 6}. Films characterized by UV-Vis showed optical transmission > 80% in the visible spectrum. The inverters are analyzed with AC input signals at frequencies of 100 and 500 Hz. The AC response shows an average rise and fall time transitions of 0.65 and 0.44 ms, respectively. Measured inverters delay is in the order of 0.21 ms. - Highlights: • Logic inverters based on zinc oxide thin film transistors. • Inverters fabricated using temperatures below 100 °C and standard photolithography. • Transparent aluminum-doped zinc oxide as gate, drain and source electrodes. • Devices with total transmittance in the visible range above 80%. • AC inverter response up to 500 Hz.

  1. Fully patterned and low temperature transparent ZnO-based inverters

    International Nuclear Information System (INIS)

    Gutierrez-Heredia, G.; Mejia, I.; Rivas-Aguilar, M.E.; Hernandez-Como, N.; Martinez-Landeros, V.H.; Aguirre-Tostado, F.S.; Quevedo-Lopez, M.A.

    2013-01-01

    The fabrication and characterization of transparent logic inverters based on zinc oxide (ZnO) thin film transistors (TFTs) is reported. The inverters are fabricated using standard photolithographic techniques on glass substrates, and the entire fabrication process temperature is maintained < 100 °C, which render the devices suitable for flexible and transparent electronics applications. Pulsed laser deposition is used to deposit aluminum-doped zinc oxide and ZnO as electrode and active semiconductor materials, respectively. Electrical characterization for individual TFTs demonstrate mobilities of ∼ 10 cm 2 /V-s, threshold voltages of 6 V, sub-threshold slopes of 630 mV/decade and I ON /I OFF ratios of 5 × 10 6 . Films characterized by UV-Vis showed optical transmission > 80% in the visible spectrum. The inverters are analyzed with AC input signals at frequencies of 100 and 500 Hz. The AC response shows an average rise and fall time transitions of 0.65 and 0.44 ms, respectively. Measured inverters delay is in the order of 0.21 ms. - Highlights: • Logic inverters based on zinc oxide thin film transistors. • Inverters fabricated using temperatures below 100 °C and standard photolithography. • Transparent aluminum-doped zinc oxide as gate, drain and source electrodes. • Devices with total transmittance in the visible range above 80%. • AC inverter response up to 500 Hz

  2. Integrated Power Flow and Short Circuit Calculation Method for Distribution Network with Inverter Based Distributed Generation

    Directory of Open Access Journals (Sweden)

    Shan Yang

    2016-01-01

    Full Text Available Power flow calculation and short circuit calculation are the basis of theoretical research for distribution network with inverter based distributed generation. The similarity of equivalent model for inverter based distributed generation during normal and fault conditions of distribution network and the differences between power flow and short circuit calculation are analyzed in this paper. Then an integrated power flow and short circuit calculation method for distribution network with inverter based distributed generation is proposed. The proposed method let the inverter based distributed generation be equivalent to Iθ bus, which makes it suitable to calculate the power flow of distribution network with a current limited inverter based distributed generation. And the low voltage ride through capability of inverter based distributed generation can be considered as well in this paper. Finally, some tests of power flow and short circuit current calculation are performed on a 33-bus distribution network. The calculated results from the proposed method in this paper are contrasted with those by the traditional method and the simulation method, whose results have verified the effectiveness of the integrated method suggested in this paper.

  3. A New N-Level Inverter Based on Z-NPC

    Directory of Open Access Journals (Sweden)

    E. Babaei

    2017-12-01

    Full Text Available First of all, in this paper, the topology and operation of the three-phase three-level Z-source inverter based on neutral-point-clamped (Z-NPC are studied. Moreover, different combinations of permissible switching states and control signals are explained for this inverter. In this paper, the topology of the three-phase three-level Z-NPC inverter is extended for an n-level state. Also, a combination of allowed switching states with relevant mathematical equations is presented for the proposed n-level Z-NPC inverter. In comparison with multilevel voltage-source inverters (only voltage-boost capability, the proposed multilevel Z-NPC inverter is a single-stage converter and it has a buck-boost capability of voltage. On the other hand, the control of two-stage converters compared to single-stage converters can be more difficult because of existing more active and passive components. In this paper, two new PWM control methods are also proposed for various multilevel Z-NPC inverters. One advantage of the proposed PWM control methods in comparison with conventional PWM control methods is maintaining the charge balance of the dc-link capacitors in neutral point. The correct performance of the proposed multilevel Z-NPC topology and PWM control methods are verified by the obtained results of analysis and simulations performed in the PSCAD software.

  4. Active Damping Techniques for LCL-Filtered Inverters-Based Microgrids

    DEFF Research Database (Denmark)

    Lorzadeh, Iman; Firoozabadi, Mehdi Savaghebi; Askarian Abyaneh, Hossein

    2015-01-01

    LCL-type filters are widely used in gridconnected voltage source inverters, since it provides switching ripples reduction with lower cost and weight than the L-type counterpart. However, the inclusion of LCL-filters in voltage source inverters complicates the current control design regarding system...... the different active damping approaches for grid-connected inverters with LCL filters, which are based on high-order filters and additional feedbacks methods. These techniques are analyzed and discussed in detail....... stability issues; because an inherent resonance peak appears due to zero impedance at that resonance frequency. Moreover, in grid-interactive low-voltage microgrids, the interactions among the LCL-filtered-based parallel inverters may result in a more complex multiresonance issue which may compromise...

  5. Digital DC-Reconstruction of AC-Coupled Electrophysiological Signals with a Single Inverting Filter

    DEFF Research Database (Denmark)

    Abächerli, Roger; Isaksen, Jonas; Schmid, Ramun

    2016-01-01

    Since the introduction of digital electrocardiographs, high-pass filters have been necessary for successful analog-to-digital conversion with a reasonable amplitude resolution. On the other hand, such high-pass filters may distort the diagnostically significant ST-segment of the ECG, which can...

  6. 5kVa power inverter design and simulation based on boost ...

    African Journals Online (AJOL)

    Five (5) kVA power inverter was designed and simulated base on two topologies; Boost converter and Half-bridge inverter topology. A 555 timer IC was used as the control at fixed frequencies of 25 kHz and 50 Hz for the two stages. The results of the simulation were obtained. The graphs for both stages were plotted and the ...

  7. Selective Dirac voltage engineering of individual graphene field-effect transistors for digital inverter and frequency multiplier integrations.

    Science.gov (United States)

    Sul, Onejae; Kim, Kyumin; Jung, Yungwoo; Choi, Eunsuk; Lee, Seung-Beck

    2017-09-15

    The ambipolar band structure of graphene presents unique opportunities for novel electronic device applications. A cycle of gate voltage sweep in a conventional graphene transistor produces a frequency-doubled output current. To increase the frequency further, we used various graphene doping control techniques to produce Dirac voltage engineered graphene channels. The various surface treatments and substrate conditions produced differently doped graphene channels that were integrated on a single substrate and multiple Dirac voltages were observed by applying a single gate voltage sweep. We applied the Dirac voltage engineering techniques to graphene field-effect transistors on a single chip for the fabrication of a frequency multiplier and a logic inverter demonstrating analog and digital circuit application possibilities.

  8. Selective Dirac voltage engineering of individual graphene field-effect transistors for digital inverter and frequency multiplier integrations

    Science.gov (United States)

    Sul, Onejae; Kim, Kyumin; Jung, Yungwoo; Choi, Eunsuk; Lee, Seung-Beck

    2017-09-01

    The ambipolar band structure of graphene presents unique opportunities for novel electronic device applications. A cycle of gate voltage sweep in a conventional graphene transistor produces a frequency-doubled output current. To increase the frequency further, we used various graphene doping control techniques to produce Dirac voltage engineered graphene channels. The various surface treatments and substrate conditions produced differently doped graphene channels that were integrated on a single substrate and multiple Dirac voltages were observed by applying a single gate voltage sweep. We applied the Dirac voltage engineering techniques to graphene field-effect transistors on a single chip for the fabrication of a frequency multiplier and a logic inverter demonstrating analog and digital circuit application possibilities.

  9. Long-term Performance of Granular Bases Including the Effect of Wet-Dry Cycles on Inverted Base Pavement Performance

    Science.gov (United States)

    2017-06-01

    The main objective of this study was to advance the understanding of alternative pavement designs. In particular, potential techniques such as inverted base pavements (IBP) have increased the importance of granular aggregate bases (GAB) in pavement s...

  10. Frequency scanning-based stability analysis method for grid-connected inverter system

    DEFF Research Database (Denmark)

    Wang, Yanbo; Wang, Xiongfei; Blaabjerg, Frede

    2017-01-01

    This paper proposes a frequency scanning-based impedance analysis for stability assessment of grid-connected inverter system, which is able to perform stability assessment without using system mathematical models and inherit the superior feature of impedance-based stability criterion with conside......This paper proposes a frequency scanning-based impedance analysis for stability assessment of grid-connected inverter system, which is able to perform stability assessment without using system mathematical models and inherit the superior feature of impedance-based stability criterion...... with consideration of the inverter nonlinearities. Small current disturbance is injected into grid-connected inverter system in a particular frequency range, and the impedance is computed according to the harmonic-frequency response using Fourier analysis, and then the stability is predicted on the basis...... of the impedance stability criterion. The stability issues of grid-connected inverters with grid-current feedback and the converter-current feedback are addressed using the proposed method. The results obtained from simulation and experiments validate the effectiveness of the method. The frequency scanning...

  11. A New Family of Multilevel Grid Connected Inverters Based on Packed U Cell Topology.

    Science.gov (United States)

    Pakdel, Majid; Jalilzadeh, Saeid

    2017-09-29

    In this paper a novel packed U cell (PUC) based multilevel grid connected inverter is proposed. Unlike the U cell arrangement which consists of two power switches and one capacitor, in the proposed converter topology a lower DC power supply from renewable energy resources such as photovoltaic arrays (PV) is used as a base power source. The proposed topology offers higher efficiency and lower cost using a small number of power switches and a lower DC power source which is supplied from renewable energy resources. Other capacitor voltages are extracted from the base lower DC power source using isolated DC-DC power converters. The operation principle of proposed transformerless multilevel grid connected inverter is analyzed theoretically. Operation of the proposed multilevel grid connected inverter is verified through simulation studies. An experimental prototype using STM32F407 discovery controller board is performed to verify the simulation results.

  12. Light sensing in a photoresponsive, organic-based complementary inverter.

    Science.gov (United States)

    Kim, Sungyoung; Lim, Taehoon; Sim, Kyoseung; Kim, Hyojoong; Choi, Youngill; Park, Keechan; Pyo, Seungmoon

    2011-05-01

    A photoresponsive organic complementary inverter was fabricated and its light sensing characteristics was studied. An organic circuit was fabricated by integrating p-channel pentacene and n-channel copper hexadecafluorophthalocyanine (F16CuPc) organic thin-film transistors (OTFTs) with a polymeric gate dielectric. The F16CuPc OTFT showed typical n-type characteristics and a strong photoresponse under illumination. Whereas under illumination, the pentacene OTFT showed a relatively weak photoresponse with typical p-type characteristics. The characteristics of the organic electro-optical circuit could be controlled by the incident light intensity, a gate bias, or both. The logic threshold (V(M), when V(IN) = V(OUT)) was reduced from 28.6 V without illumination to 19.9 V at 6.94 mW/cm². By using solely optical or a combination of optical and electrical pulse signals, light sensing was demonstrated in this type of organic circuit, suggesting that the circuit can be potentially used in various optoelectronic applications, including optical sensors, photodetectors and electro-optical transceivers.

  13. Mission Profile Based Sizing of IGBT Chip Area for PV Inverter Applications

    DEFF Research Database (Denmark)

    Shen, Yanfeng; Wang, Huai; Yang, Yongheng

    2016-01-01

    Maximizing the total energy generation is of importance for Photovoltaic (PV) plants. This paper proposes a method to optimize the IGBT chip area for PV inverters to minimize the annual energy loss of the active switches based on long-term operation conditions (i.e., mission profile). The design...... yearly mission profile. Simulation results are given to verify the thermal characteristics. Furthermore, a Monte Carlo based lifetime evaluation is presented to check the IGBT reliability. The proposed design method enables a reliability-oriented energy optimized sizing of active switches for PV inverter...

  14. Hybrid islanding detection method by using grid impedance estimation in parallel-inverters-based microgrid

    DEFF Research Database (Denmark)

    Ghzaiel, Walid; Jebali-Ben Ghorbal, Manel; Slama-Belkhodja, Ilhem

    2014-01-01

    This paper presents a hybrid islanding detection algorithm integrated on the distributed generation unit more close to the point of common coupling of a Microgrid based on parallel inverters where one of them is responsible to control the system. The method is based on resonance excitation under...... parameters, both resistive and inductive parts, from the injected resonance frequency determination. Finally, the inverter will disconnect the microgrid from the faulty grid and reconnect the parallel inverter system to the controllable distributed system in order to ensure high power quality. This paper...... shows that grid impedance variation detection estimation can be an efficient method for islanding detection in microgrid systems. Theoretical analysis and simulation results are presented to validate the proposed method....

  15. Reactive power and voltage control strategy based on dynamic and adaptive segment for DG inverter

    Science.gov (United States)

    Zhai, Jianwei; Lin, Xiaoming; Zhang, Yongjun

    2018-03-01

    The inverter of distributed generation (DG) can support reactive power to help solve the problem of out-of-limit voltage in active distribution network (ADN). Therefore, a reactive voltage control strategy based on dynamic and adaptive segment for DG inverter is put forward to actively control voltage in this paper. The proposed strategy adjusts the segmented voltage threshold of Q(U) droop curve dynamically and adaptively according to the voltage of grid-connected point and the power direction of adjacent downstream line. And then the reactive power reference of DG inverter can be got through modified Q(U) control strategy. The reactive power of inverter is controlled to trace the reference value. The proposed control strategy can not only control the local voltage of grid-connected point but also help to maintain voltage within qualified range considering the terminal voltage of distribution feeder and the reactive support for adjacent downstream DG. The scheme using the proposed strategy is compared with the scheme without the reactive support of DG inverter and the scheme using the Q(U) control strategy with constant segmented voltage threshold. The simulation results suggest that the proposed method has a significant improvement on solving the problem of out-of-limit voltage, restraining voltage variation and improving voltage quality.

  16. Digital Inverter Amine Sensing via Synergistic Responses by n and p Organic Semiconductors.

    Science.gov (United States)

    Tremblay, Noah J; Jung, Byung Jun; Breysse, Patrick; Katz, Howard E

    2011-11-22

    Chemiresistors and sensitive OFETs have been substantially developed as cheap, scalable, and versatile sensing platforms. While new materials are expanding OFET sensing capabilities, the device architectures have changed little. Here we report higher order logic circuits utilizing OFETs sensitive to amine vapors. The circuits depend on the synergistic responses of paired p- and n-channel organic semiconductors, including an unprecedented analyte-induced current increase by the n-channel semiconductor. This represents the first step towards 'intelligent sensors' that utilize analog signal changes in sensitive OFETs to produce direct digital readouts suitable for further logic operations.

  17. Real field mission profile oriented design of a SiC-based PV-inverter application

    DEFF Research Database (Denmark)

    Sintamarean, Nicolae Christian; Blaabjerg, Frede; Wang, Huai

    2013-01-01

    This paper introduces a real field mission profile oriented design tool for the new generation of grid connected PV-inverters applications based on SiC-devices. The proposed design tool consists of a grid connected PV-inverter model, an ElectroThermal model, a converter safe operating area (SOA...... Zth_H in order to perform in a safe mode for the whole operating range. Furthermore, the proposed design tool considers the mission profile (the measured solar irradiance and ambient temperature) from the real field where the converter will operate. Thus, a realistic loading of the converter devices......) model, a mission profile model and an the evaluation block. The PV-system model involves a three level bipolar switch neutral point clamped (3L-BS NPC) inverter connected to the three phase grid through a LCL-filter. Moreover, the SOA model calculates the required converter heatsink thermal impedance...

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

    Directory of Open Access Journals (Sweden)

    Mohanty Kant Nalin

    2010-01-01

    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.

  19. Z-Source-Inverter-Based Flexible Distributed Generation System Solution for Grid Power Quality Improvement

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Vilathgamuwa, D. M.; Loh, Poh Chiang

    2009-01-01

    Distributed generation (DG) systems are usually connected to the grid using power electronic converters. Power delivered from such DG sources depends on factors like energy availability and load demand. The converters used in power conversion do not operate with their full capacity all the time......-stage buck-boost inverter, recently proposed Z-source inverter (ZSI) is a good candidate for future DG systems. This paper presents a controller design for a ZSI-based DG system to improve power quality of distribution systems. The proposed control method is tested with simulation results obtained using...

  20. Stabilizing Planar Inverted Pendulum System Based on Fuzzy Nine-point Controller

    OpenAIRE

    Qi Qian; Liu Feng; Tang Yong-chuan; Yang Yang

    2013-01-01

    In order to stabilize planar inverted pendulum, after analyzing the physical characteristics of the planar inverted pendulum system, a pendulum nine-point controller and a car nine-point controller for X-axis and Y-axis were designed respectively. Then a fuzzy coordinator was designed using the fuzzy control theory based on the priority of those two controllers, and the priority level of the pendulum is higher than the car. Thus, the control tasks of each controller in each axis were harmoniz...

  1. Development of a digital solar simulator based on full-bridge converter

    Science.gov (United States)

    Liu, Chen; Feng, Jian; Liu, Zhilong; Tong, Weichao; Ji, Yibo

    2014-02-01

    With the development of solar photovoltaic, distribution schemes utilized in power grid had been commonly application, and photovoltaic (PV) inverter is an essential equipment in grid. In this paper, a digital solar simulator based on full-bridge structure is presented. The output characteristic curve of system is electrically similar to silicon solar cells, which can greatly simplify research methods of PV inverter, improve the efficiency of research and development. The proposed simulator consists on a main control board based on TM320F28335, phase-shifted zero-voltage-switching (ZVS) DC-DC full-bridge converter and voltage and current sampling circuit, that allows emulating the voltage-current curve with the open-circuit voltage (Voc) of 900V and the short-circuit current (Isc) of 18A .When the system connected to a PV inverter, the inverter can quickly track from the open-circuit to the maximum power point and keep stability.

  2. A Fuzzy Logic Based Three phase Inverter with Single DC Source for Grid Connected PV System Employing Three Phase Transformer

    OpenAIRE

    Mani, venkatesan; Ramachandran, Rajeswari; N, Deverajan

    2016-01-01

    A fuzzy based three phase inverter with single DC source for grid connected photo voltaic (PV) system employing three phase transformer is presented in this paper. Space Vector Pulse Width Modulation (SVPWM) control scheme is effectively used to generate the appropriate switching sequences to the inverter switches. The intend of the fuzzy logic approach is to meet high quality output, fast response and high robustness. Finally Total Harmonics Distortion (THD) generated by the inverter is comp...

  3. Transient Monitoring Function–Based Fault Detection for Inverter-Interfaced Microgrids

    DEFF Research Database (Denmark)

    Sadeghkhani, Iman; Esmail Hamedani Golshan, Mohamad; Mehrizi-Sani, Ali

    2018-01-01

    One of the major challenges in protection of the inverter-interfaced islanded microgrids is their limited fault current level. This degrades the performance of traditional overcurrent protection schemes. This paper proposes a fault detection strategy based on monitoring the transient response......-domain simulation case studies using the CIGRE benchmark low voltage microgrid network....

  4. A New Inverted Torsion Pendulum-Based Mechanical Spectrometer to Study Soft Matter

    Directory of Open Access Journals (Sweden)

    Lei M.L.

    2016-03-01

    Full Text Available A new multifunctional mechanical spectrometer is developed based on an inverted torsion pendulum showing high precision in a wide frequency range to study soft matter. Apart from measuring the internal friction of solids it can also be used to study viscoelasticity. In this report we describe basic principles of the novel instrument.

  5. Lyapunov-Based Control Scheme for Single-Phase Grid-Connected PV Central Inverters

    NARCIS (Netherlands)

    Meza, C.; Biel, D.; Jeltsema, D.; Scherpen, J. M. A.

    A Lyapunov-based control scheme for single-phase single-stage grid-connected photovoltaic central inverters is presented. Besides rendering the closed-loop system globally stable, the designed controller is able to deal with the system uncertainty that depends on the solar irradiance. A laboratory

  6. Modeling and real time simulation of an HVDC inverter feeding a weak AC system based on commutation failure study.

    Science.gov (United States)

    Mankour, Mohamed; Khiat, Mounir; Ghomri, Leila; Chaker, Abdelkader; Bessalah, Mourad

    2018-06-01

    This paper presents modeling and study of 12-pulse HVDC (High Voltage Direct Current) based on real time simulation where the HVDC inverter is connected to a weak AC system. In goal to study the dynamic performance of the HVDC link, two serious kind of disturbance are applied at HVDC converters where the first one is the single phase to ground AC fault and the second one is the DC link to ground fault. The study is based on two different mode of analysis, which the first is to test the performance of the DC control and the second is focalized to study the effect of the protection function on the system behavior. This real time simulation considers the strength of the AC system to witch is connected and his relativity with the capacity of the DC link. The results obtained are validated by means of RT-lab platform using digital Real time simulator Hypersim (OP-5600), the results carried out show the effect of the DC control and the influence of the protection function to reduce the probability of commutation failures and also for helping inverter to take out from commutation failure even while the DC control fails to eliminate them. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

  7. Transformer-based asymmetrical embedded Z-source neutral point clamped inverters with continuous input current and enhanced voltage boost capability

    DEFF Research Database (Denmark)

    Mo, W.; Loh, Poh Chiang; Blaabjerg, Frede

    2013-01-01

    Z-source Neutral Point Clamped (NPC) inverters were introduced to integrate both the advantages of Z-source inverters and NPC inverters. However, traditional Z-source inverters suffer from high voltage stress and chopping input current. This paper proposes six types transformer-based impedance-so......-source NPC inverters which have enhanced voltage boost capability and continuous input current by utilizing of transformer and embedded dc source configuration. Experimental results are presented to verify the theory validation....

  8. Fault diagnosis method based on FFT-RPCA-SVM for Cascaded-Multilevel Inverter.

    Science.gov (United States)

    Wang, Tianzhen; Qi, Jie; Xu, Hao; Wang, Yide; Liu, Lei; Gao, Diju

    2016-01-01

    Thanks to reduced switch stress, high quality of load wave, easy packaging and good extensibility, the cascaded H-bridge multilevel inverter is widely used in wind power system. To guarantee stable operation of system, a new fault diagnosis method, based on Fast Fourier Transform (FFT), Relative Principle Component Analysis (RPCA) and Support Vector Machine (SVM), is proposed for H-bridge multilevel inverter. To avoid the influence of load variation on fault diagnosis, the output voltages of the inverter is chosen as the fault characteristic signals. To shorten the time of diagnosis and improve the diagnostic accuracy, the main features of the fault characteristic signals are extracted by FFT. To further reduce the training time of SVM, the feature vector is reduced based on RPCA that can get a lower dimensional feature space. The fault classifier is constructed via SVM. An experimental prototype of the inverter is built to test the proposed method. Compared to other fault diagnosis methods, the experimental results demonstrate the high accuracy and efficiency of the proposed method. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

  9. Single DV-DXCCII Based Voltage Controlled First Order All-pass Filter with Inverting and Non-inverting responses

    Directory of Open Access Journals (Sweden)

    B Chaturvedi

    2015-12-01

    Full Text Available In this paper, a new voltage controlled first order all-pass filter is presented. The proposed circuit employs a single differential voltage dual-X second generation current conveyor (DV-DXCCII and a grounded capacitor only. The proposed all-pass filter provides both inverting and non inverting voltage-mode outputs from the same configuration simultaneously without any matching condition. Non-ideal analysis along with sensitivity analysis is also investigated. The proposed circuit has low active and passive sensitivities. As an application the proposed all-pass filter is connected in cascade to get higher order filter. The theoretical results are validated thorough PSPICE simulations using TSMC 0.18µm CMOS process parameters.

  10. Nine-phase hex-tuple inverter for five-level output based on double carrier PWM technique

    DEFF Research Database (Denmark)

    Padmanaban, S.; Bhaskar, M.S.; Blaabjerg, F.

    2016-01-01

    This work articulates double carrier based five-level pulsewidth modulation for a nine-phase hex-tuple inverter AC drive. A set of standard three-phase voltage source inverter (VSI) with slight modification is used for framing the ninephase AC drive. In particular VSI packed with one bidirectiona...

  11. Optimized Carrier Based Multilevel Generated Modified Dual Three-Phase Open-Winding Inverter for Medium Power Applications

    DEFF Research Database (Denmark)

    Padmanaban, Sanjeevi Kumar; Blaabjerg, Frede; Wheeler, Patrick

    2016-01-01

    This paper presents a novel carrier based multilevel modulation for modified dual three-phase open-winding inverter applicable for low-voltage/high-current applications. A standard three-phase voltage source inverter (VSI) is connected across the open-winding of both ends of the motor. Each VSI i...

  12. Design of Solar PV Cell Based Inverter for Unbalanced and Distorted Industrial Loads

    Directory of Open Access Journals (Sweden)

    Naga Ananth D

    2015-04-01

    Full Text Available PV cell is getting importance in low and medium power generation due to easy installation, low maintenance and subsidies in price from respective nation. Most of the loads in distribution system are unbalanced and distorted, due to which there will be unbalanced voltage and current occur at load and may disturb its overall performance. Due to these loads voltage unbalance, distorted voltage and current and variable power factors in each phase can be observed. An efficient algorithm to mitigate unbalanced and distorted load and source voltage and current in solar photo voltaic (PV inverter for isolated load system was considered. This solar PV system can be applicable to remote located industrial loads like heating, welding and small arc furnace type distorted loads and also for unbalanced loads. The PV inverter is designed such that it will maintain nearly constant voltage magnitude and can mitigate harmonics in voltage and current near the load terminals. A MATLAB/ SIMULINK based solar PV inverter was simulated and results are compared with standard AC three phase grid connected system. The proposed shows that the inverter is having very less voltage and current harmonic content and can maintain nearly constant voltage profile for highly unbalanced system.

  13. Grid-Connected Control Strategy of Five-level Inverter Based on Passive E-L Model

    Directory of Open Access Journals (Sweden)

    Tao Li

    2017-10-01

    Full Text Available At present, the research on five-level inverters mainly involves the modulation algorithm and topology, and few articles study the five-level inverter from the control strategy. In this paper, the nonlinear passivity-based control (PBC method is proposed for single-phase uninterruptible power supply inverters. The proposed PBC method is based on an energy shaping and damping injection idea, which is performed to regulate the energy flow of an inverter to a desired level and to assure global asymptotic stability, respectively. Furthermore, this paper presents a control algorithm based on the theory of passivity that gives an inverter in a photovoltaic system additional functions: power factor correction, harmonic currents compensation, and the ability to stabilize the system under varying injection damping. Finally, the effectiveness of the PBC method in terms of both stability and harmonic distortion is verified by the simulation and experiments under resistive and inductive loads.

  14. Low-Cost Digital Implementation of Proportional-Resonant Current Controllers for PV Inverter Applications Using Delta Operator

    DEFF Research Database (Denmark)

    Sera, Dezso; Kerekes, Tamas; Lungeanu, Marian

    2005-01-01

    the possibility of selective harmonic compensation. However, in case of digital implementation on a low-cost fixedpoint DSP, the limited computational power and the limited numerical representation precision can restrict the utilization of it. The present paper proposes a different way of digital implementation...... of the P+Resonant controller with selective harmonic compensation on a low-cost fixed-point DSP. The resonant part of the P+R has been implemented as a second order filter based on Delta operator. The current controller, together with harmonic compensation for the 3rd, 5th, and 7th harmonics has been...

  15. High speed capacitor-inverter based carbon nanotube full adder.

    Science.gov (United States)

    Navi, K; Rashtian, M; Khatir, A; Keshavarzian, P; Hashemipour, O

    2010-03-18

    Carbon Nanotube filed-effect transistor (CNFET) is one of the promising alternatives to the MOS transistors. The geometry-dependent threshold voltage is one of the CNFET characteristics, which is used in the proposed Full Adder cell. In this paper, we present a high speed Full Adder cell using CNFETs based on majority-not (Minority) function. Presented design uses eight transistors and eight capacitors. Simulation results show significant improvement in terms of delay and power-delay product in comparison to contemporary CNFET Adder Cells. Simulations were carried out using HSPICE based on CNFET model with 0.6 V VDD.

  16. Mission profile based multi-disciplinary analysis of power modules in single-phase transformerless photovoltaic inverters

    DEFF Research Database (Denmark)

    Yang, Yongheng; Wang, Huai; Blaabjerg, Frede

    2013-01-01

    years) has been set as a main target and an emerging demand from the customers, which imposes a new challenge on grid-connected transformerless inverters. In order to reduce maintenance cost, it is essential to predict the lifetime of the transformerless PV inverter and its components based......The popularity of transformerless photovoltaic (PV) inverters in Europe proves that these topologies can achieve higher efficiency (e.g., ≥ 98% has been reported). Along with the advanced power electronics technology and the booming development of PV power systems, a long service time (e.g. 25...... on the mission profiles — solar irradiance and ambient temperature. In this paper, a mission profile based analysis approach is proposed and it is demonstrated by three main single-phase transformerless PV inverters — Full-Bridge (FB) with bipolar modulation scheme, the FB inverter with DC bypass (FB...

  17. A new on-chip all-digital three-phase full-bridge dc/ac power inverter with feedforward and frequency control techniques.

    Science.gov (United States)

    Chen, Jiann-Jong; Kung, Che-Min

    2010-09-01

    The communication speed between components is far from satisfactory. To achieve high speed, simple control system configuration, and low cost, a new on-chip all-digital three-phase dc/ac power inverter using feedforward and frequency control techniques is proposed. The controller of the proposed power inverter, called the shift register, consists of six-stage D-latch flip-flops with a goal of achieving low-power consumption and area efficiency. Variable frequency is achieved by controlling the clocks of the shift register. One advantage regarding the data signal (D) and the common clock (CK) is that, regardless of the phase difference between the two, all of the D-latch flip-flops are capable of delaying data by one CK period. To ensure stability, the frequency of CK must be six times higher than that of D. The operation frequency of the proposed power inverter ranges from 10 Hz to 2 MHz, and the maximum output loading current is 0.8 A. The prototype of the proposed circuit has been fabricated with TSMC 0.35 μm 2P4M CMOS processes. The total chip area is 2.333 x 1.698 mm2. The three-phase dc/ac power inverter is applicable in uninterrupted power supplies, cold cathode fluorescent lamps, and motors, because of its ability to convert the dc supply voltage into the three-phase ac power sources.

  18. Robustness of delayed multistable systems with application to droop-controlled inverter-based microgrids

    Science.gov (United States)

    Efimov, Denis; Schiffer, Johannes; Ortega, Romeo

    2016-05-01

    Motivated by the problem of phase-locking in droop-controlled inverter-based microgrids with delays, the recently developed theory of input-to-state stability (ISS) for multistable systems is extended to the case of multistable systems with delayed dynamics. Sufficient conditions for ISS of delayed systems are presented using Lyapunov-Razumikhin functions. It is shown that ISS multistable systems are robust with respect to delays in a feedback. The derived theory is applied to two examples. First, the ISS property is established for the model of a nonlinear pendulum and delay-dependent robustness conditions are derived. Second, it is shown that, under certain assumptions, the problem of phase-locking analysis in droop-controlled inverter-based microgrids with delays can be reduced to the stability investigation of the nonlinear pendulum. For this case, corresponding delay-dependent conditions for asymptotic phase-locking are given.

  19. Inverting the diastereoselectivity of the mukaiyama-michael addition with graphite-based catalysts

    KAUST Repository

    Acocella, Maria Rosaria

    2014-02-07

    Here, we show that graphite-based catalysts, mainly graphite oxide (GO) and exfoliated GO, are effective recyclable catalysts for a relevant stereoselective Mukaiyama-Michael addition, outperforming currently available catalysts. Moreover, the graphite-based catalysts described here invert the diastereoselectivity relative to that observed with known catalysts, with the unprecedented large prevalence of the anti diastereoisomer. This inverted diastereoselectivity is increased when the catalyst concentration is reduced and after catalyst recycling. Density functional theory calculations suggest that the selectivity is determined by two types of supramolecular interactions operating between the catalyst and the substrates at the diastereoselectivity- determining transition state, specifically, the π-stacking of b-nitrostyrene with graphite and the van der Waals interaction between the SiMe3 group of the silyl ether and the graphite. © 2013 American Chemical Society.

  20. An All-Solution-Based Hybrid CMOS-Like Quantum Dot/Carbon Nanotube Inverter.

    Science.gov (United States)

    Shulga, Artem G; Derenskyi, Vladimir; Salazar-Rios, Jorge Mario; Dirin, Dmitry N; Fritsch, Martin; Kovalenko, Maksym V; Scherf, Ullrich; Loi, Maria A

    2017-09-01

    The development of low-cost, flexible electronic devices is subordinated to the advancement in solution-based and low-temperature-processable semiconducting materials, such as colloidal quantum dots (QDs) and single-walled carbon nanotubes (SWCNTs). Here, excellent compatibility of QDs and SWCNTs as a complementary pair of semiconducting materials for fabrication of high-performance complementary metal-oxide-semiconductor (CMOS)-like inverters is demonstrated. The n-type field effect transistors (FETs) based on I - capped PbS QDs (V th = 0.2 V, on/off = 10 5 , S S-th = 114 mV dec -1 , µ e = 0.22 cm 2 V -1 s -1 ) and the p-type FETs with tailored parameters based on low-density random network of SWCNTs (V th = -0.2 V, on/off > 10 5 , S S-th = 63 mV dec -1 , µ h = 0.04 cm 2 V -1 s -1 ) are integrated on the same substrate in order to obtain high-performance hybrid inverters. The inverters operate in the sub-1 V range (0.9 V) and have high gain (76 V/V), large maximum-equal-criteria noise margins (80%), and peak power consumption of 3 nW, in combination with low hysteresis (10 mV). © 2017 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Perovskite-based solar cells with inorganic inverted hybrid planar heterojunction structure

    Directory of Open Access Journals (Sweden)

    Wei-Chih Lai

    2018-01-01

    Full Text Available We demonstrated the good performance of inorganic inverted CH3NH3PbI3 perovskite-based solar cells (SCs with glass/ITO/NiOx/CH3NH3PbI3 perovskite/C60/ room temperature (RT-sputtered ZnO/Al structure. We adopted spin coating and RT sputtering for the deposition of NiOx and ZnO, respectively. The inorganic hole and electron transport layer of NiOx and RT-sputtered ZnO, respectively, could improve the open-circuit voltage (VOC, short-circuit current density (JSC, and power conversion efficiency (η% of the SCs. We obtained inorganic inverted CH3NH3PbI3 perovskite-based SCs with a JSC of 21.96 A/cm2, a VOC of 1.02 V, a fill factor (FF% of 68.2%, and an η% of 15.3% despite the sputtering damage of the RT-sputtered ZnO deposition. Moreover, the RT-sputtered ZnO could function as a diffusion barrier for Al, moisture, and O2. The inorganic inverted CH3NH3PbI3 perovskite-based SCs demonstrated improved storage reliability.

  2. Perovskite-based solar cells with inorganic inverted hybrid planar heterojunction structure

    Science.gov (United States)

    Lai, Wei-Chih; Lin, Kun-Wei; Guo, Tzung-Fang; Chen, Peter; Liao, Yuan-Yu

    2018-01-01

    We demonstrated the good performance of inorganic inverted CH3NH3PbI3 perovskite-based solar cells (SCs) with glass/ITO/NiOx/CH3NH3PbI3 perovskite/C60/ room temperature (RT)-sputtered ZnO/Al structure. We adopted spin coating and RT sputtering for the deposition of NiOx and ZnO, respectively. The inorganic hole and electron transport layer of NiOx and RT-sputtered ZnO, respectively, could improve the open-circuit voltage (VOC), short-circuit current density (JSC), and power conversion efficiency (η%) of the SCs. We obtained inorganic inverted CH3NH3PbI3 perovskite-based SCs with a JSC of 21.96 A/cm2, a VOC of 1.02 V, a fill factor (FF%) of 68.2%, and an η% of 15.3% despite the sputtering damage of the RT-sputtered ZnO deposition. Moreover, the RT-sputtered ZnO could function as a diffusion barrier for Al, moisture, and O2. The inorganic inverted CH3NH3PbI3 perovskite-based SCs demonstrated improved storage reliability.

  3. New Power Sharing Control for Inverter-Dominated Microgrid Based on Impedance Match Concept

    Science.gov (United States)

    Gu, Herong; Wang, Deyu; Shen, Hong; Zhao, Wei; Guo, Xiaoqiang

    2013-01-01

    Power flow control is one of the most important issues for operating the inverter-dominated autonomous microgrid. A technical challenge is how to achieve the accurate active/reactive power sharing of inverters. P-F and Q-V droop control schemes have been widely used for power sharing in the past decades. But they suffer from the poor power sharing in the presence of unequal line impedance. In order to solve the problem, a comprehensive analysis of the power droop control is presented, and a new droop control based on the impedance match concept is proposed in this paper. In addition, the design guidelines of control coefficients and virtual impedance are provided. Finally, the performance evaluation is carried out, and the evaluation results verify the effectiveness of the proposed method. PMID:24453910

  4. New power sharing control for inverter-dominated microgrid based on impedance match concept.

    Science.gov (United States)

    Gu, Herong; Wang, Deyu; Shen, Hong; Zhao, Wei; Guo, Xiaoqiang

    2013-01-01

    Power flow control is one of the most important issues for operating the inverter-dominated autonomous microgrid. A technical challenge is how to achieve the accurate active/reactive power sharing of inverters. P-F and Q-V droop control schemes have been widely used for power sharing in the past decades. But they suffer from the poor power sharing in the presence of unequal line impedance. In order to solve the problem, a comprehensive analysis of the power droop control is presented, and a new droop control based on the impedance match concept is proposed in this paper. In addition, the design guidelines of control coefficients and virtual impedance are provided. Finally, the performance evaluation is carried out, and the evaluation results verify the effectiveness of the proposed method.

  5. A high-performance complementary inverter based on transition metal dichalcogenide field-effect transistors.

    Science.gov (United States)

    Cho, Ah-Jin; Park, Kee Chan; Kwon, Jang-Yeon

    2015-01-01

    For several years, graphene has been the focus of much attention due to its peculiar characteristics, and it is now considered to be a representative 2-dimensional (2D) material. Even though many research groups have studied on the graphene, its intrinsic nature of a zero band-gap, limits its use in practical applications, particularly in logic circuits. Recently, transition metal dichalcogenides (TMDs), which are another type of 2D material, have drawn attention due to the advantage of having a sizable band-gap and a high mobility. Here, we report on the design of a complementary inverter, one of the most basic logic elements, which is based on a MoS2 n-type transistor and a WSe2 p-type transistor. The advantages provided by the complementary metal-oxide-semiconductor (CMOS) configuration and the high-performance TMD channels allow us to fabricate a TMD complementary inverter that has a high-gain of 13.7. This work demonstrates the operation of the MoS2 n-FET and WSe2 p-FET on the same substrate, and the electrical performance of the CMOS inverter, which is based on a different driving current, is also measured.

  6. Damping Methods for Resonances Caused by LCL-Filter-Based Current-Controlled Grid-Tied Power Inverters

    DEFF Research Database (Denmark)

    Wu, Weimin; Liu, Yuan; He, Yuanbin

    2017-01-01

    Grid-tied voltage source inverters using LCL filter have been widely adopted in distributed power generation systems (DPGSs). As high-order LCL filters contain multiple resonant frequencies, switching harmonics generated by the inverter and current harmonics generated by the active/passive loads...... innovative damping methods have been proposed. A comprehensive overview on those contributions and their classification on the inverter- and grid-side damping measures are presented. Based on the concept of the impedance-based stability analysis, all damping methods can ensure the system stability...

  7. Modified Synchronous Reference Frame Based Shunt Active Power Filter with Fuzzy Logic Control Pulse Width Modulation Inverter

    Directory of Open Access Journals (Sweden)

    Suleiman Musa

    2017-05-01

    Full Text Available Harmonic distortion in power networks has greatly reduced power quality and this affects system stability. In order to mitigate this power quality issue, the shunt active power filter (SAPF has been widely applied and it is proven to be the best solution to current harmonics. This paper evaluates the performance of the modified synchronous reference frame extraction (MSRF algorithm with fuzzy logic controller (FLC based current control pulse width modulation (PWM inverter of three-phase three-wire SAPF to mitigate current harmonics. The proposed FLC is designed with a reduced amount of membership functions (MFs and rules, and thus significantly reduces the computational time and memory size. Modeling and simulations of SAPF are carried out using MATLAB/Simulink R2012a with the power system toolbox under steady-state condition, and this is followed with hardware implementation using a TMS320F28335 digital signal processor (DSP, Specrum Digital Inc., Stafford, TX, USA. The results obtained demonstrate a good and satisfactory response to mitigate the harmonics in the system. The total harmonic distortion (THD for the system has been reduced from 25.60% to 0.92% and 1.41% in the simulation study with and without FLC, respectively. Similarly for the experimental study, the SAPF can compensate for the three-phase load current by reducing THD to 5.07% and 7.4% with and without FLC, respectively.

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

    Directory of Open Access Journals (Sweden)

    N. Belhaouchet

    2008-03-01

    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.

  9. Simulation of Processes in Dual Three-Phase System on the Base of Four Inverters with Synchronized Modulation

    OpenAIRE

    Oleschuk, Valentin; Grandi, Gabriele; Sanjeevikumar, Padmanaban

    2011-01-01

    Novel method of space-vector-based pulse-width modulation (PWM) has been disseminated for synchronous control of four inverters feeding six-phase drive on the base of asymmetrical induction motor which has two sets of windings spatially shifted by 30 electrical degrees. Basic schemes of synchronized PWM, applied for control of four separate voltage-source inverters, allow both continuous phase voltages synchronization in the system and required power sharing between DC sources. Detailed MATLA...

  10. Non Isolated and Non-Inverting Cockcroft Walton Multiplier Based Hybrid 2Nx Interleaved Boost Converter For Renewable Energy Applications

    DEFF Research Database (Denmark)

    Bhaskar, Mahajan Sagar; Padamanaban, Sanjeevi Kumar; Blaabjerg, Frede

    2016-01-01

    In this paper hybrid non isolated and non-invertingCockcroft-Walton multiplier based 2Nx InterleavedBoost converter (2Nx IBC) for renewable energy applications is presented. The presented hybrid boost converter topology is derived from non-inverting Nx Multilevel Boost Converter (Nx MBC......) and inverting Nx Multilevel Boost Converter (Nx MBC). In renewable energy applications, generated voltage needs to be stepped up with high conversion ratio using a DC-DC converter at voltage levels as per the application requirement. The advantages of the presentedtopology of interleaved converter are high...

  11. Digital control card based on digital signal processor

    International Nuclear Information System (INIS)

    Hou Shigang; Yin Zhiguo; Xia Le

    2008-01-01

    A digital control card based on digital signal processor was developed. Two Freescale DSP-56303 processors were utilized to achieve 3 channels proportional- integral-differential regulations. The card offers high flexibility for 100 MeV cyclotron RF system development. It was used as feedback controller in low level radio frequency control prototype, with the feedback gain parameters continuously adjustable. By using high precision analog to digital converter with 500 kHz sampling rate, a regulation bandwidth of 20 kHz was achieved. (authors)

  12. Low voltage ride-through capability control for single-stage inverter-based grid-connected photovoltaic power plant

    DEFF Research Database (Denmark)

    Al-Shetwi, Ali Q.; Sujod, Muhamad Zahim; Blaabjerg, Frede

    2018-01-01

    to enhance the LVRT capability based on the Malaysian standards and modern grid codes connection requirements. The proposed control overcomes the problems of dc-link over-voltage and ac over-current that may cause disconnection or damage to the inverter. For this purpose, dc-chopper brake controller...... to improve the capability of ride-through fault safely and keep the inverter connected, but also to provide grid support through active and reactive power control at different type of faults....

  13. Thermal Equilibrium Dynamic Control Based on DPWM Dual-Mode Modulation of High Power NPC Three-Level Inverter

    OpenAIRE

    Xu, Shi-Zhou; He, Feng-You

    2016-01-01

    In some special applications of NPC three-level inverters, such as mine hoist, there exist special conditions of overloading during the whole hoisting process and large overload in starting stage, during which the power-loss calculation of power devices and thermal control are important factors affecting the thermal stability of inverters. The principles of SVPWM and DPWM were described in this paper firstly, based on which the dynamic power losses of the two modulations of hoist in single pe...

  14. Y-source inverter

    DEFF Research Database (Denmark)

    Siwakoti, Yam P.; Town, Graham; Loh, Poh Chiang

    2014-01-01

    This paper introduces a new 3-phase Y-source inverter whose gain is presently not matched by classical impedance-network-based inverters operating at the same duty ratio. The proposed network uses a tightly coupled transformer with three windings. By squeezing the shoot-through range while keeping...... higher boost, the inverter can operate at a higher modulation index, thereby minimizing switching device stress and providing better output power quality. In addition, the inverter has more degrees of freedom for setting the voltage gain and modulation index than other classical impedance-source networks...

  15. UP-scaling of inverted small molecule based organic solar cells

    DEFF Research Database (Denmark)

    Patil, Bhushan Ramesh; Madsen, Morten

    Organic solar cells (OSC), in spite of being a promising technology, still face challenges regarding large-scale fabrication. Although efficiencies of up to 12 % has been reached for small molecule OSC, their performance, both in terms of device efficiency and stability, is significantly reduced...... during up-scaling processes. The work presented here is focused on an approach towards up-scaling of small molecule based OSC with inverted device configuration. Bilayer OSC from Tetraphenyldibenzoperiflanthene (DBP) and Fullerenes (C70), as electron donor and acceptor respectively, with cell area...

  16. Control Method of Single-phase Inverter Based Grounding System in Distribution Networks

    DEFF Research Database (Denmark)

    Wang, Wen; Yan, L.; Zeng, X.

    2016-01-01

    of neutral-to-ground voltage is critical for the safety of distribution networks. An active grounding system based on single-phase inverter is proposed to achieve this objective. Relationship between output current of the system and neutral-to-ground voltage is derived to explain the principle of neutral......The asymmetry of the inherent distributed capacitances causes the rise of neutral-to-ground voltage in ungrounded system or high resistance grounded system. Overvoltage may occur in resonant grounded system if Petersen coil is resonant with the distributed capacitances. Thus, the restraint...

  17. Research on the control strategy of distributed energy resources inverter based on improved virtual synchronous generator.

    Science.gov (United States)

    Gao, Changwei; Liu, Xiaoming; Chen, Hai

    2017-08-22

    This paper focus on the power fluctuations of the virtual synchronous generator(VSG) during the transition process. An improved virtual synchronous generator(IVSG) control strategy based on feed-forward compensation is proposed. Adjustable parameter of the compensation section can be modified to achieve the goal of reducing the order of the system. It can effectively suppress the power fluctuations of the VSG in transient process. To verify the effectiveness of the proposed control strategy for distributed energy resources inverter, the simulation model is set up in MATLAB/SIMULINK platform and physical experiment platform is established. Simulation and experiment results demonstrate the effectiveness of the proposed IVSG control strategy.

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

    Directory of Open Access Journals (Sweden)

    Oleschuk V.I.

    2015-12-01

    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. Mitigation Emission Strategy Based on Resonances from a Power Inverter System in Electric Vehicles

    Directory of Open Access Journals (Sweden)

    Li Zhai

    2016-05-01

    Full Text Available Large dv/dt and di/dt outputs of power devices in the DC-fed motor power inverter can generate conducted and/or radiated emissions through parasitics that interfere with low voltage electric systems in electric vehicles (EVs and nearby vehicles. The electromagnetic interference (EMI filters, ferrite chokes, and shielding added in the product process based on the “black box” approach can reduce the emission levels in a specific frequency range. However, these countermeasures may also introduce an unexpected increase in EMI noises in other frequency ranges due to added capacitances and inductances in filters resonating with elements of the power inverter, and even increase the weight and dimension of the power inverter system in EVs with limited space. In order to predict the interaction between the mitigation techniques and power inverter geometry, an accurate model of the system is needed. A power inverter system was modeled based on series of two-port network measurements to study the impact of EMI generated by power devices on radiated emission of AC cables. Parallel resonances within the circuit can cause peaks in the S21 (transmission coefficient between the phase-node-to-chassis voltage and the center-conductor-to-shield voltage of the AC cable connecting to the motor and Z11 (input impedance at Port 1 between the Insulated gate bipolar transistor (IGBT phase node and chassis at those resonance frequencies and result in enlarged noise voltage peaks at Port 1. The magnitude of S21 between two ports was reduced to decrease the amount of energy coupled from the noise source between the phase node and chassis to the end of the AC cable by lowering the corresponding quality factor. The equivalent circuits were built by analyzing current-following paths at three critical resonance frequencies. Interference voltage peaks can be suppressed by mitigating the resonances. The capacitances and inductances generating the parallel resonances and

  20. Multiband Split-Ring Resonator Based Planar Inverted-F Antenna for 5G Applications

    Directory of Open Access Journals (Sweden)

    Muhammad Kamran Ishfaq

    2017-01-01

    Full Text Available 5G, the fifth generation of wireless communications, is focusing on multiple frequency bands, such as 6 GHz, 10 GHz, 15 GHz, 28 GHz, and 38 GHz, to achieve high data rates up to 10 Gbps or more. The industry demands multiband antennas to cover these distant frequency bands, which is a task much more challenging. In this paper, we have designed a novel multiband split-ring resonator (SRR based planar inverted-F antenna (PIFA for 5G applications. It is composed of a PIFA, an inverted-L parasitic element, a rectangular shaped parasitic element, and a split-ring resonator (SRR etched on the top plate of the PIFA. The basic PIFA structure resonates at 6 GHz. An addition of a rectangular shaped parasitic element produces a resonance at 15 GHz. The introduction of a split-ring resonator produces a band notch at 8 GHz, and a resonance at 10 GHz, while the insertion of an inverted-L shaped parasitic element further enhances the impedance bandwidth in the 10 GHz band. The frequency bands covered, each with more than 1 GHz impedance bandwidth, are 6 GHz (5–7 GHz, 10 GHz (9–10.8 GHz, and 15 GHz (14-15 GHz, expected for inclusion in next-generation wireless communications, that is, 5G. The design is simulated using Ansys Electromagnetic Suite 17 simulation software package. The simulated and the measured results are compared and analyzed which are generally in good agreement.

  1. Highly Flexible Hybrid CMOS Inverter Based on Si Nanomembrane and Molybdenum Disulfide.

    Science.gov (United States)

    Das, Tanmoy; Chen, Xiang; Jang, Houk; Oh, Il-Kwon; Kim, Hyungjun; Ahn, Jong-Hyun

    2016-11-01

    2D semiconductor materials are being considered for next generation electronic device application such as thin-film transistors and complementary metal-oxide-semiconductor (CMOS) circuit due to their unique structural and superior electronics properties. Various approaches have already been taken to fabricate 2D complementary logics circuits. However, those CMOS devices mostly demonstrated based on exfoliated 2D materials show the performance of a single device. In this work, the design and fabrication of a complementary inverter is experimentally reported, based on a chemical vapor deposition MoS 2 n-type transistor and a Si nanomembrane p-type transistor on the same substrate. The advantages offered by such CMOS configuration allow to fabricate large area wafer scale integration of high performance Si technology with transition-metal dichalcogenide materials. The fabricated hetero-CMOS inverters which are composed of two isolated transistors exhibit a novel high performance air-stable voltage transfer characteristic with different supply voltages, with a maximum voltage gain of ≈16, and sub-nano watt power consumption. Moreover, the logic gates have been integrated on a plastic substrate and displayed reliable electrical properties paving a realistic path for the fabrication of flexible/transparent CMOS circuits in 2D electronics. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

    Directory of Open Access Journals (Sweden)

    Wenzhou Lu

    2016-01-01

    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.

  3. Stability Analysis and Active Damping for LLCL-filter-Based Grid-Connected Inverters

    DEFF Research Database (Denmark)

    Huang, Min; Wang, Xiongfei; Loh, Poh Chiang

    2015-01-01

    to use either passive or active damping methods. This paper analyzes the stability of the LLCL-filter based grid-connected inverter and identifies a critical resonant frequency for the LLCL-filter when sampling and transport delays are considered. In a high resonant frequency region the active damping...... is not required but in a low resonant frequency region the active damping is necessary. The basic LLCL resonance damping properties of different feedback states based on a notch filter concept are also studied. Then an active damping method which is using the capacitor current feedback for LLCL......-filter is introduced. Based on this active damping method, a design procedure for the controller is given. Last, both simulation and experimental results are provided to validate the theoretical analysis of this paper....

  4. A composite passive damping method of the LLCL-filter based grid-tied inverter

    DEFF Research Database (Denmark)

    Wu, Weimin; Huang, Min; Sun, Yunjie

    2012-01-01

    This paper investigates the maximum and the minimum gain of the proportional resonant based grid current controller for a grid-tied inverter with a passive damped high-order power filter. It is found that the choice of the controller gain is limited to the local maximum amplitude determined by Q......-factor around the characteristic frequency of the filter and grid impedance. To obtain the Q-factor of a high-order system, an equivalent circuit analysis method is proposed and illustrated through several classical passive damped LCL- and LLCL-filters. It is shown that both the RC parallel damper...... that is in parallel with the capacitor of the LCL-filter or with the Lf-Cf resonant circuit of the LLCL-filter, and the RL series damper in series with the grid-side inductor have their own application limits. Thus, a composite passive damped LLCL-filter for the grid-tied inverter is proposed, which can effectively...

  5. A ZnO nanowire-based photo-inverter with pulse-induced fast recovery.

    Science.gov (United States)

    Raza, Syed Raza Ali; Lee, Young Tack; Hosseini Shokouh, Seyed Hossein; Ha, Ryong; Choi, Heon-Jin; Im, Seongil

    2013-11-21

    We demonstrate a fast response photo-inverter comprised of one transparent gated ZnO nanowire field-effect transistor (FET) and one opaque FET respectively as the driver and load. Under ultraviolet (UV) light the transfer curve of the transparent gate FET shifts to the negative side and so does the voltage transfer curve (VTC) of the inverter. After termination of UV exposure the recovery of photo-induced current takes a long time in general. This persistent photoconductivity (PPC) is due to hole trapping on the surface of ZnO NWs. Here, we used a positive voltage short pulse after UV exposure, for the first time resolving the PPC issue in nanowire-based photo-detectors by accumulating electrons at the ZnO/dielectric interface. We found that a pulse duration as small as 200 ns was sufficient to reach a full recovery to the dark state from the UV induced state, realizing a fast UV detector with a voltage output.

  6. Energy Saving Performance Analysis of An Inverter-based Regenerative Power Re-utilization Device for Urban Rail Transit

    Science.gov (United States)

    Li, Jin; Qiu, Zhiling; Hu, Leilei

    2018-04-01

    The inverter-based regenerative braking power utilization devices can re-utilize the regenerative energy, thus reduce the energy consumption of urban rail transit. In this paper the power absorption principle of the inverter-based device is introduced, then the key influencing factors of energy saving performance are analyzed based on the absorption model. The field operation data verified that the control DC voltage plays an important role and lower control DC voltage yields more energy saving. Also, the one year energy saving performance data of an inverter-based re-utilization device located in NanJing S8 line is provided, and more than 1.2 million kWh energy is recovered in the one year operation.

  7. Understanding Platform-Based Digital Currencies

    OpenAIRE

    Ben Fung; Hanna Halaburda

    2014-01-01

    Given technological advances and the widespread use of the Internet, various digital currencies have emerged. In most cases, Internet platforms such as Facebook and Amazon restrict the functionality of their digital currencies to enhance the business model and maximize their profits. While platform-based digital currencies could increase the efficiency of retail payments, they could also raise some important policy issues if they were to become widely used outside of the platform. Thus, it is...

  8. Comparative study of SiC- and Si-based photovoltaic inverters

    Science.gov (United States)

    Ando, Yuji; Oku, Takeo; Yasuda, Masashi; Shirahata, Yasuhiro; Ushijima, Kazufumi; Murozono, Mikio

    2017-01-01

    This article reports comparative study of 150-300 W class photovoltaic inverters (Si inverter, SiC inverter 1, and SiC inverter 2). In these sub-kW class inverters, the ON-resistance was considered to have little influence on the efficiency. The developed SiC inverters, however, have exhibited an approximately 3% higher direct current (DC)-alternating current (AC) conversion efficiency as compared to the Si inverter. Power loss analysis indicated a reduction in the switching and reverse recovery losses of SiC metal-oxide-semiconductor field-effect transistors used for the DC-AC converter is responsible for this improvement. In the SiC inverter 2, an increase of the switching frequency up to 100 kHz achieved a state-of-the-art combination of the weight (1.25 kg) and the volume (1260 cm3) as a 150-250 W class inverter. Even though the increased switching frequency should cause the increase of the switching losses, the SiC inverter 2 exhibited an efficiency comparable to the SiC inverter 1 with a switching frequency of 20 kHz. The power loss analysis also indicated a decreased loss of the DC-DC converter built with SiC Schottky barrier diodes led to the high efficiency for its increased switching frequency. These results clearly indicated feasibility of SiC devices even for sub-kW photovoltaic inverters, which will be available for the applications where compactness and efficiency are of tremendous importance.

  9. Analysis of balance control methods based on inverted pendulum for legged robots

    OpenAIRE

    Denisov, A.; Iakovlev, R.; Mamaev, I.; Pavliuk, N.

    2017-01-01

    Methods of balance control for a legged robot, the model of which is presented as a two-section inverted pendulum, are considered. The following balance methods for humanoid robots are analysed: the parallel algorithm of the network operator method; the method of natural synergies; the method of fuzzy control, the spherical inverted pendulum mode, a dual length linear inverted pendulum method. The best of these methods will be used in the development of the Russian anthropomorphic robot Antares.

  10. Analysis of balance control methods based on inverted pendulum for legged robots

    Directory of Open Access Journals (Sweden)

    Denisov Alexander

    2017-01-01

    Full Text Available Methods of balance control for a legged robot, the model of which is presented as a two-section inverted pendulum, are considered. The following balance methods for humanoid robots are analysed: the parallel algorithm of the network operator method; the method of natural synergies; the method of fuzzy control, the spherical inverted pendulum mode, a dual length linear inverted pendulum method. The best of these methods will be used in the development of the Russian anthropomorphic robot Antares.

  11. FPGA Techniques Based New Hybrid Modulation Strategies for Voltage Source Inverters

    Science.gov (United States)

    Sudha, L. U.; Baskaran, J.; Elankurisil, S. A.

    2015-01-01

    This paper corroborates three different hybrid modulation strategies suitable for single-phase voltage source inverter. The proposed method is formulated using fundamental switching and carrier based pulse width modulation methods. The main tale of this proposed method is to optimize a specific performance criterion, such as minimization of the total harmonic distortion (THD), lower order harmonics, switching losses, and heat losses. The proposed method is articulated using fundamental switching and carrier based pulse width modulation methods. Thus, the harmonic pollution in the power system will be reduced and the power quality will be augmented with better harmonic profile for a target fundamental output voltage. The proposed modulation strategies are simulated in MATLAB r2010a and implemented in a Xilinx spartan 3E-500 FG 320 FPGA processor. The feasibility of these modulation strategies is authenticated through simulation and experimental results. PMID:25821852

  12. Comparison between Different Control Strategies of a Z-Source Inverter Based Dynamic Voltage Restorer

    Directory of Open Access Journals (Sweden)

    Abolfazl Kazemdehdashti

    2013-01-01

    Full Text Available In this paper, dynamic voltage restorer (DVR compensation methods are compared to each other for the load side connected shunt converter topology of z-source inverter based DVR to choose the best method. Four different topologies are recognized for DVR that two of them have energy storage devices, and two topologies have no energy storage that take ener\\-gy from the grid during the period of compensation. Here the load side connected shunt converter topology that takes necessary energy from the grid is used. Pre-sag compensation, in-phase compensation, energy-optimized methods are the three DVR compensation methods that studied and compared. A deep analysis through different diagrams would show the advantages or disadvantages of each compensation method. Equations for all methods are derived and the characteristics of algorithms are compared with each other. The simulation results done by SIMULINK/ MATLAB shows compensating by this topology based on the compensation methods.

  13. Inverted oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Yuce, C [Physics Department, Anadolu University, Eskisehir (Turkey); Kilic, A [Physics Department, Anadolu University, Eskisehir (Turkey); Coruh, A [Physics Department, Sakarya University, Sakarya (Turkey)

    2006-07-15

    The inverted harmonic oscillator problem is investigated quantum mechanically. The exact wavefunction for the confined inverted oscillator is obtained and it is shown that the associated energy eigenvalues are discrete, and the energy is given as a linear function of the quantum number n.

  14. Modular inverter system

    Science.gov (United States)

    Ma, Mingyao; Hu, Haibing; Kutkut, Nasser; Batarseh, Issa; Shen, John; , Bkayrat, Raed

    2017-08-01

    A system connected to an AC power grid having an AC phase signal includes an inverter module including a first inverter coupled to a DC voltage, actuated based on the AC phase signal. The first inverter provides a first voltage signal having predetermined harmonic components. A second inverter includes second switch elements coupled to the DC voltage and actuated by a second set of control signals phase delayed with respect to the first control signals. A transformer module has first and second primary windings coupled to the first and second inverters. The transformer module further includes a secondary winding coupled to first primary winding, the second primary winding, and the AC power grid. The secondary winding is configured to provide a secondary output voltage to the AC power grid by combining the first voltage signal and the second voltage signal such that the predetermined harmonic components are substantially cancelled.

  15. Three-dimensional motion-picture imaging of dynamic object by parallel-phase-shifting digital holographic microscopy using an inverted magnification optical system

    Science.gov (United States)

    Fukuda, Takahito; Shinomura, Masato; Xia, Peng; Awatsuji, Yasuhiro; Nishio, Kenzo; Matoba, Osamu

    2017-04-01

    We constructed a parallel-phase-shifting digital holographic microscopy (PPSDHM) system using an inverted magnification optical system, and succeeded in three-dimensional (3D) motion-picture imaging for 3D displacement of a microscopic object. In the PPSDHM system, the inverted and afocal magnification optical system consisted of a microscope objective (16.56 mm focal length and 0.25 numerical aperture) and a convex lens (300 mm focal length and 82 mm aperture diameter). A polarization-imaging camera was used to record multiple phase-shifted holograms with a single-shot exposure. We recorded an alum crystal, sinking down in aqueous solution of alum, by the constructed PPSDHM system at 60 frames/s for about 20 s and reconstructed high-quality 3D motion-picture image of the crystal. Then, we calculated amounts of displacement of the crystal from the amounts in the focus plane and the magnifications of the magnification optical system, and obtained the 3D trajectory of the crystal by that amounts.

  16. Power control based on particle swarm optimization of grid-connected inverter for hybrid renewable energy system

    International Nuclear Information System (INIS)

    García-Triviño, Pablo; Gil-Mena, Antonio José; Llorens-Iborra, Francisco; García-Vázquez, Carlos Andrés; Fernández-Ramírez, Luis M.; Jurado, Francisco

    2015-01-01

    Highlights: • Three PSO-based PI controllers for a grid-connected inverter were presented. • Two online PSO-based PI controllers were compared with an offline PSO-tuned PI. • The HRES and the inverter were evaluated under power changes and grid voltage sags. • Online ITAE-based PSO reduced ITAE (current THD) by 15.24% (5.32%) versus offline one. - Abstract: This paper is focused on the study of particle swarm optimization (PSO)-based PI controllers for the power control of a grid-connected inverter supplied from a hybrid renewable energy system. It is composed of two renewable energy sources (wind turbine and photovoltaic – PV – solar panels) and two energy storage systems (battery and hydrogen system, integrated by fuel cell and electrolyzer). Three PSO-based PI controllers are implemented: (1) conventional PI controller with offline tuning by PSO algorithm based on the integral time absolute error (ITAE) index; (2) PI controllers with online self-tuning by PSO algorithm based on the error; and (3) PI controllers with online self-tuning by PSO algorithm based on the ITAE index. To evaluate and compare the three controllers, the hybrid renewable energy system and the grid-connected inverter are simulated under changes in the active and reactive power values, as well as under a grid voltage sag. The results show that the online PSO-based PI controllers that optimize the ITAE index achieves the best response

  17. Filter optimization of Si and SiC semiconductor-based H5 and Conergy-NPC transformerless PV inverters

    DEFF Research Database (Denmark)

    Saridakis, Stefanos; Koutroulis, Eftichios; Blaabjerg, Frede

    2013-01-01

    Single-phase transformerless Photovoltaic (PV) inverters are synthesized by combining available solutions in terms of the power section topology, power semiconductors manufacturing technology and structure of the output filter. A design method is presented in this paper for optimizing the power......C-based PV inverters will inject more energy into the electric grid, compared to the Si-based structures and enable the reduction of the output filter size, weight and cost. Employing an LLCL-type output filter and simultaneously reducing the cost of SiC power semiconductors to the level of their Si...

  18. Thermal Equilibrium Dynamic Control Based on DPWM Dual-Mode Modulation of High Power NPC Three-Level Inverter

    Directory of Open Access Journals (Sweden)

    Shi-Zhou Xu

    2016-01-01

    Full Text Available In some special applications of NPC three-level inverters, such as mine hoist, there exist special conditions of overloading during the whole hoisting process and large overload in starting stage, during which the power-loss calculation of power devices and thermal control are important factors affecting the thermal stability of inverters. The principles of SVPWM and DPWM were described in this paper firstly, based on which the dynamic power losses of the two modulations of hoist in single period were calculated. Secondly, a thermal equilibrium dynamic control based on DPMW dual-mode modulation was proposed, which can switch the modulation dynamically according to the change of dynamic power loss to realize dynamic control of power loss and thermal equilibrium of inverter. Finally, simulation and experiment prove the effectiveness of the proposed strategy.

  19. A unified triangle carrier based PWM strategy for three-phase N-level diode clamped inverters

    DEFF Research Database (Denmark)

    Li, Kai; Xie, Chuan; Wei, Min

    2017-01-01

    The triangle carrier based pulse width modulation (TCB-PWM) can be functionally equivalent to space vector base PWM (SVB-PWM). For multi-level inverter, it is very difficult to realize the SVB-PWM because its vector space is very complex. In this paper, a unified TCB-PWM strategy for three-phase ...

  20. On-state voltage drop based power limit detection of IGBT inverters

    DEFF Research Database (Denmark)

    Trintis, Ionut; Ghimire, Pramod; Munk-Nielsen, Stig

    2015-01-01

    Power density is a key performance factor in order to reduce the cost and size of a power converter. Because of the unknown junction temperature, today’s design margins are relatively high to ensure safe and a reliable operation. In this paper, the on-state voltage drop is measured online for all...... insulated gate bipolar transistors (IGBTs) in the inverter, using advanced gate driver. The die temperature is estimated and monitored on each device during power converter operation. Based on the monitored temperature in real time, the maximum power capability is detected. The output power is increased...... until a safe operating temperature of power modules. This enable a power density is increased by 11.16 kW/litre to 19.13 kW/litre in a low voltage power stack which is typically used in wind power converters. Experiment results are shown for safe operation of converter at around 1.2 MW, which is built...

  1. Inkjet printed ambipolar transistors and inverters based on carbon nanotube/zinc tin oxide heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Bongjun; Jang, Seonpil; Dodabalapur, Ananth, E-mail: ananth.dodabalapur@engr.utexas.edu [Microelectronics Research Center, The University of Texas at Austin, Austin, Texas 78758 (United States); Department of Electrical and Computer Engineering, The University of Texas at Austin, Austin, Texas 78712 (United States); Geier, Michael L.; Prabhumirashi, Pradyumna L. [Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208 (United States); Hersam, Mark C. [Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208 (United States); Department of Chemistry, Northwestern University, Evanston, Illinois 60208 (United States); Department of Medicine, Northwestern University, Evanston, Illinois 60208 (United States)

    2014-02-10

    We report ambipolar field-effect transistors (FETs) consisting of inkjet printed semiconductor bilayer heterostructures utilizing semiconducting single-walled carbon nanotubes (SWCNTs) and amorphous zinc tin oxide (ZTO). The bilayer structure allows for electron transport to occur principally in the amorphous oxide layer and hole transport to occur exclusively in the SWCNT layer. This results in balanced electron and hole mobilities exceeding 2 cm{sup 2} V{sup −1} s{sup −1} at low operating voltages (<5 V) in air. We further show that the SWCNT-ZTO hybrid ambipolar FETs can be integrated into functional inverter circuits that display high peak gain (>10). This work provides a pathway for realizing solution processable, inkjet printable, large area electronic devices, and systems based on SWCNT-amorphous oxide heterostructures.

  2. Stability analysis and active damping for LLCL-filter based grid-connected inverters

    DEFF Research Database (Denmark)

    Huang, Min; Blaabjerg, Frede; Loh, Poh Chiang

    2014-01-01

    A higher order passive power filter (LLCL-filter) for the grid-tied inverter is becoming attractive for the industrial applications due to the possibility to reduce the cost of the copper and the magnetic material. To avoid the well-known stability problems of the LLCL-filter it is requested to use...... either passive or active damping methods. This paper analyzes the stability when damping is required and when damping is not necessary considering sampling and transport delay. Basic LLCL resonance damping properties of different feedback states are also studied. Then an active damping method which...... is using the capacitor current feedback for LLCL-filter is introduced. Based on this method, a design procedure for the control method is given. Last, both simulation and experimental results are provided to validate the theoretical analysis of this paper....

  3. A new virtual-flux-vector based droop control strategy for parallel connected inverters in microgrids

    DEFF Research Database (Denmark)

    Hu, Jiefeng; Zhu, Jianguo; Qu, Yanqing

    2013-01-01

    Voltage and frequency droop method is commonly used in microgrids to achieve proper autonomous power sharing without rely on intercommunication systems. This paper proposes a new control strategy for parallel connected inverters in microgrid applications by drooping the flux instead of the invert...

  4. The influences of load mass changing on inverted pendulum stability based on simulation study

    Science.gov (United States)

    Pangaribuan, Timbang; Nasruddin, M. N.; Marlianto, Eddy; Sigiro, Mula

    2017-09-01

    An inverted pendulum has nonlinear dynamic, so it is not easy to do in analysis to see its behavior. From many observations which have been made, there are two things that need to be added on the perfection of inverted pendulum. Firstly, when the pendulum has a large mass, and the second when the pendulum is given a load mass much larger than mass of the inverted pendulum. There are some question, first, how big the load mass can be given so that the movement of the inverted pendulum stay stable is. Second, how weight the changes and moves of load mass which can be given. For all the changes, it hopes the inverted pendulum is stay stable. Finally, the final result is still expected to be as stable, it must need conclude what kind of controller is capable of carrying such a mass burden, and how large the mass load limit can be given.

  5. Non-classical logic inverter coupling a ZnO nanowire-based Schottky barrier transistor and adjacent Schottky diode.

    Science.gov (United States)

    Hosseini Shokouh, Seyed Hossein; Raza, Syed Raza Ali; Lee, Hee Sung; Im, Seongil

    2014-08-21

    On a single ZnO nanowire (NW), we fabricated an inverter-type device comprising a Schottky diode (SD) and field-effect transistor (FET), aiming at 1-dimensional (1D) electronic circuits with low power consumption. The SD and adjacent FET worked respectively as the load and driver, so that voltage signals could be easily extracted as the output. In addition, NW FET with a transparent conducting oxide as top gate turned out to be very photosensitive, although ZnO NW SD was blind to visible light. Based on this, we could achieve an array of photo-inverter cells on one NW. Our non-classical inverter is regarded as quite practical for both logic and photo-sensing due to its performance as well as simple device configuration.

  6. Experimental OAI-Based Digital Library Systems

    Science.gov (United States)

    Nelson, Michael L. (Editor); Maly, Kurt (Editor); Zubair, Mohammad (Editor); Rusch-Feja, Diann (Editor)

    2002-01-01

    The objective of Open Archives Initiative (OAI) is to develop a simple, lightweight framework to facilitate the discovery of content in distributed archives (http://www.openarchives.org). The focus of the workshop held at the 5th European Conference on Research and Advanced Technology for Digital Libraries (ECDL 2001) was to bring researchers in the area of digital libraries who are building OAI based systems so as to share their experiences, problems they are facing, and approaches they are taking to address them. The workshop consisted of invited talks from well-established researchers working in building OAI based digital library system along with short paper presentations.

  7. Orthogonally Based Digital Content Management Applicable to Projects-bases

    Directory of Open Access Journals (Sweden)

    Daniel MILODIN

    2009-01-01

    Full Text Available There is defined the concept of digital content. The requirements of an efficient management of the digital content are established. There are listed the quality characteristics of digital content. Orthogonality indicators of digital content are built up. They are meant to measure the image, the sound as well as the text orthogonality as well. Projects-base concept is introduced. There is presented the model of structuring the content in order to maximize orthogonality via a convergent iterative process. The model is instantiated for the digital content of a projects-base. It is introduced the application used to test the model. The paper ends with conclusions.

  8. Interaction Admittance Based Modeling of Multi-Paralleled Grid-Connected Inverter with LCL-Filter

    DEFF Research Database (Denmark)

    Lu, Minghui; Blaabjerg, Frede; Wang, Xiongfei

    2016-01-01

    This paper investigates the mutual interaction and stability issues of multi-parallel LCL-filtered inverters. The stability and power quality of multiple grid-tied inverters are gaining more and more research attention as the penetration of renewables increases. In this paper, interactions...... and coupling effects among the multi-paralleled inverters and power grid are explicitly revealed. An Interaction Admittance concept is introduced to express and model the interaction through the physical admittances of the network. Compared to the existing modeling methods, the proposed analysis provides...

  9. Shunt Active-Power-Filter Topology Based on Parallel Interleaved Inverters

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Asiminoaei, Lucian; Aeloiza, E.

    2008-01-01

    In this paper, an interleaved active-power-filter concept with reduced size of passive components is discussed. The topology is composed of two pulsewidth-modulation interleaved voltage-source inverters connected together on the ac line and sharing the same dc-link capacitor. The advantages......, because the power sharing allows one to use a higher switching frequency in each inverter. This paper analyzes the design of the passive components and gives a practical and low-cost solution for the minimization of the circulation currents between the inverters, by using common-mode coils. Several...

  10. A field application of nanoparticle-based invert emulsion drilling fluids

    Energy Technology Data Exchange (ETDEWEB)

    Borisov, Alexey S.; Husein, Maen, E-mail: mhusein@ucalgary.ca [University of Calgary, Department of Chemical & Petroleum Engineering (Canada); Hareland, Geir [Oklahoma State University, Department of Chemical Engineering (United States)

    2015-08-15

    Application of nanotechnology in drilling fluids for the oil and gas industry has been a focus of several recent studies. A process for the in situ synthesis of nanoparticles (NPs) into drilling fluids has been developed previously in our group and showed that calcium-based NPs (CNPs) and iron-based NPs (INPs), respectively, with concentrations of 0.5–2.0 wt% can dramatically improve filtration properties of commercial drilling fluids in a laboratory environment. In this work, a modified process for the emulsion-based synthesis of NPs on a 20 m{sup 3} volume and its subsequent full-scale field testing are presented. Comparison between NP carrier fluids prepared under controlled environment in the laboratory and those prepared on a large scale in a mixing facility revealed very little variation in the main characteristics of the drilling fluid; including the size of the solid constituents. Transmission electron microscopy photographs suggest an average CNP particle size in the carrier fluid of 51 ± 11 nm. Results from the full-scale field test showed that total mud losses while drilling with CNP-based invert emulsion were on average 27 % lower than in the case of conventional fluids. This loss prevention falls within the range observed in the laboratory.

  11. Design and fabrication of ZnO/TiO2-based thin-film inverter circuits using solution processing techniques

    International Nuclear Information System (INIS)

    Liau, Leo Chau-Kuang; Kuo, Juo-Wei; Chiang, Hsin-Ni

    2012-01-01

    Novel and cost-effective ceramic-based thin-film inverter circuits, based on two layers of TiO 2 and ZnO films to construct junction field-effect transistors (FETs), were designed and fabricated by solution coating techniques. The double layers of the sol–gel ZnO and TiO 2 films were coated and characterized as a diode according to the current–voltage performance. Two types of FETs, the p-channel (p-FET) and the n-channel (n-FET) devices, were produced using different coating sequences of ZnO and TiO 2 layers. Both of the transistor performances were evaluated by analyzing the source–drain current versus voltage (I ds –V ds ) data with the control of the gate voltage (V g ). The ZnO/TiO 2 -based inverter circuits, such as the complementary-FET device, were further fabricated using the integration of the p-FET and the n-FET. The voltage transfer characteristics of the inverters were estimated by the tests of the input voltage (V in ) versus the output voltage (V out ) for the thin-film inverter circuits. (paper)

  12. Novel, Four-Switch, Z-Source Three-Phase Inverter

    DEFF Research Database (Denmark)

    Antal, Robert; Muntean, Nicolae; Boldea, Ion

    2010-01-01

    This paper presents a new z-source three phase inverter topology. The proposed topology combines the advantages of a traditional four-switch three-phase inverter with the advantages of the z impedance network (one front-end diode, two inductors and two X connected capacitors). This new topology......, besides the self-boost property, has low switch count and it can operate as a buck-boost inverter. In contrast to standard four-switch three-phase inverter which operates at half dc input voltage the proposed four-switch z-source inverter, by self boosting, brings the output voltage at same (or higher......) value as in six switch standard three-phase inverter. The article presents the derivation of the equations describing the operation of the converter based on space vector analysis, validation through digital simulations in PSIM and preliminary experimental results on a laboratory setup with a dsPIC30F...

  13. Monitoring and Fault Detection in Photovoltaic Systems Based On Inverter Measured String I-V Curves

    DEFF Research Database (Denmark)

    Spataru, Sergiu; Sera, Dezso; Kerekes, Tamas

    2015-01-01

    Most photovoltaic (PV) string inverters have the hardware capability to measure at least part of the current-voltage (I-V) characteristic curve of the PV strings connected at the input. However, this intrinsic capability of the inverters is not used, since I-V curve measurement and monitoring...... functions are not implemented in the inverter control software. In this paper, we aim to show how such a functionality can be useful for PV system monitoring purposes, to detect the presence and cause of power-loss in the PV strings, be it due to shading, degradation of the PV modules or balance......-of-system components through increased series resistance losses, or shunting of the PV modules. To achieve this, we propose and experimentally demonstrate three complementary PV system monitoring methods that make use of the I-V curve measurement capability of a commercial string inverter. The first method is suitable...

  14. Model-Based Fault Diagnosis in Electric Drive Inverters Using Artificial Neural Network

    National Research Council Canada - National Science Library

    Masrur, Abul; Chen, ZhiHang; Zhang, Baifang; Jia, Hongbin; Murphey, Yi-Lu

    2006-01-01

    .... A normal model and various faulted models of the inverter-motor combination were developed, and voltages and current signals were generated from those models to train an artificial neural network for fault diagnosis...

  15. Reliable inverter systems

    Science.gov (United States)

    Nagano, S.

    1979-01-01

    Base driver with common-load-current feedback protects paralleled inverter systems from open or short circuits. Circuit eliminates total system oscillation that can occur in conventional inverters because of open circuit in primary transformer winding. Common feedback signal produced by functioning modules forces operating frequency of failed module to coincide with clock drive so module resumes normal operating frequency in spite of open circuit.

  16. Real-time physics-based 3D biped character animation using an inverted pendulum model.

    Science.gov (United States)

    Tsai, Yao-Yang; Lin, Wen-Chieh; Cheng, Kuangyou B; Lee, Jehee; Lee, Tong-Yee

    2010-01-01

    We present a physics-based approach to generate 3D biped character animation that can react to dynamical environments in real time. Our approach utilizes an inverted pendulum model to online adjust the desired motion trajectory from the input motion capture data. This online adjustment produces a physically plausible motion trajectory adapted to dynamic environments, which is then used as the desired motion for the motion controllers to track in dynamics simulation. Rather than using Proportional-Derivative controllers whose parameters usually cannot be easily set, our motion tracking adopts a velocity-driven method which computes joint torques based on the desired joint angular velocities. Physically correct full-body motion of the 3D character is computed in dynamics simulation using the computed torques and dynamical model of the character. Our experiments demonstrate that tracking motion capture data with real-time response animation can be achieved easily. In addition, physically plausible motion style editing, automatic motion transition, and motion adaptation to different limb sizes can also be generated without difficulty.

  17. Zero-Axis Virtual Synchronous Coordinate Based Current Control Strategy for Grid-Connected Inverter

    Directory of Open Access Journals (Sweden)

    Longyue Yang

    2018-05-01

    Full Text Available Unbalanced power has a great influence on the safe and stable operation of the distribution network system. The static power compensator, which is essentially a grid-connected inverter, is an effective solution to the three-phase power imbalance problem. In order to solve the tracking error problem of zero-sequence AC current signals, a novel control strategy based on zero-axis virtual synchronous coordinates is proposed in this paper. By configuring the operation of filter transmission matrices, a specific orthogonal signal is obtained for zero-axis reconstruction. In addition, a controller design scheme based on this method is proposed. Compared with the traditional zero-axis direct control, this control strategy is equivalent to adding a frequency tuning module by the orthogonal signal generator. The control gain of an open loop system can be equivalently promoted through linear transformation. With its clear mathematical meaning, zero- sequence current control can be controlled with only a first-order linear controller. Through reasonable parameter design, zero steady-state error, fast response and strong stability can be achieved. Finally, the performance of the proposed control strategy is verified by both simulations and experiments.

  18. Light-Triggered Ternary Device and Inverter Based on Heterojunction of van der Waals Materials.

    Science.gov (United States)

    Shim, Jaewoo; Jo, Seo-Hyeon; Kim, Minwoo; Song, Young Jae; Kim, Jeehwan; Park, Jin-Hong

    2017-06-27

    Multivalued logic (MVL) devices/circuits have received considerable attention because the binary logic used in current Si complementary metal-oxide-semiconductor (CMOS) technology cannot handle the predicted information throughputs and energy demands of the future. To realize MVL, the conventional transistor platform needs to be redesigned to have two or more distinctive threshold voltages (V TH s). Here, we report a finding: the photoinduced drain current in graphene/WSe 2 heterojunction transistors unusually decreases with increasing gate voltage under illumination, which we refer to as the light-induced negative differential transconductance (L-NDT) phenomenon. We also prove that such L-NDT phenomenon in specific bias ranges originates from a variable potential barrier at a graphene/WSe 2 junction due to a gate-controllable graphene electrode. This finding allows us to conceive graphene/WSe 2 -based MVL logic circuits by using the I D -V G characteristics with two distinctive V TH s. Based on this finding, we further demonstrate a light-triggered ternary inverter circuit with three stable logical states (ΔV out of each state <0.05 V). Our study offers the pathway to substantialize MVL systems.

  19. Performance Comparison of Grid-Faulty Control Schemes for Inverter-Based Industrial Microgrids

    Directory of Open Access Journals (Sweden)

    Antonio Camacho

    2017-12-01

    Full Text Available Several control schemes specifically designed to operate inverter-based industrial microgrids during voltage sags have been recently proposed. This paper first classifies these control schemes in three categories and then performs a comparative analysis of them. Representative control schemes of each category are selected, described and used to identify the main features and performance of the considered category. The comparison is based on the evaluation of several indexes, which measure the power quality of the installation and utility grid during voltage sags, including voltage regulation, reactive current injection and transient response. The paper includes selected simulation results from a 500 kVA industrial microgrid to validate the expected features of the considered control schemes. Finally, in view of the obtained results, the paper proposes an alternative solution to cope with voltage sags, which includes the use of a static compensator in parallel with the microgrid. The novelty of this proposal is the suitable selection of the control schemes for both the microgrid and the static compensator. The superior performance of the proposal is confirmed by the analysis of the quality indexes. Its practical limitations are also revealed, showing that the topic studied in this paper is still open for further research.

  20. Fully Digital Chaotic Differential Equation-based Systems And Methods

    KAUST Repository

    Radwan, Ahmed Gomaa Ahmed

    2012-09-06

    Various embodiments are provided for fully digital chaotic differential equation-based systems and methods. In one embodiment, among others, a digital circuit includes digital state registers and one or more digital logic modules configured to obtain a first value from two or more of the digital state registers; determine a second value based upon the obtained first values and a chaotic differential equation; and provide the second value to set a state of one of the plurality of digital state registers. In another embodiment, a digital circuit includes digital state registers, digital logic modules configured to obtain outputs from a subset of the digital shift registers and to provide the input based upon a chaotic differential equation for setting a state of at least one of the subset of digital shift registers, and a digital clock configured to provide a clock signal for operating the digital shift registers.

  1. Fully Digital Chaotic Differential Equation-based Systems And Methods

    KAUST Repository

    Radwan, Ahmed Gomaa Ahmed; Zidan, Mohammed A.; Salama, Khaled N.

    2012-01-01

    Various embodiments are provided for fully digital chaotic differential equation-based systems and methods. In one embodiment, among others, a digital circuit includes digital state registers and one or more digital logic modules configured to obtain a first value from two or more of the digital state registers; determine a second value based upon the obtained first values and a chaotic differential equation; and provide the second value to set a state of one of the plurality of digital state registers. In another embodiment, a digital circuit includes digital state registers, digital logic modules configured to obtain outputs from a subset of the digital shift registers and to provide the input based upon a chaotic differential equation for setting a state of at least one of the subset of digital shift registers, and a digital clock configured to provide a clock signal for operating the digital shift registers.

  2. sideSPIM – selective plane illumination based on a conventional inverted microscope

    Science.gov (United States)

    Hedde, Per Niklas; Malacrida, Leonel; Ahrar, Siavash; Siryaporn, Albert; Gratton, Enrico

    2017-01-01

    Previously described selective plane illumination microscopy techniques typically offset ease of use and sample handling for maximum imaging performance or vice versa. Also, to reduce cost and complexity while maximizing flexibility, it is highly desirable to implement light sheet microscopy such that it can be added to a standard research microscope instead of setting up a dedicated system. We devised a new approach termed sideSPIM that provides uncompromised imaging performance and easy sample handling while, at the same time, offering new applications of plane illumination towards fluidics and high throughput 3D imaging of multiple specimen. Based on an inverted epifluorescence microscope, all of the previous functionality is maintained and modifications to the existing system are kept to a minimum. At the same time, our implementation is able to take full advantage of the speed of the employed sCMOS camera and piezo stage to record data at rates of up to 5 stacks/s. Additionally, sample handling is compatible with established methods and switching magnification to change the field of view from single cells to whole organisms does not require labor intensive adjustments of the system. PMID:29026679

  3. sideSPIM - selective plane illumination based on a conventional inverted microscope.

    Science.gov (United States)

    Hedde, Per Niklas; Malacrida, Leonel; Ahrar, Siavash; Siryaporn, Albert; Gratton, Enrico

    2017-09-01

    Previously described selective plane illumination microscopy techniques typically offset ease of use and sample handling for maximum imaging performance or vice versa . Also, to reduce cost and complexity while maximizing flexibility, it is highly desirable to implement light sheet microscopy such that it can be added to a standard research microscope instead of setting up a dedicated system. We devised a new approach termed sideSPIM that provides uncompromised imaging performance and easy sample handling while, at the same time, offering new applications of plane illumination towards fluidics and high throughput 3D imaging of multiple specimen. Based on an inverted epifluorescence microscope, all of the previous functionality is maintained and modifications to the existing system are kept to a minimum. At the same time, our implementation is able to take full advantage of the speed of the employed sCMOS camera and piezo stage to record data at rates of up to 5 stacks/s. Additionally, sample handling is compatible with established methods and switching magnification to change the field of view from single cells to whole organisms does not require labor intensive adjustments of the system.

  4. Phase Angle Control of Three Level Inverter Based D-STATCOM Using Neuro-Fuzzy Controller

    Directory of Open Access Journals (Sweden)

    COTELI, R.

    2012-02-01

    Full Text Available Distribution Static Compensator (D-STATCOM is a shunt compensation device used to improve electric power quality in distribution systems. It is well-known that D-STATCOM is a nonlinear, semi-defined and time-varying system. Therefore, control of D-STATCOM by the conventional control techniques is very difficult task. In this paper, the control of D-STATCOM is carried out by the neuro-fuzzy controller (NFC which has non-linear and robust structure. For this aim, an experimental setup based on three-level H-bridge inverter is constructed. Phase angle control method is used for control of D-STATCOM's output reactive power. Control algorithm for this experimental setup is prepared in MATLAB/Simulink and downloaded to DS1103 controller card. A Mamdani type NFC is designed for control of D-STATCOM's reactive current. Output of NFC is integrated to increase tracking performance of controller in steady state. The performance of D-STATCOM is experimentally evaluated by changing reference reactive current as on-line. The experimental results show that the proposed controller gives very satisfactory performance under different loading conditions.

  5. Gradient based filtering of digital elevation models

    DEFF Research Database (Denmark)

    Knudsen, Thomas; Andersen, Rune Carbuhn

    We present a filtering method for digital terrain models (DTMs). The method is based on mathematical morphological filtering within gradient (slope) defined domains. The intention with the filtering procedure is to improbé the cartographic quality of height contours generated from a DTM based...

  6. Attribute-Based Digital Signature System

    NARCIS (Netherlands)

    Ibraimi, L.; Asim, Muhammad; Petkovic, M.

    2011-01-01

    An attribute-based digital signature system comprises a signature generation unit (1) for signing a message (m) by generating a signature (s) based on a user secret key (SK) associated with a set of user attributes, wherein the signature generation unit (1) is arranged for combining the user secret

  7. Γ-source Neutral Point Clamped Inverter

    DEFF Research Database (Denmark)

    Mo, Wei; Loh, Poh Chiang; Blaabjerg, Frede

    Transformer based Z-source inverters are recently proposed to achieve promising buck-boost capability. They have improved higher buck-boost capability, smaller size and less components count over Z-source inverters. On the other hand, neutral point clamped inverters have less switching stress...... and better output performance comparing with traditional two-level inverters. Integrating these two types of configurations can help neutral point inverters achieve enhanced votlage buck-boost capability....

  8. Stochastic p -Bits for Invertible Logic

    Science.gov (United States)

    Camsari, Kerem Yunus; Faria, Rafatul; Sutton, Brian M.; Datta, Supriyo

    2017-07-01

    Conventional semiconductor-based logic and nanomagnet-based memory devices are built out of stable, deterministic units such as standard metal-oxide semiconductor transistors, or nanomagnets with energy barriers in excess of ≈40 - 60 kT . In this paper, we show that unstable, stochastic units, which we call "p -bits," can be interconnected to create robust correlations that implement precise Boolean functions with impressive accuracy, comparable to standard digital circuits. At the same time, they are invertible, a unique property that is absent in standard digital circuits. When operated in the direct mode, the input is clamped, and the network provides the correct output. In the inverted mode, the output is clamped, and the network fluctuates among all possible inputs that are consistent with that output. First, we present a detailed implementation of an invertible gate to bring out the key role of a single three-terminal transistorlike building block to enable the construction of correlated p -bit networks. The results for this specific, CMOS-assisted nanomagnet-based hardware implementation agree well with those from a universal model for p -bits, showing that p -bits need not be magnet based: any three-terminal tunable random bit generator should be suitable. We present a general algorithm for designing a Boltzmann machine (BM) with a symmetric connection matrix [J ] (Ji j=Jj i) that implements a given truth table with p -bits. The [J ] matrices are relatively sparse with a few unique weights for convenient hardware implementation. We then show how BM full adders can be interconnected in a partially directed manner (Ji j≠Jj i) to implement large logic operations such as 32-bit binary addition. Hundreds of stochastic p -bits get precisely correlated such that the correct answer out of 233 (≈8 ×1 09) possibilities can be extracted by looking at the statistical mode or majority vote of a number of time samples. With perfect directivity (Jj i=0 ) a small

  9. Electronic Document Management Using Inverted Files System

    Science.gov (United States)

    Suhartono, Derwin; Setiawan, Erwin; Irwanto, Djon

    2014-03-01

    The amount of documents increases so fast. Those documents exist not only in a paper based but also in an electronic based. It can be seen from the data sample taken by the SpringerLink publisher in 2010, which showed an increase in the number of digital document collections from 2003 to mid of 2010. Then, how to manage them well becomes an important need. This paper describes a new method in managing documents called as inverted files system. Related with the electronic based document, the inverted files system will closely used in term of its usage to document so that it can be searched over the Internet using the Search Engine. It can improve document search mechanism and document save mechanism.

  10. Electronic Document Management Using Inverted Files System

    Directory of Open Access Journals (Sweden)

    Suhartono Derwin

    2014-03-01

    Full Text Available The amount of documents increases so fast. Those documents exist not only in a paper based but also in an electronic based. It can be seen from the data sample taken by the SpringerLink publisher in 2010, which showed an increase in the number of digital document collections from 2003 to mid of 2010. Then, how to manage them well becomes an important need. This paper describes a new method in managing documents called as inverted files system. Related with the electronic based document, the inverted files system will closely used in term of its usage to document so that it can be searched over the Internet using the Search Engine. It can improve document search mechanism and document save mechanism.

  11. Dual-view inverted selective plane illumination microscopy (diSPIM) with improved background rejection for accurate 3D digital pathology

    Science.gov (United States)

    Hu, Bihe; Bolus, Daniel; Brown, J. Quincy

    2018-02-01

    Current gold-standard histopathology for cancerous biopsies is destructive, time consuming, and limited to 2D slices, which do not faithfully represent true 3D tumor micro-morphology. Light sheet microscopy has emerged as a powerful tool for 3D imaging of cancer biospecimens. Here, we utilize the versatile dual-view inverted selective plane illumination microscopy (diSPIM) to render digital histological images of cancer biopsies. Dual-view architecture enabled more isotropic resolution in X, Y, and Z; and different imaging modes, such as adding electronic confocal slit detection (eCSD) or structured illumination (SI), can be used to improve degraded image quality caused by background signal of large, scattering samples. To obtain traditional H&E-like images, we used DRAQ5 and eosin (D&E) staining, with 488nm and 647nm laser illumination, and multi-band filter sets. Here, phantom beads and a D&E stained buccal cell sample have been used to verify our dual-view method. We also show that via dual view imaging and deconvolution, more isotropic resolution has been achieved for optical cleared human prostate sample, providing more accurate quantitation of 3D tumor architecture than was possible with single-view SPIM methods. We demonstrate that the optimized diSPIM delivers more precise analysis of 3D cancer microarchitecture in human prostate biopsy than simpler light sheet microscopy arrangements.

  12. Study on unitized inverter with photovoltaic grid-connected and stand-alone functions

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Haining; Su, Jianhui; Ding, Ming [Hefei University of Technology, Hefei (China)

    2008-07-01

    The main circuit and algorithm of unitized single phase inverter are presented, in which photovoltaic (PV) grid-connected algorithm, independency sine inverter algorithm and storage battery charge administer are all integrated basing on DSP (Digital Signal Processor). The control system identifies utility failure initiatively and then switches to independency power supply automatically. The methods of charging battery are multiform. Basing on material term to use utility or solar array to charge can optimize charge efficiency, assure the capacitance of battery and prolong life-span of battery. In addition, some results are offered basing on the prototype of a 2.5kW single phase inverter. (orig.)

  13. The CMOS integration of a power inverter

    Science.gov (United States)

    Mannarino, Eric Francis

    Due to their falling costs, the use of renewable energy systems is expanding around the world. These systems require the conversion of DC power into grid-synchronous AC power. Currently, the inverters that carry out this task are built using discrete transistors. TowerJazz Semiconductor Corp. has created a commercial CMOS process that allows for blocking voltages of up to 700 V, effectively removing the barrier to integrating power inverters onto a single chip. This thesis explores this process using two topologies. The first is a cell-based switched-capacitor topology first presented by Ke Zou. The second is a novel topology that explores the advantage of using a bused input-output system, as in digital electronics. Simulations run on both topologies confirm the high-efficiency demonstrated in Zou’s process as well as the advantage the bus-based system has in output voltage levels.

  14. An evaporation based digital microflow meter

    NARCIS (Netherlands)

    Nie, C; Frijns, A J H; Mandamparambil, R; Zevenbergen, M A G; den Toonder, J M J

    2015-01-01

    In this work, we present a digital microflow meter operating in the range 30-250 nl min-1 for water. The principle is based on determining the evaporation rate of the liquid via reading the number of wetted pore array structures in a microfluidic system, through which continuous evaporation takes

  15. An evaporation based digital microflow meter

    NARCIS (Netherlands)

    Nie, C.; Frijns, A.J.H.; Mandamparambil, R.; Zevenbergen, M.A.G.; Toonder, den J.M.J.

    2015-01-01

    In this work, we present a digital microflow meter operating in the range 30–250 nl min-1 for water. The principle is based on determining the evaporation rate of the liquid via reading the number of wetted pore array structures in a microfluidic system, through which continuous evaporation takes

  16. Domesticating Digital Game-based Learning

    Directory of Open Access Journals (Sweden)

    Helga Dís Sigurdardottir

    2016-07-01

    Full Text Available This paper analyses the use of digital game-based learning (DGBL in schools in Norway. It investigates the types of games used in Norwegian schools and how pupils experience that practice. Digital game-based learning is being widely employed throughout Norway as a result of the increased focus on digital skills in Norwegian education. This paper analyses that development by way of focus group interviews with a total of sixty-four pupils at four schools. Drawing upon domestication and actor-network theory, the paper provides a novel approach to the study of DGBL. The broad empirical investigation into DGBL practices furthermore provides a contribution to scholarly literature on the subject. A noteworthy finding of this study is the diversity of games employed in schools—around 30 different titles— indicating that the choice of games lies at the discretion of individual teachers. Findings from this research show that the domestication of digital game-based learning occurs through the construction of complex game-based learning assemblages. This includes the classroom and home as gaming sites, group work and individual assignments as practices, and PCs and iPads as platforms.

  17. Precise Modeling Based on Dynamic Phasors for Droop-Controlled Parallel-Connected Inverters

    DEFF Research Database (Denmark)

    Wang, L.; Guo, X.Q.; Gu, H.R.

    2012-01-01

    This paper deals with the precise modeling of droop controlled parallel inverters. This is very attractive since that is a common structure that can be found in a stand-alone droopcontrolled MicroGrid. The conventional small-signal dynamic is not able to predict instabilities of the system, so...

  18. Optimization of PV-based energy production by dynamic PV-panel/inverter configuration

    DEFF Research Database (Denmark)

    Paasch, Kasper; Nymand, Morten; Haase, Frerk

    This paper investigates the possible increase in annual energy production of a PV system with more than one MPPT (maximum power point tracker) input channels under Nordic illumination conditions, in case a concept of dynamic switching of the PV panels is used at the inputs of the inverters....

  19. PI and repetitive control for single phase inverter based on virtual rotating coordinate system

    Science.gov (United States)

    Li, Mengqi; Tong, Yibin; Jiang, Jiuchun; Liang, Jiangang

    2018-03-01

    Microgrid technology developed rapidly and nonlinear loads were connected increasingly. A new control strategy was proposed for single phase inverter when connected nonlinear loads under island condition. PI and repetitive compound controller was realized under synchronous rotating coordinate system and acquired high quality sinusoidal voltage output without voltage spike when loads step changed. Validity and correctness were verified by simulation using MATLAB/Simulink.

  20. A laboratory grid simulator based on three-phase four-leg inverter

    DEFF Research Database (Denmark)

    Li, Fei; Wang, Xiongfei; Chen, Zhe

    2011-01-01

    This paper presents the design and implementation of a laboratory grid simulator which is used to test the grid-connected devices according to the strict standards. Three-phase four-leg inverter with direct voltage control in Natural Frame is adopted in this grid simulator, which significantly...

  1. Optimization of SiC-based H5 and conergy-NPC transformerless PV inverters

    DEFF Research Database (Denmark)

    Saridakis, Stefanos; Koutroulis, Eftichios; Blaabjerg, Frede

    2015-01-01

    The transformerless dc/ac inverters are critical components in the rapidly growing market of grid-connected photovoltaic (PV) applications. They are synthesized by combining available solutions in terms of the power-section topology, power-semiconductors manufacturing technology, and structure...

  2. MEMS based digital transform spectrometers

    Science.gov (United States)

    Geller, Yariv; Ramani, Mouli

    2005-09-01

    Earlier this year, a new breed of Spectrometers based on Micro-Electro-Mechanical-System (MEMS) engines has been introduced to the commercial market. The use of these engines combined with transform mathematics, produces powerful spectrometers at unprecedented low cost in various spectral regions.

  3. GENETIC ALGORITHM BASED SOLUTION IN PWM CONVERTER SWITCHING FOR VOLTAGE SOURCE INVERTER FEEDING AN INDUCTION MOTOR DRIVE

    Directory of Open Access Journals (Sweden)

    V. Jegathesan

    2017-11-01

    Full Text Available This paper presents an efficient and reliable Genetic Algorithm based solution for Selective Harmonic Elimination (SHE switching pattern. This method eliminates considerable amount of lower order line voltage harmonics in Pulse Width Modulation (PWM inverter. Determination of pulse pattern for the elimination of some lower order harmonics of a PWM inverter necessitates solving a system of nonlinear transcendental equations. Genetic Algorithm is used to solve nonlinear transcendental equations for PWM-SHE. Many methods are available to eliminate the higher order harmonics and it can be easily removed. But the greatest challenge is to eliminate the lower order harmonics and this is successfully achieved using Genetic Algorithm without using Dual transformer. Simulations using MATLABTM and Powersim with experimental results are carried out to validate the solution. The experimental results show that the harmonics up to 13th were totally eliminated.

  4. An improved fault-tolerant control scheme for PWM inverter-fed induction motor-based EVs.

    Science.gov (United States)

    Tabbache, Bekheïra; Benbouzid, Mohamed; Kheloui, Abdelaziz; Bourgeot, Jean-Matthieu; Mamoune, Abdeslam

    2013-11-01

    This paper proposes an improved fault-tolerant control scheme for PWM inverter-fed induction motor-based electric vehicles. The proposed strategy deals with power switch (IGBTs) failures mitigation within a reconfigurable induction motor control. To increase the vehicle powertrain reliability regarding IGBT open-circuit failures, 4-wire and 4-leg PWM inverter topologies are investigated and their performances discussed in a vehicle context. The proposed fault-tolerant topologies require only minimum hardware modifications to the conventional off-the-shelf six-switch three-phase drive, mitigating the IGBTs failures by specific inverter control. Indeed, the two topologies exploit the induction motor neutral accessibility for fault-tolerant purposes. The 4-wire topology uses then classical hysteresis controllers to account for the IGBT failures. The 4-leg topology, meanwhile, uses a specific 3D space vector PWM to handle vehicle requirements in terms of size (DC bus capacitors) and cost (IGBTs number). Experiments on an induction motor drive and simulations on an electric vehicle are carried-out using a European urban driving cycle to show that the proposed fault-tolerant control approach is effective and provides a simple configuration with high performance in terms of speed and torque responses. Copyright © 2013 ISA. Published by Elsevier Ltd. All rights reserved.

  5. EMI performance comparison of two-level and three-level inverters in small dc-link capacitors based motor drives

    DEFF Research Database (Denmark)

    Maheshwari, Ram Krishan; Munk-Nielsen, Stig; Busquets-Monge, S.

    2012-01-01

    The size of passive components in an adjustable speed drive can be reduced by using small dc-link capacitors. The EMI filter in the drive also consists of passive components. The size of the filter can be reduced by using a three-level inverter, which can have low output voltage distortion. However......, the three-level inverter based on small dc-link capacitors requires a PWM strategy to maintain neutral-point voltage balance. In this paper, the common mode voltage, which is the determining factor for the EMI filter size, is analyzed for a virtual-vector-based PWM strategy. The common mode voltage......, the shaft voltage, and the conducted emission for the small dc-link capacitor based three-level inverter are compared with that of the two-level inverter operated with space vector PWM strategy. Experimental results for the common mode voltage, the shaft voltage, and the conducted emission are presented...

  6. Wavelet Entropy-Based Traction Inverter Open Switch Fault Diagnosis in High-Speed Railways

    Directory of Open Access Journals (Sweden)

    Keting Hu

    2016-03-01

    Full Text Available In this paper, a diagnosis plan is proposed to settle the detection and isolation problem of open switch faults in high-speed railway traction system traction inverters. Five entropy forms are discussed and compared with the traditional fault detection methods, namely, discrete wavelet transform and discrete wavelet packet transform. The traditional fault detection methods cannot efficiently detect the open switch faults in traction inverters because of the low resolution or the sudden change of the current. The performances of Wavelet Packet Energy Shannon Entropy (WPESE, Wavelet Packet Energy Tsallis Entropy (WPETE with different non-extensive parameters, Wavelet Packet Energy Shannon Entropy with a specific sub-band (WPESE3,6, Empirical Mode Decomposition Shannon Entropy (EMDESE, and Empirical Mode Decomposition Tsallis Entropy (EMDETE with non-extensive parameters in detecting the open switch fault are evaluated by the evaluation parameter. Comparison experiments are carried out to select the best entropy form for the traction inverter open switch fault detection. In addition, the DC component is adopted to isolate the failure Isolated Gate Bipolar Transistor (IGBT. The simulation experiments show that the proposed plan can diagnose single and simultaneous open switch faults correctly and timely.

  7. Induced over voltage test on transformers using enhanced Z-source inverter based circuit

    Science.gov (United States)

    Peter, Geno; Sherine, Anli

    2017-09-01

    The normal life of a transformer is well above 25 years. The economical operation of the distribution system has its roots in the equipments being used. The economy being such, that it is financially advantageous to replace transformers with more than 15 years of service in the second perennial market. Testing of transformer is required, as its an indication of the extent to which a transformer can comply with the customers specified requirements and the respective standards (IEC 60076-3). In this paper, induced over voltage testing on transformers using enhanced Z source inverter is discussed. Power electronic circuits are now essential for a whole array of industrial electronic products. The bulky motor generator set, which is used to generate the required frequency to conduct the induced over voltage testing of transformers is nowadays replaced by static frequency converter. First conventional Z-source inverter, and second an enhanced Z source inverter is being used to generate the required voltage and frequency to test the transformer for induced over voltage test, and its characteristics is analysed.

  8. Resonant snubber inverter

    Science.gov (United States)

    Lai, Jih-Sheng; Young, Sr., Robert W.; Chen, Daoshen; Scudiere, Matthew B.; Ott, Jr., George W.; White, Clifford P.; McKeever, John W.

    1997-01-01

    A resonant, snubber-based, soft switching, inverter circuit achieves lossless switching during dc-to-ac power conversion and power conditioning with minimum component count and size. Current is supplied to the resonant snubber branches solely by the main inverter switches. Component count and size are reduced by use of a single semiconductor switch in the resonant snubber branches. Component count is also reduced by maximizing the use of stray capacitances of the main switches as parallel resonant capacitors. Resonance charging and discharging of the parallel capacitances allows lossless, zero voltage switching. In one embodiment, circuit component size and count are minimized while achieving lossless, zero voltage switching within a three-phase inverter.

  9. A Fast-Processing Modulation Strategy for Three-Phase Four-Leg Neutral-Point-Clamped Inverter Based on the Circuit-Level Decoupling Concept

    DEFF Research Database (Denmark)

    Ghoreishy, Hoda; Zhang, Zhe; Thomsen, Ole Cornelius

    2012-01-01

    In this paper, a modulation strategy based on the circuit-level decoupling concept is proposed and investigated for the three-level four-leg neutral-point-clamped (NPC) inverter,with the aim of delivering power to all sorts of loads, linear/nonlinear and balanced/unbalanced. By applying the propo......In this paper, a modulation strategy based on the circuit-level decoupling concept is proposed and investigated for the three-level four-leg neutral-point-clamped (NPC) inverter,with the aim of delivering power to all sorts of loads, linear/nonlinear and balanced/unbalanced. By applying...... the proposed modulation strategy, the four-leg NPC inverter can be decoupled into three three-level Buck converters in each defined operating section. This makes the controller design much simpler compared to the conventional four-leg NPC inverter controllers. Also, this technique can be implemented...

  10. Challenging Ubiquitous Inverted Files

    NARCIS (Netherlands)

    de Vries, A.P.

    2000-01-01

    Stand-alone ranking systems based on highly optimized inverted file structures are generally considered ‘the’ solution for building search engines. Observing various developments in software and hardware, we argue however that IR research faces a complex engineering problem in the quest for more

  11. Curriculum-based neurosurgery digital library.

    Science.gov (United States)

    Langevin, Jean-Philippe; Dang, Thai; Kon, David; Sapo, Monica; Batzdorf, Ulrich; Martin, Neil

    2010-11-01

    Recent work-hour restrictions and the constantly evolving body of knowledge are challenging the current ways of teaching neurosurgery residents. To develop a curriculum-based digital library of multimedia content to face the challenges in neurosurgery education. We used the residency program curriculum developed by the Congress of Neurological Surgeons to structure the library and Microsoft Sharepoint as the user interface. This project led to the creation of a user-friendly and searchable digital library that could be accessed remotely and throughout the hospital, including the operating rooms. The electronic format allows standardization of the content and transformation of the operating room into a classroom. This in turn facilitates the implementation of a curriculum within the training program and improves teaching efficiency. Future work will focus on evaluating the efficacy of the library as a teaching tool for residents.

  12. Enhancement of Performance and Mechanism Studies of All-Solution Processed Small-Molecule based Solar Cells with an Inverted Structure.

    Science.gov (United States)

    Long, Guankui; Wu, Bo; Yang, Xuan; Kan, Bin; Zhou, Ye-Cheng; Chen, Li-Chuan; Wan, Xiangjian; Zhang, Hao-Li; Sum, Tze Chien; Chen, Yongsheng

    2015-09-30

    Both solution-processed polymers and small molecule based solar cells have achieved PCEs over 9% with the conventional device structure. However, for the practical applications of photovoltaic technology, further enhancement of both device performance and stability are urgently required, particularly for the inverted structure devices, since this architecture will probably be most promising for the possible coming commercialization. In this work, we have fabricated both conventional and inverted structure devices using the same small molecular donor/acceptor materials and compared the performance of both device structures, and found that the inverted structure based device gave significantly improved performance, the highest PCE so far for inverted structure based device using small molecules as the donor. Furthermore, the inverted device shows a remarkable stability with almost no obvious degradation after three months. Systematic device physics and charge generation dynamics studies, including optical simulation, light-intensity-dependent current-voltage experiments, photocurrent density-effective voltage analyses, transient absorption measurements, and electrical simulations, indicate that the significantly enhanced performance using inverted device is ascribed to the increasing of Jsc compared to the conventional device, which in turn is mainly attributed to the increased absorption of photons in the active layers, rather than the reduced nongeminate recombination.

  13. Dynamic Phasors-Based Modeling and Stability Analysis of Droop-Controlled Inverters for Microgrid Applications

    DEFF Research Database (Denmark)

    Guo, Xiaoqiang; Lu, Zhigang; Wang, Baocheng

    2014-01-01

    models fail to predict the system instabilities. In order to solve the problem, a new modeling approach for inverter-dominated microgrids by using dynamic phasors is presented in this paper. Our findings indicate that the proposed dynamic phasor model is able to predict accurately the stability margins...... of the system, while the conventional reduced-order small signal model fails. In addition, the virtual ω-E frame power control method, which deals with the power coupling caused by the line impedance X/R characteristic, has also been chosen as an application example of the proposed modeling technique....

  14. A Simple PV Inverter Power Factor Control Method Based on Solar Irradiance Variation

    DEFF Research Database (Denmark)

    Gökmen, Nuri; Hu, Weihao; Chen, Zhe

    2017-01-01

    There has been a significant rise in photovoltaic (PV) system installations throughout the last decade. This has posed some technical challenges to the distribution grid operators. Unfamiliar impacts of these relatively new energy sources now should be handled more comprehensively. The rigidity...... of these impacts mostly depends on PV penetration level, grid and weather characteristics as well as the interaction of load and generation. In this study, a reactive power control method is proposed benefitting from solar irradiance measurements in weather stations. Accordingly, power factors of PV inverters...

  15. Microelectromechanical resonator based digital logic elements

    KAUST Repository

    Hafiz, Md Abdullah Al

    2016-10-20

    Micro/nano-electromechanical resonator based mechanical computing has recently attracted significant attention. However, its full realization has been hindered by the difficulty in realizing complex combinational logics, in which the logic function is constructed by cascading multiple smaller logic blocks. In this work we report an alternative approach for implementation of digital logic core elements, multiplexer and demultiplexer, which can be used to realize combinational logic circuits by suitable concatenation. Toward this, shallow arch shaped microresonators are electrically connected and their resonance frequencies are tuned based on an electrothermal frequency modulation scheme. This study demonstrates that by reconfiguring the same basic building block, the arch microresonator, complex logic circuits can be realized.

  16. Microelectromechanical resonator based digital logic elements

    KAUST Repository

    Hafiz, Md Abdullah Al; Kosuru, Lakshmoji; Younis, Mohammad I.; Fariborzi, Hossein

    2016-01-01

    Micro/nano-electromechanical resonator based mechanical computing has recently attracted significant attention. However, its full realization has been hindered by the difficulty in realizing complex combinational logics, in which the logic function is constructed by cascading multiple smaller logic blocks. In this work we report an alternative approach for implementation of digital logic core elements, multiplexer and demultiplexer, which can be used to realize combinational logic circuits by suitable concatenation. Toward this, shallow arch shaped microresonators are electrically connected and their resonance frequencies are tuned based on an electrothermal frequency modulation scheme. This study demonstrates that by reconfiguring the same basic building block, the arch microresonator, complex logic circuits can be realized.

  17. Single-Phase Boost Inverter-Based Electric Vehicle Charger With Integrated Vehicle to Grid Reactive Power Compensation

    DEFF Research Database (Denmark)

    Wickramasinghe Abeywardana, Damith Buddika; Acuna, Pablo; Hredzak, Branislav

    2018-01-01

    Vehicle to grid (V2G) reactive power compensation using electric vehicle (EV) onboard chargers helps to ensure grid power quality by achieving unity power factor operation. However, the use of EVs for V2G reactive power compensation increases the second-order harmonic ripple current component...... from the grid, exposes the EV battery to these undesirable ripple current components for a longer period and discharges the battery due to power conversion losses. This paper presents a way to provide V2G reactive power compensation through a boost inverter-based single stage EV charger and a DC...

  18. A Novel Grid Impedance Estimation Technique based on Adaptive Virtual Resistance Control Loop Applied to Distributed Generation Inverters

    DEFF Research Database (Denmark)

    Ghzaiel, Walid; Jebali-Ben Ghorbal, Manel; Slama-Belkhodja, Ilhem

    2013-01-01

    and to take the decision of either keep the DG connected, or disconnect it from the utility grid. The proposed method is based on a fast and easy grid fault detection method. A virtual damping resistance is used to drive the system to the resonance in order to extract the grid impedance parameters, both...... the power quality and even damage some sensitive loads connected at the point of the common coupling (PCC). This paper presents detection-estimation method of the grid impedance variation. This estimation tehnique aims to improve the dynamic of the distributed generation (DG) interfacing inverter control...

  19. Optimal Overcurrent Relay Coordination in Presence of Inverter-based Wind Farms and Electrical Energy Storage Devices

    DEFF Research Database (Denmark)

    Javadi, Mohammad Sadegh; Esmaeel Nezhad, Ali; Anvari-Moghaddam, Amjad

    2018-01-01

    This paper investigates the coordination problem of overcurrent relays (OCRs) in presence of wind power generation and electrical energy storage (EES) systems. As the injected short-circuit current of inverter-based devices connected to the electrical grid is a function of the power electronic...... mainly matter for the EES system operating in either charging or discharging modes, as well. This paper evaluates different operation strategies considering the variations of the load demand and the presence of large-scale wind farms as well as an EES system, while validating the suggested method...

  20. Accurate and Less-Disturbing Active Anti-Islanding Method based on PLL for Grid-Connected PV Inverters

    DEFF Research Database (Denmark)

    Ciobotaru, Mihai; Agelidis, Vassilios; Teodorescu, Remus

    2008-01-01

    Islanding prediction is a necessary feature of inverter-based photovoltaic (PV) system in order to meet stringent standard requirements for interconnection with the electrical grid. Both passive and active anti-islanding methods exist. Typically, active methods modify a given parameter, which also...... extracted from the voltage at PCC moves outside of a preset threshold value. This new active anti-islanding method meets both standard requirements IEEE 929-2000, IEEE 1547.1 and VDE 0126.1.1. The disturbance used by this method is small compared to other active anti-islanding methods, such as active...

  1. Fabrication of Hybrid Polymer Solar Cells By Inverted Structure Based on P3HT:PCBM Active Layer

    Directory of Open Access Journals (Sweden)

    Shobih Shobih

    2017-08-01

    Full Text Available Hybrid polymer solar cell has privilege than its conventional structure, where it usually has structure of (ITO/PEDOT:PSS/Active Layer/Al. In humid environment the PEDOT:PSS will absorb water and hence can easily etch the ITO. Therefore it is necessary to use an alternative method to avoid this drawback and obtain more stable polymer solar cells, namely by using hybrid polymer solar cells structure with an inverted device architecture from the conventional, by reversing the nature of charge collection. In this paper we report the results of the fabrication of inverted bulk heterojunction polymer solar cells based on P3HT:PCBM as active layer, utilizing ZnO interlayer as buffer layer between the ITO and active layer with a stacked structure of ITO/ZnO/P3HT:PCBM/PEDOT:PSS/Ag. The ZnO interlayer is formed through short route, i.e. by dissolving ZnO nanoparticles powder in chloroform-methanol solvent blend rather than by sol-gel process. Based on the measurement results on electrical characteristics of inverted polymer solar cells under 500 W/m2 illumination and AM 1.5 direct filter at room temperature, cell with annealing process of active layer at 110 °C for 10 minutes results in higher cell performance than without annealing, with an open-circuit voltage of 0.21 volt, a short-circuit current density of 1.33 mA/cm2 , a fill factor of 43.1%, and a power conversion efficiency of 0.22%. The low cell’s performance is caused by very rough surface of ZnO interlayer.

  2. Digital game-based learning in secondary education

    NARCIS (Netherlands)

    Huizenga, J.C.

    2017-01-01

    This PhD thesis presents research on digital game-based learning in secondary education. The main research question is: How do digital games contribute to learning, engagement and motivation to learn? The thesis contains seven chapters. Chapter one is an introduction to digital game-based learning

  3. Random number generation based on digital differential chaos

    KAUST Repository

    Zidan, Mohammed A.; Radwan, Ahmed G.; Salama, Khaled N.

    2012-01-01

    In this paper, we present a fully digital differential chaos based random number generator. The output of the digital circuit is proved to be chaotic by calculating the output time series maximum Lyapunov exponent. We introduce a new post processing

  4. Highly efficient inverted polymer solar cells based on a cross-linkable water-/alcohol-soluble conjugated polymer interlayer.

    Science.gov (United States)

    Zhang, Kai; Zhong, Chengmei; Liu, Shengjian; Mu, Cheng; Li, Zhengke; Yan, He; Huang, Fei; Cao, Yong

    2014-07-09

    A cross-linkable water/alcohol soluble conjugated polymer (WSCP) material poly[9,9-bis(6'-(N,N-diethylamino)propyl)-fluorene-alt-9,9-bis(3-ethyl(oxetane-3-ethyloxy)-hexyl) fluorene] (PFN-OX) was designed. The cross-linkable nature of PFN-OX is good for fabricating inverted polymer solar cells (PSCs) with well-defined interface and investigating the detailed working mechanism of high-efficiency inverted PSCs based on poly[4,8-bis(2-ethylhexyloxyl)benzo[1,2-b:4,5-b']dithio-phene-2,6-diyl-alt-ethylhexyl-3-fluorothithieno[3,4-b]thiophene-2-carboxylate-4,6-diyl] (PTB7) and (6,6)-phenyl-C71-butyric acid methyl ester (PC71BM) blend active layer. The detailed working mechanism of WSCP materials in high-efficiency PSCs were studied and can be summarized into the following three effects: a) PFN-OX tunes cathode work function to enhance open-circuit voltage (Voc); b) PFN-OX dopes PC71BM at interface to facilitate electron extraction; and c) PFN-OX extracts electrons and blocks holes to enhance fill factor (FF). On the basis of this understanding, the hole-blocking function of the PFN-OX interlayer was further improved with addition of a ZnO layer between ITO and PFN-OX, which led to inverted PSCs with a power conversion efficiency of 9.28% and fill factor high up to 74.4%.

  5. Design of DSP-based high-power digital solar array simulator

    Science.gov (United States)

    Zhang, Yang; Liu, Zhilong; Tong, Weichao; Feng, Jian; Ji, Yibo

    2013-12-01

    To satisfy rigid performance specifications, a feedback control was presented for zoom optical lens plants. With the increasing of global energy consumption, research of the photovoltaic(PV) systems get more and more attention. Research of the digital high-power solar array simulator provides technical support for high-power grid-connected PV systems research.This paper introduces a design scheme of the high-power digital solar array simulator based on TMS320F28335. A DC-DC full-bridge topology was used in the system's main circuit. The switching frequency of IGBT is 25kHz.Maximum output voltage is 900V. Maximum output current is 20A. Simulator can be pre-stored solar panel IV curves.The curve is composed of 128 discrete points .When the system was running, the main circuit voltage and current values was feedback to the DSP by the voltage and current sensors in real-time. Through incremental PI,DSP control the simulator in the closed-loop control system. Experimental data show that Simulator output voltage and current follow a preset solar panels IV curve. In connection with the formation of high-power inverter, the system becomes gridconnected PV system. The inverter can find the simulator's maximum power point and the output power can be stabilized at the maximum power point (MPP).

  6. Optical voice encryption based on digital holography.

    Science.gov (United States)

    Rajput, Sudheesh K; Matoba, Osamu

    2017-11-15

    We propose an optical voice encryption scheme based on digital holography (DH). An off-axis DH is employed to acquire voice information by obtaining phase retardation occurring in the object wave due to sound wave propagation. The acquired hologram, including voice information, is encrypted using optical image encryption. The DH reconstruction and decryption with all the correct parameters can retrieve an original voice. The scheme has the capability to record the human voice in holograms and encrypt it directly. These aspects make the scheme suitable for other security applications and help to use the voice as a potential security tool. We present experimental and some part of simulation results.

  7. Designing an Inverter-based Operational Transconductance Amplifier-capacitor Filter with Low Power Consumption for Biomedical Applications.

    Science.gov (United States)

    Yousefinezhad, Sajad; Kermani, Saeed; Hosseinnia, Saeed

    2018-01-01

    The operational transconductance amplifier-capacitor (OTA-C) filter is one of the best structures for implementing continuous-time filters. It is particularly important to design a universal OTA-C filter capable of generating the desired filter response via a single structure, thus reducing the filter circuit power consumption as well as noise and the occupied space on the electronic chip. In this study, an inverter-based universal OTA-C filter with very low power consumption and acceptable noise was designed with applications in bioelectric and biomedical equipment for recording biomedical signals. The very low power consumption of the proposed filter was achieved through introducing bias in subthreshold MOSFET transistors. The proposed filter is also capable of simultaneously receiving favorable low-, band-, and high-pass filter responses. The performance of the proposed filter was simulated and analyzed via HSPICE software (level 49) and 180 nm complementary metal-oxide-semiconductor technology. The rate of power consumption and noise obtained from simulations are 7.1 nW and 10.18 nA, respectively, so this filter has reduced noise as well as power consumption. The proposed universal OTA-C filter was designed based on the minimum number of transconductance blocks and an inverter circuit by three transconductance blocks (OTA).

  8. Biped Robot Gait Planning Based on 3D Linear Inverted Pendulum Model

    Science.gov (United States)

    Yu, Guochen; Zhang, Jiapeng; Bo, Wu

    2018-01-01

    In order to optimize the biped robot’s gait, the biped robot’s walking motion is simplify to the 3D linear inverted pendulum motion mode. The Center of Mass (CoM) locus is determined from the relationship between CoM and the Zero Moment Point (ZMP) locus. The ZMP locus is planned in advance. Then, the forward gait and lateral gait are simplified as connecting rod structure. Swing leg trajectory using B-spline interpolation. And the stability of the walking process is discussed in conjunction with the ZMP equation. Finally the system simulation is carried out under the given conditions to verify the validity of the proposed planning method.

  9. Design and Field Tests of an Inverted Based Remote MicroGrid on a Korean Island

    Directory of Open Access Journals (Sweden)

    Woo-Kyu Chae

    2015-08-01

    Full Text Available In this paper, we present the results of an economic feasibility study and propose a system structure to test and maintain electrical stability. In addition, we present real operation results after constructing a remote microgrid on an island in South Korea. To perform the economic feasibility study, a commercial tool called HOMER was used. The developed remote microgrid consists of a 400 kW wind turbine (WT generator, 314 kW photovoltaic (PV generator, 500 kVA × 2 grid forming inverter, 3 MWh lithium ion battery, and an energy management system (EMS. The predicted renewable energy fraction was 91% and real operation result was 82%. The frequency maintaining rate of the diesel power plants was 57% but the remote microgrid was 100%. To improve the operating efficiency of the remote microgrid, we investigated the output range of a diesel generator.

  10. Three-Level Inverters with Common-Mode Voltage Cancellation Based on Synchronous Pulsewidth Modulation

    DEFF Research Database (Denmark)

    Oleschuk, Valentin; Blaabjerg, Frede

    2002-01-01

    A novel method of direct synchronous pulse-width modulation (PWM) is disseminated to three-level voltage source inverters with control algorithms with elimination of the common-mode voltages in three-phase drive systems with PWM. It provides smooth pulses-ratio changing and a quarter-wave symmetry...... of the voltage waveforms during the whole control range including overmodulation. Continuous, discontinuous and "direct-direct" schemes of synchronous PWM with both algebraic and trigonometric control functions have been analysed and compared. Simulations give the behaviour of the proposed methods and show some...... advantages of synchronous PWM in comparison with asynchronous at low ratios between the switching frequency and fundamental frequency....

  11. Dynamic reliability of digital-based transmitters

    Energy Technology Data Exchange (ETDEWEB)

    Brissaud, Florent, E-mail: florent.brissaud.2007@utt.f [Institut National de l' Environnement Industriel et des Risques (INERIS), Parc Technologique Alata, BP 2, 60550 Verneuil-en-Halatte (France) and Universite de Technologie de Troyes - UTT, Institut Charles Delaunay - ICD and UMR CNRS 6279 STMR, 12 rue Marie Curie, BP 2060, 10010 Troyes Cedex (France); Smidts, Carol [Ohio State University (OSU), Nuclear Engineering Program, Department of Mechanical Engineering, Scott Laboratory, 201 W 19th Ave, Columbus OH 43210 (United States); Barros, Anne; Berenguer, Christophe [Universite de Technologie de Troyes (UTT), Institut Charles Delaunay (ICD) and UMR CNRS 6279 STMR, 12 rue Marie Curie, BP 2060, 10010 Troyes Cedex (France)

    2011-07-15

    Dynamic reliability explicitly handles the interactions between the stochastic behaviour of system components and the deterministic behaviour of process variables. While dynamic reliability provides a more efficient and realistic way to perform probabilistic risk assessment than 'static' approaches, its industrial level applications are still limited. Factors contributing to this situation are the inherent complexity of the theory and the lack of a generic platform. More recently the increased use of digital-based systems has also introduced additional modelling challenges related to specific interactions between system components. Typical examples are the 'intelligent transmitters' which are able to exchange information, and to perform internal data processing and advanced functionalities. To make a contribution to solving these challenges, the mathematical framework of dynamic reliability is extended to handle the data and information which are processed and exchanged between systems components. Stochastic deviations that may affect system properties are also introduced to enhance the modelling of failures. A formalized Petri net approach is then presented to perform the corresponding reliability analyses using numerical methods. Following this formalism, a versatile model for the dynamic reliability modelling of digital-based transmitters is proposed. Finally the framework's flexibility and effectiveness is demonstrated on a substantial case study involving a simplified model of a nuclear fast reactor.

  12. A Comprehensive Strategy for Accurate Reactive Power Distribution, Stability Improvement, and Harmonic Suppression of Multi-Inverter-Based Micro-Grid

    Directory of Open Access Journals (Sweden)

    Henan Dong

    2018-03-01

    Full Text Available Among the issues of accurate power distribution, stability improvement, and harmonic suppression in micro-grid, each has been well studied as an individual, and most of the strategies about these issues aim at one inverter-based micro-grid, hence there is a need to establish a model to achieve these functions as a whole, aiming at a multi-inverter-based micro-grid. This paper proposes a comprehensive strategy which achieves this goal successfully; since the output voltage and frequency of micro-grid all consist of fundamental and harmonic components, the strategy contains two parts accordingly. On one hand, a fundamental control strategy is proposed upon the conventional droop control. The virtual impedance is introduced to solve the problem of accurate allocation of reactive power between inverters. Meanwhile, a secondary power balance controller is added to improve the stability of voltage and frequency while considering the aggravating problem of stability because of introducing virtual impedance. On the other hand, the fractional frequency harmonic control strategy is proposed. It can solve the influence of nonlinear loads, micro-grid inverters, and the distribution network on output voltage of inverters, which is focused on eliminating specific harmonics caused by the nonlinear loads, micro-grid converters, and the distribution network so that the power quality of micro-grid can be improved effectively. Finally, small signal analysis is used to analyze the stability of the multi-converter parallel system after introducing the whole control strategy. The simulation results show that the strategy proposed in this paper has a great performance on distributing reactive power, regulating and stabilizing output voltage of inverters and frequency, eliminating harmonic components, and improving the power quality of multi-inverter-based micro-grid.

  13. Tunable conduction type of solution-processed germanium nanoparticle based field effect transistors and their inverter integration.

    Science.gov (United States)

    Meric, Zeynep; Mehringer, Christian; Karpstein, Nicolas; Jank, Michael P M; Peukert, Wolfgang; Frey, Lothar

    2015-09-14

    In this work we demonstrate the fabrication of germanium nanoparticle (NP) based electronics. The whole process chain from the nanoparticle production up to the point of inverter integration is covered. Ge NPs with a mean diameter of 33 nm and a geometric standard deviation of 1.19 are synthesized in the gas phase by thermal decomposition of GeH4 precursor in a seeded growth process. Dispersions of these particles in ethanol are employed to fabricate thin particulate films (60 to 120 nm in thickness) on substrates with a pre-patterned interdigitated aluminum electrode structure. The effect of temperature treatment, polymethyl methacrylate encapsulation and alumina coating by plasma-assisted atomic layer deposition (employing various temperatures) on the performance of these layers as thin film transistors (TFTs) is investigated. This coating combined with thermal annealing delivers ambipolar TFTs which show an Ion/Ioff ratio in the range of 10(2). We report fabrication of n-type, p-type or ambipolar Ge NP TFTs at maximum temperatures of 450 °C. For the first time, a circuit using two ambipolar TFTs is demonstrated to function as a NOT gate with an inverter gain of up to 4 which can be operated at room temperature in ambient air.

  14. Inverter ratio failure detector

    Science.gov (United States)

    Wagner, A. P.; Ebersole, T. J.; Andrews, R. E. (Inventor)

    1974-01-01

    A failure detector which detects the failure of a dc to ac inverter is disclosed. The inverter under failureless conditions is characterized by a known linear relationship of its input and output voltages and by a known linear relationship of its input and output currents. The detector includes circuitry which is responsive to the detector's input and output voltages and which provides a failure-indicating signal only when the monitored output voltage is less by a selected factor, than the expected output voltage for the monitored input voltage, based on the known voltages' relationship. Similarly, the detector includes circuitry which is responsive to the input and output currents and provides a failure-indicating signal only when the input current exceeds by a selected factor the expected input current for the monitored output current based on the known currents' relationship.

  15. A Simple Differential Mode EMI Suppressor for the LLCL-Filter-Based Single-Phase Grid-Tied Transformerless Inverter

    DEFF Research Database (Denmark)

    Ji, Junhao; Wu, Weimin; He, Yuanbin

    2015-01-01

    The single-phase power converter topologies evolving of photovoltaic applications are still including passive filters, like the LCLor LLCL-filter. Compared with the LCL-filter, the total inductance of the LLCL-filter can be reduced a lot. However, due to the resonant inductor in series...... with the bypass capacitor, the differential mode (DM) electromagnetic interference (EMI) noise attenuation of an LLCL-filter-based grid-tied inverter declines. Conventionally, a capacitor was inserted in parallel with the LC resonant circuit branch of the LLCL-filter to suppress the DM EMI noise. In order...... to achieve a small value of capacitor as well as to minimize the additional reactive power, a novel simple DM EMI suppressor for the LLCL-filter-based system is proposed. The characters of two kinds of DM EMI suppressor are analyzed and compared in detail. Simulations and experiments on a 0.5-kW 110-V/50-Hz...

  16. Investigation of multimodule buck–boost inverter-based HVDC transmission system

    Directory of Open Access Journals (Sweden)

    Ahmed A. Elserougi

    2015-01-01

    Full Text Available In high voltage direct current (HVDC systems, the semiconductor devices have to be connected in series to obtain the required high-voltage ratings. This study proposes a new HVDC configuration, namely, multimodule buck–boost inverter for HVDC transmission applications which avoids series connection of large number of semiconductor switches. In addition, it provides a blocking capability against DC side faults. The proposed configuration consists of several simple buck–boost converters which are assembled together to meet the requirements of high-voltage high-power applications. This paper studies the dynamic performance of the proposed system under different operating conditions, and the results were satisfactory. The main advantages of the proposed configuration are: (i pure sinusoidal output which minimises/eliminates the requirements for supplementary AC filters and offers an inherent suppression to the common mode voltages, (ii very low dv/dt stresses and (iii complete blocking capability of AC side contributions during DC side faults. This study discusses the system architecture, passive components selections, voltage and current ratings of its semiconductor devices and the required controllers. A comparison between the proposed configuration and other existing HVDC technologies is also presented in this study.

  17. Ultra-lightweight and Reconfigurable Tristate Inverter Based Physical Unclonable Function Design

    OpenAIRE

    Cui, Yijun; Gu, Chongyan; Wang, Chenghua; O'Neill, Maire; Liu, Weiqiang

    2018-01-01

    A physical unclonable function (PUF) is a promising security primitive which utilizes the manufacturing process variations to generate a unique unclonable digital fingerprint for a chip. It is especially suitable for resource constrained security applications, e.g. internet of things (IoT) devices. The ring oscillator (RO) PUF and the static RAM (SRAM) PUF are two of the most extensively studied PUFdesigns. However, previous RO PUF designs require a lot of hardware resources for ROs to be rob...

  18. Digital movie-based on automatic titrations.

    Science.gov (United States)

    Lima, Ricardo Alexandre C; Almeida, Luciano F; Lyra, Wellington S; Siqueira, Lucas A; Gaião, Edvaldo N; Paiva Junior, Sérgio S L; Lima, Rafaela L F C

    2016-01-15

    This study proposes the use of digital movies (DMs) in a flow-batch analyzer (FBA) to perform automatic, fast and accurate titrations. The term used for this process is "Digital movie-based on automatic titrations" (DMB-AT). A webcam records the DM during the addition of the titrant to the mixing chamber (MC). While the DM is recorded, it is decompiled into frames ordered sequentially at a constant rate of 26 frames per second (FPS). The first frame is used as a reference to define the region of interest (ROI) of 28×13pixels and the R, G and B values, which are used to calculate the Hue (H) values for each frame. The Pearson's correlation coefficient (r) is calculated between the H values of the initial frame and each subsequent frame. The titration curves are plotted in real time using the r values and the opening time of the titrant valve. The end point is estimated by the second derivative method. A software written in C language manages all analytical steps and data treatment in real time. The feasibility of the method was attested by application in acid/base test samples and edible oils. Results were compared with classical titration and did not present statistically significant differences when the paired t-test at the 95% confidence level was applied. The proposed method is able to process about 117-128 samples per hour for the test and edible oil samples, respectively, and its precision was confirmed by overall relative standard deviation (RSD) values, always less than 1.0%. Copyright © 2015 Elsevier B.V. All rights reserved.

  19. Scaling-based forest structural change detection using an inverted geometric-optical model in the Three Gorges region of China

    NARCIS (Netherlands)

    Zeng, Y.; Schaepman, M.E.; Wu, B.; Clevers, J.G.P.W.; Bregt, A.K.

    2008-01-01

    We use the Li-Strahler geometric-optical model combined with a scaling-based approach to detect forest structural changes in the Three Gorges region of China. The physical-based Li-Strahler model can be inverted to retrieve forest structural properties. One of the main input variables for the

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

    DEFF Research Database (Denmark)

    Oleschuk, Valentin; Blaabjerg, Frede

    2002-01-01

    This paper presents results of analysis and comparison of novel synchronised schemes of pulsewidth modulation (PWM), applied to three-level voltage source inverters with control algorithms providing elimination of the common-mode voltage. The proposed approach is based on a new strategy of digital...

  1. Digital reactivity meter construction based on PC

    International Nuclear Information System (INIS)

    Yusi-Eko-Yulianto; Kristedjo-Kurnianto

    2003-01-01

    The reactivitymeter is a core reactivity measuring equipment, which inform the reactor operator the neutron flux development in the core. This digital reactivitymeter is needed to replace analog reactivitymeter, whenever it fails in the future. The replacement of thus reactivitymeter can keep the continuation of reactor operation. The digital reactivitymeter is constructed by using the digital signal processing and computer. Thus real time signal processing is displayed on the monitor graphically. This reactivitymeter has been tested in RSG-GAS and perform a good work. This performance is worthy to use this digital reactivitymeter for RSG-GAS operation

  2. A facile route to inverted polymer solar cells using a precursor based zinc oxide electron transport layer

    NARCIS (Netherlands)

    Bruyn, P. de; Moet, D.J.D.; Blom, P.W.M.

    2010-01-01

    Inverted polymer:fullerene solar cells with ZnO and MoO3 transport layers are demonstrated. ZnO films are prepared through spin casting of a zinc acetylacetonate hydrate solution, followed by low temperature annealing under ambient conditions. The performance of solar cells with an inverted

  3. A facile route to inverted polymer solar cells using a precursor based zinc oxide electron transport layer

    NARCIS (Netherlands)

    de Bruyn, P.; Moet, D. J. D.; Blom, P. W. M.

    Inverted polymer: fullerene solar cells with ZnO and MoO(3) transport layers are demonstrated. ZnO films are prepared through spin casting of a zinc acetylacetonate hydrate solution, followed by low temperature annealing under ambient conditions. The performance of solar cells with an inverted

  4. A new time-digital convert circuit based on digital delay line

    International Nuclear Information System (INIS)

    Liu Haifeng; Guo Ying; Zhang Zhi

    2004-01-01

    An introduction of a new method of time-digital convert circuit based on digital delay line is given. High precision and good reliability can be realized when it is combined with traditional counting convert method in the measurement of large scale pulse width and low frequency self-excitation oscillator. (authors)

  5. Creation of a Cell-Based Digital Cadastral Mapping System (Digital ...

    African Journals Online (AJOL)

    Digital cadastre enhances land transaction activities to be conducted in a business manner. Similarly, land subdivision or boundary redefinition, land registration and land marketing are achieved with better accuracy. This paper discusses the need to introduce a national Cell-Based Digital Cadastral Mapping System model ...

  6. Three-Phase Cascaded Multilevel Inverter Using Power Cells With Two Inverter Legs in Series

    NARCIS (Netherlands)

    Waltrich, G.; Barbi, I.

    2010-01-01

    In this paper, a modular three-phase multilevel inverter specially suited for electrical drive applications is proposed. Unlike the cascaded H-bridge inverter, this topology is based on power cells connected in cascade using two inverter legs in series. A detailed analysis of the structure and the

  7. CRADA Final Report for CRADA Number ORNL98-0521 : Development of an Electric Bus Inverter Based on ORNL Auxiliary Resonant Tank (ART) Soft-Switching Technology; TOPICAL

    International Nuclear Information System (INIS)

    Ayers, C.W.

    2001-01-01

    The Power Electronics and Electric Machinery Research Center (PEEMRC) of Oak Ridge National Laboratory (ORNL) has for many years been developing technologies for power converters for motor drives and many other applications. Some of the research goals are to improve efficiency and reduce audible and electromagnetic interference noise generation for inverters and the driven loads. The converters are being required to produce more power with reduced weight and volume, which requires improvements in heat removal from the electronics, as well as improved circuit designs that have fewer electrical losses. PEEMRC has recently developed and patented a soft-switching inverter topology called an Auxiliary Resonant Tank (ART), and this design has been tested and proven at ORNL using a 10-kW laboratory prototype. The objective of this project was to develop, test, and install the ART inverter technology in an electric transit bus with the final goal of evaluating performance of the ORNL inverter under field conditions in a vehicle. A scaled-up inverter with the capacity to drive a 22-e bus was built based on the 10-kW ORNL laboratory prototype ART soft-switching inverter. Most (if not all) commercially available inverters for traction drive and other applications use hard-switching inverters. A Cooperative Research and Development Agreement was established with the Chattanooga Area Regional Transit Authority (CARTA), the Electric Transit Vehicle Institute (ETVI), and Advanced Vehicle Systems (AVS), all of Chattanooga, along with ORNL. CARTA, which maintains and operates the public transit system in Chattanooga, provided an area for testing the vehicle alongside other similar vehicles in the normal operating environment. ETVI offers capabilities in standardized testing and reporting and also provides exposure in the electric transit vehicle arena for ORNL's technologies. The third Chattanooga partner, (AVS) manufactures all-electric and hybrid electric transit buses using

  8. Nanowire NMOS Logic Inverter Characterization.

    Science.gov (United States)

    Hashim, Yasir

    2016-06-01

    This study is the first to demonstrate characteristics optimization of nanowire N-Channel Metal Oxide Semiconductor (NW-MOS) logic inverter. Noise margins and inflection voltage of transfer characteristics are used as limiting factors in this optimization. A computer-based model used to produce static characteristics of NW-NMOS logic inverter. In this research two circuit configuration of NW-NMOS inverter was studied, in first NW-NMOS circuit, the noise margin for (low input-high output) condition was very low. For second NMOS circuit gives excellent noise margins, and results indicate that optimization depends on applied voltage to the inverter. Increasing gate to source voltage with (2/1) nanowires ratio results better noise margins. Increasing of applied DC load transistor voltage tends to increasing in decreasing noise margins; decreasing this voltage will improve noise margins significantly.

  9. Towards Knowledge-Based Digital Libraries

    NARCIS (Netherlands)

    Feng, L.; Jeusfeld, M.A.; Hoppenbrouwers, J.

    From the standpoint of satisfying human's information needs, the current digital library (DL) systems suffer from the following two shortcomings: (i) inadequate high-level cognition support; (ii) inadequate knowledge sharing facilities. In this article, we introduce a two-layered digital library

  10. A carrier-based approach for overmodulation of three-level neutral-point-lamped inverter with zero neutral-point current

    DEFF Research Database (Denmark)

    Maheshwari, Ram Krishan; Munk-Nielsen, Stig; Busquets-Monge, S.

    2012-01-01

    In a voltage source inverter, overmodulation is required to extend the range of operation and enhance the dc-link voltage utilization. A carrier-based implementation of a modulation strategy for the three-level neutral-point-clamped inverter is proposed for the overmodulation region. The modulation...... strategy ensures zero average neutral-point current in a switching period. A newly proposed boundary compression is used to regulate the dc-link voltage at all operating points. A description of the algorithm to implement the modulation strategy is also presented. The main advantage of the proposed...

  11. Towards Trustable Digital Evidence with PKIDEV: PKI Based Digital Evidence Verification Model

    Science.gov (United States)

    Uzunay, Yusuf; Incebacak, Davut; Bicakci, Kemal

    How to Capture and Preserve Digital Evidence Securely? For the investigation and prosecution of criminal activities that involve computers, digital evidence collected in the crime scene has a vital importance. On one side, it is a very challenging task for forensics professionals to collect them without any loss or damage. On the other, there is the second problem of providing the integrity and authenticity in order to achieve legal acceptance in a court of law. By conceiving digital evidence simply as one instance of digital data, it is evident that modern cryptography offers elegant solutions for this second problem. However, to our knowledge, there is not any previous work proposing a systematic model having a holistic view to address all the related security problems in this particular case of digital evidence verification. In this paper, we present PKIDEV (Public Key Infrastructure based Digital Evidence Verification model) as an integrated solution to provide security for the process of capturing and preserving digital evidence. PKIDEV employs, inter alia, cryptographic techniques like digital signatures and secure time-stamping as well as latest technologies such as GPS and EDGE. In our study, we also identify the problems public-key cryptography brings when it is applied to the verification of digital evidence.

  12. Static Characteristics of the Ferroelectric Transistor Inverter

    Science.gov (United States)

    Mitchell, Cody; Laws, crystal; MacLeond, Todd C.; Ho, Fat D.

    2010-01-01

    The inverter is one of the most fundamental building blocks of digital logic, and it can be used as the foundation for understanding more complex logic gates and circuits. This paper presents the characteristics of an inverter circuit using a ferroelectric field-effect transistor. The voltage transfer characteristics are analyzed with respect to varying parameters such as supply voltage, input voltage, and load resistance. The effects of the ferroelectric layer between the gate and semiconductor are examined, and comparisons are made between the inverters using ferroelectric transistors and those using traditional MOSFETs.

  13. PC-based digital feedback control for scanning force microscope

    International Nuclear Information System (INIS)

    Mohd Ashhar Khalid

    2002-01-01

    In the past, most digital feedback implementation for scanned-probe microscope were based on a digital signal processor (DSP). At present DSP plug-in card with the input-output interface module is still expensive compared to a fast pentium PC motherboard. For a magnetic force microscope (MFM) digital feedback has an advantage where the magnetic signal can be easily separated from the topographic signal. In this paper, a simple low-cost PC-based digital feedback and imaging system for Scanning Force Microscope (SFM) is presented. (Author)

  14. Advances in PV Inverters

    DEFF Research Database (Denmark)

    Anthon, Alexander

    and preferably low complexity leads to new research demands. This is especially true in the field of low cost residential PV inverters where efficiencies are used as major selling arguments. Traditional converter topologies equipped with conventional Silicon based semiconductors to date reach their limitations......, a replacement of only two switching devices per phase leg can greatly reduce the semiconductor losses. The Hybrid-NPC converter can be seen as an attractive and cost competitive alternative to the Silicon Carbide based converter, also allowing to overcome the major drawbacks with the conventional Silicon IGBT...

  15. Collaborative learning model inquiring based on digital game

    Science.gov (United States)

    Yuan, Jiugen; Xing, Ruonan

    2012-04-01

    With the development of computer education software, digital educational game has become an important part in our life, entertainment and education. Therefore how to make full use of digital game's teaching functions and educate through entertainment has become the focus of current research. The thesis make a connection between educational game and collaborative learning, the current popular teaching model, and concludes digital game-based collaborative learning model combined with teaching practice.

  16. An Incomplete Cryptography based Digital Rights Management with DCFF

    OpenAIRE

    Thanh, Ta Minh; Iwakiri, Munetoshi

    2014-01-01

    In general, DRM (Digital Rights Management) system is responsible for the safe distribution of digital content, however, DRM system is achieved with individual function modules of cryptography, watermarking and so on. In this typical system flow, it has a problem that all original digital contents are temporarily disclosed with perfect condition via decryption process. In this paper, we propose the combination of the differential codes and fragile fingerprinting (DCFF) method based on incompl...

  17. Novel Differential Current Control Strategy Based on a Modified Three-Level SVPWM for Two Parallel-Connected Inverters

    DEFF Research Database (Denmark)

    Zorig, Abdelmalik; Barkat, Said; Belkheiri, Mohammed

    2017-01-01

    Recently, parallel inverters have been investigated to provide multilevel characteristics besides their advantage to increase the power system capacity, reliability, and efficiency. However, the issue of differential currents imbalance remains a challenge in parallel inverter operation. The distr......Recently, parallel inverters have been investigated to provide multilevel characteristics besides their advantage to increase the power system capacity, reliability, and efficiency. However, the issue of differential currents imbalance remains a challenge in parallel inverter operation....... The distribution of switching vectors of the resulting multilevel topology has a certain degree of self-differential current balancing properties. Nevertheless, the method alone is not sufficient to maintain balanced differential current in practical applications. This paper proposes a closed-loop differential...... current control method by introducing a control variable adjusting the dwell time of the selected switching vectors and thus maintaining the differential currents balanced without affecting the overall system performance. The control strategy, including distribution of switching sequence, selection...

  18. High-Performance Control of Paralleled Three-Phase Inverters for Residential Microgrid Architectures Based on Online Uninterruptable Power Systems

    DEFF Research Database (Denmark)

    Zhang, Chi; Guerrero, Josep M.; Vasquez, Juan Carlos

    2015-01-01

    In this paper, a control strategy for the parallel operation of three-phase inverters forming an online uninterruptible power system (UPS) is presented. The UPS system consists of a cluster of paralleled inverters with LC filters directly connected to an AC critical bus and an AC/DC forming a DC...... bus. The proposed control scheme is performed on two layers: (i) a local layer that contains a “reactive power vs phase” in order to synchronize the phase angle of each inverter and a virtual resistance loop that guarantees equal power sharing among inverters; (ii) a central controller that guarantees...... synchronization with an external real/fictitious utility, and critical bus voltage restoration. Constant transient and steady-state frequency, active, reactive and harmonic power sharing, and global phase-locked loop resynchronization capability are achieved. Detailed system topology and control architecture...

  19. DC-DC Type High-Frequency Link DC for Improved Power Quality of Cascaded Multilevel Inverter

    Science.gov (United States)

    Sadikin, Muhammad; Senjyu, Tomonobu; Yona, Atsushi

    2013-06-01

    Multilevel inverters are emerging as a new breed of power converter options for power system applications. Recent advances in power switching devices enabled the suitability of multilevel inverters for high voltage and high power applications because they are connecting several devices in series without the need of component matching. Usually, a transformerless battery energy storage system, based on a cascaded multilevel inverter, is used as a measure for voltage and frequency deviations. System can be reduced in size, weight, and cost of energy storage system. High-frequency link circuit topology is advantageous in realizing compact and light-weight power converters for uninterruptible power supply systems, new energy systems using photovoltaic-cells, fuel-cells and so on. This paper presents a DC-DC type high-frequency link DC (HFLDC) cascaded multilevel inverter. Each converter cell is implemented a control strategy for two H-bridge inverters that are controlled with the same multicarrier pulse width modulation (PWM) technique. The proposed cascaded multilevel inverter generates lower voltage total harmonic distortion (THD) in comparison with conventional cascaded multilevel inverter. Digital simulations are carried out using PSCAD/EMTDC to validate the performance of the proposed cascaded multilevel inverter.

  20. ITO electrode/photoactive layer interface engineering for efficient inverted polymer solar cells based on P3HT and PCBM using a solution-processed titanium chelate

    International Nuclear Information System (INIS)

    Zhang Wenqing; Zheng Hua; Tan Zhan'ao; Qian Deping; Li Liangjie; Xu Qi; Li Shusheng; Li Yongfang

    2012-01-01

    We report efficient inverted polymer solar cells (PSCs) based on poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl-C 61 -butyric acid methyl ester (PCBM) using alcohol-soluble titanium (diisopropoxide) bis (2,4-pentanedionate) (TIPD) as an electron selective layer between the indium tin oxide (ITO) electrode and the photoactive layer. The thermally annealed TIPD layer is highly transparent in the visible range and shows effective electron collection ability. By optimizing the electron-collecting layer, the photoactive layer and the hole-collecting layer, the power conversion efficiency (PCE) of the inverted device with the structure ITO/TIPD/P3HT : PCBM/MoO 3 /Ag reaches 4.10% under the illumination of AM1.5G, 100 mW cm -2 , which is among the highest values for inverted PSCs based on P3HT : PCBM. The PCE of the inverted device is improved in comparison with the conventional device (3.77%) under the same experimental conditions. (paper)

  1. Digital Printing Quality Detection and Analysis Technology Based on CCD

    Science.gov (United States)

    He, Ming; Zheng, Liping

    2017-12-01

    With the help of CCD digital printing quality detection and analysis technology, it can carry out rapid evaluation and objective detection of printing quality, and can play a certain control effect on printing quality. It can be said CDD digital printing quality testing and analysis of the rational application of technology, its digital printing and printing materials for a variety of printing equipments to improve the quality of a very positive role. In this paper, we do an in-depth study and discussion based on the CCD digital print quality testing and analysis technology.

  2. Design-based learning in classrooms using playful digital toolkits

    NARCIS (Netherlands)

    Scheltenaar, K.J.; van der Poel, J.E.C.; Bekker, Tilde

    2015-01-01

    The goal of this paper is to explore how to implement Design Based Learning (DBL) with digital toolkits to teach 21st century skills in (Dutch) schools. It describes the outcomes of a literature study and two design case studies in which such a DBL approach with digital toolkits was iteratively

  3. Harmonic Instability Assessment Using State-Space Modeling and Participation Analysis in Inverter-Fed Power Systems

    DEFF Research Database (Denmark)

    Wang, Yanbo; Wang, Xiongfei; Blaabjerg, Frede

    2017-01-01

    parameters on the harmonic instability of the power system. Moreover, the harmonic-frequency oscillation modes are identified, where participation analysis is presented to evaluate the contributions of different states to these modes and to further reveal how the system gives rise to harmonic instability......This paper presents a harmonic instability analysis method using state-space modeling and participation analysis in the inverter-fed ac power systems. A full-order state-space model for the droop-controlled Distributed Generation (DG) inverter is built first, including the time delay of the digital...... control system, inner current and voltage control loops, and outer droop-based power control loop. Based on the DG inverter model, an overall state-space model of a two-inverter-fed system is established. The eigenvalue-based stability analysis is then presented to assess the influence of controller...

  4. Direct model-based predictive control scheme without cost function for voltage source inverters with reduced common-mode voltage

    Science.gov (United States)

    Kim, Jae-Chang; Moon, Sung-Ki; Kwak, Sangshin

    2018-04-01

    This paper presents a direct model-based predictive control scheme for voltage source inverters (VSIs) with reduced common-mode voltages (CMVs). The developed method directly finds optimal vectors without using repetitive calculation of a cost function. To adjust output currents with the CMVs in the range of -Vdc/6 to +Vdc/6, the developed method uses voltage vectors, as finite control resources, excluding zero voltage vectors which produce the CMVs in the VSI within ±Vdc/2. In a model-based predictive control (MPC), not using zero voltage vectors increases the output current ripples and the current errors. To alleviate these problems, the developed method uses two non-zero voltage vectors in one sampling step. In addition, the voltage vectors scheduled to be used are directly selected at every sampling step once the developed method calculates the future reference voltage vector, saving the efforts of repeatedly calculating the cost function. And the two non-zero voltage vectors are optimally allocated to make the output current approach the reference current as close as possible. Thus, low CMV, rapid current-following capability and sufficient output current ripple performance are attained by the developed method. The results of a simulation and an experiment verify the effectiveness of the developed method.

  5. Secondary Interactions Arrest the Hemiaminal Intermediate To Invert the Modus Operandi of Schiff Base Reaction: A Route to Benzoxazinones.

    Science.gov (United States)

    Patel, Ketan; Deshmukh, Satej S; Bodkhe, Dnyaneshwar; Mane, Manoj; Vanka, Kumar; Shinde, Dinesh; Rajamohanan, Pattuparambil R; Nandi, Shyamapada; Vaidhyanathan, Ramanathan; Chikkali, Samir H

    2017-04-21

    Discovered by Hugo Schiff, condensation between amine and aldehyde represents one of the most ubiquitous reactions in chemistry. This classical reaction is widely used to manufacture pharmaceuticals and fine chemicals. However, the rapid and reversible formation of Schiff base prohibits formation of alternative products, of which benzoxazinones are an important class. Therefore, manipulating the reactivity of two partners to invert the course of this reaction is an elusive target. Presented here is a synthetic strategy that regulates the sequence of Schiff base reaction via weak secondary interactions. Guided by the computational models, reaction between 2,3,4,5,6-pentafluoro-benzaldehyde with 2-amino-6-methylbenzoic acid revealed quantitative (99%) formation of 5-methyl-2-(perfluorophenyl)-1,2-dihydro-4H-benzo[d][1,3]oxazin-4-one (15). Electron donating and electron withdrawing ortho-substituents on 2-aminobenzoic acid resulted in the production of benzoxazinones 9-36. The mode of action was tracked using low temperature NMR, UV-vis spectroscopy, and isotopic ( 18 O) labeling experiments. These spectroscopic mechanistic investigations revealed that the hemiaminal intermediate is arrested by the hydrogen-bonding motif to yield benzoxazinone. Thus, the mechanistic investigations and DFT calculations categorically rule out the possibility of in situ imine formation followed by ring-closing, but support instead hydrogen-bond assisted ring-closing to prodrugs. This unprecedented reaction represents an interesting and competitive alternative to metal catalyzed and classical methods of preparing benzoxazinone.

  6. A Refined Self-Tuning Filter-Based Instantaneous Power Theory Algorithm for Indirect Current Controlled Three-Level Inverter-Based Shunt Active Power Filters under Non-sinusoidal Source Voltage Conditions

    Directory of Open Access Journals (Sweden)

    Yap Hoon

    2017-02-01

    Full Text Available In this paper, a refined reference current generation algorithm based on instantaneous power (pq theory is proposed, for operation of an indirect current controlled (ICC three-level neutral-point diode clamped (NPC inverter-based shunt active power filter (SAPF under non-sinusoidal source voltage conditions. SAPF is recognized as one of the most effective solutions to current harmonics due to its flexibility in dealing with various power system conditions. As for its controller, pq theory has widely been applied to generate the desired reference current due to its simple implementation features. However, the conventional dependency on self-tuning filter (STF in generating reference current has significantly limited mitigation performance of SAPF. Besides, the conventional STF-based pq theory algorithm is still considered to possess needless features which increase computational complexity. Furthermore, the conventional algorithm is mostly designed to suit operation of direct current controlled (DCC SAPF which is incapable of handling switching ripples problems, thereby leading to inefficient mitigation performance. Therefore, three main improvements are performed which include replacement of STF with mathematical-based fundamental real power identifier, removal of redundant features, and generation of sinusoidal reference current. To validate effectiveness and feasibility of the proposed algorithm, simulation work in MATLAB-Simulink and laboratory test utilizing a TMS320F28335 digital signal processor (DSP are performed. Both simulation and experimental findings demonstrate superiority of the proposed algorithm over the conventional algorithm.

  7. A PWM strategy for acoustic noise reduction for grid-connected single-phase inverters

    Energy Technology Data Exchange (ETDEWEB)

    Shao, R.; Guo, Z.; Chang, L. [New Brunswick Univ., Fredericton, NB (Canada). Dept. of Electrical and Computer Engineering

    2006-07-01

    This paper presented a newly proposed and improved pulse width modulation (PWM) strategy for grid-connected single-phase inverters. Small distributed generators using energy from renewable resources such as PV and wind systems typically use grid-connected single-phase inverters as voltage source inverters for good acoustic performance. PWM is generally applied in these inverters in order to achieve good waveforms of output current as required by interconnection standards. In routine simultaneous switching PWM methods, the current ripples through the inverter output filter inductor are at the carrier switching frequency, which is one of the major causes for inverter acoustic noise. The new PWM strategy effectively alleviates acoustic noise and improves output power quality. It is based on the principle of evenly splitting the switching of Insulated Gate Bipolar Transistors (IGBT) in each switching cycle among all IGBTs of the full bridge, thereby using a non-simultaneous mode of PWM which doubles the output current ripple frequency. This increases the inductor current ripple frequency to twice the carrier frequency. It is therefore possible to increase the current ripple frequency, or noise frequency into the range of ultrasonic which is inaudible to the human ear, without increasing the inverter's switching frequency to which the inverter's switching loss is proportional. In addition, this new PWM scheme can reduce the output current harmonics distortion and dc link current ripples. As such, lower capacitance in dc link capacitors and lower inductance of output inductor are needed. The improved PWM scheme was verified in a 3 kW grid-connected single-phase inverter. It was shown that the PWM strategy can be readily implemented with a digital signal processing microcontroller. 8 refs., 11 figs.

  8. High-performance inverted planar heterojunction perovskite solar cells based on a solution-processed CuOx hole transport layer.

    Science.gov (United States)

    Sun, Weihai; Li, Yunlong; Ye, Senyun; Rao, Haixia; Yan, Weibo; Peng, Haitao; Li, Yu; Liu, Zhiwei; Wang, Shufeng; Chen, Zhijian; Xiao, Lixin; Bian, Zuqiang; Huang, Chunhui

    2016-05-19

    During the past several years, methylammonium lead halide perovskites have been widely investigated as light absorbers for thin-film photovoltaic cells. Among the various device architectures, the inverted planar heterojunction perovskite solar cells have attracted special attention for their relatively simple fabrication and high efficiencies. Although promising efficiencies have been obtained in the inverted planar geometry based on poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) sulfonic acid ( PSS) as the hole transport material (HTM), the hydrophilicity of the PSS is a critical factor for long-term stability. In this paper, a CuOx hole transport layer from a facile solution-processed method was introduced into the inverted planar heterojunction perovskite solar cells. After the optimization of the devices, a champion PCE of 17.1% was obtained with an open circuit voltage (Voc) of 0.99 V, a short-circuit current (Jsc) of 23.2 mA cm(-2) and a fill factor (FF) of 74.4%. Furthermore, the unencapsulated device cooperating with the CuOx film exhibited superior performance in the stability test, compared to the device involving the PSS layer, indicating that CuOx could be a promising HTM for replacing PSS in inverted planar heterojunction perovskite solar cells.

  9. Comparative Study of Modulation-Based Individual Inverter Techniques for Direct and Inverse by using Star-Connection Induction Motor in Extra Low Voltage Application

    Directory of Open Access Journals (Sweden)

    Ardhia Wishnuprakasa

    2016-12-01

    Full Text Available In this study, the IEEE 519 Standard as a basis benchmarking for voltage (THDV and current (THDI in draft performance. Comparative Study based onthree-techniques of 2-Level Converter (2LC by using a Star-Connection Induction Motor (Y-CIM in ExtraLow Voltage (ELV Configuration.For the detail explanation, a primary inverter as Direct-Inverterby PWMdirect (PWM degreesand asecondary inverter as Inverse-Inverterby PWMinverse(PWM + PI degrees. It tends a modified algorithm,for eachof SPWM in six rules, and FHIPWM in 5th harmonics Injectedin standard modulation as the purpose for the Open-Ends of Pre-Dual Inverter in Decoupled SPWM for twelve rules, and Decoupled FHIPWM in combination of 5th harmonics Injectedin combination of two-standard-modulation. Those techniques are the purpose of two-inverter combination, which namelythe Equal Direct-Inverse (EDI algorithmproduct of prototyping in similarities. The observation is restricted in voltage scope between Simulation by using Power Simulator (PSIMand Application by using Microcontroller ARM STM32F4 Discovery.

  10. Accuracy of Digital Impressions and Fitness of Single Crowns Based on Digital Impressions

    Science.gov (United States)

    Yang, Xin; Lv, Pin; Liu, Yihong; Si, Wenjie; Feng, Hailan

    2015-01-01

    In this study, the accuracy (precision and trueness) of digital impressions and the fitness of single crowns manufactured based on digital impressions were evaluated. #14-17 epoxy resin dentitions were made, while full-crown preparations of extracted natural teeth were embedded at #16. (1) To assess precision, deviations among repeated scan models made by intraoral scanner TRIOS and MHT and model scanner D700 and inEos were calculated through best-fit algorithm and three-dimensional (3D) comparison. Root mean square (RMS) and color-coded difference images were offered. (2) To assess trueness, micro computed tomography (micro-CT) was used to get the reference model (REF). Deviations between REF and repeated scan models (from (1)) were calculated. (3) To assess fitness, single crowns were manufactured based on TRIOS, MHT, D700 and inEos scan models. The adhesive gaps were evaluated under stereomicroscope after cross-sectioned. Digital impressions showed lower precision and better trueness. Except for MHT, the means of RMS for precision were lower than 10 μm. Digital impressions showed better internal fitness. Fitness of single crowns based on digital impressions was up to clinical standard. Digital impressions could be an alternative method for single crowns manufacturing. PMID:28793417

  11. Accuracy of Digital Impressions and Fitness of Single Crowns Based on Digital Impressions

    Directory of Open Access Journals (Sweden)

    Xin Yang

    2015-06-01

    Full Text Available In this study, the accuracy (precision and trueness of digital impressions and the fitness of single crowns manufactured based on digital impressions were evaluated. #14-17 epoxy resin dentitions were made, while full-crown preparations of extracted natural teeth were embedded at #16. (1 To assess precision, deviations among repeated scan models made by intraoral scanner TRIOS and MHT and model scanner D700 and inEos were calculated through best-fit algorithm and three-dimensional (3D comparison. Root mean square (RMS and color-coded difference images were offered. (2 To assess trueness, micro computed tomography (micro-CT was used to get the reference model (REF. Deviations between REF and repeated scan models (from (1 were calculated. (3 To assess fitness, single crowns were manufactured based on TRIOS, MHT, D700 and inEos scan models. The adhesive gaps were evaluated under stereomicroscope after cross-sectioned. Digital impressions showed lower precision and better trueness. Except for MHT, the means of RMS for precision were lower than 10 μm. Digital impressions showed better internal fitness. Fitness of single crowns based on digital impressions was up to clinical standard. Digital impressions could be an alternative method for single crowns manufacturing.

  12. Numerical simulation and experimental validation of inverted planar perovskite solar cells based on NiOx hole transport layer

    Science.gov (United States)

    Wei, Xiaoqing; Wang, Xian; Jiang, Hailong; Huang, Yongliang; Han, Anjun; Gao, Qi; Bian, Jiantao; Liu, Zhengxin

    2017-12-01

    Numerical simulation of inverted planar perovskite solar cells based on NiOx hole transport layer was performed with AMPS-1D program. The simulated device parameters were shown to agree well with our experimental work. The simulated results revealed that the device contained typical p-i-n junction configuration. The optimum thickness of the absorber, the effects of the absorber quality, the defect density of interfaces, the effects of VBO and CBO, the interface contact at front and back electrodes were analyzed. Open-circuit voltage mainly depended on the defect density in CH3NH3PbI3 layer, the recombination at HTL/CH3NH3PbI3 and ETL/CH3NH3PbI3 interface, the values of VBO and CBO, while short-circuit current mainly depended on the thickness of CH3NH3PbI3 layer. Fill factor was significantly influenced by the interface contact at front and back electrodes. Remarkably, a power conversion efficiency of 21.8% is obtained under optimised conditions. Real devices with PCE of up to 15% were obtained by initially optimizing the preparation of CH3NH3PbI3 absorber layer. Our work can provide some important guidance for device design and optimization from the considerations of both theory and experiment.

  13. Security Attributes Based Digital Rights Management

    NARCIS (Netherlands)

    Chong, C.N.; van Buuren, R.; van Buuren, R.F.; Hartel, Pieter H.; Kleinhuis, Geert; Boavida, F.; Monteiro, E.; Orvalho, J.

    2002-01-01

    Most real-life systems delegate responsibilities to different authorities. We apply this model to a digital rights management system, to achieve flexible security. In our model a hierarchy of authorities issues certificates that are linked by cryptographic means. This linkage establishes a chain of

  14. Design of Low Inductance Switching Power Cell for GaN HEMT Based Inverter

    DEFF Research Database (Denmark)

    Gurpinar, Emre; Iannuzzo, Francesco; Yang, Yongheng

    2018-01-01

    . The design of gate drivers for the GaN HEMT devices is presented. Parasitic inductance and resistance of the proposed design are extracted with finite element analysis and discussed. Common-mode behaviours based on the SPICE model of the converter are analyzed. Experimental results on the designed 3L......In this paper, an ultra-low inductance power cell is designed for a three-Level Active Neutral Point Clamped (3LANPC) based on 650 V gallium nitride (GaN) HEMT devices. The 3L-ANPC topology with GaN HEMT devices and the selected modulation scheme suitable for wide-bandgap (WBG) devices...... are presented. The commutation loops, which mainly contribute to voltage overshoots and increase of switching losses, are discussed. The ultra-low inductance power cell design based on a four-layer Printed Circuit Board (PCB) with the aim to maximize the switching performance of GaN HEMTs is explained...

  15. Uluru Inverted

    Directory of Open Access Journals (Sweden)

    David Brooks

    2014-12-01

    Full Text Available Uluru is an Australian ‘icon’, an impressively huge red boulder located centrally in the arid continent and tapping deeply into the indigenous past. Often seen as the paramount sacred site of the Aboriginal Dreaming, it is a focal point for many Dreaming ‘tracks’ of the people of the Western Desert ‘bloc’ who are its ‘traditional owners’. Endless busloads of tourists are taken on walks around the base by Aboriginal guides and exhorted not to show disrespect by climbing to the peak. In a country as divided about indigenous issues as Australia, this is a site that, for once, unambiguously presents a positive and unified face, a space where ‘things Aboriginal’ are held up and admired for their richness and sublimity. A space where a serious attitude is appropriate. While the occasional young tourist plays pranks foolishly flouting this, who would imagine that some Aboriginal people from the same cultural group as the owners are willing to have a good laugh at themselves over the whole Uluru phenomenon? Yet so it is. Men whom I have known for nearly thirty years suddenly told me about a commercial film they said they had once watched together, involving a whitefella who constructed an elaborate and clever joke puncturing the seriousness that envelops Aboriginal Uluru, and about how it had them in stitches. This paper relates my search for the film, and explores the many factors that led to the surprising inversion that my friends’ telling of the story expresses.

  16. FUZZY-LOGIC-BASED CONTROLLERS FOR EFFICIENCY OPTIMIZATION OF INVERTER-FED INDUCTION MOTOR DRIVES

    Science.gov (United States)

    This paper describes a fuzzy-logic-based energy optimizing controller to improve the efficiency of induction motor/drives operating at various load (torque) and speed conditions. Improvement of induction motor efficiency is important not only from the considerations of energy sav...

  17. Low Power Systolic Array Based Digital Filter for DSP Applications

    Directory of Open Access Journals (Sweden)

    S. Karthick

    2015-01-01

    Full Text Available Main concepts in DSP include filtering, averaging, modulating, and correlating the signals in digital form to estimate characteristic parameter of a signal into a desirable form. This paper presents a brief concept of low power datapath impact for Digital Signal Processing (DSP based biomedical application. Systolic array based digital filter used in signal processing of electrocardiogram analysis is presented with datapath architectural innovations in low power consumption perspective. Implementation was done with ASIC design methodology using TSMC 65 nm technological library node. The proposed systolic array filter has reduced leakage power up to 8.5% than the existing filter architectures.

  18. Digital Communication Devices Based on Nonlinear Dynamics and Chaos

    National Research Council Canada - National Science Library

    Larson, Lawrence

    2003-01-01

    The final report of the ARO MURI "Digital Communications Based on Chaos and Nonlinear Dynamics" contains research results in the areas of chaos and nonlinear dynamics applied to wireless and optical communications...

  19. Stability Analysis of a Microgrid System based on Inverter-Interfaced Distributed Generators

    Directory of Open Access Journals (Sweden)

    CUSIDO, J.

    2013-08-01

    Full Text Available This paper presents a phase-plane trajectory analysis and the appliance of Lyapunov's methodology to evaluate the stability limits of a small signal model of a Microgrid system. The work done is based on a non-linear tool and several computer simulations. The study indicates how to analyze a Microgrid system that is subjected to a severe transient disturbance by using its large signal model without the necessity of the small signal analysis as it is commonly applied.

  20. Design of Low Inductance Switching Power Cell for GaN HEMT Based Inverter

    Energy Technology Data Exchange (ETDEWEB)

    Gurpinar, Emre [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Power Electronics and Electric Machinery Research Group; Iannuzzo, Francesco [Aalborg Univ., Aalborg (Denmark). Dept. of Energy Technology; Yang, Yongheng [Aalborg Univ., Aalborg (Denmark). Dept. of Energy Technology; Castellazzi, Alberto [Univ. of Nottingham (United Kingdom). Power Electronics, Machines and Control (PEMC); Blaabjerg, Frede [Aalborg Univ., Aalborg (Denmark). Dept. of Energy Technology

    2017-11-23

    Here in this paper, an ultra-low inductance power cell is designed for a three-Level Active Neutral Point Clamped (3LANPC) based on 650 V gallium nitride (GaN) HEMT devices. The 3L-ANPC topology with GaN HEMT devices and the selected modulation scheme suitable for wide-bandgap (WBG) devices are presented. The commutation loops, which mainly contribute to voltage overshoots and increase of switching losses, are discussed. The ultra-low inductance power cell design based on a fourlayer Printed Circuit Board (PCB) with the aim to maximize the switching performance of GaN HEMTs is explained. The design of gate drivers for the GaN HEMT devices is presented. Parasitic inductance and resistance of the proposed design are extracted with finite element analysis and discussed. Common mode behaviours based on the SPICE model of the converter are analyzed. Experimental results on the designed 3L-ANPC with the output power of up to 1 kW are presented, which verifies the performance of the proposed design in terms of ultra-low inductance.

  1. Design of Low Inductance Switching Power Cell for GaN HEMT Based Inverter

    International Nuclear Information System (INIS)

    Gurpinar, Emre; Iannuzzo, Francesco; Yang, Yongheng; Castellazzi, Alberto; Blaabjerg, Frede

    2017-01-01

    Here in this paper, an ultra-low inductance power cell is designed for a three-Level Active Neutral Point Clamped (3LANPC) based on 650 V gallium nitride (GaN) HEMT devices. The 3L-ANPC topology with GaN HEMT devices and the selected modulation scheme suitable for wide-bandgap (WBG) devices are presented. The commutation loops, which mainly contribute to voltage overshoots and increase of switching losses, are discussed. The ultra-low inductance power cell design based on a fourlayer Printed Circuit Board (PCB) with the aim to maximize the switching performance of GaN HEMTs is explained. The design of gate drivers for the GaN HEMT devices is presented. Parasitic inductance and resistance of the proposed design are extracted with finite element analysis and discussed. Common mode behaviours based on the SPICE model of the converter are analyzed. Experimental results on the designed 3L-ANPC with the output power of up to 1 kW are presented, which verifies the performance of the proposed design in terms of ultra-low inductance.

  2. Development of Propulsion Inverter Control System for High-Speed Maglev based on Long Stator Linear Synchronous Motor

    Directory of Open Access Journals (Sweden)

    Jeong-Min Jo

    2017-02-01

    Full Text Available In the case of a long-stator linear drive, unlike rotative drives for which speed or position sensors are a single unit attached to the shaft, these sensors extend along the guideway. The position signals transmitted from a maglev vehicle cannot meet the need of the real-time propulsion control in the on-ground inverter power substations. In this paper the design of the propulsion inverter control system with a position estimator for driving a long-stator synchronous motor in a high-speed maglev train is proposed. The experiments have been carried out at the 150 m long guideway at the O-song test track. To investigate the performance of the position estimator, the propulsion control system with, and without, the position estimator are compared. The result confirms that the proposed strategy can meet the dynamic property needs of the propulsion inverter control system for driving long-stator linear synchronous motors.

  3. Intermediate Frequency Digital Receiver Based on Multi-FPGA System

    Directory of Open Access Journals (Sweden)

    Chengchang Zhang

    2016-01-01

    Full Text Available Aiming at high-cost, large-size, and inflexibility problems of traditional analog intermediate frequency receiver in the aerospace telemetry, tracking, and command (TTC system, we have proposed a new intermediate frequency (IF digital receiver based on Multi-FPGA system in this paper. Digital beam forming (DBF is realized by coordinated rotation digital computer (CORDIC algorithm. An experimental prototype has been developed on a compact Multi-FPGA system with three FPGAs to receive 16 channels of IF digital signals. Our experimental results show that our proposed scheme is able to provide a great convenience for the design of IF digital receiver, which offers a valuable reference for real-time, low power, high density, and small size receiver design.

  4. Ultrabright femtosecond source of biphotons based on a spatial mode inverter.

    Science.gov (United States)

    Jarutis, Vygandas; Juodkazis, Saulius; Mizeikis, Vygantas; Sasaki, Keiji; Misawa, Hiroaki

    2005-02-01

    A method of enhancing the efficiency of entangled biphoton sources based on a type II femtosecond spontaneous parametric downconversion (SPDC) process is proposed and implemented experimentally. Enhancement is obtained by mode inversion of one of the SPDC output beams, which allows the beams to overlap completely, thus maximizing the number of SPDC photon pairs with optimum spatiotemporal overlap. By use of this method, biphoton count rates as high as 16 kHz from a single 0.5-mm-long beta-barium borate crystal pumped by second-harmonic radiation from a Ti:sapphire laser were obtained.

  5. Inkjet printed ambipolar transistors and inverters based on carbon nanotube/zinc tin oxide heterostructures

    International Nuclear Information System (INIS)

    Kim, Bongjun; Jang, Seonpil; Dodabalapur, Ananth; Geier, Michael L.; Prabhumirashi, Pradyumna L.; Hersam, Mark C.

    2014-01-01

    We report ambipolar field-effect transistors (FETs) consisting of inkjet printed semiconductor bilayer heterostructures utilizing semiconducting single-walled carbon nanotubes (SWCNTs) and amorphous zinc tin oxide (ZTO). The bilayer structure allows for electron transport to occur principally in the amorphous oxide layer and hole transport to occur exclusively in the SWCNT layer. This results in balanced electron and hole mobilities exceeding 2 cm 2 V −1 s −1 at low operating voltages ( 10). This work provides a pathway for realizing solution processable, inkjet printable, large area electronic devices, and systems based on SWCNT-amorphous oxide heterostructures

  6. The presence of aggression cues inverts the relation between digit ratio (2D:4D) and pro-social behaviour in a dictator game

    NARCIS (Netherlands)

    Millet, K.; Dewitte, S.

    2009-01-01

    Digit ratio (2D:4D) is a sexually dimorphic trait. Men have relatively shorter index (2D) compared to ring (4D) fingers than women. More masculine ratios are thought to be influenced by higher prenatal testosterone levels. In the present paper, we aim to show the context-dependency of the relation

  7. A Flexible Experimental Laboratory for Distributed Generation Networks Based on Power Inverters

    Directory of Open Access Journals (Sweden)

    Jaume Miret

    2017-10-01

    Full Text Available In the recently deregulated electricity market, distributed generation based on renewable sources is becoming more and more relevant. In this area, two main distributed scenarios are focusing the attention of recent research: grid-connected mode, where the generation sources are connected to a grid mainly supplied by big power plants, and islanded mode, where the distributed sources, energy storage devices, and loads compose an autonomous entity that in its general form can be named a microgrid. To conduct a successful research in these two scenarios, it is essential to have a flexible experimental setup. This work deals with the description of a real laboratory setup composed of four nodes that can emulate both scenarios of a distributed generation network. A comprehensive description of the hardware and software setup will be done, focusing especially in the dual-core DSP used for control purposes, which is next to the industry standards and able to emulate real complexities. A complete experimental section will show the main features of the system.

  8. Digitization

    DEFF Research Database (Denmark)

    Finnemann, Niels Ole

    2014-01-01

    what a concept of digital media might add to the understanding of processes of mediatization and what the concept of mediatization might add to the understanding of digital media. It is argued that digital media open an array of new trajectories in human communication, trajectories which were...

  9. Multilevel inverter switching controller using a field programmable ...

    African Journals Online (AJOL)

    Conducted simulation and measurement results verified and validated the switching controller design functionality and requirement. Keywords: multilevel inverter, switching controller; FPGA, general purpose processor (GPP);digital signal processing (DSP); IGBT; Verilog, power consumption; harmonic elimination (SHE).

  10. Active power control strategies for inverter-based distributed power generation adapted to grid-fault ride-through requirements

    NARCIS (Netherlands)

    Wang, F.; Duarte, J.L.; Hendrix, M.A.M.

    2009-01-01

    Distributed power generation is expected to deliver power into the grid without interruption during voltage dips. To improve system ride-through capabilities, a generalized active power control strategy is proposed for grid-interfacing inverters. Specifically, a current reference generation strategy

  11. DC-to-AC inverter ratio failure detector

    Science.gov (United States)

    Ebersole, T. J.; Andrews, R. E.

    1975-01-01

    Failure detection technique is based upon input-output ratios, which is independent of inverter loading. Since inverter has fixed relationship between V-in/V-out and I-in/I-out, failure detection criteria are based on this ratio, which is simply inverter transformer turns ratio, K, equal to primary turns divided by secondary turns.

  12. Field study to assess the feasibility of disposing of diesel invert-based cuttings residues using land application

    International Nuclear Information System (INIS)

    Ashworth, J.

    1990-08-01

    The use of diesel oil-based invert drilling muds in oil and gas well drilling has become widespread in Alberta. The safe disposal of the residue (DIMR) has become an issue of concern to environmentalists and energy producers. A study was conducted on land treatment as a disposal option in which DIMR was rototilled into the surface soil of small plots in June 1986 and various soil amendments were employed before seeding with a mixture of grasses. Due to the CaCl 2 component of the DIMR used, all treated plots were too saline for effective revegetation in the season of application. However, the salts were mostly leached away in 1986 and 1987, and oil degradation was rapid on fertilized plots, especially those given a surface mulch of manure. Plots which were fertilized and cultivated required an extra season for complete revegetation when treated with 300 or 450 m 3 /hectare of DIMR. Fertilization alone was not successful for revegetation. Unfertilized plots showed some oil degradation but little or no growth. Polyaromatic hydrocarbons (PAH) in the DIMR had half-lives of only a few months in soil; all hydrocarbons were retained near the surface and there was very little leaching. Only background concentrations of PAH were found in healthy plants on plots successfully revegetated. Results from the test site indicate that land treatment is a practical and environmentally acceptable disposal option for DIMR, provided that rates of application are not excessive and the level of site management needed for successful revegetation and safe degradation of hydrocarbons can be sustained for several seasons. Desirable soil properties for DIMR land treatment include adequate permeability, organic content, and microbiological activity. 18 refs., 12 figs., 5 tabs

  13. Fast reconstruction of off-axis digital holograms based on digital spatial multiplexing.

    Science.gov (United States)

    Sha, Bei; Liu, Xuan; Ge, Xiao-Lu; Guo, Cheng-Shan

    2014-09-22

    A method for fast reconstruction of off-axis digital holograms based on digital multiplexing algorithm is proposed. Instead of the existed angular multiplexing (AM), the new method utilizes a spatial multiplexing (SM) algorithm, in which four off-axis holograms recorded in sequence are synthesized into one SM function through multiplying each hologram with a tilted plane wave and then adding them up. In comparison with the conventional methods, the SM algorithm simplifies two-dimensional (2-D) Fourier transforms (FTs) of four N*N arrays into a 1.25-D FTs of one N*N arrays. Experimental results demonstrate that, using the SM algorithm, the computational efficiency can be improved and the reconstructed wavefronts keep the same quality as those retrieved based on the existed AM method. This algorithm may be useful in design of a fast preview system of dynamic wavefront imaging in digital holography.

  14. Inverting an Introductory Statistics Classroom

    Science.gov (United States)

    Kraut, Gertrud L.

    2015-01-01

    The inverted classroom allows more in-class time for inquiry-based learning and for working through more advanced problem-solving activities than does the traditional lecture class. The skills acquired in this learning environment offer benefits far beyond the statistics classroom. This paper discusses four ways that can make the inverted…

  15. Fault-Tolerant Control of ANPC Three-Level Inverter Based on Order-Reduction Optimal Control Strategy under Multi-Device Open-Circuit Fault.

    Science.gov (United States)

    Xu, Shi-Zhou; Wang, Chun-Jie; Lin, Fang-Li; Li, Shi-Xiang

    2017-10-31

    The multi-device open-circuit fault is a common fault of ANPC (Active Neutral-Point Clamped) three-level inverter and effect the operation stability of the whole system. To improve the operation stability, this paper summarized the main solutions currently firstly and analyzed all the possible states of multi-device open-circuit fault. Secondly, an order-reduction optimal control strategy was proposed under multi-device open-circuit fault to realize fault-tolerant control based on the topology and control requirement of ANPC three-level inverter and operation stability. This control strategy can solve the faults with different operation states, and can works in order-reduction state under specific open-circuit faults with specific combined devices, which sacrifices the control quality to obtain the stability priority control. Finally, the simulation and experiment proved the effectiveness of the proposed strategy.

  16. Non-traditional method-based solution for elimination of lower order harmonics in voltage source inverter feeding an induction motor drive

    Directory of Open Access Journals (Sweden)

    Vargese Jegathesan

    2008-01-01

    Full Text Available This paper presents an efficient and reliable Genetic Algorithm-based solution for Specific Harmonic Elimination (SHE switching pattern. This method eliminates considerable amount of lower order line voltage harmonics in Pulse Width Modulation (PWM inverter. The determination of pulse pattern for the elimination of some lower order harmonics of a PWM inverter necessitates solving a system of nonlinear transcendental equations. Genetic Algorithm is used to solve nonlinear transcendental equations for PWM-SHE. In this proposed method, harmonics up to 17th are eliminated using Genetic Algorithm without using Dual transformer. Simulations using Matlab 7.0 and PSIM 6.1 are carried out so as to validate the solution.

  17. Multiple access chaotic digital communication based on generalized synchronization

    International Nuclear Information System (INIS)

    Lu Junguo

    2005-01-01

    A novel method for multiple access chaotic digital communication based on the concept of chaos generalized synchronization and the on-line least square method is proposed. This method can be used for transmitting multiple digital information signals concurrently. We illustrate the method using a Lorenz system driving a Chua's circuit and then examine the robustness of the proposed method with respect to noise in communication channel

  18. An Embedded Based Digital Controller for Thermal Process

    Directory of Open Access Journals (Sweden)

    A. Lakshmi Sangeetha

    2008-01-01

    Full Text Available This paper describes a low cost virtual instrumentation (VI system to monitor and control the electrically heated water bath temperature. The PIC16F877 based digital microcontroller is used as thermostat which controls and monitors the temperature. The digital controller also allows the user to modify the sensor (PT100 calibration data values if necessary. The developed programmable on/off control function provides on-line display of measuring temperature, set point as well as the control function output plots through the parallel port. This bus interaction is realized in Visual Basic/Assembly Language and uses a 16 bit, 10 ms sampling analog-to-digital converter (ADS 7805 for monitoring and controlling the parameters of the temperature local digital controller.

  19. Synchronisation Strategy in Complex Digital Voter-based Systems

    Directory of Open Access Journals (Sweden)

    SZÁSZ Csaba

    2017-10-01

    Full Text Available Researchers in microelectronics generally agree that reliability and computing power are the two most important factors for next generation digital systems. Redundancy techniques are implemented widely to increase the reliability and fault tolerance of these systems. In this paper a triple modular redundancy (TMR majority voter based fault-tolerant digital system architecture is presented and analyzed. The vast majority of researchers that design and implement such systems usually assume that in these configurations the voter operates perfectly while is not true. This presentation outlines a specific situation when under same conditions the digital voter is exposed to misleading operation generating wrong information on its output. To overcome such situations there a versatile method has been proposed and implemented that is well suited to overcome the improper operation of TMR structures. The experimental results prove the theoretical assumptions and validate the initial expectations regarding the considered digital system fault-tolerant operation.

  20. Next Generation Inverter

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Zilai [General Motors LLC, Detroit, MI (United States); Gough, Charles [General Motors LLC, Detroit, MI (United States)

    2016-04-22

    The goal of this Cooperative Agreement was the development of a Next Generation Inverter for General Motors’ electrified vehicles, including battery electric vehicles, range extended electric vehicles, plug-in hybrid electric vehicles and hybrid electric vehicles. The inverter is a critical electronics component that converts battery power (DC) to and from the electric power for the motor (AC).

  1. Enhanced Power Quality and Minimized Peak Current Control in An Inverter based Microgrid under Unbalanced Grid Faults

    DEFF Research Database (Denmark)

    Liu, Wenzhao; Guo, Xiaoqiang; Sulligoi, Giorgio

    2016-01-01

    The microgrid inverter experiences the power oscillations and current harmonics in case of the unbalanced grid voltage faults. However, there is a trade-off between power oscillations and current harmonics should be considered in three phase three wire inverter systems during the conventional fault...... ride through control. In order to solve this problem, a novel control strategy is proposed to enhance the output current quality while mitigating the active and reactive output power oscillations. Moreover, a simple current-limited control strategy can be achieved without the necessity of the voltage....../current positive/negative sequence extraction. Finally, the simulation tests of the conventional and proposed control solutions are carried out. The results verify the effectiveness of the proposed strategy....

  2. A kind of video image digitizing circuit based on computer parallel port

    International Nuclear Information System (INIS)

    Wang Yi; Tang Le; Cheng Jianping; Li Yuanjing; Zhang Binquan

    2003-01-01

    A kind of video images digitizing circuit based on parallel port was developed to digitize the flash x ray images in our Multi-Channel Digital Flash X ray Imaging System. The circuit can digitize the video images and store in static memory. The digital images can be transferred to computer through parallel port and can be displayed, processed and stored. (authors)

  3. Mobile Inverted Constructivism: Education of Interaction Technology in Social Media

    Science.gov (United States)

    Chai, Jia-Xiang; Fan, Kuo-Kuang

    2016-01-01

    The combination of social media and invert teaching is a new path to inverting interation technology education and reconstructing the curriculum of context. In this paper, based on the theory of constructivism learning, a model named Mobile Inverted Constructivism (MIC) is provided. Moreover, in view of the functional quality of social media in…

  4. Low voltage ride-through capability control for single-stage inverter-based grid-connected photovoltaic power plant

    DEFF Research Database (Denmark)

    Al-Shetwi, Ali Q.; Sujod, Muhamad Zahim; Blaabjerg, Frede

    2018-01-01

    and current limiter are used to absorb the excessive dc-voltage and limits excessive ac current, respectively. This control strategy can also ensure the reactive power support through the injection of reactive current according to the standard requirements as soon as the voltage sag is detected. Furthermore...... to improve the capability of ride-through fault safely and keep the inverter connected, but also to provide grid support through active and reactive power control at different type of faults....

  5. Current control design for three-phase grid-connected inverters using a pole placement technique based on numerical models

    OpenAIRE

    Citro, Costantino; Gavriluta, Catalin; Nizak Md, H. K.; Beltran, H.

    2012-01-01

    This paper presents a design procedure for linear current controllers of three-phase grid-connected inverters. The proposed method consists in deriving a numerical model of the converter by using software simulations and applying the pole placement technique to design the controller with the desired performances. A clear example on how to apply the technique is provided. The effectiveness of the proposed design procedure has been verified through the experimental results obtained with ...

  6. High gain, low noise, fully complementary logic inverter based on bi-layer WSe{sub 2} field effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Das, Saptarshi; Roelofs, Andreas [Center for Nanoscale Material, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Dubey, Madan [U.S. Army Research Laboratory, Adelphi, Maryland 20783 (United States)

    2014-08-25

    In this article, first, we show that by contact work function engineering, electrostatic doping and proper scaling of both the oxide thickness and the flake thickness, high performance p- and n-type WSe{sub 2} field effect transistors (FETs) can be realized. We report record high drive current of 98 μA/μm for the electron conduction and 110 μA/μm for the hole conduction in Schottky barrier WSe{sub 2} FETs. Then, we combine high performance WSe{sub 2} PFET with WSe{sub 2} NFET in double gated transistor geometry to demonstrate a fully complementary logic inverter. We also show that by adjusting the threshold voltages for the NFET and the PFET, the gain and the noise margin of the inverter can be significantly enhanced. The maximum gain of our chemical doping free WSe{sub 2} inverter was found to be ∼25 and the noise margin was close to its ideal value of ∼2.5 V for a supply voltage of V{sub DD} = 5.0 V.

  7. Digital notch filter based active damping for LCL filters

    DEFF Research Database (Denmark)

    Yao, Wenli; Yang, Yongheng; Zhang, Xiaobin

    2015-01-01

    . In contrast, the active damping does not require any dissipation elements, and thus has become of increasing interest. As a result, a vast of active damping solutions have been reported, among which multi-loop control systems and additional sensors are necessary, leading to increased cost and complexity....... In this paper, a notch filter based active damping without the requirement of additional sensors is proposed, where the inverter current is employed as the feedback variable. Firstly, a design method of the notch filter for active damping is presented. The entire system stability has then been investigated...... in the z-domain. Simulations and experiments are carried out to verify the proposed active damping method. Both results have confirmed that the notch filter based active damping can ensure the entire system stability in the case of resonances with a good system performance....

  8. Automated digital image analysis of islet cell mass using Nikon's inverted eclipse Ti microscope and software to improve engraftment may help to advance the therapeutic efficacy and accessibility of islet transplantation across centers.

    Science.gov (United States)

    Gmyr, Valery; Bonner, Caroline; Lukowiak, Bruno; Pawlowski, Valerie; Dellaleau, Nathalie; Belaich, Sandrine; Aluka, Isanga; Moermann, Ericka; Thevenet, Julien; Ezzouaoui, Rimed; Queniat, Gurvan; Pattou, Francois; Kerr-Conte, Julie

    2015-01-01

    Reliable assessment of islet viability, mass, and purity must be met prior to transplanting an islet preparation into patients with type 1 diabetes. The standard method for quantifying human islet preparations is by direct microscopic analysis of dithizone-stained islet samples, but this technique may be susceptible to inter-/intraobserver variability, which may induce false positive/negative islet counts. Here we describe a simple, reliable, automated digital image analysis (ADIA) technique for accurately quantifying islets into total islet number, islet equivalent number (IEQ), and islet purity before islet transplantation. Islets were isolated and purified from n = 42 human pancreata according to the automated method of Ricordi et al. For each preparation, three islet samples were stained with dithizone and expressed as IEQ number. Islets were analyzed manually by microscopy or automatically quantified using Nikon's inverted Eclipse Ti microscope with built-in NIS-Elements Advanced Research (AR) software. The AIDA method significantly enhanced the number of islet preparations eligible for engraftment compared to the standard manual method (p image analysis utilizing the Nikon Instruments software is an unbiased, simple, and reliable teaching tool to comprehensively assess the individual size of each islet cell preparation prior to transplantation. Implementation of this technology to improve engraftment may help to advance the therapeutic efficacy and accessibility of islet transplantation across centers.

  9. Novel T-Z source inverter with high voltage gain and reduced transformer turn ratio

    DEFF Research Database (Denmark)

    Mostaan, Ali; Sharifi Malfejani, Saeed; Soltani, Mohsen

    2015-01-01

    Novel voltage source inverter based on the Z source inverter structure is introduced in this paper. In this new inverter, two inductors of the impedance network in conventional Z source inverter are replaced with two transformers or coupled inductors, but unlike the T-Z source inverter that it......'s voltage gain is raised with increasing the transformers turn ratio, the voltage gain in the proposed inverter is raised with lowering the transformer turn ratio. Therefore, transformers with lower turn ratio are required in the proposed inverter in compare with T- Z source inverter that can lead to lower...

  10. Nonlinear dynamics based digital logic and circuits.

    Science.gov (United States)

    Kia, Behnam; Lindner, John F; Ditto, William L

    2015-01-01

    We discuss the role and importance of dynamics in the brain and biological neural networks and argue that dynamics is one of the main missing elements in conventional Boolean logic and circuits. We summarize a simple dynamics based computing method, and categorize different techniques that we have introduced to realize logic, functionality, and programmability. We discuss the role and importance of coupled dynamics in networks of biological excitable cells, and then review our simple coupled dynamics based method for computing. In this paper, for the first time, we show how dynamics can be used and programmed to implement computation in any given base, including but not limited to base two.

  11. Fermilab Recycler Ring BPM Upgrade Based on Digital Receiver Technology

    Science.gov (United States)

    Webber, R.; Crisp, J.; Prieto, P.; Voy, D.; Briegel, C.; McClure, C.; West, R.; Pordes, S.; Mengel, M.

    2004-11-01

    Electronics for the 237 BPMs in the Fermilab Recycler Ring have been upgraded from a log-amplifier based system to a commercially produced digitizer-digital down converter based system. The hardware consists of a pre-amplifier connected to a split-plate BPM, an analog differential receiver-filter module and an 8-channel 80-MHz digital down converter VME board. The system produces position and intensity with a dynamic range of 30 dB and a resolution of ±10 microns. The position measurements are made on 2.5-MHz bunched beam and barrier buckets of the un-bunched beam. The digital receiver system operates in one of six different signal processing modes that include 2.5-MHz average, 2.5-MHz bunch-by-bunch, 2.5-MHz narrow band, unbunched average, un-bunched head/tail and 89-kHz narrow band. Receiver data is acquired on any of up to sixteen clock events related to Recycler beam transfers and other machine activities. Data from the digital receiver board are transferred to the front-end CPU for position and intensity computation on an on-demand basis through the VME bus. Data buffers are maintained for each of the acquisition events and support flash, closed orbit and turn-by-turn measurements. A calibration system provides evaluation of the BPM signal path and application programs.

  12. DIGITAL

    Data.gov (United States)

    Federal Emergency Management Agency, Department of Homeland Security — The Digital Flood Insurance Rate Map (DFIRM) Database depicts flood risk information and supporting data used to develop the risk data. The primary risk...

  13. Extended Stable Boundary of LCL-Filtered Grid-Connected Inverter Based on An Improved Grid-Voltage Feedforward Control

    DEFF Research Database (Denmark)

    Lu, Minghui; Xin, Zhen; Wang, Xiongfei

    2016-01-01

    should be designed under one-sixth of sampling frequency. However, the low resonance frequency leads to a comparatively large filter inductance or/and capacitance. To extend the stable boundary to the region above fs/6, this paper proposes a novel voltage feedforward scheme for the LCL-filtered inverter....... Theoretical analysis is then provided to validate its feasibility and stability. Compared to other widely used active damping strategies, no extra sensors are needed because the filter capacitor voltage, which is used for voltage feedforward control, is also sampled for phase-locked loop in this paper...

  14. Creative Digital Worksheet Base on Mobile Learning

    Science.gov (United States)

    Wibawa, S. C.; Cholifah, R.; Utami, A. W.; Nurhidayat, A. I.

    2018-01-01

    The student is required to understand and act in the classroom and it is very important for selecting the media learning to determine the learning outcome. An instructional media is needed to help students achieve the best learning outcome. The objectives of this study are (1) to make Android-based student worksheet, (2) to know the students’ response on Android-based student worksheet in multimedia subject, (3) to determine the student result using Android-based student worksheet. The method used was Research and Development (R&D) using post-test-only in controlled quasi-experimental group design. The subjects of the study were 2 classes, a control class and an experimental class. The results showed (1) Android-based student worksheet was categorized very good as percentage of 85%; (2) the students’ responses was categorized very good as percentage of 86.42%; (3) the experimental class results were better than control class. The average result on cognitive tests on the experimental class was 89.97 and on control class was 78.31; whether the average result on psychomotor test on the experimental class was 89.90 and on the control class was 79.83. In conclusion, student result using Android-based student worksheet was better than those without it.

  15. Digital Simulation-Based Training: A Meta-Analysis

    Science.gov (United States)

    Gegenfurtner, Andreas; Quesada-Pallarès, Carla; Knogler, Maximilian

    2014-01-01

    This study examines how design characteristics in digital simulation-based learning environments moderate self-efficacy and transfer of learning. Drawing on social cognitive theory and the cognitive theory of multimedia learning, the meta-analysis psychometrically cumulated k?=?15 studies of 25 years of research with a total sample size of…

  16. Digital Game-Based Learning in Accounting and Business Education

    Science.gov (United States)

    Carenys, Jordi; Moya, Soledad

    2016-01-01

    This article presents a review of the accounting and business literature on digital game-based learning (DGBL). The article classifies what is already settled in the literature about the theoretical foundations of DGBL's effectiveness and its practical use into three categories. The first comprises what is known about the evaluation of digital…

  17. Progressive development of a digital cadastral data base

    NARCIS (Netherlands)

    Thompson, R.J.

    2013-01-01

    A Digital Cadastral Data Base (DCDB) is a big investment for a jurisdiction tasked with the administration of land boundaries. In the past, the development of such a database produced no real pay-back on investment until many years, and millions of dollars had been committed. The Land Administration

  18. 500 MHz transient digitizers based on GaAs CCDs

    International Nuclear Information System (INIS)

    Bryman, D.; Cresswell, J.V.; LeNoble, M.; Poutissou, R.

    1990-10-01

    A wide bandwidth transient digitizer based on a recently produced gallium arsenide charged coupled device is under development. The CCDs have 128 pixels and operate at 500 MHz. Initial testing of prototype modules in Experiment 787 at Brookhaven National Laboratory is reported. (Author) (8 refs., 10 figs.)

  19. Intelligent assembly time analysis, using a digital knowledge based approach

    NARCIS (Netherlands)

    Jin, Y.; Curran, R.; Butterfield, J.; Burke, R.; Welch, B.

    2009-01-01

    The implementation of effective time analysis methods fast and accurately in the era of digital manufacturing has become a significant challenge for aerospace manufacturers hoping to build and maintain a competitive advantage. This paper proposes a structure oriented, knowledge-based approach for

  20. 500 MHz transient digitizers based on GaAs CCDs

    International Nuclear Information System (INIS)

    Bryman, D.A.; Constable, M.; Cresswell, J.V.; Daviel, A.; LeNoble, M.; Mildenberger, J.; Poutissou, R.

    1996-11-01

    A system of 500 MHz transient digitizers based on gallium arsenide resistive gate charged coupled devices has been developed for an experiment studying rare K decays. CCDs with dynamic range of 8-bits and 128 or 320 pixels are used as analog pipelines. The CCD's are driven by a single phase transport system. Data readout and manipulation occurs at 15.6 MHz. (authors)

  1. Designing Digital Problem Based Learning Tasks that Motivate Students

    Science.gov (United States)

    van Loon, Anne-Marieke; Ros, Anje; Martens, Rob

    2013-01-01

    This study examines whether teachers are able to apply the principles of autonomy support and structure support in designing digital problem based learning (PBL) tasks. We examine whether these tasks are more autonomy- and structure-supportive and whether primary and secondary school students experience greater autonomy, competence, and motivation…

  2. Principle and Design of a Single-phase Inverter-Based Grounding System for Neutral-to-ground Voltage Compensation in Distribution Networks

    DEFF Research Database (Denmark)

    Wang, Wen; Yan, Lingjie; Zeng, Xiangjun

    2017-01-01

    Neutral-to-ground overvoltage may occur in non-effectively grounded power systems because of the distributed parameters asymmetry and resonance between Petersen coil and distributed capacitances. Thus, the constraint of neutral-to-ground voltage is critical for the safety of distribution networks....... In this paper, an active grounding system based on single-phase inverter and its control parameter design method is proposed to achieve this objective. Relationship between its output current and neutral-to-ground voltage is derived to explain the principle of neutral-to-ground voltage compensation. Then...

  3. Digital Correlation based on Wavelet Transform for Image Detection

    International Nuclear Information System (INIS)

    Barba, L; Vargas, L; Torres, C; Mattos, L

    2011-01-01

    In this work is presented a method for the optimization of digital correlators to improve the characteristic detection on images using wavelet transform as well as subband filtering. It is proposed an approach of wavelet-based image contrast enhancement in order to increase the performance of digital correlators. The multiresolution representation is employed to improve the high frequency content of images taken into account the input contrast measured for the original image. The energy of correlation peaks and discrimination level of several objects are improved with this technique. To demonstrate the potentiality in extracting characteristics using the wavelet transform, small objects inside reference images are detected successfully.

  4. Random number generation based on digital differential chaos

    KAUST Repository

    Zidan, Mohammed A.

    2012-07-29

    In this paper, we present a fully digital differential chaos based random number generator. The output of the digital circuit is proved to be chaotic by calculating the output time series maximum Lyapunov exponent. We introduce a new post processing technique to improve the distribution and statistical properties of the generated data. The post-processed output passes the NIST Sp. 800-22 statistical tests. The system is written in Verilog VHDL and realized on Xilinx Virtex® FPGA. The generator can fit into a very small area and have a maximum throughput of 2.1 Gb/s.

  5. Multilevel DC link inverter

    Science.gov (United States)

    Su, Gui-Jia

    2003-06-10

    A multilevel DC link inverter and method for improving torque response and current regulation in permanent magnet motors and switched reluctance motors having a low inductance includes a plurality of voltage controlled cells connected in series for applying a resulting dc voltage comprised of one or more incremental dc voltages. The cells are provided with switches for increasing the resulting applied dc voltage as speed and back EMF increase, while limiting the voltage that is applied to the commutation switches to perform PWM or dc voltage stepping functions, so as to limit current ripple in the stator windings below an acceptable level, typically 5%. Several embodiments are disclosed including inverters using IGBT's, inverters using thyristors. All of the inverters are operable in both motoring and regenerating modes.

  6. Reliability analysis of digital based I and C system

    Energy Technology Data Exchange (ETDEWEB)

    Kang, I. S.; Cho, B. S.; Choi, M. J. [KOPEC, Yongin (Korea, Republic of)

    1999-10-01

    Rapidly, digital technology is being widely applied in replacing analog component installed in existing plant and designing new nuclear power plant for control and monitoring system in Korea as well as in foreign countries. Even though many merits of digital technology, it is being faced with a new problem of reliability assurance. The studies for solving this problem are being performed vigorously in foreign countries. The reliability of KNGR Engineered Safety Features Component Control System (ESF-CCS), digital based I and C system, was analyzed to verify fulfillment of the ALWR EPRI-URD requirement for reliability analysis and eliminate hazards in design applied new technology. The qualitative analysis using FMEA and quantitative analysis using reliability block diagram were performed. The results of analyses are shown in this paper.

  7. Carbon Nanotubes-Based Digitally Programmable Current Follower

    Directory of Open Access Journals (Sweden)

    S. K. Tripathi

    2018-01-01

    Full Text Available The physical constraints of ever-shrinking CMOS transistors are rapidly approaching atomistic and quantum mechanical limits. Therefore, research is now directed towards the development of nanoscale devices that could work efficiently in the sub-10 nm regime. This coupled with the fact that recent design trend for analog signal processing applications is moving towards current-mode circuits which offer lower voltage swings, higher bandwidth, and better signal linearity is the motivation for this work. A digitally controlled DVCC has been realized using CNFETs. This work exploited the CNFET’s parameters like chirality, pitch, and numbers of CNTs to perform the digital control operation. The circuit has minimum number of transistors and can control the output current digitally. A similar CMOS circuit with 32 nm CMOS parameters was also simulated and compared. The result shows that CMOS-based circuit requires 418.6 μW while CNFET-based circuit consumes 352.1 μW only. Further, the proposed circuit is used to realize a CNFET-based instrumentation amplifier with digitally programmable gain. The amplifier has a CMRR of 100 dB and ICMR equal to 0.806 V. The 3 dB bandwidth of the amplifier is 11.78 GHz which is suitable for the applications like navigation, radar instrumentation, and high-frequency signal amplification and conditioning.

  8. Digital Resonant Controller based on Modified Tustin Discretization Method

    Directory of Open Access Journals (Sweden)

    STOJIC, D.

    2016-11-01

    Full Text Available Resonant controllers are used in power converter voltage and current control due to their simplicity and accuracy. However, digital implementation of resonant controllers introduces problems related to zero and pole mapping from the continuous to the discrete time domain. Namely, some discretization methods introduce significant errors in the digital controller resonant frequency, resulting in the loss of the asymptotic AC reference tracking, especially at high resonant frequencies. The delay compensation typical for resonant controllers can also be compromised. Based on the existing analysis, it can be concluded that the Tustin discretization with frequency prewarping represents a preferable choice from the point of view of the resonant frequency accuracy. However, this discretization method has a shortcoming in applications that require real-time frequency adaptation, since complex trigonometric evaluation is required for each frequency change. In order to overcome this problem, in this paper the modified Tustin discretization method is proposed based on the Taylor series approximation of the frequency prewarping function. By comparing the novel discretization method with commonly used two-integrator-based proportional-resonant (PR digital controllers, it is shown that the resulting digital controller resonant frequency and time delay compensation errors are significantly reduced for the novel controller.

  9. Hardware Development of a Laboratory-Scale Microgrid Phase 1--Single Inverter in Island Mode Operation: Base Year Report, December 2000 -- November 2001

    Energy Technology Data Exchange (ETDEWEB)

    Venkataramanan, G.; Illindala, M. S.; Houle, C.; Lasseter, R. H.

    2002-11-01

    This report summarizes the activities of the first year of a three-year project to develop control software for micro-source distributed generation systems. The focus of this phase was on internal energy storage requirements, the modification of an off-the-shelf motor drive system inverter to supply utility-grade ac power, and a single inverter system operating in island mode. The report provides a methodology for determining battery energy storage requirements, a method for converting a motor drive inverter into a utility-grade inverter, and typical characteristics and test results of using such an inverter in a complex load environment.

  10. Component-Minimized Buck-Boost Voltage Source Inverters

    DEFF Research Database (Denmark)

    Gao, F.; Loh, P.C.; Blaabjerg, Frede

    2007-01-01

    This paper presents the design of buck-boost B4 inverters that can be derived from either Ćuk- or SEPIC-derived buck-boost B6 inverters. Unlike traditional inverters, the integration of front-end voltage boost circuitry and inverter circuitry allows it to perform buck-boost voltage inversion...... between capacitors. Modulation wise, the proposed buck-boost B4 inverters can be controlled using a carefully designed carrier-based pulse-width modulation (PWM) scheme that will always ensure balanced threephase outputs as desired, while simultaneously achieving minimal voltage stress across...

  11. Enhanced photovoltaic performance of inverted pyramid-based nanostructured black-silicon solar cells passivated by an atomic-layer-deposited Al2O3 layer.

    Science.gov (United States)

    Chen, Hong-Yan; Lu, Hong-Liang; Ren, Qing-Hua; Zhang, Yuan; Yang, Xiao-Feng; Ding, Shi-Jin; Zhang, David Wei

    2015-10-07

    Inverted pyramid-based nanostructured black-silicon (BS) solar cells with an Al2O3 passivation layer grown by atomic layer deposition (ALD) have been demonstrated. A multi-scale textured BS surface combining silicon nanowires (SiNWs) and inverted pyramids was obtained for the first time by lithography and metal catalyzed wet etching. The reflectance of the as-prepared BS surface was about 2% lower than that of the more commonly reported upright pyramid-based SiNW BS surface over the whole of the visible light spectrum, which led to a 1.7 mA cm(-2) increase in short circuit current density. Moreover, the as-prepared solar cells were further passivated by an ALD-Al2O3 layer. The effect of annealing temperature on the photovoltaic performance of the solar cells was investigated. It was found that the values of all solar cell parameters including short circuit current, open circuit voltage, and fill factor exhibit a further increase under an optimized annealing temperature. Minority carrier lifetime measurements indicate that the enhanced cell performance is due to the improved passivation quality of the Al2O3 layer after thermal annealing treatments. By combining these two refinements, the optimized SiNW BS solar cells achieved a maximum conversion efficiency enhancement of 7.6% compared to the cells with an upright pyramid-based SiNWs surface and conventional SiNx passivation.

  12. A modified implementation of tristate inverter based static master-slave flip-flop with improved power-delay-area product.

    Science.gov (United States)

    Singh, Kunwar; Tiwari, Satish Chandra; Gupta, Maneesha

    2014-01-01

    The paper introduces novel architectures for implementation of fully static master-slave flip-flops for low power, high performance, and high density. Based on the proposed structure, traditional C(2)MOS latch (tristate inverter/clocked inverter) based flip-flop is implemented with fewer transistors. The modified C(2)MOS based flip-flop designs mC(2)MOSff1 and mC(2)MOSff2 are realized using only sixteen transistors each while the number of clocked transistors is also reduced in case of mC(2)MOSff1. Postlayout simulations indicate that mC(2)MOSff1 flip-flop shows 12.4% improvement in PDAP (power-delay-area product) when compared with transmission gate flip-flop (TGFF) at 16X capacitive load which is considered to be the best design alternative among the conventional master-slave flip-flops. To validate the correct behaviour of the proposed design, an eight bit asynchronous counter is designed to layout level. LVS and parasitic extraction were carried out on Calibre, whereas layouts were implemented using IC station (Mentor Graphics). HSPICE simulations were used to characterize the transient response of the flip-flop designs in a 180 nm/1.8 V CMOS technology. Simulations were also performed at 130 nm, 90 nm, and 65 nm to reveal the scalability of both the designs at modern process nodes.

  13. CMOS based capacitance to digital converter circuit for MEMS sensor

    Science.gov (United States)

    Rotake, D. R.; Darji, A. D.

    2018-02-01

    Most of the MEMS cantilever based system required costly instruments for characterization, processing and also has large experimental setups which led to non-portable device. So there is a need of low cost, highly sensitive, high speed and portable digital system. The proposed Capacitance to Digital Converter (CDC) interfacing circuit converts capacitance to digital domain which can be easily processed. Recent demand microcantilever deflection is part per trillion ranges which change the capacitance in 1-10 femto farad (fF) range. The entire CDC circuit is designed using CMOS 250nm technology. Design of CDC circuit consists of a D-latch and two oscillators, namely Sensor controlled oscillator (SCO) and digitally controlled oscillator (DCO). The D-latch is designed using transmission gate based MUX for power optimization. A CDC design of 7-stage, 9-stage and 11-stage tested for 1-18 fF and simulated using mentor graphics Eldo tool with parasitic. Since the proposed design does not use resistance component, the total power dissipation is reduced to 2.3621 mW for CDC designed using 9-stage SCO and DCO.

  14. Active Layer Spin Coating Speed Dependence of Inverted Organic Solar Cell Based on Eosin-Y-Coated ZnO Nanorod Arrays

    Science.gov (United States)

    Ginting, R. T.; Yap, C. C.; Yahaya, M.; Fauzia, V.; Salleh, M. M.

    2013-04-01

    The active layer spin coating speed dependence of the performance of inverted organic solar cells (OSCs) based on Eosin-Y-coated ZnOnanorods has been investigated. An active layer consisted of poly(2-methoxy-5-(2'-ethyl)-hexyloxy-p-phenylenevinylene) (MEH-PPV) as donor and phenyl-c61-butyric acid methyl ester (PCBM) as acceptor was employed, whereas ZnO nanorods were utilized as electron transporting layer. The active layer was deposited on top of Eosin-Y-coated ZnO nanorods with various spin coating speeds (1000-4000 rpm). Inverted OSCs with a structure of FTO/Eosin-Y-coated ZnO nanorods/MEH-PPV:PCBM /Ag were characterized through the current density-voltage (J-V) measurement under illumination intensity of 100 mW/cm2. Based on the investigation, the short circuit current density (Jsc) and the power conversion efficiency (PCE) enhanced significantly, where as fill factor slightly increased with spin coating speed. The two-diode equivalent model was found to fit the experimental J-V curves very well. The optimum PCE of 1.18 ± 0.07% was achieved at the highest spin coating speed of 4000 rpm, as a result of the decrement of diffusion current density (Jdiff), recombination current density (Jrec), and ideality factor, thus further confirms the strong built-in electric field in thinner photoactive layer.

  15. An inverter-based capacitive trans-impedance amplifier readout with offset cancellation and temporal noise reduction for IR focal plane array

    Science.gov (United States)

    Chen, Hsin-Han; Hsieh, Chih-Cheng

    2013-09-01

    This paper presents a readout integrated circuit (ROIC) with inverter-based capacitive trans-impedance amplifier (CTIA) and pseudo-multiple sampling technique for infrared focal plane array (IRFPA). The proposed inverter-based CTIA with a coupling capacitor [1], executing auto-zeroing technique to cancel out the varied offset voltage from process variation, is used to substitute differential amplifier in conventional CTIA. The tunable detector bias is applied from a global external bias before exposure. This scheme not only retains stable detector bias voltage and signal injection efficiency, but also reduces the pixel area as well. Pseudo-multiple sampling technique [2] is adopted to reduce the temporal noise of readout circuit. The noise reduction performance is comparable to the conventional multiple sampling operation without need of longer readout time proportional to the number of samples. A CMOS image sensor chip with 55×65 pixel array has been fabricated in 0.18um CMOS technology. It achieves a 12um×12um pixel size, a frame rate of 72 fps, a power-per-pixel of 0.66uW/pixel, and a readout temporal noise of 1.06mVrms (16 times of pseudo-multiple sampling), respectively.

  16. Near State Vector Selection-Based Model Predictive Control with Common Mode Voltage Mitigation for a Three-Phase Four-Leg Inverter

    Directory of Open Access Journals (Sweden)

    Abdul Mannan Dadu

    2017-12-01

    Full Text Available A high computational burden is required in conventional model predictive control, as all of the voltage vectors of a power inverter are used to predict the future behavior of the system. Apart from that, the common mode voltage (CMV of a three-phase four-leg inverter utilizes up to half of the DC-link voltage due to the use of all of the available voltage vectors. Thus, this paper proposes a near state vector selection-based model predictive control (NSV-MPC scheme to mitigate the CMV and reduce computational burden. In the proposed technique, only six active voltage vectors are used in the predictive model, and the vectors are selected based on the position of the future reference vector. In every sampling period, the position of the reference current is used to detect the voltage vectors surrounding the reference voltage vector. Besides the six active vectors, one of the zero vectors is also used. The proposed technique is compared with the conventional control scheme in terms of execution time, CMV variation, and load current ripple in both simulation and an experimental setup. The LabVIEW Field programmable gate array rapid prototyping controller is used to validate the proposed control scheme experimentally, and demonstrate that the CMV can be bounded within one-fourth of the DC-link voltage.

  17. Trans-Z-source Neutral Point Clamped inverter

    DEFF Research Database (Denmark)

    Mo, W.; Loh, P. C.; Li, D.

    2012-01-01

    Transformer based Z-source (trans-Z-source) inverters are recently proposed by extending the traditional Z-source inverter with higher buck-boost capability as well as reducing the passive components at the same time. Multi-Level Z-source inverters are single-stage topological solutions used...... for buck-boost energy conversion with all the favourable advantages of multi-level switching retained. This paper presents three-level trans-Z-source Neutral Point Clamped (NPC) inverter topology, which achieves both the advantages of trans-Z-source and three-level NPC inverter configuration. With proper...... modulation scheme, the three-level trans-Z-source inverter can function with minimum of six device commutations per half carrier cycle (same as the traditional buck NPC inverter), while maintaining to produce the designed volt-sec average and inductive voltage boosting at ac output terminals. The designed...

  18. Control algorithm for the inverter fed induction motor drive with DC current feedback loop based on principles of the vector control

    Energy Technology Data Exchange (ETDEWEB)

    Vuckovic, V.; Vukosavic, S. (Electrical Engineering Inst. Nikola Tesla, Viktora Igoa 3, Belgrade, 11000 (Yugoslavia))

    1992-01-01

    This paper brings out a control algorithm for VSI fed induction motor drives based on the converter DC link current feedback. It is shown that the speed and flux can be controlled over the wide speed and load range quite satisfactorily for simpler drives. The base commands of both the inverter voltage and frequency are proportional to the reference speed, but each of them is further modified by the signals derived from the DC current sensor. The algorithm is based on the equations well known from the vector control theory, and is aimed to obtain the constant rotor flux and proportionality between the electrical torque, the slip frequency and the active component of the stator current. In this way, the problems of slip compensation, Ri compensation and correction of U/f characteristics are solved in the same time. Analytical considerations and computer simulations of the proposed control structure are in close agreement with the experimental results measured on a prototype drive.

  19. Smartphone based scalable reverse engineering by digital image correlation

    Science.gov (United States)

    Vidvans, Amey; Basu, Saurabh

    2018-03-01

    There is a need for scalable open source 3D reconstruction systems for reverse engineering. This is because most commercially available reconstruction systems are capital and resource intensive. To address this, a novel reconstruction technique is proposed. The technique involves digital image correlation based characterization of surface speeds followed by normalization with respect to angular speed during rigid body rotational motion of the specimen. Proof of concept of the same is demonstrated and validated using simulation and empirical characterization. Towards this, smart-phone imaging and inexpensive off the shelf components along with those fabricated additively using poly-lactic acid polymer with a standard 3D printer are used. Some sources of error in this reconstruction methodology are discussed. It is seen that high curvatures on the surface suppress accuracy of reconstruction. Reasons behind this are delineated in the nature of the correlation function. Theoretically achievable resolution during smart-phone based 3D reconstruction by digital image correlation is derived.

  20. Charge transport studies in donor-acceptor block copolymer PDPP-TNT and PC71BM based inverted organic photovoltaic devices processed in room conditions

    International Nuclear Information System (INIS)

    Srivastava, Shashi B.; Singh, Samarendra P.; Sonar, Prashant

    2015-01-01

    Diketopyrrolopyrole-naphthalene polymer (PDPP-TNT), a donor-acceptor co-polymer, has shown versatile behavior demonstrating high performances in organic field-effect transistors (OFETs) and organic photovoltaic (OPV) devices. In this paper we report investigation of charge carrier dynamics in PDPP-TNT, and [6,6]-phenyl C 71 butyric acid methyl ester (PC71BM) bulk-heterojunction based inverted OPV devices using current density-voltage (J-V) characteristics, space charge limited current (SCLC) measurements, capacitance-voltage (C-V) characteristics, and impedance spectroscopy (IS). OPV devices in inverted architecture, ITO/ZnO/PDPP-TNT:PC71BM/MoO 3 /Ag, are processed and characterized at room conditions. The power conversion efficiency (PCE) of these devices are measured ∼3.8%, with reasonably good fill-factor 54.6%. The analysis of impedance spectra exhibits electron’s mobility ∼2 × 10 −3 cm 2 V −1 s −1 , and lifetime in the range of 0.03-0.23 ms. SCLC measurements give hole mobility of 1.12 × 10 −5 cm 2 V −1 s −1 , and electron mobility of 8.7 × 10 −4 cm 2 V −1 s −1

  1. 500 MHz transient digitizers based on GaAs CCDs

    Energy Technology Data Exchange (ETDEWEB)

    Bryman, D A; Constable, M; Cresswell, J V; Daviel, A; LeNoble, M; Mildenberger, J; Poutissou, R

    1996-11-01

    A system of 500 MHz transient digitizers based on gallium arsenide resistive gate charged coupled devices has been developed for an experiment studying rare K decays. CCDs with dynamic range of 8-bits and 128 or 320 pixels are used as analog pipelines. The CCD`s are driven by a single phase transport system. Data readout and manipulation occurs at 15.6 MHz. (authors). 12 refs., 15 figs.

  2. Extending the Linear Modulation Range to the Full Base Speed Using a Single DC-Link Multilevel Inverter With Capacitor-Fed H-Bridges for IM Drives

    DEFF Research Database (Denmark)

    Rahul, Arun; Pramanick, Sumit; Kaarthik, R. Sudharshan

    2017-01-01

    In this paper, a new space vector pulse width modulation method to extend the linear modulation range of a cascaded five level inverter topology with a single dc supply is presented. Using this method, the inverter can be controlled linearly and the peak phase fundamental output voltage of the in......In this paper, a new space vector pulse width modulation method to extend the linear modulation range of a cascaded five level inverter topology with a single dc supply is presented. Using this method, the inverter can be controlled linearly and the peak phase fundamental output voltage...... of the inverter can be increased from 0.577 to 0.637Vdc without increasing the dc bus voltage and without exceeding the induction motor voltage rating. This new technique makes use of cascaded inverter pole voltage redundancy and property of the space vector structure for its operation. Using this, the induction...

  3. SEEPAGE/INVERT INTERACTIONS

    International Nuclear Information System (INIS)

    P.S. Domski

    2000-01-01

    As directed by a written development plan (CRWMS M andO 1999a), a conceptual model for water entering the drift and reacting with the invert materials is to be developed. The purpose of this conceptual model is to assist Performance Assessment Operations (PAO) and its Engineered Barrier Performance Department in modeling the geochemical environment within a repository drift, thus allowing PAO to provide a more detailed and complete in-drift geochemical model abstraction, and to answer the key technical issues (KTI) raised in the NRC Issue Resolution Status Report (IRSR) for the Evolution of the Near-Field Environment (NFE), Revision 2 (NRC 1999). This AMR also seeks to: (1) Develop a logical conceptual model for physical/chemical interactions between seepage and the invert materials; (2) screen potential processes and reactions that may occur between seepage and invert to evaluate the potential consequences of the interactions; and (3) outline how seepage/invert processes may be quantified. This document provides the conceptual framework for screening out insignificant processes and for identifying and evaluating those seepage/invert interactions that have the potential to be important to subsequent PAO analyses including the Engineered Barrier System (EBS) physical and chemical model abstraction effort. This model has been developed to serve as a basis for the in-drift geochemical analyses performed by PAO. Additionally, the concepts discussed within this report may also apply to certain near and far-field geochemical processes and may have conceptual application within the unsaturated zone (UZ) and saturated zone (SZ) transport modeling efforts. The seepage/invert interactions will not directly affect any principal factors

  4. Origin-Dependent Inverted-Repeat Amplification: Tests of a Model for Inverted DNA Amplification.

    Directory of Open Access Journals (Sweden)

    Bonita J Brewer

    2015-12-01

    Full Text Available DNA replication errors are a major driver of evolution--from single nucleotide polymorphisms to large-scale copy number variations (CNVs. Here we test a specific replication-based model to explain the generation of interstitial, inverted triplications. While no genetic information is lost, the novel inversion junctions and increased copy number of the included sequences create the potential for adaptive phenotypes. The model--Origin-Dependent Inverted-Repeat Amplification (ODIRA-proposes that a replication error at pre-existing short, interrupted, inverted repeats in genomic sequences generates an extrachromosomal, inverted dimeric, autonomously replicating intermediate; subsequent genomic integration of the dimer yields this class of CNV without loss of distal chromosomal sequences. We used a combination of in vitro and in vivo approaches to test the feasibility of the proposed replication error and its downstream consequences on chromosome structure in the yeast Saccharomyces cerevisiae. We show that the proposed replication error-the ligation of leading and lagging nascent strands to create "closed" forks-can occur in vitro at short, interrupted inverted repeats. The removal of molecules with two closed forks results in a hairpin-capped linear duplex that we show replicates in vivo to create an inverted, dimeric plasmid that subsequently integrates into the genome by homologous recombination, creating an inverted triplication. While other models have been proposed to explain inverted triplications and their derivatives, our model can also explain the generation of human, de novo, inverted amplicons that have a 2:1 mixture of sequences from both homologues of a single parent--a feature readily explained by a plasmid intermediate that arises from one homologue and integrates into the other homologue prior to meiosis. Our tests of key features of ODIRA lend support to this mechanism and suggest further avenues of enquiry to unravel the origins

  5. Origin-Dependent Inverted-Repeat Amplification: Tests of a Model for Inverted DNA Amplification.

    Science.gov (United States)

    Brewer, Bonita J; Payen, Celia; Di Rienzi, Sara C; Higgins, Megan M; Ong, Giang; Dunham, Maitreya J; Raghuraman, M K

    2015-12-01

    DNA replication errors are a major driver of evolution--from single nucleotide polymorphisms to large-scale copy number variations (CNVs). Here we test a specific replication-based model to explain the generation of interstitial, inverted triplications. While no genetic information is lost, the novel inversion junctions and increased copy number of the included sequences create the potential for adaptive phenotypes. The model--Origin-Dependent Inverted-Repeat Amplification (ODIRA)-proposes that a replication error at pre-existing short, interrupted, inverted repeats in genomic sequences generates an extrachromosomal, inverted dimeric, autonomously replicating intermediate; subsequent genomic integration of the dimer yields this class of CNV without loss of distal chromosomal sequences. We used a combination of in vitro and in vivo approaches to test the feasibility of the proposed replication error and its downstream consequences on chromosome structure in the yeast Saccharomyces cerevisiae. We show that the proposed replication error-the ligation of leading and lagging nascent strands to create "closed" forks-can occur in vitro at short, interrupted inverted repeats. The removal of molecules with two closed forks results in a hairpin-capped linear duplex that we show replicates in vivo to create an inverted, dimeric plasmid that subsequently integrates into the genome by homologous recombination, creating an inverted triplication. While other models have been proposed to explain inverted triplications and their derivatives, our model can also explain the generation of human, de novo, inverted amplicons that have a 2:1 mixture of sequences from both homologues of a single parent--a feature readily explained by a plasmid intermediate that arises from one homologue and integrates into the other homologue prior to meiosis. Our tests of key features of ODIRA lend support to this mechanism and suggest further avenues of enquiry to unravel the origins of interstitial

  6. Digital case-based learning system in school.

    Science.gov (United States)

    Gu, Peipei; Guo, Jiayang

    2017-01-01

    With the continuing growth of multi-media learning resources, it is important to offer methods helping learners to explore and acquire relevant learning information effectively. As services that organize multi-media learning materials together to support programming learning, the digital case-based learning system is needed. In order to create a case-oriented e-learning system, this paper concentrates on the digital case study of multi-media resources and learning processes with an integrated framework. An integration of multi-media resources, testing and learning strategies recommendation as the learning unit is proposed in the digital case-based learning framework. The learning mechanism of learning guidance, multi-media materials learning and testing feedback is supported in our project. An improved personalized genetic algorithm which incorporates preference information and usage degree into the crossover and mutation process is proposed to assemble the personalized test sheet for each learner. A learning strategies recommendation solution is proposed to recommend learning strategies for learners to help them to learn. The experiments are conducted to prove that the proposed approaches are capable of constructing personalized sheets and the effectiveness of the framework.

  7. Digital case-based learning system in school.

    Directory of Open Access Journals (Sweden)

    Peipei Gu

    Full Text Available With the continuing growth of multi-media learning resources, it is important to offer methods helping learners to explore and acquire relevant learning information effectively. As services that organize multi-media learning materials together to support programming learning, the digital case-based learning system is needed. In order to create a case-oriented e-learning system, this paper concentrates on the digital case study of multi-media resources and learning processes with an integrated framework. An integration of multi-media resources, testing and learning strategies recommendation as the learning unit is proposed in the digital case-based learning framework. The learning mechanism of learning guidance, multi-media materials learning and testing feedback is supported in our project. An improved personalized genetic algorithm which incorporates preference information and usage degree into the crossover and mutation process is proposed to assemble the personalized test sheet for each learner. A learning strategies recommendation solution is proposed to recommend learning strategies for learners to help them to learn. The experiments are conducted to prove that the proposed approaches are capable of constructing personalized sheets and the effectiveness of the framework.

  8. Digital image correlation based on a fast convolution strategy

    Science.gov (United States)

    Yuan, Yuan; Zhan, Qin; Xiong, Chunyang; Huang, Jianyong

    2017-10-01

    In recent years, the efficiency of digital image correlation (DIC) methods has attracted increasing attention because of its increasing importance for many engineering applications. Based on the classical affine optical flow (AOF) algorithm and the well-established inverse compositional Gauss-Newton algorithm, which is essentially a natural extension of the AOF algorithm under a nonlinear iterative framework, this paper develops a set of fast convolution-based DIC algorithms for high-efficiency subpixel image registration. Using a well-developed fast convolution technique, the set of algorithms establishes a series of global data tables (GDTs) over the digital images, which allows the reduction of the computational complexity of DIC significantly. Using the pre-calculated GDTs, the subpixel registration calculations can be implemented efficiently in a look-up-table fashion. Both numerical simulation and experimental verification indicate that the set of algorithms significantly enhances the computational efficiency of DIC, especially in the case of a dense data sampling for the digital images. Because the GDTs need to be computed only once, the algorithms are also suitable for efficiently coping with image sequences that record the time-varying dynamics of specimen deformations.

  9. Digital differential confocal microscopy based on spatial shift transformation.

    Science.gov (United States)

    Liu, J; Wang, Y; Liu, C; Wilson, T; Wang, H; Tan, J

    2014-11-01

    Differential confocal microscopy is a particularly powerful surface profilometry technique in industrial metrology due to its high axial sensitivity and insensitivity to noise. However, the practical implementation of the technique requires the accurate positioning of point detectors in three-dimensions. We describe a simple alternative based on spatial transformation of a through-focus series of images obtained from a homemade beam scanning confocal microscope. This digital differential confocal microscopy approach is described and compared with the traditional Differential confocal microscopy approach. The ease of use of the digital differential confocal microscopy system is illustrated by performing measurements on a 3D standard specimen. © 2014 The Authors Journal of Microscopy © 2014 Royal Microscopical Society.

  10. improvement of digital image watermarking techniques based on FPGA implementation

    International Nuclear Information System (INIS)

    EL-Hadedy, M.E

    2006-01-01

    digital watermarking provides the ownership of a piece of digital data by marking the considered data invisibly or visibly. this can be used to protect several types of multimedia objects such as audio, text, image and video. this thesis demonstrates the different types of watermarking techniques such as (discrete cosine transform (DCT) and discrete wavelet transform (DWT) and their characteristics. then, it classifies these techniques declaring their advantages and disadvantages. an improved technique with distinguished features, such as peak signal to noise ratio ( PSNR) and similarity ratio (SR) has been introduced. the modified technique has been compared with the other techniques by measuring heir robustness against differ attacks. finally, field programmable gate arrays (FPGA) based implementation and comparison, for the proposed watermarking technique have been presented and discussed

  11. A Computer- Based Digital Signal Processing for Nuclear Scintillator Detectors

    International Nuclear Information System (INIS)

    Ashour, M.A.; Abo Shosha, A.M.

    2000-01-01

    In this paper, a Digital Signal Processing (DSP) Computer-based system for the nuclear scintillation signals with exponential decay is presented. The main objective of this work is to identify the characteristics of the acquired signals smoothly, this can be done by transferring the signal environment from random signal domain to deterministic domain using digital manipulation techniques. The proposed system consists of two major parts. The first part is the high performance data acquisition system (DAQ) that depends on a multi-channel Logic Scope. Which is interfaced with the host computer through the General Purpose Interface Board (GPIB) Ver. IEEE 488.2. Also, a Graphical User Interface (GUI) has been designed for this purpose using the graphical programming facilities. The second of the system is the DSP software Algorithm which analyses, demonstrates, monitoring these data to obtain the main characteristics of the acquired signals; the amplitude, the pulse count, the pulse width, decay factor, and the arrival time

  12. Digital coal mine integrated automation system based on Controlnet

    Energy Technology Data Exchange (ETDEWEB)

    Jin-yun Chen; Shen Zhang; Wei-ran Zuo [China University of Mining and Technology, Xuzhou (China). School of Chemical Engineering and Technology

    2007-06-15

    A three-layer model for digital communication in a mine is proposed. Two basic platforms are discussed: a uniform transmission network and a uniform data warehouse. An actual, ControlNet based, transmission network platform suitable for the Jining No.3 coal mine in China is presented. This network is an information superhighway intended to integrate all existing and new automation subsystems. Its standard interface can be used with future subsystems. The network, data structure and management decision-making all employ this uniform hardware and software. This effectively avoids the problems of system and information islands seen in traditional mine-automation systems. The construction of the network provides a stable foundation for digital communication in the Jining No.3 coal mine. 9 refs., 5 figs.

  13. High efficiency rubrene based inverted top-emission organic light emitting devices with a mixed single layer

    International Nuclear Information System (INIS)

    Wang, Zhaokui; Lou, Yanhui; Naka, Shigeki; Okada, Hiroyuki

    2010-01-01

    Inverted top-emission organic light emitting devices (TEOLEDs) with a mixed single layer by mixing of electron transport materials (PyPySPyPy and Alq 3 ), hole transport material (α-NPD) and dope material (rubrene) were investigated. Maximum power efficiency of 3.5 lm/W and maximum luminance of 7000 cd/m 2 were obtained by optimizing the mixing ratio of PyPySPyPy:Alq 3 :α-NPD:rubrene=25:50:25:1. Luminance and power efficiency of mixed single layer device were two times improved compared to bi-layer heterojunction device and tri-layer heterojunction device. Lifetime test also shows that the mixed single layer device exhibits longer operational lifetimes of 343 h, which is three times longer than the 109 h for tri-layer device, and two times longer than the 158 h for bi-layer device. In addition, the maximum luminance and power efficiency were obtained at 20,000 cd/m 2 and 7.5 lm/W, respectively, when a TPD layer of 45 nm was capped onto the top metal electrode.

  14. Handwritten Digit Recognition using Edit Distance-Based KNN

    OpenAIRE

    Bernard , Marc; Fromont , Elisa; Habrard , Amaury; Sebban , Marc

    2012-01-01

    We discuss the student project given for the last 5 years to the 1st year Master Students which follow the Machine Learning lecture at the University Jean Monnet in Saint Etienne, France. The goal of this project is to develop a GUI that can recognize digits and/or letters drawn manually. The system is based on a string representation of the dig- its using Freeman codes and on the use of an edit-distance-based K-Nearest Neighbors classifier. In addition to the machine learning knowledge about...

  15. A Digital Signature Scheme Based on MST3 Cryptosystems

    Directory of Open Access Journals (Sweden)

    Haibo Hong

    2014-01-01

    Full Text Available As special types of factorization of finite groups, logarithmic signature and cover have been used as the main components of cryptographic keys for secret key cryptosystems such as PGM and public key cryptosystems like MST1, MST2, and MST3. Recently, Svaba et. al proposed a revised MST3 encryption scheme with greater security. Meanwhile, they put forward an idea of constructing signature schemes on the basis of logarithmic signatures and random covers. In this paper, we firstly design a secure digital signature scheme based on logarithmic signatures and random covers. In order to complete the task, we devise a new encryption scheme based on MST3 cryptosystems.

  16. Energy-Saving Inverter

    Science.gov (United States)

    Rippel, W. E.; Edwards, D. B.

    1984-01-01

    Commutation by field-effect transistor allows more efficient operation. High voltage field-effect transistor (FET) controls silicon controlled rectifiers (SCR's). Circuit requires only one capacitor and one inductor in commutation circuit: simpler, more efficient, and more economical than conventional inverters. Adaptable to dc-to-dc converters.

  17. Argonne inverted sputter source

    International Nuclear Information System (INIS)

    Yntema, J.L.; Billquist, P.J.

    1983-01-01

    The emittance of the inverted sputter source with immersion lenses was measured to be about 5π mm mrad MeV/sup 1/2/ at the 75% level over a wide range of beam intensities. The use of the source in experiments with radioactive sputter targets and hydrogen loaded targets is described. Self contamination of the source is discussed

  18. A Modular Cascaded Multilevel Inverter Based Shunt Hybrid Active Power Filter for Selective Harmonic and Reactive Power Compensation Under Distorted/Unbalanced Grid Voltage Conditions

    Directory of Open Access Journals (Sweden)

    T. Demirdelen

    2016-10-01

    Full Text Available In recent years, shunt hybrid active power filters are being increasingly considered as a viable alternative to both passive filters and active power filters for compensating harmonics. In literature, their applications are restricted to balanced systems and low voltage applications and therefore not for industrial applications. This paper investigates the performance of a modular cascaded multilevel inverter based Shunt Hybrid Active Power Filter (SHAPF for reactive power compensation and selective harmonics elimination under distorted/unbalanced grid voltage conditions in medium voltage levels. In the proposed control method, reactive power compensation is achieved successfully with a perceptible amount and the performance results of harmonic compensation are satisfactory. Theoretical analysis and simulation results are obtained from an actual industrial network model in PSCAD. The simulation results are presented for a proposed system in order to demonstrate that the harmonic compensation performance meets the IEEE-519 standard.

  19. Digital chaotic sequence generator based on coupled chaotic systems

    International Nuclear Information System (INIS)

    Shu-Bo, Liu; Jing, Sun; Jin-Shuo, Liu; Zheng-Quan, Xu

    2009-01-01

    Chaotic systems perform well as a new rich source of cryptography and pseudo-random coding. Unfortunately their digital dynamical properties would degrade due to the finite computing precision. Proposed in this paper is a modified digital chaotic sequence generator based on chaotic logistic systems with a coupling structure where one chaotic subsystem generates perturbation signals to disturb the control parameter of the other one. The numerical simulations show that the length of chaotic orbits, the output distribution of chaotic system, and the security of chaotic sequences have been greatly improved. Moreover the chaotic sequence period can be extended at least by one order of magnitude longer than that of the uncoupled logistic system and the difficulty in decrypting increases 2 128 *2 128 times indicating that the dynamical degradation of digital chaos is effectively improved. A field programmable gate array (FPGA) implementation of an algorithm is given and the corresponding experiment shows that the output speed of the generated chaotic sequences can reach 571.4 Mbps indicating that the designed generator can be applied to the real-time video image encryption. (general)

  20. An image adaptive, wavelet-based watermarking of digital images

    Science.gov (United States)

    Agreste, Santa; Andaloro, Guido; Prestipino, Daniela; Puccio, Luigia

    2007-12-01

    In digital management, multimedia content and data can easily be used in an illegal way--being copied, modified and distributed again. Copyright protection, intellectual and material rights protection for authors, owners, buyers, distributors and the authenticity of content are crucial factors in solving an urgent and real problem. In such scenario digital watermark techniques are emerging as a valid solution. In this paper, we describe an algorithm--called WM2.0--for an invisible watermark: private, strong, wavelet-based and developed for digital images protection and authenticity. Using discrete wavelet transform (DWT) is motivated by good time-frequency features and well-matching with human visual system directives. These two combined elements are important in building an invisible and robust watermark. WM2.0 works on a dual scheme: watermark embedding and watermark detection. The watermark is embedded into high frequency DWT components of a specific sub-image and it is calculated in correlation with the image features and statistic properties. Watermark detection applies a re-synchronization between the original and watermarked image. The correlation between the watermarked DWT coefficients and the watermark signal is calculated according to the Neyman-Pearson statistic criterion. Experimentation on a large set of different images has shown to be resistant against geometric, filtering and StirMark attacks with a low rate of false alarm.

  1. Quasi-Y-source inverter

    DEFF Research Database (Denmark)

    Siwakoti, Yam Prasad; Blaabjerg, Frede; Loh, Poh Chiang

    2015-01-01

    This paper introduces a new inverter topology called a “quasi-Y-source inverter”. The proposed inverter inherits all the advantages of the original Y-source inverter. In addition, the new topology draws continuous current from the source which is required for many renewable sources. It also has dc......-current-blocking capacitors, which avoids saturation in the transformer core. Simulations and experimental results have proved the validity of the proposed inverter....

  2. Inverter communications using output signal

    Science.gov (United States)

    Chapman, Patrick L.

    2017-02-07

    Technologies for communicating information from an inverter configured for the conversion of direct current (DC) power generated from an alternative source to alternating current (AC) power are disclosed. The technologies include determining information to be transmitted from the inverter over a power line cable connected to the inverter and controlling the operation of an output converter of the inverter as a function of the information to be transmitted to cause the output converter to generate an output waveform having the information modulated thereon.

  3. A New Design Method for the Passive Damped LCL and LLCL Filter-Based Single-Phase Grid-Tied Inverter

    DEFF Research Database (Denmark)

    Wu, Weimin; He, Yuanbin; Tang, Tianhao

    2013-01-01

    A higher order passive power filter (LLCL filter) for the grid-tied inverter is becoming attractive for industrial applications due to the possibility to reduce the cost of the copper and the magnetic material. However, similar to the conventional LCL filter, the grid-tied inverter is facing...

  4. Versatile microfluidic total internal reflection (TIR)-based devices: application to microbeads velocity measurement and single molecule detection with upright and inverted microscope.

    Science.gov (United States)

    Le, Nam Cao Hoai; Yokokawa, Ryuji; Dao, Dzung Viet; Nguyen, Thien Duy; Wells, John C; Sugiyama, Susumu

    2009-01-21

    A poly(dimethylsiloxane) (PDMS) chip for Total Internal Reflection (TIR)-based imaging and detection has been developed using Si bulk micromachining and PDMS casting. In this paper, we report the applications of the chip on both inverted and upright fluorescent microscopes and confirm that two types of sample delivery platforms, PDMS microchannel and glass microchannel, can be easily integrated depending on the magnification of an objective lens needed to visualize a sample. Although any device configuration can be achievable, here we performed two experiments to demonstrate the versatility of the microfluidic TIR-based devices. The first experiment was velocity measurement of Nile red microbeads with nominal diameter of 500 nm in a pressure-driven flow. The time-sequenced fluorescent images of microbeads, illuminated by an evanescent field, were cross-correlated by a Particle Image Velocimetry (PIV) program to obtain near-wall velocity field of the microbeads at various flow rates from 500 nl/min to 3000 nl/min. We then evaluated the capabilities of the device for Single Molecule Detection (SMD) of fluorescently labeled DNA molecules from 30 bp to 48.5 kbp and confirm that DNA molecules as short as 1105 bp were detectable. Our versatile, integrated device could provide low-cost and fast accessibility to Total Internal Reflection Fluorescent Microscopy (TIRFM) on both conventional upright and inverted microscopes. It could also be a useful component in a Micro-Total Analysis System (micro-TAS) to analyze nanoparticles or biomolecules near-wall transport or motion.

  5. Inverting the Linear Algebra Classroom

    Science.gov (United States)

    Talbert, Robert

    2014-01-01

    The inverted classroom is a course design model in which students' initial contact with new information takes place outside of class meetings, and students spend class time on high-level sense-making activities. The inverted classroom model is so called because it inverts or "flips" the usual classroom design where typically class…

  6. Milliwatt dc/dc Inverter

    Science.gov (United States)

    Mclyman, C. W.

    1983-01-01

    Compact dc/dc inverter uses single integrated-circuit package containing six inverter gates that generate and amplify 100-kHz square-wave switching signal. Square-wave switching inverts 10-volt local power to isolated voltage at another desired level. Relatively high operating frequency reduces size of filter capacitors required, resulting in small package unit.

  7. Finishing report for the 'SolcelleInverter' project

    Energy Technology Data Exchange (ETDEWEB)

    Boekhoej Kjaer, S.

    2005-03-01

    The main objective for this research project was to develop an inverter for the AC module, where one PV module is equipped with its own dedicated inverter, and connected to the grid. A topology, among many different candidates, has been selected, based on analysis's. The inverter has been optimized in respect to cost, reliability, and efficiency, and a prototype has been build. (au)

  8. Digital video steganalysis using motion vector recovery-based features.

    Science.gov (United States)

    Deng, Yu; Wu, Yunjie; Zhou, Linna

    2012-07-10

    As a novel digital video steganography, the motion vector (MV)-based steganographic algorithm leverages the MVs as the information carriers to hide the secret messages. The existing steganalyzers based on the statistical characteristics of the spatial/frequency coefficients of the video frames cannot attack the MV-based steganography. In order to detect the presence of information hidden in the MVs of video streams, we design a novel MV recovery algorithm and propose the calibration distance histogram-based statistical features for steganalysis. The support vector machine (SVM) is trained with the proposed features and used as the steganalyzer. Experimental results demonstrate that the proposed steganalyzer can effectively detect the presence of hidden messages and outperform others by the significant improvements in detection accuracy even with low embedding rates.

  9. Progressive development of a digital cadastral data base

    OpenAIRE

    Thompson, R.J.

    2013-01-01

    A Digital Cadastral Data Base (DCDB) is a big investment for a jurisdiction tasked with the administration of land boundaries. In the past, the development of such a database produced no real pay-back on investment until many years, and millions of dollars had been committed. The Land Administration Domain Model (LADM) (ISO-TC211 2012) provides a model of a schema in which a progressive creation and improvement of a DCDB is possible, to allow benefits to be obtained even in the early stages o...

  10. Design of Multimedia-based Digital Storybooks for Preschool Education

    Directory of Open Access Journals (Sweden)

    Didik Dwi Prasetya

    2018-02-01

    Full Text Available Storytelling is one of the suitable approaches to deliver the right information and build the character education of young children. The story content presented by utilizing multimedia elements is able to offer more attractive and increase interest for children. This paper proposes an ICT approach through multimedia-based digital storybook design with an EPUB reflowable format that can be accessed using various electronic devices, whether desktop, laptop, or mobile. The research subjects are limited to 4-5-year-old preschool children. The research reveals that children were very enthusiastic about storybooks, with or without supports from teachers

  11. Enhancement of DFIG-Wind Turbine’s LVRT capability using novel DVR based Odd-nary Cascaded Asymmetric Multi-Level Inverter

    Directory of Open Access Journals (Sweden)

    A.D. Falehi

    2017-06-01

    Full Text Available One of the most prominent issues relevant to Doubly Fed Induction Generator (DFIG is augmentation of its Low Voltage Ride Through (LVRT capability. Dynamic Voltage Restorer (DVR is a series kind of Distributed-Flexible AC Transmission Systems (D-FACTS that is here occupied to preserve the DFIG from the voltage sag whenever a fault to be occurred in the power system. Multi-Level Inverter (MLI is the beating-heart of DVR with unique responsibility of synthesizing a staircase sinusoidal voltage from the DC voltage sources. In this regard, it is immensely important a high performance and cost-effective MLI to be embedded into the DVR. In this paper, a novel MLI is introduced to provide a staircase sinusoidal voltage with high level numbers against less switch numbers as compared to the other kinds of MLIs. By adding the bi-directional switches and capacitors of sub-MLI as well as amount of DC sources, the held forth MLI can also operate as so-called “Odd-nary” Cascaded Asymmetric Multi-Level Inverter (OCAMLI. The performance of proposed DVR based on OCAMLI i.e., DVR-OCAMLI has been thoroughly evaluated under deep and shallow balanced and unbalanced voltage sags so that its LVRT capability to be cleared up. To more scrutinize the performance of DVR-OCAMLI, it has been withal dealt with under severe and slight voltage swells as well as harmonic voltage. The accuracy and performance of DVR-OCAMLI has been furthermore compared with conventional DVR. To sum up, the relevant analytical study along with the simulation results has transparently corroborated the performance of OCAMLI as compared to other MLIs. Meanwhile, the DVR-OCAMLI has significantly compensated deep and shallow symmetric and asymmetric voltage sags to enhance the LVRT capability of DFIG; correspondingly, the severe and slight symmetric and asymmetric voltage swells as well as voltage harmonic have been exceptionally compensated as compared to conventional DVR.

  12. Power Hardware-in-the-Loop Evaluation of PV Inverter Grid Support on Hawaiian Electric Feeders

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, Austin A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Prabakar, Kumaraguru [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Nagarajan, Adarsh [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Nepal, Shaili [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Hoke, Anderson F [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Asano, Marc [Hawaiian Electric Company; Ueda, Reid [Hawaiian Electric Company; Ifuku, Earle [Hawaiian Electric Company

    2017-10-03

    As more grid-connected photovoltaic (PV) inverters become compliant with evolving interconnections requirements, there is increased interest from utilities in understanding how to best deploy advanced grid-support functions (GSF) in the field. One efficient and cost-effective method to examine such deployment options is to leverage power hardware-in-the-loop (PHIL) testing methods, which combine the fidelity of hardware tests with the flexibility of computer simulation. This paper summarizes a study wherein two Hawaiian Electric feeder models were converted to real-time models using an OPAL-RT real-time digital testing platform, and integrated with models of GSF capable PV inverters based on characterization test data. The integrated model was subsequently used in PHIL testing to evaluate the effects of different fixed power factor and volt-watt control settings on voltage regulation of the selected feeders using physical inverters. Selected results are presented in this paper, and complete results of this study were provided as inputs for field deployment and technical interconnection requirements for grid-connected PV inverters on the Hawaiian Islands.

  13. DIGITAL ONCOLOGY PATIENT RECORD - HETEROGENEOUS FILE BASED APPROACH

    Directory of Open Access Journals (Sweden)

    Nikolay Sapundzhiev

    2010-12-01

    Full Text Available Introduction: Oncology patients need extensive follow-up and meticulous documentation. The aim of this study was to introduce a simple, platform independent file based system for documentation of diagnostic and therapeutic procedures in oncology patients and test its function.Material and methods: A file-name based system of the type M1M2M3.F2 was introduced, where M1 is a unique identifier for the patient, M2 is the date of the clinical intervention/event, M3 is an identifier for the author of the medical record and F2 is the specific software generated file-name extension.Results: This system is in use at 5 institutions, where a total of 11 persons on 14 different workstations inputted 16591 entries (files for 2370. The merge process was tested on 2 operating systems - when copied together all files sort up as expected by patient, and for each patient in a chronological order, providing a digital cumulative patient record, which contains heterogeneous file formats.Conclusion: The file based approach for storing heterogeneous digital patient related information is an reliable system, which can handle open-source, proprietary, general and custom file formats and seems to be easily scalable. Further development of software for automatic checks of the integrity and searching and indexing of the files is expected to produce a more user-friendly environment

  14. Design and Implementation of nine level multilevel Inverter

    Science.gov (United States)

    Dhineshkumar, K.; Subramani, C.

    2018-04-01

    In this paper the solar based boost converter integrated Nine level multilevel inverter presented. It uses 7 switches to produce nine level output stepped waveform. The aim of the work to produce 9 level wave form using solar and boost converter. The conventional inverter has multiple sources and has 16 switches are required and also more number of voltage sources required. The proposed inverter required single solar panel and reduced number of switches and integrated boost converter which increase the input voltage of the inverter. The proposed inverter simulated and compared with R load using Mat lab and prototype model experimentally verified. The proposed inverter can be used in n number of solar applications.

  15. Spectral features based tea garden extraction from digital orthophoto maps

    Science.gov (United States)

    Jamil, Akhtar; Bayram, Bulent; Kucuk, Turgay; Zafer Seker, Dursun

    2018-05-01

    The advancements in the photogrammetry and remote sensing technologies has made it possible to extract useful tangible information from data which plays a pivotal role in various application such as management and monitoring of forests and agricultural lands etc. This study aimed to evaluate the effectiveness of spectral signatures for extraction of tea gardens from 1 : 5000 scaled digital orthophoto maps obtained from Rize city in Turkey. First, the normalized difference vegetation index (NDVI) was derived from the input images to suppress the non-vegetation areas. NDVI values less than zero were discarded and the output images was normalized in the range 0-255. Individual pixels were then mapped into meaningful objects using global region growing technique. The resulting image was filtered and smoothed to reduce the impact of noise. Furthermore, geometrical constraints were applied to remove small objects (less than 500 pixels) followed by morphological opening operator to enhance the results. These objects served as building blocks for further image analysis. Finally, for the classification stage, a range of spectral values were empirically calculated for each band and applied on candidate objects to extract tea gardens. For accuracy assessment, we employed an area based similarity metric by overlapping obtained tea garden boundaries with the manually digitized tea garden boundaries created by experts of photogrammetry. The overall accuracy of the proposed method scored 89 % for tea gardens from 10 sample orthophoto maps. We concluded that exploiting the spectral signatures using object based analysis is an effective technique for extraction of dominant tree species from digital orthophoto maps.

  16. A digital memories based user authentication scheme with privacy preservation.

    Directory of Open Access Journals (Sweden)

    JunLiang Liu

    Full Text Available The traditional username/password or PIN based authentication scheme, which still remains the most popular form of authentication, has been proved insecure, unmemorable and vulnerable to guessing, dictionary attack, key-logger, shoulder-surfing and social engineering. Based on this, a large number of new alternative methods have recently been proposed. However, most of them rely on users being able to accurately recall complex and unmemorable information or using extra hardware (such as a USB Key, which makes authentication more difficult and confusing. In this paper, we propose a Digital Memories based user authentication scheme adopting homomorphic encryption and a public key encryption design which can protect users' privacy effectively, prevent tracking and provide multi-level security in an Internet & IoT environment. Also, we prove the superior reliability and security of our scheme compared to other schemes and present a performance analysis and promising evaluation results.

  17. Inverted emulsion drilling fluid

    Energy Technology Data Exchange (ETDEWEB)

    Ana, I; Astanei, E; Mireanu, G; Orosz, M; Popescu, F; Vasile, I

    1979-07-28

    The subject of the invention is the method of obtaining inverted drilling fluid which is required during stripping of a productive bed and ending of a well where difficulties develop during drilling of the argillaceous rock. Example: in a reservoir with capacity 30 m/sup 3/, 10 m/sup 3/ of diesel fuel are added. A total of 1000 kg of emulsifier are added to the diesel fuel consisting of: 85 mass% of a mixture of sodium and potassium salts of fatty acids, residues of fatty acids or naphthene acids with high molecular weight taken in proportion of 10:90; 5 mass% of a mixture of polymers with hydrophilic-hydrophobic properties obtained by mixing 75 mass% of polyethylene oxide with molecular weight 10,000 and 25 mass% of propylene oxide with molecular weight 15,000, and 10 mass% of salt on alkaline earth metal (preferably calcium chloride). The mixture is mixed into complete dissolving. Then 1200 kg of filtering accelerator are added obtained from concentrated sulfuric acid serving for sulfur oxidation, asphalt substance with softening temperature 85-104/sup 0/C and fatty acids C/sub 10/-C/sub 20/ taken in a proportion of 23.70 and 7 mass% The mixture obtained in this manner is neutralized by adding calcium hydroxide and equal quantities of alumina and activated bentonite clay in a concentration of 1-10 mass%, more preferably 5 mass% in relation to the initial mixture. The obtained mass is mixed until complete dispersion, after which 200 kg of organophilic clay are added obtained from bentonite of the type montmorillonite of sodium by processing with derivate obtained from amine of the type of the quaternary base of ammonium salt, and agent of hydrophobization of the type of fatty alcohols, fatty acids, nonion surfactants of the block-polymer type. After complete dispersion of the organophilic clay, 100 kg of stabilizer of emulsion of the surfactant type was added with molecular weight of 250010,000, more preferably 5000, in concentration of 0.1-5.0 mass%, more

  18. Integrated optical 3D digital imaging based on DSP scheme

    Science.gov (United States)

    Wang, Xiaodong; Peng, Xiang; Gao, Bruce Z.

    2008-03-01

    We present a scheme of integrated optical 3-D digital imaging (IO3DI) based on digital signal processor (DSP), which can acquire range images independently without PC support. This scheme is based on a parallel hardware structure with aid of DSP and field programmable gate array (FPGA) to realize 3-D imaging. In this integrated scheme of 3-D imaging, the phase measurement profilometry is adopted. To realize the pipeline processing of the fringe projection, image acquisition and fringe pattern analysis, we present a multi-threads application program that is developed under the environment of DSP/BIOS RTOS (real-time operating system). Since RTOS provides a preemptive kernel and powerful configuration tool, with which we are able to achieve a real-time scheduling and synchronization. To accelerate automatic fringe analysis and phase unwrapping, we make use of the technique of software optimization. The proposed scheme can reach a performance of 39.5 f/s (frames per second), so it may well fit into real-time fringe-pattern analysis and can implement fast 3-D imaging. Experiment results are also presented to show the validity of proposed scheme.

  19. A digital bandlimited chaos-based communication system

    Science.gov (United States)

    Fontes, Rodrigo T.; Eisencraft, Marcio

    2016-08-01

    In recent years, many communication systems that use a function to encode an information in a chaotic signal were proposed. Since every transmission channel is bandlimited in nature, it is required to determine and to control the chaotic signal spectrum. This way, a bandlimited chaos-based communication system (CBCS) was proposed using digital filters and chaotic synchronization. As the filters modify the original chaotic system, it is necessary to study how their insertion affects chaotic synchronization. In this work, we present a digital discrete-time bandlimited CBCS system analysis, considering practical settings encountered in conventional communication systems. The proposed system is based on master-slave chaotic synchronization and the required conditions for its synchronization is obtained analytically for a general K-dimensional chaos generator map. The performance of this system is evaluated in terms of bit error rate. As a way to improve the signal to noise ratio, we also propose to filter the out-of-band noise in the receiver. Numerical simulations show the advantages of using such a scheme.

  20. A Modified Design of a Thermocouple Based Digital Temperature Indicator with Opto-Isolation

    Directory of Open Access Journals (Sweden)

    S. C. BERA

    2008-01-01

    Full Text Available In the conventional thermocouple based digital temperature indicator the millivolt signal obtained from a thermocouple is first amplified and then converted into a digital signal by using analog-to-digital converter (ADC. This digital signal is then indicated as digital display of temperature using digital counter circuit or microprocessor/microcontroller based circuitry. In the present paper a modified AD conversion technique along with opto-isolation is used to indicate digitally the temperature without using any conventional analog-to-digital converter. The theory and design of the measuring technique are described in the paper. The non-linearity of thermocouple is eliminated by using look-up table within software program. The performance of the circuit has been experimentally tested by using mV input signal instead of a thermocouple as well as using a K-type thermocouple. The experimental results are reported in the paper.

  1. Traction Inverter Open Switch Fault Diagnosis Based on Choi–Williams Distribution Spectral Kurtosis and Wavelet-Packet Energy Shannon Entropy

    Directory of Open Access Journals (Sweden)

    Shuangshuang Lin

    2017-09-01

    Full Text Available In this paper, a new approach for fault detection and location of open switch faults in the closed-loop inverter fed vector controlled drives of Electric Multiple Units is proposed. Spectral kurtosis (SK based on Choi–Williams distribution (CWD as a statistical tool can effectively indicate the presence of transients and locations in the frequency domain. Wavelet-packet energy Shannon entropy (WPESE is appropriate for the transient changes detection of complex non-linear and non-stationary signals. Based on the analyses of currents in normal and fault conditions, SK based on CWD and WPESE are combined with the DC component method. SK based on CWD and WPESE are used for the fault detection, and the DC component method is used for the fault localization. This approach can diagnose the specific locations of faulty Insulated Gate Bipolar Transistors (IGBTs with high accuracy, and it requires no additional devices. Experiments on the RT-LAB platform are carried out and the experimental results verify the feasibility and effectiveness of the diagnosis method.

  2. Analysis, control and design of a non-inverting buck-boost converter

    DEFF Research Database (Denmark)

    Almasi, Omid Naghash; Fereshtehpoor, Vahid; Khooban, Mohammad Hassan

    2017-01-01

    In this paper, a new modified fuzzy Two-Level Control Scheme (TLCS) is proposed to control a non-inverting buck-boost converter. Each level of fuzzy TLCS consists of a tuned fuzzy PI controller. In addition, a Takagi–Sugeno–Kang (TSK) fuzzy switch proposed to transfer the fuzzy PI controllers...... to eliminate these oscillations and improve the system performance. Some simulations and digital signal processor based experiments are conducted on a non-inverting buck-boost converter to support the effectiveness of the proposed TLCS in controlling the converter output voltage....... to each other in the control system. The major difficulty in designing fuzzy TLCS which degrades its performance is emerging unwanted drastic oscillations in the converter output voltage during replacing the controllers. Thereby, the fuzzy PI controllers in each level of TLCS structure are modified...

  3. PROBLEM-BASED LEARNING IN THE DIGITAL AGE

    DEFF Research Database (Denmark)

    Kolbæk, Ditte

    Problem-based and project-organized learning (PBL) was originally developed to facilitate collaboration between physically present students; however, due to digitalization, collaboration, dialogues, and other PBL activities should take place online as well. With a theoretical point of departure...... from Dewey and a methodological point of departure from netnography, this study focused on a blended learning module at Aalborg University, where teaching is based on PBL. A primary research question was investigated: “How can IT support collaborative learning among learner communities in a PBL Master......’s program at Aalborg University?” The ways teachers and groups of students could benefit from utilizing IT as a platform for learning were examined. Netnography was the chosen methodology, and the data consisted of the course materials, the reflections, and the dialogues available online. The study showed...

  4. Digital time stamping system based on open source technologies.

    Science.gov (United States)

    Miskinis, Rimantas; Smirnov, Dmitrij; Urba, Emilis; Burokas, Andrius; Malysko, Bogdan; Laud, Peeter; Zuliani, Francesco

    2010-03-01

    A digital time stamping system based on open source technologies (LINUX-UBUNTU, OpenTSA, OpenSSL, MySQL) is described in detail, including all important testing results. The system, called BALTICTIME, was developed under a project sponsored by the European Commission under the Program FP 6. It was designed to meet the requirements posed to the systems of legal and accountable time stamping and to be applicable to the hardware commonly used by the national time metrology laboratories. The BALTICTIME system is intended for the use of governmental and other institutions as well as personal bodies. Testing results demonstrate that the time stamps issued to the user by BALTICTIME and saved in BALTICTIME's archives (which implies that the time stamps are accountable) meet all the regulatory requirements. Moreover, the BALTICTIME in its present implementation is able to issue more than 10 digital time stamps per second. The system can be enhanced if needed. The test version of the BALTICTIME service is free and available at http://baltictime. pfi.lt:8080/btws/ and http://baltictime.lnmc.lv:8080/btws/.

  5. Digital holographic-based cancellable biometric for personal authentication

    International Nuclear Information System (INIS)

    Verma, Gaurav; Sinha, Aloka

    2016-01-01

    In this paper, we propose a new digital holographic-based cancellable biometric scheme for personal authentication and verification. The realization of cancellable biometric is presented by using an optoelectronic experimental approach, in which an optically recorded hologram of the fingerprint of a person is numerically reconstructed. Each reconstructed feature has its own perspective, which is utilized to generate user-specific fingerprint features by using a feature-extraction process. New representations of the user-specific fingerprint features can be obtained from the same hologram, by changing the reconstruction distance (d) by an amount Δd between the recording plane and the reconstruction plane. This parameter is the key to make the cancellable user-specific fingerprint features using a digital holographic technique, which allows us to choose different reconstruction distances when reissuing the user-specific fingerprint features in the event of compromise. We have shown theoretically that each user-specific fingerprint feature has a unique identity with a high discrimination ability, and the chances of a match between them are minimal. In this aspect, a recognition system has also been demonstrated using the fingerprint biometric of the enrolled person at a particular reconstruction distance. For the performance evaluation of a fingerprint recognition system—the false acceptance ratio, the false rejection ratio and the equal error rate are calculated using correlation. The obtained results show good discrimination ability between the genuine and the impostor populations with the highest recognition rate of 98.23%. (paper)

  6. Digital waterway construction based on inland electronic navigation chart

    Science.gov (United States)

    Wang, Xue; Pan, Junfeng; Zhu, Weiwei

    2015-12-01

    With advantages of large capacity, long distance, low energy consumption, low cost, less land occupation and light pollution, inland waterway transportation becomes one of the most important constituents of the comprehensive transportation system and comprehensive water resources utilization in China. As one of "three elements" of navigation, waterway is the important basis for the development of water transportation and plays a key supporting role in shipping economic. The paper discuss how to realize the informatization and digitization of waterway management based on constructing an integrated system of standard inland electronic navigation chart production, waterway maintenance, navigation mark remote sensing and control, ship dynamic management, and water level remote sensing and report, which can also be the foundation of the intelligent waterway construction. Digital waterway construction is an information project and also has a practical meaning for waterway. It can not only meet the growing high assurance and security requirements for waterway, but also play a significant advantage in improving transport efficiency, reducing costs, promoting energy conservation and so on. This study lays a solid foundation on realizing intelligent waterway and building a smooth, efficient, safe, green modern inland waterway system, and must be considered as an unavoidable problem for the coordinated development between "low carbon" transportation and social economic.

  7. Development of PIC-based digital survey meter

    International Nuclear Information System (INIS)

    Nor Arymaswati Abdullah; Nur Aira Abdul Rahman; Mohd Ashhar Khalid; Taiman Kadni; Glam Hadzir Patai Mohamad; Abd Aziz Mhd Ramli; Chong Foh Yong

    2006-01-01

    The need of radiation monitoring and monitoring of radioactive contamination in the workplace is very important especially when x-ray machines, linear accelerators, electron beam machines and radioactive sources are present. The appropriate use of radiation detector is significant in order to maintain a radiation and contamination free workplace. This paper reports on the development of a prototype of PIC-based digital survey meter. This prototype of digital survey meter is a hand held instrument for general-purpose radiation monitoring and surface contamination meter. Generally, the device is able to detect some or all of the three major types of ionizing radiation, namely alpha, beta and gamma. It uses a Geiger-Muller tube as a radiation detector, which converts gamma radiation quanta to electric pulses and further processed by the electronic devices. The development involved the design of the controller, counter and high voltage circuit. All these circuit are assembled and enclosed in a plastic casing together with a GM detector and LCD display to form a prototype survey meter. The number of counts of the pulses detected by the survey meter varies due to the random nature of radioactivity. By averaging the reading over a time-period, more accurate and stable reading is achieved. To test the accuracy and the linearity of the design, the prototype was calibrated using standard procedure at the Secondary Standard Dosimetry Laboratory (SSDL) in MINT. (Author)

  8. The effect of anneal, solar irradiation and humidity on the adhesion/cohesion properties of P3HT:PCBM based inverted polymer solar cells

    KAUST Repository

    Dupont, Stephanie R.; Voroshazi, Eszter; Heremans, Paul; Dauskardt, Reinhold H.

    2012-01-01

    We use a thin-film adhesion technique that enables us to precisely measure the energy required to separate adjacent layers in OPV cells. We demonstrate the presence of weak interfaces in prototypical inverted polymer solar cells, either prepared

  9. LVRT Capability of Single-Phase Grid-Connected HERIC Inverter in PV Systems by a Look-up Table Based Predictive Control

    DEFF Research Database (Denmark)

    Zangeneh Bighash, Esmaeil; Sadeghzadeh, Seyed Mohammad; Ebrahimzadeh, Esmaeil

    2017-01-01

    Nowadays capacity of the photovoltaic systems in the grid is remarkable and provides a major part of energy in the grid. Therefore, an abruption of these systems from the grid can create a damage to the grid. Unlike in the past that PV systems disconnected from the grid when a voltage drop occurred......, nowadays these systems should have Low Voltage Ride-Through (LVRT) capability. The PV system should stay connected to the grid at fault time and help to recover the grid voltage by injecting the reactive power like in a power plant or a custom power device. There are two important factors for single phase...... grid connected PV inverters. The first one is the structure of the inverter and the second one is the control part. In this regard, the HERIC inverter can be a good selection among the transformerless inverters for a PV system due to its high efficiency. For the control part, this paper presents a look...

  10. A design tool to study the impact of mission-profile on the reliability of SiC-based PV-inverter devices

    DEFF Research Database (Denmark)

    Sintamarean, Nicolae Cristian; Wang, Huai; Blaabjerg, Frede

    2014-01-01

    and is further used as an input to a lifetime model. The proposed reliability oriented design tool is used to study the impact of MP and device degradation (aging) in the PV-inverter lifetime. The obtained results indicate that the MP of the field where the PV-inverter is operating has an important impact......This paper introduces a reliability-oriented design tool for a new generation of grid connected PV-inverters. The proposed design tool consists of a real field mission profile model (for one year operation in USA-Arizona), a PV-panel model, a grid connected PV-inverter model, an electro......-thermal model and the lifetime model of the power semiconductor devices. A simulation model able to consider one year real field operation conditions (solar irradiance and ambient temperature) is developed. Thus, one year estimation of the converter devices thermal loading distribution is achieved...

  11. Interfacial Energy-Level Alignment for High-Performance All-Inorganic Perovskite CsPbBr3 Quantum Dot-Based Inverted Light-Emitting Diodes.

    Science.gov (United States)

    Subramanian, Alagesan; Pan, Zhenghui; Zhang, Zhenbo; Ahmad, Imtiaz; Chen, Jing; Liu, Meinan; Cheng, Shuang; Xu, Yijun; Wu, Jun; Lei, Wei; Khan, Qasim; Zhang, Yuegang

    2018-04-18

    All-inorganic perovskite light-emitting diode (PeLED) has a high stability in ambient atmosphere, but it is a big challenge to achieve high performance of the device. Basically, device design, control of energy-level alignment, and reducing the energy barrier between adjacent layers in the architecture of PeLED are important factors to achieve high efficiency. In this study, we report a CsPbBr 3 -based PeLED with an inverted architecture using lithium-doped TiO 2 nanoparticles as the electron transport layer (ETL). The optimal lithium doping balances the charge carrier injection between the hole transport layer and ETL, leading to superior device performance. The device exhibits a current efficiency of 3 cd A -1 , a luminance efficiency of 2210 cd m -2 , and a low turn-on voltage of 2.3 V. The turn-on voltage is one of the lowest values among reported CsPbBr 3 -based PeLEDs. A 7-fold increase in device efficiencies has been obtained for lithium-doped TiO 2 compared to that for undoped TiO 2 -based devices.

  12. Integral inverter/battery charger for use in electric vehicles

    Science.gov (United States)

    Thimmesch, D.

    1983-01-01

    The design and test results of a thyristor based inverter/charger are discussed. A battery charger is included integral to the inverter by using a subset of the inverter power circuit components. The resulting charger provides electrical isolation between the vehicle propulsion battery and ac line and is capable of charging a 25 kWh propulsion battery in 8 hours from a 220 volt ac line. The integral charger employs the inverter commutation components at a resonant ac/dc isolated converter rated at 3.6 kW. Charger efficiency and power factor at an output power of 3.6 kW are 86% and 95% respectively. The inverter, when operated with a matching polyphase ac induction motor and nominal 132 volt propulsion battery, can provide a peak shaft power of 34 kW (45 ph) during motoring operation and 45 kW (60 hp) during regeneration. Thyristors are employed for the inverter power switching devices and are arranged in an input-commutated topology. This configuration requires only two thyristors to commutate the six main inverter thyristors. Inverter efficiency during motoring operation at motor shaft speeds above 450 rad/sec (4300 rpm) is 92-94% for output power levels above 11 KW (15 hp). The combined ac inverter/charger package weighs 47 kg (103 lbs).

  13. Voltage resonant inverter as a power source

    OpenAIRE

    Lupenko, Anatoliy; Stakhiv, Petro

    2014-01-01

    The operation mode of a voltage resonant inverter as a power source with variable load is analyzed. In order to reduce load power variations, an approach to development of the inverter’s load power response based on providing similar positive and negative power deviations from its nominal value has been proposed. The design procedure for resonant inverter with open loop structure as a power source has been elaborated. For a high pressure sodium lamp as a load, the power deviation of about 4% ...

  14. Multilayer control for inverters in parallel operation without signal interconnection

    DEFF Research Database (Denmark)

    Hua, Ming; Hu, Haibing; Xing, Yan

    2011-01-01

    A multilayer control is proposed for inverters with wireless parallel operation in this paper. The control is embedded in every inverter respectively and consists of three layers. The first layer is based on an improved droop method, which shares the active and reactive power in each module...

  15. Assessing Digital Student Productions, a Design-Based Research Study on the Development of a Criteria-Based Assessment Tool for Students’ Digital Multimodal Productions

    DEFF Research Database (Denmark)

    Hoffmeyer, Mikkeline; Jensen, Jesper Juellund; Olsen, Marie Veisegaard

    2017-01-01

    Digital multimodal production is becoming increasingly important as a 21st century skill and as a learning condition in school (K-12). Moreover, there is a growing attention to the significance of criteria-based assessment for learning. Nevertheless, assessment of students’ digital multimodal...... productions is often vague or lacking. Therefore, the research project aims at developing a tool to support assessment of student’s digital multimodal productions through a design-based research method. This paper presents a proposal for issues to be considered through a prototyping phase, based on interviews...

  16. Low photon count based digital holography for quadratic phase cryptography.

    Science.gov (United States)

    Muniraj, Inbarasan; Guo, Changliang; Malallah, Ra'ed; Ryle, James P; Healy, John J; Lee, Byung-Geun; Sheridan, John T

    2017-07-15

    Recently, the vulnerability of the linear canonical transform-based double random phase encryption system to attack has been demonstrated. To alleviate this, we present for the first time, to the best of our knowledge, a method for securing a two-dimensional scene using a quadratic phase encoding system operating in the photon-counted imaging (PCI) regime. Position-phase-shifting digital holography is applied to record the photon-limited encrypted complex samples. The reconstruction of the complex wavefront involves four sparse (undersampled) dataset intensity measurements (interferograms) at two different positions. Computer simulations validate that the photon-limited sparse-encrypted data has adequate information to authenticate the original data set. Finally, security analysis, employing iterative phase retrieval attacks, has been performed.

  17. Solar Charged Stand Alone Inverter

    OpenAIRE

    M.Vasugi; Prof R.Jayaraman

    2014-01-01

    This paper deals with solar powered stand alone inverter which converts the variable dc output of a photovoltaic solar panel into ac that can be fed to loads. Stand alone inverters are used in systems where the inverter get its energy from batteries charged by photo voltaic arrays. A charge controller limits the rate at which electric current is added to or drawn from electric batteries. This charge discharge controller is needed to prevent the battery from being overcharged o...

  18. Gas cooled traction drive inverter

    Science.gov (United States)

    Chinthavali, Madhu Sudhan

    2013-10-08

    The present invention provides a modular circuit card configuration for distributing heat among a plurality of circuit cards. Each circuit card includes a housing adapted to dissipate heat in response to gas flow over the housing. In one aspect, a gas-cooled inverter includes a plurality of inverter circuit cards, and a plurality of circuit card housings, each of which encloses one of the plurality of inverter cards.

  19. Modeling the frequency response of photovoltaic inverters

    NARCIS (Netherlands)

    Ernauli Christine Aprilia, A.; Cuk, V.; Cobben, J.F.G.; Ribeiro, P.F.; Kling, W.L.

    2012-01-01

    The increased presence of photovoltaic (PV) systems inevitably affects the power quality in the grid. This new reality demands grid power quality studies involving PV inverters. This paper proposes several frequency response models in the form of equivalent circuits. Models are based on laboratory

  20. An Inverted Curriculum for CS1

    DEFF Research Database (Denmark)

    Caspersen, Michael Edelgaard

    2003-01-01

    present and discuss the inverted curriculum for our introductory object-oriented programming course, and our experiences from teaching this course for four years. We identify four levels for the systematic construction of programs, and the structure of our programming course is based on these four levels......: the modeling level, the design level, the class level, and the algorithmic level....

  1. Surface Distresses Detection of Pavement Based on Digital Image Processing

    OpenAIRE

    Ouyang , Aiguo; Luo , Chagen; Zhou , Chao

    2010-01-01

    International audience; Pavement crack is the main form of early diseases of pavement. The use of digital photography to record pavement images and subsequent crack detection and classification has undergone continuous improvements over the past decade. Digital image processing has been applied to detect the pavement crack for its advantages of large amount of information and automatic detection. The applications of digital image processing in pavement crack detection, distresses classificati...

  2. Speech-Based Information Retrieval for Digital Libraries

    National Research Council Canada - National Science Library

    Oard, Douglas W

    1997-01-01

    Libraries and archives collect recorded speech and multimedia objects that contain recorded speech, and such material may comprise a substantial portion of the collection in future digital libraries...

  3. Micro-Structure Measurement and Imaging Based on Digital Holography

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kyeong Suk; Jung, Hyun Chul; Chang, Ho Seob; Akhter, Naseem [Chosun University, Gwangju (Korea, Republic of); Kee, Chang Doo [Chonnam National University, Gwangju (Korea, Republic of)

    2010-06-15

    Advancements in the imaging and computing technology have opened the path to digital holography for non-destructive investigations of technical samples, material property measurement, vibration analysis, flow visualization and stress analysis in aerospace industry which has widened the application of digital holography in the above fields. In this paper, we demonstrate the non-destructive investigation and micro-structure measurement application of digital holography to the small particles and a biological sample. This paper gives a brief description of the digital holograms recorded with this system and illustratively demonstrated

  4. Micro-Structure Measurement and Imaging Based on Digital Holography

    International Nuclear Information System (INIS)

    Kim, Kyeong Suk; Jung, Hyun Chul; Chang, Ho Seob; Akhter, Naseem; Kee, Chang Doo

    2010-01-01

    Advancements in the imaging and computing technology have opened the path to digital holography for non-destructive investigations of technical samples, material property measurement, vibration analysis, flow visualization and stress analysis in aerospace industry which has widened the application of digital holography in the above fields. In this paper, we demonstrate the non-destructive investigation and micro-structure measurement application of digital holography to the small particles and a biological sample. This paper gives a brief description of the digital holograms recorded with this system and illustratively demonstrated

  5. Proposed Novel Multiphase-Multilevel Inverter Configuration for Open-End Winding Loads

    DEFF Research Database (Denmark)

    Padamanaban, Sanjeevi Kumar; Wheeler, Patrick; Blaabjerg, Frede

    2016-01-01

    This paper presents a new multiphase-multilevel inverter configuration for open-winding loads and suitable for medium power (low-voltage/high-current) applications such as `More Electric Aircraft'. Modular structure comprised of standard dual three-phase voltage source inverter (VSI) along with one...... is developed in this work and overcomes the complexity of standard space vector modulations, easy for real implementation purposes in digital processors. Proposed six-phase multilevel inverter configuration generates multilevel outputs with benefit in comprises with standard multilevel inverter topologies...

  6. An Active Power Filter Based on a Three-Level Inverter and 3D-SVPWM for Selective Harmonic and Reactive Compensation

    Directory of Open Access Journals (Sweden)

    José Luis Monroy-Morales

    2017-03-01

    Full Text Available Active Power Filters (APFs have been used for reducing waveform distortion and improving power quality. However, this function can be improved by means of a selective harmonic compensation. Since an APF has rating restrictions, it is convenient to have the option of selecting an individual or a set of particular harmonics in order to compensate and apply the total APF capabilities to eliminate these harmonics, in particular those with a greater impact on the Total Harmonic Distortion (THD. This paper presents the development of a new APF prototype based on a three-phase three-level Neutral Point Clamped (NPC inverter with selective harmonic compensation capabilities and reactive power compensation. The selective harmonic compensation approach uses several Synchronous Rotating Frames (SRF, to detect and control individual or a set of harmonics using d and q variables. The APF includes a Three-Dimensional Space Vector Modulator (3D-SVPWM in order to generate the compensation currents. Because of its multilevel topology, the proposed active power filter can be used in diverse power quality applications at sub-transmission and distribution voltage levels. Simulation and experimental results are shown to validate the proposed solution and assess the prototype performance in different scenarios.

  7. Simulation study of the second-generation MR-compatible SPECT system based on the inverted compound-eye gamma camera design

    Science.gov (United States)

    Lai, Xiaochun; Meng, Ling-Jian

    2018-02-01

    In this paper, we present simulation studies for the second-generation MRI compatible SPECT system, MRC-SPECT-II, based on an inverted compound eye (ICE) gamma camera concept. The MRC-SPECT-II system consists of a total of 1536 independent micro-pinhole-camera-elements (MCEs) distributed in a ring with an inner diameter of 6 cm. This system provides a FOV of 1 cm diameter and a peak geometrical efficiency of approximately 1.3% (the typical levels of 0.1%-0.01% found in modern pre-clinical SPECT instrumentations), while maintaining a sub-500 μm spatial resolution. Compared to the first-generation MRC-SPECT system (MRC-SPECT-I) (Cai 2014 Nucl. Instrum. Methods Phys. Res. A 734 147-51) developed in our lab, the MRC-SPECT-II system offers a similar resolution with dramatically improved sensitivity and greatly reduced physical dimension. The latter should allow the system to be placed inside most clinical and pre-clinical MRI scanners for high-performance simultaneous MRI and SPECT imaging.

  8. MEH-PPV and PCBM Solution Concentration Dependence of Inverted-Type Organic Solar Cells Based on Eosin-Y-Coated ZnO Nanorod Arrays

    Directory of Open Access Journals (Sweden)

    Riski Titian Ginting

    2013-01-01

    Full Text Available The influence of polymer solution concentration on the performance of chlorobenzene- (CB- and chloroform- (CF- based inverted-type organic solar cells has been investigated. The organic photoactive layers consisted of poly(2-methoxy-5-(2-ethyl hexyloxy-1,4-phenylenevinylene (MEH-PPV and (6,6-phenyl C61 butyric acid methyl ester (PCBM were spin coated from CF with concentrations of 4, 6, and 8 mg/mL and from CB with concentrations of 6, 8, and 10 mg/mL onto Eosin-Y-coated ZnO nanorod arrays (NRAs. Fluorine doped tin oxide (FTO and silver (Ag were used as electron collecting electrode and hole collecting electrode, respectively. Experimental results showed that the short circuit current density and power conversion efficiency increased with decrease of solution concentration for both CB and CF devices, which could be attributed to reducing charge recombination in thinner photoactive layer and larger contact area between the rougher photoactive layer and Ag contact. However, the open circuit voltage decreased with decreasing solution concentration due to increase of leakage current from ZnO NRAs to Ag as the ZnO NRAs were not fully covered by the polymer blend. The highest power conversion efficiencies of 0.54 ± 0.10% and 0.87 ± 0.15% were achieved at the respective lowest solution concentrations of CB and CF.

  9. Enhancement of ZnO nanorod arrays-based inverted type hybrid organic solar cell using spin-coated Eosin-Y

    International Nuclear Information System (INIS)

    Lim, Eng Liang; Yap, Chi Chin; Yahaya, Muhammad; Salleh, Muhamad Mat

    2013-01-01

    This paper reports the effect of Eosin-Y coating concentration on the performance of inverted type hybrid organic solar cell based on ZnO nanorod arrays and poly(3-hexylthiophene-2,5-diyl) (P3HT). The Eosin-Y solution with concentrations of 0.05, 0.2, 2.0 and 5.0 mM was spin-coated onto the ZnO nanorod arrays grown on the fluorine-doped tin oxide glass substrate. The P3HT film was then spin-coated onto Eosin-Y-coated ZnO nanorod arrays, followed by deposition of silver (Ag) as anode using magnetron sputtering technique. The short circuit current density increased with the Eosin-Y coating concentration up to 0.2 mM, after which it started to decrease, mainly due to the aggregation of Eosin-Y which reduced the charge extraction from P3HT to ZnO. Meanwhile, the open circuit voltage increased with the Eosin-Y coating concentration, indicating reduced back charge recombination of electron on the ZnO and hole on the P3HT, as well as reduced leakage current through the direct contact between the ZnO nanorods and the Ag metal contact. The power conversion efficiency of the device with the optimum coating concentration was approximately eight times higher than that without Eosin-Y modification. (paper)

  10. Enhancement of ZnO nanorod arrays-based inverted type hybrid organic solar cell using spin-coated Eosin-Y

    Science.gov (United States)

    Lim, Eng Liang; Yap, Chi Chin; Yahaya, Muhammad; Mat Salleh, Muhamad

    2013-04-01

    This paper reports the effect of Eosin-Y coating concentration on the performance of inverted type hybrid organic solar cell based on ZnO nanorod arrays and poly(3-hexylthiophene-2,5-diyl) (P3HT). The Eosin-Y solution with concentrations of 0.05, 0.2, 2.0 and 5.0 mM was spin-coated onto the ZnO nanorod arrays grown on the fluorine-doped tin oxide glass substrate. The P3HT film was then spin-coated onto Eosin-Y-coated ZnO nanorod arrays, followed by deposition of silver (Ag) as anode using magnetron sputtering technique. The short circuit current density increased with the Eosin-Y coating concentration up to 0.2 mM, after which it started to decrease, mainly due to the aggregation of Eosin-Y which reduced the charge extraction from P3HT to ZnO. Meanwhile, the open circuit voltage increased with the Eosin-Y coating concentration, indicating reduced back charge recombination of electron on the ZnO and hole on the P3HT, as well as reduced leakage current through the direct contact between the ZnO nanorods and the Ag metal contact. The power conversion efficiency of the device with the optimum coating concentration was approximately eight times higher than that without Eosin-Y modification.

  11. Numerical study of a novel procedure for installing the tower and Rotor Nacelle Assembly of offshore wind turbines based on the inverted pendulum principle

    Science.gov (United States)

    Guachamin Acero, Wilson; Gao, Zhen; Moan, Torgeir

    2017-09-01

    Current installation costs of offshore wind turbines (OWTs) are high and profit margins in the offshore wind energy sector are low, it is thus necessary to develop installation methods that are more efficient and practical. This paper presents a numerical study (based on a global response analysis of marine operations) of a novel procedure for installing the tower and Rotor Nacelle Assemblies (RNAs) on bottom-fixed foundations of OWTs. The installation procedure is based on the inverted pendulum principle. A cargo barge is used to transport the OWT assembly in a horizontal position to the site, and a medium-size Heavy Lift Vessel (HLV) is then employed to lift and up-end the OWT assembly using a special upending frame. The main advantage of this novel procedure is that the need for a huge HLV (in terms of lifting height and capacity) is eliminated. This novel method requires that the cargo barge is in the leeward side of the HLV (which can be positioned with the best heading) during the entire installation. This is to benefit from shielding effects of the HLV on the motions of the cargo barge, so the foundations need to be installed with a specific heading based on wave direction statistics of the site and a typical installation season. Following a systematic approach based on numerical simulations of actual operations, potential critical installation activities, corresponding critical events, and limiting (response) parameters are identified. In addition, operational limits for some of the limiting parameters are established in terms of allowable limits of sea states. Following a preliminary assessment of these operational limits, the duration of the entire operation, the equipment used, and weather- and water depth-sensitivity, this novel procedure is demonstrated to be viable.

  12. 2015 Inverter Workshop | Photovoltaic Research | NREL

    Science.gov (United States)

    Inverter Workshop 2015 Inverter Workshop Wednesday, February 25, 2015 Chair: Jack Flicker In about inverters. This workshop represented a follow-on to the inverter workshops that Sandia National conversations between module and inverter experts. Agenda For a detailed schedule of the day's events, access

  13. Resonant-inductor-voltage feedback active damping based control for grid-connected inverters with LLCL-filters

    DEFF Research Database (Denmark)

    Huang, Min; Wang, Xiongfei; Loh, Poh Chiang

    2014-01-01

    damping method with an extra feedback provides a high rejection of the resonance so that the dynamic is improved. In this paper, taking a Proportional-Resonant (PR) together with a harmonic compensator (HC), resonant-inductor-voltage-feedback active damping is applied on an LLCL-filter based three...... of the proposed method is investigated in simulation and by experimental results....

  14. SOI Digital Accelerometer Based on Pull-in Time Configuration

    NARCIS (Netherlands)

    Pakula, L.S.; Rajaraman, V.; French, P.J.

    2009-01-01

    The operation principle, design, fabrication and measurement results of a quasi digital accelerometer fabricated on a thin silicon-on-insulator (SOI) substrate is presented. The accelerometer features quasi-digital output, therefore eliminating the need for analogue signal conditioning. The

  15. Microcomputer-Based Digital Signal Processing Laboratory Experiments.

    Science.gov (United States)

    Tinari, Jr., Rocco; Rao, S. Sathyanarayan

    1985-01-01

    Describes a system (Apple II microcomputer interfaced to flexible, custom-designed digital hardware) which can provide: (1) Fast Fourier Transform (FFT) computation on real-time data with a video display of spectrum; (2) frequency synthesis experiments using the inverse FFT; and (3) real-time digital filtering experiments. (JN)

  16. Construction of a Digital Learning Environment Based on Cloud Computing

    Science.gov (United States)

    Ding, Jihong; Xiong, Caiping; Liu, Huazhong

    2015-01-01

    Constructing the digital learning environment for ubiquitous learning and asynchronous distributed learning has opened up immense amounts of concrete research. However, current digital learning environments do not fully fulfill the expectations on supporting interactive group learning, shared understanding and social construction of knowledge.…

  17. Analogue Building Blocks Based on Digital CMOS Gates

    DEFF Research Database (Denmark)

    Mucha, Igor

    1996-01-01

    Low-performance analogue circuits built of digital MOS gates are presented. Depending on the threshold voltages of the technology used the final circuits can be operated using low supply voltages. The main advantage using the proposed circuits is the simplicity and ultimate compatibility...... with the design of digital circuits....

  18. Semantic Web-based digital, field and virtual geological

    Science.gov (United States)

    Babaie, H. A.

    2012-12-01

    Digital, field and virtual Semantic Web-based education (SWBE) of geological mapping requires the construction of a set of searchable, reusable, and interoperable digital learning objects (LO) for learners, teachers, and authors. These self-contained units of learning may be text, image, or audio, describing, for example, how to calculate the true dip of a layer from two structural contours or find the apparent dip along a line of section. A collection of multi-media LOs can be integrated, through domain and task ontologies, with mapping-related learning activities and Web services, for example, to search for the description of lithostratigraphic units in an area, or plotting orientation data on stereonet. Domain ontologies (e.g., GeologicStructure, Lithostratigraphy, Rock) represent knowledge in formal languages (RDF, OWL) by explicitly specifying concepts, relations, and theories involved in geological mapping. These ontologies are used by task ontologies that formalize the semantics of computational tasks (e.g., measuring the true thickness of a formation) and activities (e.g., construction of cross section) for all actors to solve specific problems (making map, instruction, learning support, authoring). A SWBE system for geological mapping should also involve ontologies to formalize teaching strategy (pedagogical styles), learner model (e.g., for student performance, personalization of learning), interface (entry points for activities of all actors), communication (exchange of messages among different components and actors), and educational Web services (for interoperability). In this ontology-based environment, actors interact with the LOs through educational servers, that manage (reuse, edit, delete, store) ontologies, and through tools which communicate with Web services to collect resources and links to other tools. Digital geological mapping involves a location-based, spatial organization of geological elements in a set of GIS thematic layers. Each layer

  19. Field-Programmable Gate Array-based fluxgate magnetometer with digital integration

    Science.gov (United States)

    Butta, Mattia; Janosek, Michal; Ripka, Pavel

    2010-05-01

    In this paper, a digital magnetometer based on printed circuit board fluxgate is presented. The fluxgate is pulse excited and the signal is extracted by gate integration. We investigate the possibility to perform integration on very narrow gates (typically 500 ns) by using digital techniques. The magnetometer is based on field-programmable gate array (FPGA) card: we will show all the advantages and disadvantages, given by digitalization of fluxgate output voltage by means of analog-to-digital converter on FPGA card, as well as digitalization performed by external digitizer. Due to very narrow gate, it is shown that a magnetometer entirely based on a FPGA card is preferable, because it avoids noise due to trigger instability. Both open loop and feedback operative mode are described and achieved results are presented.

  20. Ultra-Low Inductance Design for a GaN HEMT Based 3L-ANPC Inverter

    DEFF Research Database (Denmark)

    Gurpinar, Emre; Castellazzi, Alberto; Iannuzzo, Francesco

    2016-01-01

    contributors to voltage overshoots and increase of switching losses, are discussed. The ultra-low inductance power cell design based on a four layer PCB with the aim to maximise the switching performance of GaN HEMTs is explained. Gate driver design for GaN HEMT devices is presented. Common-mode behaviours......In this paper, an ultra-low inductance power cell design for a 3L-ANPC based on 650 V GaN HEMT devices is presented. The 3L-ANPC topology with GaN HEMT devices and the selected modulation scheme suitable for wide-bandgap (WBG) devices are presented. The commutation loops, which are the main...

  1. DIGITAL FILTERS IMPLEMENTATION IN MICROPROCESSOR-BASED RELAY PROTECTION

    Directory of Open Access Journals (Sweden)

    Yu. V. Rumiantsev

    2016-01-01

    Full Text Available This article presents the implementation of digital filters used in digital relay protection current measuring elements. Mathematical descriptions of the considered digital filters as well as the computer programs for their coefficients calculation are described. It has been shown that in order to reliable estimate the digital filter performance its input signals waveforms must be close to the actual secondary current waveform of the current transformer to which the digital protection with the estimated digital filter is connected. For these purposes in MatLab–Simulink dynamic simulation environment the power system and the current measuring element models were developed. Performed calculations allowed to reveal that the exponentially decaying DC component which in some cases contains in primary fault current drives the current transformer core into saturation even when its nominal parameters are not exceeded. This results in distortion of the current transformer secondary current which in this case contains higher and inter-harmonics. Moreover, such harmonic content is not completely taking into account during coefficients calculation of the considered digital filters what results in signal magnitude estimation inaccuracy. Comparison of the digital filters response to the above-mentioned input signals allowed to find out such digital filter implementations which enable signal magnitude estimation with a minimum error. Ways of filtering quality improvement concerned with the window functions are proposed. Thus, the joint usage of digital filter and Hamming window allows to achieve the zero value of the signal magnitude gain factor in high-frequency range and substantially suppress all spectral components above 100 Hz. The increasing of the signal magnitude settling time in this case can be reduced by choosing the most optimal parameters of the all components of the current measuring element.

  2. Self-balanced modulation and magnetic rebalancing method for parallel multilevel inverters

    Science.gov (United States)

    Li, Hui; Shi, Yanjun

    2017-11-28

    A self-balanced modulation method and a closed-loop magnetic flux rebalancing control method for parallel multilevel inverters. The combination of the two methods provides for balancing of the magnetic flux of the inter-cell transformers (ICTs) of the parallel multilevel inverters without deteriorating the quality of the output voltage. In various embodiments a parallel multi-level inverter modulator is provide including a multi-channel comparator to generate a multiplexed digitized ideal waveform for a parallel multi-level inverter and a finite state machine (FSM) module coupled to the parallel multi-channel comparator, the FSM module to receive the multiplexed digitized ideal waveform and to generate a pulse width modulated gate-drive signal for each switching device of the parallel multi-level inverter. The system and method provides for optimization of the output voltage spectrum without influence the magnetic balancing.

  3. Grid-Voltage-Feedforward Active Damping for Grid-Connected Inverter with LCL Filter

    DEFF Research Database (Denmark)

    Lu, Minghui; Wang, Xiongfei; Blaabjerg, Frede

    2016-01-01

    For the grid-connected voltage source inverters, the feedforward scheme of grid voltage is commonly adopted to mitigate the current distortion caused by grid background voltages harmonics. This paper investigates the grid-voltage-feedforward active damping for grid connected inverter with LCL...... filter. It reveals that proportional feedforward control can not only fulfill the mitigation of grid disturbance, but also offer damping effects on the LCL filter resonance. Digital delays are intrinsic to digital controlled inverters; with these delays, the feedforward control can be equivalent...

  4. Embedded EZ-Source Inverters

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Loh, Poh Chiang; Gao, F.

    2008-01-01

    -voltage oscillations to the system. Therefore, Z-source inverters are in effect safer and less complex, and can be implemented using only passive elements with no additional active semiconductor needed. Believing in the prospects of Z-source inverters, this paper contributes by introducing a new family of embedded EZ...

  5. Embedded EZ-Source Inverters

    DEFF Research Database (Denmark)

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

    2010-01-01

    overvoltage oscillations to the system. Therefore, Z-source inverters are, in effect, safer and less complex and can be implemented using only passive elements with no additional active semiconductor needed. Believing in the prospects of Z-source inverters, this paper contributes by introducing a new family...

  6. Simplified High-Power Inverter

    Science.gov (United States)

    Edwards, D. B.; Rippel, W. E.

    1984-01-01

    Solid-state inverter simplified by use of single gate-turnoff device (GTO) to commutate multiple silicon controlled rectifiers (SCR's). By eliminating conventional commutation circuitry, GTO reduces cost, size and weight. GTO commutation applicable to inverters of greater than 1-kilowatt capacity. Applications include emergency power, load leveling, drives for traction and stationary polyphase motors, and photovoltaic-power conditioning.

  7. Research on Methodology to Prioritize Critical Digital Assets based on Nuclear Risk Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Wonjik; Kwon, Kookheui; Kim, Hyundoo [Korea Institute of Nuclear Nonproliferation and Control, Daejeon (Korea, Republic of)

    2016-10-15

    Digital systems are used in nuclear facilities to monitor and control various types of field devices, as well as to obtain and store vital information. Therefore, it is getting important for nuclear facilities to protect digital systems from cyber-attack in terms of safety operation and public health since cyber compromise of these systems could lead to unacceptable radiological consequences. Based on KINAC/RS-015 which is a cyber security regulatory standard, regulatory activities for cyber security at nuclear facilities generally focus on critical digital assets (CDAs) which are safety, security, and emergency preparedness related digital assets. Critical digital assets are estimated over 60% among all digital assets in a nuclear power plant. Therefore, it was required to prioritize critical digital assets to improve efficiency of regulation and implementation. In this paper, the research status on methodology development to prioritize critical digital assets based on nuclear risk assessment will be introduced. In this paper, to derive digital asset directly affect accident, PRA results (ET, FT, and minimal cut set) are analyzed. According to result of analysis, digital systems related to CD are derived ESF-CCS (safety-related component control system) and Process-CCS (non-safety-related component control system) as well as Engineered Safety Features Actuation System (ESFAS). These digital assets can be identified Vital Digital Asset (VDA). Hereafter, to develop general methodology which was identified VDA related to accident among CDAs, (1) method using result of minimal cut set in PRA model will be studied and (2) method quantifying result of Digital I and C PRA which is performed to reflect all digital cabinet related to system in FT will be studied.

  8. Research on Methodology to Prioritize Critical Digital Assets based on Nuclear Risk Assessment

    International Nuclear Information System (INIS)

    Kim, Wonjik; Kwon, Kookheui; Kim, Hyundoo

    2016-01-01

    Digital systems are used in nuclear facilities to monitor and control various types of field devices, as well as to obtain and store vital information. Therefore, it is getting important for nuclear facilities to protect digital systems from cyber-attack in terms of safety operation and public health since cyber compromise of these systems could lead to unacceptable radiological consequences. Based on KINAC/RS-015 which is a cyber security regulatory standard, regulatory activities for cyber security at nuclear facilities generally focus on critical digital assets (CDAs) which are safety, security, and emergency preparedness related digital assets. Critical digital assets are estimated over 60% among all digital assets in a nuclear power plant. Therefore, it was required to prioritize critical digital assets to improve efficiency of regulation and implementation. In this paper, the research status on methodology development to prioritize critical digital assets based on nuclear risk assessment will be introduced. In this paper, to derive digital asset directly affect accident, PRA results (ET, FT, and minimal cut set) are analyzed. According to result of analysis, digital systems related to CD are derived ESF-CCS (safety-related component control system) and Process-CCS (non-safety-related component control system) as well as Engineered Safety Features Actuation System (ESFAS). These digital assets can be identified Vital Digital Asset (VDA). Hereafter, to develop general methodology which was identified VDA related to accident among CDAs, (1) method using result of minimal cut set in PRA model will be studied and (2) method quantifying result of Digital I and C PRA which is performed to reflect all digital cabinet related to system in FT will be studied

  9. Electronic inverter assembly

    Science.gov (United States)

    Singh, Brij N.; Schmit, Christopher J.

    2018-05-22

    A first driver portion comprises a set of first components mounted on or associated with a first circuit board. A second circuit board is spaced apart from the first circuit board. A second driver portion comprises a set of second components mounted on or associated with the second circuit board, where the first driver portion and the second driver portion collectively are adapted to provide input signals to the control terminal of each semiconductor switch of an inverter. A first edge connector is mounted on the first circuit board. A second edge connector is mounted on the second circuit board. An interface board has mating edges that mate with the first edge connector and the second edge connector.

  10. Artificial Neural Network based DC-link Capacitance Estimation in a Diode-bridge Front-end Inverter System

    DEFF Research Database (Denmark)

    Soliman, Hammam Abdelaal Hammam; Abdelsalam, Ibrahim; Wang, Huai

    2017-01-01

    , a proposed software condition monitoring methodology based on Artificial Neural Network (ANN) algorithm is presented. Matlab software is used to train and generate the proposed ANN. The proposed methodology estimates the capacitance of the DC-link capacitor in a three phase front-end diode bridge AC......In modern design of power electronic converters, reliability of DC-link capacitors is an essential aspect to be considered. The industrial field have been attracted to the monitoring of their health condition and the estimation of their ageing process status. The existing condition monitoring...

  11. A Novel Method for Inverter Faults Detection and Diagnosis in PMSM Drives of HEVs based on Discrete Wavelet Transform

    Directory of Open Access Journals (Sweden)

    AKTAS, M.

    2012-11-01

    Full Text Available The paper proposes a novel method, based on wavelet decomposition, for detection and diagnosis of faults (switch short-circuits and switch open-circuits in the driving systems with Field Oriented Controlled Permanent Magnet Synchro?nous Motors (PMSM of Hybrid Electric Vehicles. The fault behaviour of the analyzed system was simulated by Matlab/SIMULINK R2010a. The stator currents during transients were analysed up to the sixth level detail wavelet decomposition by Symlet2 wavelet. The results prove that the proposed fault diagnosis system have very good capabilities.

  12. Transistorized PWM inverter-induction motor drive system

    Science.gov (United States)

    Peak, S. C.; Plunkett, A. B.

    1982-01-01

    This paper describes the development of a transistorized PWM inverter-induction motor traction drive system. A vehicle performance analysis was performed to establish the vehicle tractive effort-speed requirements. These requirements were then converted into a set of inverter and motor specifications. The inverter was a transistorized three-phase bridge using General Electric power Darlington transistors. The description of the design and development of this inverter is the principal object of this paper. The high-speed induction motor is a design which is optimized for use with an inverter power source. The primary feedback control is a torque angle control with voltage and torque outer loop controls. A current-controlled PWM technique is used to control the motor voltage. The drive has a constant torque output with PWM operation to base motor speed and a constant horsepower output with square wave operation to maximum speed. The drive system was dynamometer tested and the results are presented.

  13. 27-Level DC–AC inverter with single energy source

    International Nuclear Information System (INIS)

    Tsang, K.M.; Chan, W.L.

    2012-01-01

    Highlights: ► This paper reports a novel 27-level DC–AC inverter using only single renewable energy source. ► The efficiency of the inverter is very high. The output waveform is almost sinusoidal. ► The cost is low as the number of power switches required is only 12. - Abstract: A novel design of multilevel DC–AC inverter using only single renewable energy source is presented in this paper. The proposed approach enables multilevel output to be realised by a few cascaded H-bridges and a single energy source. As an illustration, a 27-level inverter has been implemented based on three cascaded H-bridges with a single energy source and two capacitors. Using the proposed novel switching strategy, 27 levels can be realized and the two virtual energy sources can be well regulated. Experimental results are included to demonstrate the effectiveness of the proposed inverter.

  14. Teaching children digital literacy through design-based learning with digital toolkits in schools

    NARCIS (Netherlands)

    Bekker, T.; Bakker, S.; Douma, I.; van der Poel, J.E.C.; Scheltenaar, K.J.

    2015-01-01

    The paper presents our work on how to teach digital literacy and design thinking to children at primary and secondary schools, with a particular focus on exploring the tools that may support children’s learning in these domains. We have conducted design explorations with input from diverse

  15. Unstable footwear as a speed-dependent noise-based training gear to exercise inverted pendulum motion during walking.

    Science.gov (United States)

    Dierick, Frédéric; Bouché, Anne-France; Scohier, Mikaël; Guille, Clément; Buisseret, Fabien

    2018-05-15

    Previous research on unstable footwear has suggested that it may induce mechanical noise during walking. The purpose of this study was to explore whether unstable footwear could be considered as a noise-based training gear to exercise body center of mass (CoM) motion during walking. Ground reaction forces were collected among 24 healthy young women walking at speeds between 3 and 6 km h -1 with control running shoes and unstable rocker-bottom shoes. The external mechanical work, the recovery of mechanical energy of the CoM during and within the step cycles, and the phase shift between potential and kinetic energy curves of the CoM were computed. Our findings support the idea that unstable rocker-bottom footwear could serve as a speed-dependent noise-based training gear to exercise CoM motion during walking. At slow speed, it acts as a stochastic resonance or facilitator that reduces external mechanical work; whereas at brisk speed it acts as a constraint that increases external mechanical work and could mimic a downhill slope.

  16. Resonance Interaction of Multi-Parallel Grid-Connected Inverters with LCL Filter

    DEFF Research Database (Denmark)

    Lu, Minghui; Wang, Xiongfei; Loh, Poh Chiang

    2017-01-01

    This letter investigates the resonance characteristics and stability problem caused by the interactions of multiparallel LCL-filtered inverters. Compared to single grid-connected inverter, the multiinverter system presents a more challenging resonance issue, where the inverter interactions may...... excite multiple resonances at various frequencies. This letter proposes a modeling and analysis method based on the current separation scheme. It reveals that an interactive resonant current that circulates between the paralleled three-phase inverters may arise, depending on the current distribution...

  17. Techniques for the optimal design of photovoltaic inverters interconnected with the electric grid

    DEFF Research Database (Denmark)

    Koutroulis, Eftichios; Blaabjerg, Frede

    2011-01-01

    the Genetic Algorithm-based optimization procedure is the PV inverter Levelized Cost Of the Electricity generated (LCOE). The proposed method has been applied for the optimal design of PV inverters installed at various sites in Europe. The simulation results indicate that the optimal values of the PV inverter...

  18. Capillary-based integrated digital PCR in picoliter droplets.

    Science.gov (United States)

    Chen, Jinyu; Luo, Zhaofeng; Li, Lin; He, Jinlong; Li, Luoquan; Zhu, Jianwei; Wu, Ping; He, Liqun

    2018-01-30

    The droplet digital polymerase chain reaction (ddPCR) is becoming more and more popular in diagnostic applications in academia and industry. In commercially available ddPCR systems, after they have been made by a generator, the droplets have to be transferred manually to modules for amplification and detection. In practice, some of the droplets (∼10%) are lost during manual transfer, leading to underestimation of the targets. In addition, the droplets are also at risk of cross-contamination during transfer. By contrast, in labs, some chip-based ddPCRs have been demonstrated where droplets always run in channels. However, the droplets easily coalesce to large ones in chips due to wall wetting as well as thermal oscillation. The loss of droplets becomes serious when such ddPCRs are applied to absolutely quantify rare mutations, such as in early diagnostics in clinical research or when measuring biological diversity at the cell level. Here, we propose a capillary-based integrated ddPCR system that is used for the first time to realize absolute quantification in this way. In this system, a HPLC T-junction is used to generate droplets and a long HPLC capillary connects the generator with both a capillary-based thermocycler and a capillary-based cytometer. The performance of the system is validated by absolute quantification of a gene specific to lung cancer (LunX). The results show that this system has very good linearity (0.9988) at concentrations ranging from NTC to 2.4 × 10 -4 copies per μL. As compared to qPCR, the all-in-one scheme is superior both in terms of the detection limit and the smaller fold changes measurement. The system of ddPCR might provide a powerful approach for clinical or academic applications where rare events are mostly considered.

  19. An Efficient and Robust Hybrid Damper for LCL- or LLCL-Based Grid-Tied Inverter With Strong Grid-Side Harmonic Voltage Effect Rejection

    DEFF Research Database (Denmark)

    Liu, Yuan; Wu, Weimin; He, Yuanbin

    2016-01-01

    to resist the effect of the BHV, a feedforward voltage compensator and a proportional resonant regulator with harmonic compensation are often adopted. However, they still have their own limitations, particularly when there are higher order BHVs at the point of common coupling and when the equivalent grid......A high-order (LCL or LLCL) power filter with a small grid-side inductor is becoming more preferred for a grid-tied inverter due to less total inductance and reduced costs. In a microgrid, the background harmonic voltage (BHV) may distort the injected currents of the grid-tied inverters. In order...

  20. Abc-frame complex-coefficient filter and controller based current harmonic elimination strategy for three-phase grid connected inverter

    DEFF Research Database (Denmark)

    Guo, Xiaoqiang; Guerrero, Josep M.

    2016-01-01

    Current quality is one of the most important issues for operating three-phase grid-connected inverter in distributed generation systems. In practice, the grid current quality is degraded in case of non-ideal utility voltage. A new control strategy is proposed for the three-phase gridconnected...... inverter. Different from the traditional method, our proposal utilizes the unique abc-frame complex-coefficient filter and controller to achieve the balanced, sinusoidal grid current. The main feature of the proposed method is simple and easy to implement without any frame transformation. The theoretical...

  1. A real-time and closed-loop control algorithm for cascaded multilevel inverter based on artificial neural network.

    Science.gov (United States)

    Wang, Libing; Mao, Chengxiong; Wang, Dan; Lu, Jiming; Zhang, Junfeng; Chen, Xun

    2014-01-01

    In order to control the cascaded H-bridges (CHB) converter with staircase modulation strategy in a real-time manner, a real-time and closed-loop control algorithm based on artificial neural network (ANN) for three-phase CHB converter is proposed in this paper. It costs little computation time and memory. It has two steps. In the first step, hierarchical particle swarm optimizer with time-varying acceleration coefficient (HPSO-TVAC) algorithm is employed to minimize the total harmonic distortion (THD) and generate the optimal switching angles offline. In the second step, part of optimal switching angles are used to train an ANN and the well-designed ANN can generate optimal switching angles in a real-time manner. Compared with previous real-time algorithm, the proposed algorithm is suitable for a wider range of modulation index and results in a smaller THD and a lower calculation time. Furthermore, the well-designed ANN is embedded into a closed-loop control algorithm for CHB converter with variable direct voltage (DC) sources. Simulation results demonstrate that the proposed closed-loop control algorithm is able to quickly stabilize load voltage and minimize the line current's THD (<5%) when subjecting the DC sources disturbance or load disturbance. In real design stage, a switching angle pulse generation scheme is proposed and experiment results verify its correctness.

  2. A Real-Time and Closed-Loop Control Algorithm for Cascaded Multilevel Inverter Based on Artificial Neural Network

    Directory of Open Access Journals (Sweden)

    Libing Wang

    2014-01-01

    Full Text Available In order to control the cascaded H-bridges (CHB converter with staircase modulation strategy in a real-time manner, a real-time and closed-loop control algorithm based on artificial neural network (ANN for three-phase CHB converter is proposed in this paper. It costs little computation time and memory. It has two steps. In the first step, hierarchical particle swarm optimizer with time-varying acceleration coefficient (HPSO-TVAC algorithm is employed to minimize the total harmonic distortion (THD and generate the optimal switching angles offline. In the second step, part of optimal switching angles are used to train an ANN and the well-designed ANN can generate optimal switching angles in a real-time manner. Compared with previous real-time algorithm, the proposed algorithm is suitable for a wider range of modulation index and results in a smaller THD and a lower calculation time. Furthermore, the well-designed ANN is embedded into a closed-loop control algorithm for CHB converter with variable direct voltage (DC sources. Simulation results demonstrate that the proposed closed-loop control algorithm is able to quickly stabilize load voltage and minimize the line current’s THD (<5% when subjecting the DC sources disturbance or load disturbance. In real design stage, a switching angle pulse generation scheme is proposed and experiment results verify its correctness.

  3. Similar digit-based working memory in deaf signers and hearing non-signers despite digit span differences

    Directory of Open Access Journals (Sweden)

    Josefine eAndin

    2013-12-01

    Full Text Available Similar working memory (WM for lexical items has been demonstrated for signers and non-signers while short-term memory (STM is regularly poorer in deaf than hearing individuals. In the present study, we investigated digit-based WM and STM in Swedish and British deaf signers and hearing non-signers. To maintain good experimental control we used printed stimuli throughout and held response mode constant across groups. We showed that deaf signers have similar digit-based WM performance, despite shorter digit spans, compared to well-matched hearing non-signers. We found no difference between signers and non-signers on STM span for letters chosen to minimize phonological similarity or in the effects of recall direction. This set of findings indicates that similar WM for signers and non-signers can be generalized from lexical items to digits and suggests that poorer STM in deaf signers compared to hearing non-signers may be due to differences in phonological similarity across the language modalities of sign and speech.

  4. Analisis Harmonisa Inverter PWM Satu Fasa

    OpenAIRE

    Rejeki Simanjorang

    2008-01-01

    Pada tesis ini dianalisis harmonisa inverter PWM satu fasa. Inverter PWM satu fasa yang akan ditinjau adalah inverter satu fasa jembatan penuh (konvensional) dan inverter komposit. Analisis difokuskan pada penentuan pola penyaklaran yang optimum agar pembangkitan harmonisa dan switching losses inverter rendah. Untuk menentukan pola penyaklaran optimum maka dilakukan analisis yang berbasis pada rangkaian ekivalen harmonisa inverter satu fasa. Dengan menggunakan pola penyaklaran optimum, kedua ...

  5. Pulse width modulation inverter with battery charger

    Science.gov (United States)

    Slicker, James M.

    1985-01-01

    An inverter is connected between a source of DC power and a three-phase AC induction motor, and a microprocessor-based circuit controls the inverter using pulse width modulation techniques. In the disclosed method of pulse width modulation, both edges of each pulse of a carrier pulse train are equally modulated by a time proportional to sin .theta., where .theta. is the angular displacement of the pulse center at the motor stator frequency from a fixed reference point on the carrier waveform. The carrier waveform frequency is a multiple of the motor stator frequency. The modulated pulse train is then applied to each of the motor phase inputs with respective phase shifts of 120.degree. at the stator frequency. Switching control commands for electronic switches in the inverter are stored in a random access memory (RAM) and the locations of the RAM are successively read out in a cyclic manner, each bit of a given RAM location controlling a respective phase input of the motor. The DC power source preferably comprises rechargeable batteries and all but one of the electronic switches in the inverter can be disabled, the remaining electronic switch being part of a "flyback" DC-DC converter circuit for recharging the battery.

  6. Digital reflection holography based systems development for MEMS testing

    Science.gov (United States)

    Singh, Vijay Raj; Liansheng, Sui; Asundi, Anand

    2010-05-01

    MEMS are tiny mechanical devices that are built onto semiconductor chips and are measured in micrometers and nanometers. Testing of MEMS device is an important part in carrying out their functional assessment and reliability analysis. Development of systems based on digital holography (DH) for MEMS inspection and characterization is presented in this paper. Two DH reflection systems, table-top and handheld types, are developed depending on the MEMS measurement requirements and their capabilities are presented. The methodologies for the systems are developed for 3D profile inspection and static & dynamic measurements, which is further integrated with in-house developed software that provides the measurement results in near real time. The applications of the developed systems are demonstrated for different MEMS devices for 3D profile inspection, static deformation/deflection measurements and vibration analysis. The developed systems are well suitable for the testing of MEMS and Microsystems samples, with full-field, static & dynamic inspection as well as to monitor micro-fabrication process.

  7. Digital Survey Meter based on PIC16F628 Microcontroller

    International Nuclear Information System (INIS)

    Al-Mohamad, A.; Shliwitt, J.

    2010-01-01

    A Digital Survey Meter based on PIC16F628 Microcontroller was designed using simple Geiger-Muller Counter ZP1320 made by Centronic in the UK as detector. The sensitivity of this tube is about 9 counts/s at 10μGy/h. It is sensitive to gamma and beta particles over 0.25 MeV. It has a sensitive length of 28mm. Count rate versus dose rate is quite linear up to about 10 4 counts/s. Indication is given by a speaker which emits one click for each count. In addition to the acoustic alarm, the meter works according one of three different measurement modes selected using appropriate 3 states switch: 1- Measurement of Dose rate ( in μGy/h) and counting rate ( in CPS) , for High counting rates. 2- Measurement of Dose rate ( in μGy/h) and counting rate ( in CPM), for Low counting rates. 3- Accumulated Counting with continues display for No. of Counts and Counting Time with a period of 2 Sec. The results are Displayed on an Alphanumerical LCD Display, and the circuit will give many hours of operation from a single 9V PP3 battery. The design of the circuit combines between accuracy, simplicity and low power consumption. We built 2 Models of this design, the first only with an internal detector, and the second is equipped with an External Detector. (author)

  8. Research of Digital Interface Layout Design based on Eye-tracking

    OpenAIRE

    Shao Jiang; Xue Chengqi; Wang Fang; Wang Haiyan; Tang Wencheng; Chen Mo; Kang Mingwu

    2015-01-01

    The aim of this paper is to improve the low service efficiency and unsmooth human-computer interaction caused by currently irrational layouts of digital interfaces for complex systems. Also, three common layout structures for digital interfaces are to be presented and five layout types appropriate for multilevel digital interfaces are to be summarized. Based on the eye tracking technology, an assessment was conducted in advantages and disadvantages of different layout types through subjects’ ...

  9. Object based classification of high resolution data in urban areas considering digital surface models

    OpenAIRE

    Oczipka, Martin Eckhard

    2010-01-01

    Over the last couple of years more and more analogue airborne cameras were replaced by digital cameras. Digitally recorded image data have significant advantages to film based data. Digital aerial photographs have a much better radiometric resolution. Image information can be acquired in shaded areas too. This information is essential for a stable and continuous classification, because no data or unclassified areas should be as small as possible. Considering this technological progress, on...

  10. A peak value searching method of the MCA based on digital logic devices

    International Nuclear Information System (INIS)

    Sang Ziru; Huang Shanshan; Chen Lian; Jin Ge

    2010-01-01

    Digital multi-channel analyzers play a more important role in multi-channel pulse height analysis technique. The direction of digitalization are characterized by powerful pulse processing ability, high throughput, improved stability and flexibility. This paper introduces a method of searching peak value of waveform based on digital logic with FPGA. This method reduce the dead time. Then data correction offline can improvement the non-linearity of MCA. It gives the α energy spectrum of 241 Am. (authors)

  11. Comparison of subset-based local and FE-based global digital image correlation: Theoretical error analysis and validation

    KAUST Repository

    Pan, B.; Wang, Bo; Lubineau, Gilles

    2016-01-01

    Subset-based local and finite-element-based (FE-based) global digital image correlation (DIC) approaches are the two primary image matching algorithms widely used for full-field displacement mapping. Very recently, the performances

  12. FFT Based VLSI Digital One Bit Electronic Warfare Receiver

    National Research Council Canada - National Science Library

    Chien-In, Henry

    1998-01-01

    ... (1 GHz) digital receiver designed for electronic warfare applications. The receiver can process two simultaneous signals and has the potential for fabrication on a single multi-chip module (MCM...

  13. Research based on matlab method of digital trapezoidal shaping filter

    International Nuclear Information System (INIS)

    Zhou Qinghua; Zhang Ruanyu; Li Taihua

    2008-01-01

    In order to develop digital shaping system fast and conveniently, the paper presents the method of optimizing the trapezoidal shaping filter's parameters by using MATLAB, and discusses the affections of the parameters to the shaping result by this method. (authors)

  14. FPGA-based digital convolution for wireless applications

    CERN Document Server

    Guan, Lei

    2017-01-01

    This book presents essential perspectives on digital convolutions in wireless communications systems and illustrates their corresponding efficient real-time field-programmable gate array (FPGA) implementations. Covering these digital convolutions from basic concept to vivid simulation/illustration, the book is also supplemented with MS PowerPoint presentations to aid in comprehension. FPGAs or generic all programmable devices will soon become widespread, serving as the “brains” of all types of real-time smart signal processing systems, like smart networks, smart homes and smart cities. The book examines digital convolution by bringing together the following main elements: the fundamental theory behind the mathematical formulae together with corresponding physical phenomena; virtualized algorithm simulation together with benchmark real-time FPGA implementations; and detailed, state-of-the-art case studies on wireless applications, including popular linear convolution in digital front ends (DFEs); nonlinear...

  15. Structural and physico-chemical analysis of calcium/strontium substituted, near-invert phosphate based glasses for biomedical applications.

    Science.gov (United States)

    Patel, U; Moss, R M; Hossain, K M Z; Kennedy, A R; Barney, E R; Ahmed, I; Hannon, A C

    2017-09-15

    Neutron diffraction, 23 Na and 31 P NMR, and FTIR spectroscopy have been used to investigate the structural effects of substituting CaO with SrO in a 40P 2 O 5 ·(16-x)CaO·20Na 2 O·24MgO·xSrO glass, where x is 0, 4, 8, 12 and 16mol%. The 31 P solid-state NMR results showed similar amounts of Q 1 and Q 2 units for all of the multicomponent glasses investigated, showing that the substitution of Sr for Ca has no effect on the phosphate network. The M-O coordinations (M=Mg, Ca, Sr, Na) were determined for binary alkali and alkaline earth metaphosphates using neutron diffraction and broad asymmetric distributions of bond length were observed, with coordination numbers that were smaller and bond lengths that were shorter than in corresponding crystals. The Mg-O coordination number was determined most reliably as 5.0(2). The neutron diffraction results for the multicomponent glasses are consistent with a structural model in which the coordination of Ca, Sr and Na is the same as in the binary metaphosphate glass, whereas there is a definite shift of Mg-O bonds to longer distance. There is also a small but consistent increase in the Mg-O coordination number and the width of the distribution of Mg-O bond lengths, as Sr substitutes for Ca. Functional properties, including glass transition temperatures, thermal processing windows, dissolution rates and ion release profiles were also investigated. Dissolution studies showed a decrease in dissolution rate with initial addition of 4mol% SrO, but further addition of SrO showed little change. The ion release profiles followed a similar trend to the observed dissolution rates. The limited changes in structure and dissolution rates observed for substitution of Ca with Sr in these fixed 40mol% P 2 O 5 glasses were attributed to their similarities in terms of ionic size and charge. Phosphate based glasses are extremely well suited for the delivery of therapeutic ions in biomedical applications, and in particular strontium plays an

  16. Experimental Evaluation of PV Inverter Anti-Islanding with Grid Support Functions in Multi-Inverter Island Scenarios

    Energy Technology Data Exchange (ETDEWEB)

    Hoke, Anderson [National Renewable Energy Lab. (NREL), Golden, CO (United States); Nelson, Austin [National Renewable Energy Lab. (NREL), Golden, CO (United States); Miller, Brian [National Renewable Energy Lab. (NREL), Golden, CO (United States); Chakraborty, Sudipta [National Renewable Energy Lab. (NREL), Golden, CO (United States); Bell, Frances [SolarCity, San Mateo, CA (United States); McCarty, Michael [SolarCity, San Mateo, CA (United States)

    2016-07-01

    As PV and other DER systems are connected to the grid at increased penetration levels, island detection may become more challenging for two reasons: 1.) In islands containing many DERs, active inverter-based anti-islanding methods may have more difficulty detecting islands because each individual inverter's efforts to detect the island may be interfered with by the other inverters in the island. 2.) The increasing numbers of DERs are leading to new requirements that DERs ride through grid disturbances and even actively try to regulate grid voltage and frequency back towards nominal operating conditions. These new grid support requirements may directly or indirectly interfere with anti-islanding controls. This report describes a series of tests designed to examine the impacts of both grid support functions and multi-inverter islands on anti-islanding effectiveness. Crucially, the multi-inverter anti-islanding tests described in this report examine scenarios with multiple inverters connected to multiple different points on the grid. While this so-called 'solar subdivision' scenario has been examined to some extent through simulation, this is the first known work to test it using hardware inverters. This was accomplished through the use of power hardware-in-the-loop (PHIL) simulation, which allows the hardware inverters to be connected to a real-time transient simulation of an electric power system that can be easily reconfigured to test various distribution circuit scenarios. The anti-islanding test design was a modified version of the unintentional islanding test in IEEE Standard 1547.1, which creates a balanced, resonant island with the intent of creating a highly challenging condition for island detection. Three common, commercially available single-phase PV inverters from three different manufacturers were tested. The first part of this work examined each inverter individually using a series of pure hardware resistive-inductive-capacitive (RLC

  17. Spectral colors capture and reproduction based on digital camera

    Science.gov (United States)

    Chen, Defen; Huang, Qingmei; Li, Wei; Lu, Yang

    2018-01-01

    The purpose of this work is to develop a method for the accurate reproduction of the spectral colors captured by digital camera. The spectral colors being the purest color in any hue, are difficult to reproduce without distortion on digital devices. In this paper, we attempt to achieve accurate hue reproduction of the spectral colors by focusing on two steps of color correction: the capture of the spectral colors and the color characterization of digital camera. Hence it determines the relationship among the spectral color wavelength, the RGB color space of the digital camera device and the CIEXYZ color space. This study also provides a basis for further studies related to the color spectral reproduction on digital devices. In this paper, methods such as wavelength calibration of the spectral colors and digital camera characterization were utilized. The spectrum was obtained through the grating spectroscopy system. A photo of a clear and reliable primary spectrum was taken by adjusting the relative parameters of the digital camera, from which the RGB values of color spectrum was extracted in 1040 equally-divided locations. Calculated using grating equation and measured by the spectrophotometer, two wavelength values were obtained from each location. The polynomial fitting method for the camera characterization was used to achieve color correction. After wavelength calibration, the maximum error between the two sets of wavelengths is 4.38nm. According to the polynomial fitting method, the average color difference of test samples is 3.76. This has satisfied the application needs of the spectral colors in digital devices such as display and transmission.

  18. Digital Microdroplet Ejection Technology-Based Heterogeneous Objects Prototyping

    OpenAIRE

    Li, Na; Yang, Jiquan; Feng, Chunmei; Yang, Jianfei; Zhu, Liya; Guo, Aiqing

    2016-01-01

    An integrate fabrication framework is presented to build heterogeneous objects (HEO) using digital microdroplets injecting technology and rapid prototyping. The heterogeneous materials part design and manufacturing method in structure and material was used to change the traditional process. The net node method was used for digital modeling that can configure multimaterials in time. The relationship of material, color, and jetting nozzle was built. The main important contributions are to combi...

  19. Internet-based information system of digital geological data providing

    Science.gov (United States)

    Yuon, Egor; Soukhanov, Mikhail; Markov, Kirill

    2015-04-01

    One of the Russian Federal аgency of mineral resources problems is to provide the geological information which was delivered during the field operation for the means of federal budget. This information should be present in the current, conditional form. Before, the leading way of presenting geological information were paper geological maps, slices, borehole diagrams reports etc. Technologies of database construction, including distributed databases, technologies of construction of distributed information-analytical systems and Internet-technologies are intensively developing nowadays. Most of geological organizations create their own information systems without any possibility of integration into other systems of the same orientation. In 2012, specialists of VNIIgeosystem together with specialists of VSEGEI started the large project - creating the system of providing digital geological materials with using modern and perspective internet-technologies. The system is based on the web-server and the set of special programs, which allows users to efficiently get rasterized and vectorised geological materials. These materials are: geological maps of scale 1:1M, geological maps of scale 1:200 000 and 1:2 500 000, the fragments of seamless geological 1:1M maps, structural zoning maps inside the seamless fragments, the legends for State geological maps 1:200 000 and 1:1 000 000, full author's set of maps and also current materials for international projects «Atlas of geological maps for Circumpolar Arctic scale 1:5 000 000» and «Atlas of Geologic maps of central Asia and adjacent areas scale 1:2 500 000». The most interesting and functional block of the system - is the block of providing structured and well-formalized geological vector materials, based on Gosgeolkart database (NGKIS), managed by Oracle and the Internet-access is supported by web-subsystem NGKIS, which is currently based on MGS-Framework platform, developed by VNIIgeosystem. One of the leading elements

  20. Transformerless PV inverters. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Borup, U.

    2009-12-15

    Since the start of the project the market for grid connected PV inverters have developed further. When the project started three - phase inverter were only available in high power systems. The technology developed within this project will enable three phase technology also to be implemented in string inverters for system down to 10 kW. We expect this to be very attractive due to the increased demand for symmetrical feed-in to the grid. The project relevance is therefore high and the sector continues to develop very much driven by technology. Especially the inverter technology is getting a lot of focus. The inverter systems are expected to take a much larger role in supporting the electrical grid in the future. The technology platform developed within the project is prepared to be extended with these utility functionalities. The main results of the project were: 1) A new technology concept for transformer-less inverters has been demonstrated with a number of prototypes. 2) Efficiency above 97,7% has been proven. 3) Efficiency and Maximum power point tracking has been optimized to ensure that almost all energy produced of the panels is transferred to the grid. 4) The platform is developed with a very fast control board, which enables extended functionality as demanding grid supporting functions in the future. Details about cost price and details about the control loop implementation is excluded from the report due to the competitive situation for Danfoss Solar Inverters A/S. (LN)

  1. Librarian-Initiated Publications Discovery: How Do Digital Depository Librarians Discover and Select Web-Based Government Publications for State Digital Depositories?

    Science.gov (United States)

    Lin, Chi-Shiou; Eschenfelder, Kristin R.

    2010-01-01

    This paper reports on a study of librarian initiated publications discovery (LIPD) in U.S. state digital depository programs using the OCLC Digital Archive to preserve web-based government publications for permanent public access. This paper describes a model of LIPD processes based on empirical investigations of four OCLC DA-based digital…

  2. Modulation of Current Source Inverter

    Directory of Open Access Journals (Sweden)

    Golam Reza Arab Markadeh

    2011-04-01

    Full Text Available Direct torque control with Current Source Inverter (CSI instead of voltage source inverter is so appropriate because of determining the torque of induction motor with machine current and air gap flux. In addition, Space-Vector Modulation (SVM is a more proper method for CSI because of low order harmonics reduction, lower switching frequency and easier implementation. This paper introduces the SVM method for CSI and uses the proposed inverter for vector control of an induction motor. The simulation results illustrate fast dynamic response and desirable torque and speed output. Fast and accurate response to changes of speed and load torque reference completely proves the prominence of this method.

  3. Detecting and mitigating inverter aging

    International Nuclear Information System (INIS)

    Gunther, W.E.; Taylor, J.H.; Aggarwal, S.K.

    1988-01-01

    Nuclear power plants use inverters to supply power to safety-related equipment, instrumentation, and controls. They convert direct current (dc) to alternating current (ac) power, thereby making low voltage ac power available even under a station blackout condition. As part of the U.S. NRC's nuclear plant aging research (NPAR) program, the operating experience of this equipment has been analyzed to determine the dominant failure modes and causes. This paper summarizes that data, and then describes methods which can be employed to detect inverter degradation prior to failure, as well as methods to minimize the failure effects. In both cases, the mitigation of inverter aging is emphasized

  4. Joint Calibration of 3d Laser Scanner and Digital Camera Based on Dlt Algorithm

    Science.gov (United States)

    Gao, X.; Li, M.; Xing, L.; Liu, Y.

    2018-04-01

    Design a calibration target that can be scanned by 3D laser scanner while shot by digital camera, achieving point cloud and photos of a same target. A method to joint calibrate 3D laser scanner and digital camera based on Direct Linear Transformation algorithm was proposed. This method adds a distortion model of digital camera to traditional DLT algorithm, after repeating iteration, it can solve the inner and external position element of the camera as well as the joint calibration of 3D laser scanner and digital camera. It comes to prove that this method is reliable.

  5. Adaptation of a fuzzy controller’s scaling gains using genetic algorithms for balancing an inverted pendulum

    Directory of Open Access Journals (Sweden)

    Duka Adrian-Vasile

    2011-12-01

    Full Text Available This paper examines the development of a genetic adaptive fuzzy control system for the Inverted Pendulum. The inverted pendulum is a classical problem in Control Engineering, used for testing different control algorithms. The goal is to balance the inverted pendulum in the upright position by controlling the horizontal force applied to its cart. Because it is unstable and has a complicated nonlinear dynamics, the inverted pendulum is a good testbed for the development of nonconventional advanced control techniques. Fuzzy logic technique has been successfully applied to control this type of system, however most of the time the design of the fuzzy controller is done in an ad-hoc manner, and choosing certain parameters (controller gains, membership functions proves difficult. This paper examines the implementation of an adaptive control method based on genetic algorithms (GA, which can be used on-line to produce the adaptation of the fuzzy controller’s gains in order to achieve the stabilization of the pendulum. The performances of the proposed control algorithms are evaluated and shown by means of digital simulation.

  6. A new MicroTCA-based waveform digitizer for the Muon g-2 experiment

    Energy Technology Data Exchange (ETDEWEB)

    Sweigart, David A. [Cornell U.

    2016-12-15

    We present the design of a new $\\mu$TCA-based waveform digitizer, which will be deployed in the Muon g-2 experiment at Fermilab and will allow our pileup identification requirement to be met. This digitizer features five independent channels, each with 12-bit, 800-MSPS digitization and a 1-Gbit memory buffer. The data storage and readout along with configuration are handled by six Xilinx Kintex-7 FPGAs. In addition, the digitizer is equipped with a mezzanine card for analog signal conditioning prior to digitization, further widening its range of possible applications. The performance results of this design are also presented, highlighting its $0.51 \\pm 0.13$ mV intrinsic noise level and $< 22$ ps intrinsic timing resolution between channels. We believe that its performance, together with its flexible design, could be of interest to future experiments in search of a cost-effective waveform digitizer.

  7. Cryocooled wideband digital channelizing radio-frequency receiver based on low-pass ADC

    International Nuclear Information System (INIS)

    Vernik, Igor V; Kirichenko, Dmitri E; Dotsenko, Vladimir V; Miller, Robert; Webber, Robert J; Shevchenko, Pavel; Talalaevskii, Andrei; Gupta, Deepnarayan; Mukhanov, Oleg A

    2007-01-01

    We have demonstrated a digital receiver performing direct digitization of radio-frequency signals over a wide frequency range from kilohertz to gigahertz. The complete system, consisting of a cryopackaged superconductor all-digital receiver (ADR) chip followed by room-temperature interface electronics and a field programmable gate array (FPGA) based post-processing module, has been developed. The ADR chip comprises a low-pass analog-to-digital converter (ADC) delta modulator with phase modulation-demodulation architecture together with digital in-phase and quadrature mixer and a pair of digital decimation filters. The chip is fabricated using a 4.5 kA cm -2 process and is cryopackaged using a commercial-off-the-shelf cryocooler. Experimental results in HF, VHF, UHF and L bands and their analysis, proving consistent operation of the cryopackaged ADR chip up to 24.32 GHz clock frequency, are presented and discussed

  8. Improvements in EMC performance of inverter-fed motor drives

    International Nuclear Information System (INIS)

    Zhong, E.; Lipo, T.A.

    1995-01-01

    An experimental investigation of conducted radio-noise emission from a conventional pulse width modulated (PWM) inverter of medium power feeding an induction motor is described. It is determined that the inverter system generates considerable impulse currents through the power leads feeding the system resulting in serious conducted electromagnetic interference (EMI) problems and significant voltage waveform distortion in the power system. The dominant emission sources in the system are identified. A proposed model of the drive system for the purpose of evaluation of EMI are developed. Several low-cost strategies for improvement in EMC performance of the PWM inverter are then proposed. Experimental results demonstrate that disturbance from the modified system can be dramatically reduced and that the EMC performance of the system has come very close to meeting the IEC CISPR and FCC limits on conducted emissions for digital devices

  9. A Study of Moment Based Features on Handwritten Digit Recognition

    Directory of Open Access Journals (Sweden)

    Pawan Kumar Singh

    2016-01-01

    Full Text Available Handwritten digit recognition plays a significant role in many user authentication applications in the modern world. As the handwritten digits are not of the same size, thickness, style, and orientation, therefore, these challenges are to be faced to resolve this problem. A lot of work has been done for various non-Indic scripts particularly, in case of Roman, but, in case of Indic scripts, the research is limited. This paper presents a script invariant handwritten digit recognition system for identifying digits written in five popular scripts of Indian subcontinent, namely, Indo-Arabic, Bangla, Devanagari, Roman, and Telugu. A 130-element feature set which is basically a combination of six different types of moments, namely, geometric moment, moment invariant, affine moment invariant, Legendre moment, Zernike moment, and complex moment, has been estimated for each digit sample. Finally, the technique is evaluated on CMATER and MNIST databases using multiple classifiers and, after performing statistical significance tests, it is observed that Multilayer Perceptron (MLP classifier outperforms the others. Satisfactory recognition accuracies are attained for all the five mentioned scripts.

  10. Information Activities and Appropriation in Teacher Trainees' Digital, Group-Based Learning

    Science.gov (United States)

    Hanell, Fredrik

    2016-01-01

    Introduction: This paper reports results from an ethnographic study of teacher trainees' information activities in digital, group-based learning and their relation to the interplay between use and appropriation of digital tools and the learning environment. Method: The participants in the present study are 249 pre-school teacher trainees in…

  11. Agriscience Teachers' Implementation of Digital Game-Based Learning in an Introductory Animal Science Course

    Science.gov (United States)

    Webb, Angela W.; Bunch, J. C.; Wallace, Maria F.

    2015-01-01

    In today's technological age, visions for technology integration in the classroom continue to be explored and examined. Digital game-based learning is one way to purposefully integrate technology while maintaining a focus on learning objectives. This case study sought to understand agriscience teachers' experiences implementing digital game-based…

  12. 77 FR 60984 - World Digital Innovations; Supplemental Notice That Initial Market-Based Rate Filing Includes...

    Science.gov (United States)

    2012-10-05

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER12-2654-001] World Digital Innovations; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for Blanket Section 204 Authorization This is a supplemental notice in the above-referenced proceeding, of World Digital...

  13. Digital Game-Based Learning for K-12 Mathematics Education: A Meta-Analysis

    Science.gov (United States)

    Byun, JaeHwan; Joung, Eunmi

    2018-01-01

    Digital games (e.g., video games or computer games) have been reported as an effective educational method that can improve students' motivation and performance in mathematics education. This meta-analysis study (a) investigates the current trend of digital game-based learning (DGBL) by reviewing the research studies on the use of DGBL for…

  14. A Computer-Assisted Learning Model Based on the Digital Game Exponential Reward System

    Science.gov (United States)

    Moon, Man-Ki; Jahng, Surng-Gahb; Kim, Tae-Yong

    2011-01-01

    The aim of this research was to construct a motivational model which would stimulate voluntary and proactive learning using digital game methods offering players more freedom and control. The theoretical framework of this research lays the foundation for a pedagogical learning model based on digital games. We analyzed the game reward system, which…

  15. Computer holography: 3D digital art based on high-definition CGH

    International Nuclear Information System (INIS)

    Matsushima, K; Arima, Y; Nishi, H; Yamashita, H; Yoshizaki, Y; Ogawa, K; Nakahara, S

    2013-01-01

    Our recent works of high-definition computer-generated holograms (CGH) and the techniques used for the creation, such as the polygon-based method, silhouette method and digitized holography, are summarized and reviewed in this paper. The concept of computer holography is proposed in terms of integrating and crystalizing the techniques into novel digital art.

  16. Digital Microdroplet Ejection Technology-Based Heterogeneous Objects Prototyping

    Science.gov (United States)

    Yang, Jiquan; Feng, Chunmei; Yang, Jianfei; Zhu, Liya; Guo, Aiqing

    2016-01-01

    An integrate fabrication framework is presented to build heterogeneous objects (HEO) using digital microdroplets injecting technology and rapid prototyping. The heterogeneous materials part design and manufacturing method in structure and material was used to change the traditional process. The net node method was used for digital modeling that can configure multimaterials in time. The relationship of material, color, and jetting nozzle was built. The main important contributions are to combine the structure, material, and visualization in one process and give the digital model for manufacture. From the given model, it is concluded that the method is effective for HEO. Using microdroplet rapid prototyping and the model given in the paper HEO could be gotten basically. The model could be used in 3D biomanufacturing. PMID:26981110

  17. Digital Microdroplet Ejection Technology-Based Heterogeneous Objects Prototyping.

    Science.gov (United States)

    Li, Na; Yang, Jiquan; Feng, Chunmei; Yang, Jianfei; Zhu, Liya; Guo, Aiqing

    2016-01-01

    An integrate fabrication framework is presented to build heterogeneous objects (HEO) using digital microdroplets injecting technology and rapid prototyping. The heterogeneous materials part design and manufacturing method in structure and material was used to change the traditional process. The net node method was used for digital modeling that can configure multimaterials in time. The relationship of material, color, and jetting nozzle was built. The main important contributions are to combine the structure, material, and visualization in one process and give the digital model for manufacture. From the given model, it is concluded that the method is effective for HEO. Using microdroplet rapid prototyping and the model given in the paper HEO could be gotten basically. The model could be used in 3D biomanufacturing.

  18. Scenario-Based Digital Forensics Challenges in Cloud Computing

    Directory of Open Access Journals (Sweden)

    Erik Miranda Lopez

    2016-10-01

    Full Text Available The aim of digital forensics is to extract information to answer the 5Ws (Why, When, Where, What, and Who from the data extracted from the evidence. In order to achieve this, most digital forensic processes assume absolute control of digital evidence. However, in a cloud environment forensic investigation, this is not always possible. Additionally, the unique characteristics of cloud computing create new technical, legal and architectural challenges when conducting a forensic investigation. We propose a hypothetical scenario to uncover and explain the challenges forensic practitioners face during cloud investigations. Additionally, we also provide solutions to address the challenges. Our hypothetical case scenario has shown that, in the long run, better live forensic tools, development of new methods tailored for cloud investigations and new procedures and standards are indeed needed. Furthermore, we have come to the conclusion that forensic investigations biggest challenge is not technical but legal.

  19. Digital Microdroplet Ejection Technology-Based Heterogeneous Objects Prototyping

    Directory of Open Access Journals (Sweden)

    Na Li

    2016-01-01

    Full Text Available An integrate fabrication framework is presented to build heterogeneous objects (HEO using digital microdroplets injecting technology and rapid prototyping. The heterogeneous materials part design and manufacturing method in structure and material was used to change the traditional process. The net node method was used for digital modeling that can configure multimaterials in time. The relationship of material, color, and jetting nozzle was built. The main important contributions are to combine the structure, material, and visualization in one process and give the digital model for manufacture. From the given model, it is concluded that the method is effective for HEO. Using microdroplet rapid prototyping and the model given in the paper HEO could be gotten basically. The model could be used in 3D biomanufacturing.

  20. Dynamic imaging through turbid media based on digital holography.

    Science.gov (United States)

    Li, Shiping; Zhong, Jingang

    2014-03-01

    Imaging through turbid media using visible or IR light instead of harmful x ray is still a challenging problem, especially in dynamic imaging. A method of dynamic imaging through turbid media using digital holography is presented. In order to match the coherence length between the dynamic object wave and the reference wave, a cw laser is used. To solve the problem of difficult focusing in imaging through turbid media, an autofocus technology is applied. To further enhance the image contrast, a spatial filtering technique is used. A description of digital holography and experiments of imaging the objects hidden in turbid media are presented. The experimental result shows that dynamic images of the objects can be achieved by the use of digital holography.

  1. Multirate Digital Filters Based on FPGA and Its Applications

    International Nuclear Information System (INIS)

    Sharaf El-Din, R.M.A.

    2013-01-01

    Digital Signal Processing (DSP) is one of the fastest growing techniques in the electronics industry. It is used in a wide range of application fields such as, telecommunications, data communications, image enhancement and processing, video signals, digital TV broadcasting, and voice synthesis and recognition. Field Programmable Gate Array (FPGA) offers good solution for addressing the needs of high performance DSP systems. The focus of this thesis is on one of the basic DSP functions, namely filtering signals to remove unwanted frequency bands. Multi rate Digital Filters (MDFs) are the main theme here. Theory and implementation of MDF, as a special class of digital filters, will be discussed. Multi rate digital filters represent a class of digital filters having a number of attractive features like, low requirements for the coefficient word lengths, significant saving in computation and storage requirements results in a significant reduction in its dynamic power consumption. This thesis introduces an efficient FPGA realization of a multi rate decimation filter with narrow pass-band and narrow transition band to reduce the frequency sample rate by factor of 64 for noise thermometer applications. The proposed multi rate decimation filter is composed of three stages; the first stage is a Cascaded Integrator Comb (CIC) decimation filter, the second stage is a two-coefficient Half-Band (HB) filter and the last stage is a sharper transition HB filter. The frequency responses of individual stages as well as the overall filter response have been demonstrated with full simulation using MATLAB. The design and implementation of the proposed MDF on FPGA (XILINX Virtex XCV800 BG432-4), using VHSIC Hardware Description Language (VHDL), has been introduced. The implementation areas of the proposed filter stages are compared. Using CIC-HB technique saves 18% of the design area, compared to using six stages HB decimation filters.

  2. Sound card based digital correlation detection of weak photoelectrical signals

    International Nuclear Information System (INIS)

    Tang Guanghui; Wang Jiangcheng

    2005-01-01

    A simple and low-cost digital correlation method is proposed to investigate weak photoelectrical signals, using a high-speed photodiode as detector, which is directly connected to a programmably triggered sound card analogue-to-digital converter and a personal computer. Two testing experiments, autocorrelation detection of weak flickering signals from a computer monitor under background of noisy outdoor stray light and cross-correlation measurement of the surface velocity of a motional tape, are performed, showing that the results are reliable and the method is easy to implement

  3. Single InAs/GaSb nanowire low-power CMOS inverter.

    Science.gov (United States)

    Dey, Anil W; Svensson, Johannes; Borg, B Mattias; Ek, Martin; Wernersson, Lars-Erik

    2012-11-14

    III-V semiconductors have so far predominately been employed for n-type transistors in high-frequency applications. This development is based on the advantageous transport properties and the large variety of heterostructure combinations in the family of III-V semiconductors. In contrast, reports on p-type devices with high hole mobility suitable for complementary metal-oxide-semiconductor (CMOS) circuits for low-power operation are scarce. In addition, the difficulty to integrate both n- and p-type devices on the same substrate without the use of complex buffer layers has hampered the development of III-V based digital logic. Here, inverters fabricated from single n-InAs/p-GaSb heterostructure nanowires are demonstrated in a simple processing scheme. Using undoped segments and aggressively scaled high-κ dielectric, enhancement mode operation suitable for digital logic is obtained for both types of transistors. State-of-the-art on- and off-state characteristics are obtained and the individual long-channel n- and p-type transistors exhibit minimum subthreshold swings of SS = 98 mV/dec and SS = 400 mV/dec, respectively, at V(ds) = 0.5 V. Inverter characteristics display a full signal swing and maximum gain of 10.5 with a small device-to-device variability. Complete inversion is measured at low frequencies although large parasitic capacitances deform the waveform at higher frequencies.

  4. Research of Digital Interface Layout Design based on Eye-tracking

    Directory of Open Access Journals (Sweden)

    Shao Jiang

    2015-01-01

    Full Text Available The aim of this paper is to improve the low service efficiency and unsmooth human-computer interaction caused by currently irrational layouts of digital interfaces for complex systems. Also, three common layout structures for digital interfaces are to be presented and five layout types appropriate for multilevel digital interfaces are to be summarized. Based on the eye tracking technology, an assessment was conducted in advantages and disadvantages of different layout types through subjects’ search efficiency. Based on data and results, this study constructed a matching model which is appropriate for multilevel digital interface layout and verified the fact that the task element is a significant and important aspect of layout design. A scientific experimental model of research on digital interfaces for complex systems is provided. Both data and conclusions of the eye movement experiment provide a reference for layout designs of interfaces for complex systems with different task characteristics.

  5. Five-Level Z-Source Neutral Point-Clamped Inverter

    DEFF Research Database (Denmark)

    Gao, F.; Loh, P.C.; Blaabjerg, Frede

    2007-01-01

    This paper proposes a five-level Z-source neutralpoint- clamped (NPC) inverter with two Z-source networks functioning as intermediate energy storages coupled between dc sources and NPC inverter circuitry. Analyzing the operational principles of Z-source network with partial dclink shoot......-through scheme reveals the hidden theories in the five-level Z-source NPC inverter unlike the operational principle appeared in the general two-level Z-source inverter, so that the five-level Z-source NPC inverter can be designed with the modulation of carrier-based phase disposition (PD) or alternative phase...

  6. Single Stage String Inverter for Gridconnected Photovoltaic System with Modified Perturb and Observe (P&O Fuzzy Logic Control(FLC-based MPPT Technique

    Directory of Open Access Journals (Sweden)

    S.Z.Mohammad Noor

    2016-06-01

    Full Text Available This paper presents an implementation of Single-phase Single stage String inverter for Grid connected Photovoltaic (PV system. The proposed system uses Modified Perturb and Observe (P&O algorithm implemented using Fuzzy Logic Control (FLC as Maximum Power Point Tracking (MPPT. The inverter is designed for 340W system using two series of STP170s24/Ac PV modules. The MPPT unit keeps tracking the maximum power from the PV array by changing the modulation index and the phase angle of inverter’s output voltage. The simulation model is developed using Matlab/Simulink to evaluate the performance of the converter. Selected experimental results are also presented in this paper.

  7. Monolithically Integrated Flexible Black Phosphorus Complementary Inverter Circuits.

    Science.gov (United States)

    Liu, Yuanda; Ang, Kah-Wee

    2017-07-25

    Two-dimensional (2D) inverters are a fundamental building block for flexible logic circuits which have previously been realized by heterogeneously wiring transistors with two discrete channel materials. Here, we demonstrate a monolithically integrated complementary inverter made using a homogeneous black phosphorus (BP) nanosheet on flexible substrates. The digital logic inverter circuit is demonstrated via effective threshold voltage tuning within a single BP material, which offers both electron and hole dominated conducting channels with nearly symmetric pinch-off and current saturation. Controllable electron concentration is achieved by accurately modulating the aluminum (Al) donor doping, which realizes BP n-FET with a room-temperature on/off ratio >10 3 . Simultaneously, work function engineering is employed to obtain a low Schottky barrier contact electrode that facilities hole injection, thus enhancing the current density of the BP p-FET by 9.4 times. The flexible inverter circuit shows a clear digital logic voltage inversion operation along with a larger-than-unity direct current voltage gain, while exhibits alternating current dynamic signal switching at a record high frequency up to 100 kHz and remarkable electrical stability upon mechanical bending with a radii as small as 4 mm. Our study demonstrates a practical monolithic integration strategy for achieving functional logic circuits on one material platform, paving the way for future high-density flexible electronic applications.

  8. Digital Storytelling in a Place-Based Composition Course

    Science.gov (United States)

    Chisholm, James S.; Trent, Brandie

    2014-01-01

    Although the study of place in the fields of composition and education has a long and compelling history, the concept has taken on increased importance in today's digital landscape. As perceptions of places shift, we're challenged to understand how and which places shape who we are. Due to its potential power to leverage student choice,…

  9. Digital signal display board design: A knowledge based study

    International Nuclear Information System (INIS)

    Chaitanya, V. Sree Krishna; Rao, C. Raghavendra

    2007-01-01

    The digital signal display board is assumed to be composed of picture tubes for the purpose of displaying characters. The signal board with the picture tubes constitutes an Information System. A methodology for obtaining the discrimable matrix or table (more decisive attributes) and knowledge reduction for the above information system is proposed

  10. development of microcontroller based binaural digital hearing aids

    African Journals Online (AJOL)

    HOD

    but only a small portion of human population seek help and use them [3], though the ... stigma of putting on of digital hearing aid will no longer be there as before. ... 36, No. 3, July 2017 911 aids including the programmability, self-monitoring,.

  11. Analysis and Experimental Verification of New Power Flow Control for Grid-Connected Inverter with LCL Filter in Microgrid

    Science.gov (United States)

    Gu, Herong; Guan, Yajuan; Wang, Huaibao; Wei, Baoze; Guo, Xiaoqiang

    2014-01-01

    Microgrid is an effective way to integrate the distributed energy resources into the utility networks. One of the most important issues is the power flow control of grid-connected voltage-source inverter in microgrid. In this paper, the small-signal model of the power flow control for the grid-connected inverter is established, from which it can be observed that the conventional power flow control may suffer from the poor damping and slow transient response. While the new power flow control can mitigate these problems without affecting the steady-state power flow regulation. Results of continuous-domain simulations in MATLAB and digital control experiments based on a 32-bit fixed-point TMS320F2812 DSP are in good agreement, which verify the small signal model analysis and effectiveness of the proposed method. PMID:24672304

  12. Analysis and experimental verification of new power flow control for grid-connected inverter with LCL filter in microgrid.

    Science.gov (United States)

    Gu, Herong; Guan, Yajuan; Wang, Huaibao; Wei, Baoze; Guo, Xiaoqiang

    2014-01-01

    Microgrid is an effective way to integrate the distributed energy resources into the utility networks. One of the most important issues is the power flow control of grid-connected voltage-source inverter in microgrid. In this paper, the small-signal model of the power flow control for the grid-connected inverter is established, from which it can be observed that the conventional power flow control may suffer from the poor damping and slow transient response. While the new power flow control can mitigate these problems without affecting the steady-state power flow regulation. Results of continuous-domain simulations in MATLAB and digital control experiments based on a 32-bit fixed-point TMS320F2812 DSP are in good agreement, which verify the small signal model analysis and effectiveness of the proposed method.

  13. The theory and implementation of a high quality pulse width modulated waveform synthesiser applicable to voltage FED inverters

    Science.gov (United States)

    Lower, Kim Nigel

    1985-03-01

    Modulation processes associated with the digital implementation of pulse width modulation (PWM) switching strategies were examined. A software package based on a portable turnkey structure is presented. Waveform synthesizer implementation techniques are reviewed. A three phase PWM waveform synthesizer for voltage fed inverters was realized. It is based on a constant carrier frequency of 18 kHz and a regular sample, single edge, asynchronous PWM switching scheme. With high carrier frequencies, it is possible to utilize simple switching strategies and as a consequence, many advantages are highlighted, emphasizing the importance to industrial and office markets.

  14. Ultraviolet-ozone surface modification for non-wetting hole transport materials based inverted planar perovskite solar cells with efficiency exceeding 18%

    Science.gov (United States)

    Xu, Xiuwen; Ma, Chunqing; Cheng, Yuanhang; Xie, Yue-Min; Yi, Xueping; Gautam, Bhoj; Chen, Shengmei; Li, Ho-Wa; Lee, Chun-Sing; So, Franky; Tsang, Sai-Wing

    2017-08-01

    Non-wetting hole transport materials (HTMs) have great potential in facilitating large-sized perovskite crystal growth and enhancing device stability by opposing moisture ingress, However, the severe non-wetting issue limits the wide application of these materials in low-temperature solution-processed inverted planar perovskite solar cells (PVSCs), and corresponding devices are rarely reported. Here, a facile ultraviolet-ozone (UVO) modification method is demonstrated to overcome this issue. By carefully controlling the UVO modification time, the surface wettability of poly-TPD can be tuned without affecting the bulk properties of the film, hence perovskite films with desired grain size and excellent coverage can be deposited via a one-step spin-coating method. Benefiting from the high-quality perovskite, well-matched energy level alignment and hydrophobic property of poly-TPD, the resulting PVSCs show a champion power conversion efficiency of 18.19% with significantly enhanced stability as compared to the PEDOT:PSS counterparts. Moreover, the UVO modification approach also demonstrates its validity when being extended to other hydrophobic HTMs. This work not only provides a general strategy to broaden the selection pool of HTMs for solution-processed inverted planar PVSCs, but also may triggers the exploration of more advanced strategies to make non-wetting HTMs applicable in solution-processed inverted planar PVSCs.

  15. Brushless DC motor drives supplied by PV power system based on Z-source inverter and FL-IC MPPT controller

    International Nuclear Information System (INIS)

    Mozaffari Niapour, S.A.KH.; Danyali, S.; Sharifian, M.B.B.; Feyzi, M.R.

    2011-01-01

    Highlights: → Employing the BLDC motor in water pumping systems. → Utilizing the ZSI as a single-stage power converter in the PV water pumping systems based on BLDC motor. → Improvement of the conventional IC MPPT method with the fuzzy logic control scheme to save more energy from the PV array. → Taking the advantages of the DTC drive of the BLDC motor. → Optimizing the water pumping system speed response characteristic by PSO. - Abstract: This paper discusses operation performance of a water pumping system consist of a brushless dc (BLDC) motor coupled a centrifugal pump and accompanying a Z-source inverter (ZSI) fed by a photovoltaic (PV) array, to be improved. Despite conventional double-stage power converters, this paper proposes utilizing a single-stage ZSI to extract the maximum power of the PV array and supply the BLDC motor simultaneously. Utilizing the ZSI provides some inherent advantages such as high efficiency and low cost, which is very promising for PV systems due to its novel voltage buck/boost capability. In addition, in order to precisely perform the maximum power point tracking (MPPT) of the PV array the fuzzy logic-incremental conductance (FL-IC) MPPT scheme is proposed. The proposed FL-IC MPPT scheme provides enough modification to the conventional IC method to enjoy an appropriate variable step size MPPT control signal for the ZSI. Moreover, direct torque control (DTC) is found more effective in comparison with hysteresis current control with current shaping to drive the BLDC motor, because it benefits from faster torque response, reduced torque ripple, less sensitivity to parameters variations, and simple implementation. In the mean time, due to the frequently variations of the PV power generation; delivered mechanical power to the centrifugal pump is variable. Thus, the BLDC motor should be driven with variable reference speed. In order to improve the speed transient response of the BLDC motor and enhance the energy saving aspect of

  16. Mapping specific soil functions based on digital soil property maps

    Science.gov (United States)

    Pásztor, László; Fodor, Nándor; Farkas-Iványi, Kinga; Szabó, József; Bakacsi, Zsófia; Koós, Sándor

    2016-04-01

    Quantification of soil functions and services is a great challenge in itself even if the spatial relevance is supposed to be identified and regionalized. Proxies and indicators are widely used in ecosystem service mapping. Soil services could also be approximated by elementary soil features. One solution is the association of soil types with services as basic principle. Soil property maps however provide quantified spatial information, which could be utilized more versatilely for the spatial inference of soil functions and services. In the frame of the activities referred as "Digital, Optimized, Soil Related Maps and Information in Hungary" (DOSoReMI.hu) numerous soil property maps have been compiled so far with proper DSM techniques partly according to GSM.net specifications, partly by slightly or more strictly changing some of its predefined parameters (depth intervals, pixel size, property etc.). The elaborated maps have been further utilized, since even DOSoReMI.hu was intended to take steps toward the regionalization of higher level soil information (secondary properties, functions, services). In the meantime the recently started AGRAGIS project requested spatial soil related information in order to estimate agri-environmental related impacts of climate change and support the associated vulnerability assessment. One of the most vulnerable services of soils in the context of climate change is their provisioning service. In our work it was approximated by productivity, which was estimated by a sequential scenario based crop modelling. It took into consideration long term (50 years) time series of both measured and predicted climatic parameters as well as accounted for the potential differences in agricultural practice and crop production. The flexible parametrization and multiple results of modelling was then applied for the spatial assessment of sensitivity, vulnerability, exposure and adaptive capacity of soils in the context of the forecasted changes in

  17. Signature Schemes Secure against Hard-to-Invert Leakage

    DEFF Research Database (Denmark)

    Faust, Sebastian; Hazay, Carmit; Nielsen, Jesper Buus

    2012-01-01

    of the secret key. As a second contribution, we construct a signature scheme that achieves security for random messages assuming that the adversary is given a polynomial-time hard to invert function. Here, polynomial-hardness is required even when given the entire public-key – so called weak auxiliary input......-theoretically reveal the entire secret key. In this work, we propose the first constructions of digital signature schemes that are secure in the auxiliary input model. Our main contribution is a digital signature scheme that is secure against chosen message attacks when given an exponentially hard-to-invert function...... security. We show that such signature schemes readily give us auxiliary input secure identification schemes...

  18. Digital acquisition and wavelength control of seed laser for space-based Lidar applications, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR Phase I proposes to establish the feasibility of using a space qualifiable Field Programmable Gate Array (FPGA) based digital controller to autonomously...

  19. Advanced Control of Wheeled Inverted Pendulum Systems

    CERN Document Server

    Li, Zhijun; Fan, Liping

    2013-01-01

    Advanced Control of Wheeled Inverted Pendulum Systems is an orderly presentation of recent ideas for overcoming the complications inherent in the control of wheeled inverted pendulum (WIP) systems, in the presence of uncertain dynamics, nonholonomic kinematic constraints as well as underactuated configurations. The text leads the reader in a theoretical exploration of problems in kinematics,dynamics modeling, advanced control design techniques,and trajectory generation for WIPs. An important concern is how to deal with various uncertainties associated with the nominal model, WIPs being characterized by unstable balance and unmodelled dynamics and being subject to time-varying external disturbances for which accurate models are hard to come by.   The book is self-contained, supplying the reader with everything from mathematical preliminaries and the basic Lagrange-Euler-based derivation of dynamics equations to various advanced motion control and force control approaches as well as trajectory generation met...

  20. Design of a digital PAD based on I/Q demodulation principle

    International Nuclear Information System (INIS)

    Geng Zheqiao; Cui Yanyan; Hou Mi; Pei Guoxi

    2005-01-01

    Conventional analog I/Q demodulator suffers from phase and amplitude imbalance and DC offset, which cause big error into the measurement. A digital PAD is designed. Based on I/Q demodulation principle, using digital algorithms, such as digital filter and Hilbert transform, the conventional measurement error can basically be removed. Measuremental results show that the digital PAD has a maximum phase error of ±0.5 degree and a resolution of 0.2 degree. Its temperature coefficient is -0.1 degree/degree C. Its dynamic ranges for phase-measurement and amplitude-measurement are -1825 dBm and -2020 dBm, respectively. The digital PAD can meet the need of the BEPC II phasing system. (authors)

  1. Digitized self-oscillating loop for piezoelectric transformer-based power converters

    DEFF Research Database (Denmark)

    Ekhtiari, Marzieh; Andersen, Thomas; Zhang, Zhe

    2016-01-01

    A new method is implemented in designing of self-oscillating loop for driving piezoelectric transformers. The implemented method is based on combining both analog and digital control systems. Digitized delay, or digitized phase shift through the self-oscillating loop results in a very precise...... frequency control and ensures an optimum operation of the piezoelectric transformer in terms of voltage gain and efficiency. In this work, additional time delay is implemented digitally for the first time through 16 bit digital-to-analog converter to the self-oscillating loop. Delay control setpoints...... updates at a rate of 417 kHz. This allows the control loop to dynamically follow frequency changes of the transformer in each resonant cycle. The operation principle behind self-oscillating is discussed in this paper. Moreover, experimental results are reported....

  2. Method and apparatus for digitally based high speed x-ray spectrometer

    International Nuclear Information System (INIS)

    Warburton, W.K.; Hubbard, B.

    1997-01-01

    A high speed, digitally based, signal processing system which accepts input data from a detector-preamplifier and produces a spectral analysis of the x-rays illuminating the detector. The system achieves high throughputs at low cost by dividing the required digital processing steps between a ''hardwired'' processor implemented in combinatorial digital logic, which detects the presence of the x-ray signals in the digitized data stream and extracts filtered estimates of their amplitudes, and a programmable digital signal processing computer, which refines the filtered amplitude estimates and bins them to produce the desired spectral analysis. One set of algorithms allow this hybrid system to match the resolution of analog systems while operating at much higher data rates. A second set of algorithms implemented in the processor allow the system to be self calibrating as well. The same processor also handles the interface to an external control computer. 19 figs

  3. From Process to Practice: Towards a Practice-Based Model of Digital Innovation

    DEFF Research Database (Denmark)

    Ciriello, Raffaele; Richter, Alexander; Schwabe, Gerhard

    2017-01-01

    companies and an extensive set of empirical data, this paper conceptualizes four interrelated digital innovation practices, namely making sense of an idea, aligning mental models, negotiating solution paths, and crafting an idea. We suggest a practice-based model of digital innovation, specify a set......The ongoing digitalization of many corporate functions, including the innovation process, brings about fundamental changes that urge us to rethink established theories. Facilitating digital innovation requires a deep understanding of the actual practices that are carried out by innovating people...... with the help of artifacts. In this paper, we study the use of artifacts and illustrate their different roles in the underlying innovation practices to provide rich insights into digital innovation from a practice perspective. Grounded in a nearly three year-long, qualitative case study at two Swiss software...

  4. DIGITAL GAME-BASED LANGUAGE LEARNING IN FOREIGN LANGUAGE TEACHER EDUCATION

    OpenAIRE

    ALYAZ, Yunus; GENC, Zubeyde Sinem

    2016-01-01

    New technologies including digital game-based language learning have increasingly received attention. However, their implementation is far from expected and desired levels due to technical, instructional, financial and sociological barriers. Previous studies suggest that there is a strong need to establish courses in order to support adaptation of game-based learning pedagogy through helping teachers experience digital games themselves before they are expected to use them in teaching. This st...

  5. Aircraft route planning based on digital map pre-treatment

    Directory of Open Access Journals (Sweden)

    Ran ZHEN

    2015-04-01

    Full Text Available Aiming at the flight path project in low complicated airspace, the influence of terrain conditions and surface threatening to aircraft flight are studied. Through the analysis of digital map and static threat, the paper explores the processing method of the digital map, and uses the Hermite function to process the map smoothly, reducing the searching range of optimal trajectory. By designing the terrain following, terrain avoidance and the way of avoiding a threat, the safety of aircraft can be guaranteed. In-depth analysis of particle swarm optimization (PSO algorithm realizes the three dimensional paths project before the aircraft performs a task. Through simulation, the difference of the maps before and after processing is shown, and offline programming of the three dimensional optimal path is achieved.

  6. Investigating User Interfaces of Non-Iranian Digital Libraries based on Social Bookmarking Capabilities and Characteristics to Use by Iranian Digital Libraries

    Directory of Open Access Journals (Sweden)

    Zahra Naseri

    2016-08-01

    Full Text Available Current study aims to investigate the status of user interfaces of non-Iranian digital libraries’ based on social bookmarking capabilities and characteristics to use by Iranian digital libraries. This research studies the characteristics and capabilities of top digital libraries’ user interfaces in the world based on social bookmarking used by library users. This capability facilitates producing, identifying, organizing, and sharing contents using tags. Survey method was used with descriptive-analytical approach in this study. Populations include non-Iranian digital libraries interfaces. Top ten digital libraries’ interfaces were selected as the sample. A researcher-made checklist prepared based on literature review and investigating four distinguished websites (Library Thing, Delicious, Amazon, and Google Book. Faced validity evaluated by 10 experts’ viewpoints, then reliability calculated 0.87.Findings of this study are important because of two reasons: first, it provides a comprehensive and an unambiguous vision for recognizing user interfaces’ basic capabilities and characteristics based on social bookmarking. Second, it can provide a base for designing digital libraries in Iran. The results showed that the majority of digital libraries around the world had not used web 2.0 characteristics such as producing, identifying, organizing, and sharing contents except two digital libraries (Google Books, and Ibiblio.

  7. A natural approach to convey numerical digits using hand activity recognition based on hand shape features

    Science.gov (United States)

    Chidananda, H.; Reddy, T. Hanumantha

    2017-06-01

    This paper presents a natural representation of numerical digit(s) using hand activity analysis based on number of fingers out stretched for each numerical digit in sequence extracted from a video. The analysis is based on determining a set of six features from a hand image. The most important features used from each frame in a video are the first fingertip from top, palm-line, palm-center, valley points between the fingers exists above the palm-line. Using this work user can convey any number of numerical digits using right or left or both the hands naturally in a video. Each numerical digit ranges from 0 to9. Hands (right/left/both) used to convey digits can be recognized accurately using the valley points and with this recognition whether the user is a right / left handed person in practice can be analyzed. In this work, first the hand(s) and face parts are detected by using YCbCr color space and face part is removed by using ellipse based method. Then, the hand(s) are analyzed to recognize the activity that represents a series of numerical digits in a video. This work uses pixel continuity algorithm using 2D coordinate geometry system and does not use regular use of calculus, contours, convex hull and datasets.

  8. Study on HRA-based method for assessing digital man-machine interface

    International Nuclear Information System (INIS)

    Li Pengcheng; Dai Licao; Zhang Li; Zhao Ming; Hu Hong

    2014-01-01

    In order to identify the design flaws of digital man-machine interface (MMI) that may trigger human errors or weaken the performance of operators, a HRA-based method (namely HCR + CREAM + HEC) for assessing digital MMI was established. Firstly, the HCR method was used to identify the risk scenarios of high human error probability from the overall event as a whole perspective. Then, for the identified high-risk scenarios, the CREAM was adopted to determine the various error modes and its error probability, and the failure probability was ranked. Finally, the human factors engineering checklist of digital MMI was established according to the characteristics of digital MMI, it was used to check the digital MMI with high error probability in order to identify the design flaws of digital MMI, and the suggestions of optimization were provided. The results show that the provided assessment method can quickly and efficiently identify the design flaws of digital MMI which easily trigger human errors, and the safety of operation of the digital control system for nuclear power plants can be enhanced by optimization of design. (authors)

  9. Evaluation of Resonant Damping Techniques for Z-Source Current-Type Inverter

    DEFF Research Database (Denmark)

    Blaabjerg, Frede; Loh, Poh Chiang; Gajanayake, C.J.

    2008-01-01

    For the renewable energy sources whose outputs vary continuously, a Z-source current-type inverter has been proposed as a possible buck-boost alternative for grid-interfacing. With a unique X-shaped LC network connected between its dc power source and inverter topology, Z-source current......-type inverter is however expected to suffer from compounded resonant complications in addition to those associated with its second-order output filter. To improve its damping performance, this paper proposes the careful integration of Posicast or three-step compensators before the inverter pulse-width modulator...... for damping triggered resonant oscillations. In total, two compensators are needed for wave-shaping the inverter boost factor and modulation ratio, and they can conveniently be implemented using first-in first-out stacks and embedded timers of modern digital signal processors widely used in motion control...

  10. Identification of the vital digital assets based on PSA results analysis

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Moon Kyoung; Seong, Poong Hyun [KAIST, Daejeon (Korea, Republic of); Son, Han Seong [Joongbu Univiersity, Geumsan (Korea, Republic of); Kim, Hyundoo [Korea Institute of Nuclear Nonproliferation and Control, Daejeon (Korea, Republic of)

    2016-10-15

    As the main systems for managing totally about the operation, control, monitoring, measurement, and safety function in an emergency, instrumentation and control systems (I and C) in nuclear power plants have been digitalized gradually for the precise operation and its convenience. The digitalization of infrastructure makes systems vulnerable to cyber threats and hybrid attacks. According to ICS-CERT report, as time goes by, the number of vulnerabilities in ICS industries increases rapidly. Recently, due to the digitalization of I and C, it has begun to rise the need of cyber security in the digitalized I and C in NPPs. However, there are too many critical digital assets (CDAs) in NPPs. More than 60% of the total critical systems are digital system. Addressing more than 100 security controls for each CDA needs too much effort for both licensee and inspector. It is necessary to focus on more significant CDAs for effective regulation. Probabilistic Safety Analysis (PSA) results are analyzed in order to identify more significant CDAs which could evoke an accident of NPPs by digital malfunction or cyber-attacks. By eliciting minimal cut sets using fault tree analyses, accident-related CDAs are drawn. Also the CDAs that must be secured from outsiders are elicited in case of some accident scenario. It is expected that effective cyber security regulation based on the graded approach can be implemented. Furthermore, defense-in-depth of digital assets for NPPs safety can be built up. Digital technologies such as computers, control systems, and data networks currently play essential roles in modern NPPs. Further, the introduction of new digitalized technologies is also being considered. These digital technologies make the operation of NPPs more convenient and economical; however, they are inherently susceptible to problems such as digital malfunction of components or cyber-attacks. Recently, needs for cyber security on digitalized nuclear Instrumentation and Control (I and C

  11. Identification of the vital digital assets based on PSA results analysis

    International Nuclear Information System (INIS)

    Choi, Moon Kyoung; Seong, Poong Hyun; Son, Han Seong; Kim, Hyundoo

    2016-01-01

    As the main systems for managing totally about the operation, control, monitoring, measurement, and safety function in an emergency, instrumentation and control systems (I and C) in nuclear power plants have been digitalized gradually for the precise operation and its convenience. The digitalization of infrastructure makes systems vulnerable to cyber threats and hybrid attacks. According to ICS-CERT report, as time goes by, the number of vulnerabilities in ICS industries increases rapidly. Recently, due to the digitalization of I and C, it has begun to rise the need of cyber security in the digitalized I and C in NPPs. However, there are too many critical digital assets (CDAs) in NPPs. More than 60% of the total critical systems are digital system. Addressing more than 100 security controls for each CDA needs too much effort for both licensee and inspector. It is necessary to focus on more significant CDAs for effective regulation. Probabilistic Safety Analysis (PSA) results are analyzed in order to identify more significant CDAs which could evoke an accident of NPPs by digital malfunction or cyber-attacks. By eliciting minimal cut sets using fault tree analyses, accident-related CDAs are drawn. Also the CDAs that must be secured from outsiders are elicited in case of some accident scenario. It is expected that effective cyber security regulation based on the graded approach can be implemented. Furthermore, defense-in-depth of digital assets for NPPs safety can be built up. Digital technologies such as computers, control systems, and data networks currently play essential roles in modern NPPs. Further, the introduction of new digitalized technologies is also being considered. These digital technologies make the operation of NPPs more convenient and economical; however, they are inherently susceptible to problems such as digital malfunction of components or cyber-attacks. Recently, needs for cyber security on digitalized nuclear Instrumentation and Control (I and C

  12. Digital radiography

    International Nuclear Information System (INIS)

    Brody, W.R.

    1984-01-01

    Digital Radiography begins with an orderly introduction to the fundamental concepts of digital imaging. The entire X-ray digital imagining system is described, from an overall characterization of image quality to specific components required for a digital radiographic system. Because subtraction is central to digital radiographic systems, the author details the use of various subtraction methods for image enhancement. Complex concepts are illustrated with numerous examples and presented in terms that can readily be understood by physicians without an advanced mathematics background. The second part of the book discusses implementations and applications of digital imagining systems based on area and scanned detector technologies. This section includes thorough coverage of digital fluoroscopy, scanned projection radiography, and film-based digital imaging systems, and features a state-of-the-art synopsis of the applications of digital subtraction angiography. The book concludes with a timely assessment of anticipated technological advances

  13. Preparation of inverted medium and processing in the inverted medium

    International Nuclear Information System (INIS)

    Zafarullah, Ijaz; Tian Minghzen; Chang Tiejun; Randall Babbitt, W.

    2007-01-01

    The processing of weak optical signals in spatial-spectral holographic (SSH) materials coherently inverted with optical frequency chirped pulses were investigated. Simulations and experimental studies in Tm 3+ :YAG were conducted to characterize the parameters of the frequency chirped laser pulse used to invert the SSH material in order to obtain high photon echo efficiency for SSH lidar processing. Collinear and angled beam geometries and single shot and accumulated processes were investigated. Echo efficiencies as high as 450% were measured, significantly higher than the typical stimulated photon echo efficiency of 10%

  14. Preparation of inverted medium and processing in the inverted medium

    Energy Technology Data Exchange (ETDEWEB)

    Zafarullah, Ijaz [Department of Physics, Montana State University, Bozeman, MT 59717 (United States)]. E-mail: ijaz@montana.edu; Tian Minghzen [Department of Physics, Montana State University, Bozeman, MT 59717 (United States); Chang Tiejun [The Spectrum Laboratory, Montana State University, Bozeman, MT 59717 (United States); Randall Babbitt, W. [Department of Physics, Montana State University, Bozeman, MT 59717 (United States)

    2007-11-15

    The processing of weak optical signals in spatial-spectral holographic (SSH) materials coherently inverted with optical frequency chirped pulses were investigated. Simulations and experimental studies in Tm{sup 3+}:YAG were conducted to characterize the parameters of the frequency chirped laser pulse used to invert the SSH material in order to obtain high photon echo efficiency for SSH lidar processing. Collinear and angled beam geometries and single shot and accumulated processes were investigated. Echo efficiencies as high as 450% were measured, significantly higher than the typical stimulated photon echo efficiency of 10%.

  15. Digital power and performance analysis of inkjet printed ring oscillators based on electrolyte-gated oxide electronics

    Science.gov (United States)

    Cadilha Marques, Gabriel; Garlapati, Suresh Kumar; Dehm, Simone; Dasgupta, Subho; Hahn, Horst; Tahoori, Mehdi; Aghassi-Hagmann, Jasmin

    2017-09-01

    Printed electronic components offer certain technological advantages over their silicon based counterparts, like mechanical flexibility, low process temperatures, maskless and additive manufacturing possibilities. However, to be compatible to the fields of smart sensors, Internet of Things, and wearables, it is essential that devices operate at small supply voltages. In printed electronics, mostly silicon dioxide or organic dielectrics with low dielectric constants have been used as gate isolators, which in turn have resulted in high power transistors operable only at tens of volts. Here, we present inkjet printed circuits which are able to operate at supply voltages as low as ≤2 V. Our transistor technology is based on lithographically patterned drive electrodes, the dimensions of which are carefully kept well within the printing resolutions; the oxide semiconductor, the electrolytic insulator and the top-gate electrodes have been inkjet printed. Our inverters show a gain of ˜4 and 2.3 ms propagation delay time at 1 V supply voltage. Subsequently built 3-stage ring oscillators start to oscillate at a supply voltage of only 0.6 V with a frequency of ˜255 Hz and can reach frequencies up to ˜350 Hz at 2 V supply voltage. Furthermore, we have introduced a systematic methodology for characterizing ring oscillators in the printed electronics domain, which has been largely missing. Benefiting from this procedure, we are now able to predict the switching capacitance and driver capability at each stage, as well as the power consumption of our inkjet printed ring oscillators. These achievements will be essential for analyzing the performance and power characteristics of future inkjet printed digital circuits.

  16. Current Harmonics from Single-Phase Grid-Connected Inverters

    DEFF Research Database (Denmark)

    Yang, Yongheng; Zhou, Keliang; Blaabjerg, Frede

    2016-01-01

    Environmental conditions and operational modes may significantly impact the distortion level of the injected current from single-phase grid-connected inverter systems, such as photovoltaic (PV) inverters, which may operate in cloudy days with a maximum power point tracking, in a non-unity power...... factor, or in the low voltage ride through mode with reactive current injection. In this paper, the mechanism of the harmonic current injection from grid-connected single-phase inverter systems is thus explored, and the analysis is conducted on single-phase PV systems. In particular, the analysis...... is focused on the impacts of the power factor and the feed-in grid current level on the quality of the feed-in grid current from single-phase inverters. As a consequence, an internal model principle based high performance current control solution is tailor-made and developed for single-phase grid-connected...

  17. An inverter/controller subsystem optimized for photovoltaic applications

    Science.gov (United States)

    Pickrell, R. L.; Merrill, W. C.; Osullivan, G.

    1978-01-01

    Conversion of solar array dc power to ac power stimulated the specification, design, and simulation testing of an inverter/controller subsystem tailored to the photovoltaic power source characteristics. This paper discusses the optimization of the inverter/controller design as part of an overall Photovoltaic Power System (PPS) designed for maximum energy extraction from the solar array. The special design requirements for the inverter/controller include: (1) a power system controller (PSC) to control continuously the solar array operating point at the maximum power level based on variable solar insolation and cell temperatures; and (2) an inverter designed for high efficiency at rated load and low losses at light loadings to conserve energy. It must be capable of operating connected to the utility line at a level set by an external controller (PSC).

  18. Design optimization of grid-connected PV inverters

    DEFF Research Database (Denmark)

    Koutroulis, Eftichios; Blaabjerg, Frede

    2011-01-01

    The DC/AC inverters are the key elements in grid-connected PV energy production systems. In this paper, new design optimization techniques focused on transformerless (very high efficiency) PV inverters are proposed. They have been developed based on an analysis of the deficiencies of the current......, state-of-the-art PV inverters design technology, which limits the amount of PV energy supplied into the electric grid. The influences of the electric grid regulations and standards and the PV array operational characteristics on the design of grid-connected PV inverters have also been considered....... The simulation results verify that the proposed optimization techniques enable the maximization of the PV energy injected into the electric grid by the optimized PV installation....

  19. Concept and benefits of the Inverted Classroom method for a competency-based biochemistry course in the pre-clinical stage of a human medicine course of studies.

    Science.gov (United States)

    Kühl, Susanne J; Toberer, Matthias; Keis, Oliver; Tolks, Daniel; Fischer, Martin R; Kühl, Michael

    2017-01-01

    Background: Medical students often have a problem recognising the relevance of basic science subjects for their later professional work in the pre-clinical stage of their studies. This can lead to a lower motivation to learn biochemical content and dissatisfaction in the courses amongst the students. Alternative teaching methods such as the Inverted Classroom (IC) method can address this deficiency. The goal of this study was: to analyse the motivation and satisfaction of the students in a biochemistry seminar through the use of the e-learning-based IC method, to investigate the acceptance against the IC teaching method in biochemistry, and to compare the learning success achieved using the IC approach with that of a traditional course. We also investigated how a biochemistry course in the pre-clinical stage of a human medicine course of studies can be successfully organised according to the IC method. Furthermore, we examined the benefits of the IC method over conventional teaching formats. Method: The IC method was implemented in accordance with the guidelines of the GMA committee "New Media" [30] in a biochemistry seminar for two student IC intervention groups with 42 students. A part of the factual knowledge from the on-site phase in the form of teaching videos together with self-learning control tasks were provided online before the seminar for both IC intervention groups. Exporting content to the self-learning phase creates new free time in the on-site phase, during which the content can be critically considered and processed and additional competency-based learning objectives can be taught. Identical biochemistry teaching content was taught in parallel control groups (14 student groups with n=299 students), but no material was handed out beforehand for a self-learning phase. These students only received the materials after the on-site phase. Motivation and satisfaction as well as the acceptance for the teaching methods were recorded by questionnaires, the

  20. Development of FPGA-based digital signal processing system for radiation spectroscopy

    International Nuclear Information System (INIS)

    Lee, Pil Soo; Lee, Chun Sik; Lee, Ju Hahn

    2013-01-01

    We have developed an FPGA-based digital signal processing system that performs both online digital signal filtering and pulse-shape analysis for both particle and gamma-ray spectroscopy. Such functionalities were made possible by a state-of-the-art programmable logic device and system architectures employed. The system performance as measured, for example, in the system dead time and accuracy for pulse-height and rise-time determination, was evaluated with standard alpha- and gamma-ray sources using a CsI(Tl) scintillation detector. It is resulted that the present system has shown its potential application to various radiation-related fields such as particle identification, radiography, and radiation imaging. - Highlights: ► An FPGA-based digital processing system was developed for radiation spectroscopy. ► Our digital system has a 14-bit resolution and a 100-MHz sampling rate. ► The FPGA implements the online digital filtering and pulse-shape analysis. ► The pileup rejection is implemented in trigger logic before digital filtering process. ► Our digital system was verified in alpha-gamma measurements using a CsI detector