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  Subjects -> ELECTRONICS (Total: 153 journals)
Advances in Biosensors and Bioelectronics     Open Access   (Followers: 1)
Advances in Electronics     Open Access   (Followers: 3)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 5)
Advances in Microelectronic Engineering     Open Access   (Followers: 2)
Advances in Power Electronics     Open Access   (Followers: 7)
Aerospace and Electronic Systems, IEEE Transactions on     Hybrid Journal   (Followers: 98)
American Journal of Electrical and Electronic Engineering     Open Access   (Followers: 12)
Annals of Telecommunications     Hybrid Journal   (Followers: 4)
APL : Organic Electronics and Photonics     Hybrid Journal   (Followers: 1)
APSIPA Transactions on Signal and Information Processing     Open Access   (Followers: 6)
Archives of Electrical Engineering     Open Access   (Followers: 9)
Autonomous Mental Development, IEEE Transactions on     Hybrid Journal   (Followers: 5)
Bell Labs Technical Journal     Hybrid Journal   (Followers: 10)
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (Followers: 16)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 15)
Biomedical Instrumentation & Technology     Hybrid Journal   (Followers: 5)
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 5)
BULLETIN of National Technical University of Ukraine. Series RADIOTECHNIQUE. RADIOAPPARATUS BUILDING     Open Access   (Followers: 2)
Bulletin of the Polish Academy of Sciences : Technical Sciences     Open Access  
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 13)
China Communications     Full-text available via subscription   (Followers: 4)
Circuits and Systems     Open Access   (Followers: 9)
Consumer Electronics Times     Open Access   (Followers: 4)
Control Systems     Hybrid Journal   (Followers: 26)
Electronic Design     Partially Free  
Electronic Markets     Hybrid Journal   (Followers: 5)
Electronic Materials Letters     Hybrid Journal   (Followers: 3)
Electronics     Open Access   (Followers: 9)
Electronics and Communications in Japan     Hybrid Journal   (Followers: 5)
Electronics Letters     Hybrid Journal   (Followers: 20)
Embedded Systems Letters, IEEE     Hybrid Journal   (Followers: 23)
Energy Harvesting and Systems : Materials, Mechanisms, Circuits and Storage     Hybrid Journal   (Followers: 1)
EPJ Quantum Technology     Open Access  
EURASIP Journal on Embedded Systems     Open Access   (Followers: 9)
Facta Universitatis, Series : Electronics and Energetics     Open Access  
Frequenz     Hybrid Journal   (Followers: 3)
Frontiers of Optoelectronics     Hybrid Journal   (Followers: 2)
Geoscience and Remote Sensing, IEEE Transactions on     Hybrid Journal   (Followers: 20)
Haptics, IEEE Transactions on     Hybrid Journal   (Followers: 3)
IEEE Antennas and Propagation Magazine     Hybrid Journal   (Followers: 15)
IEEE Antennas and Wireless Propagation Letters     Hybrid Journal   (Followers: 13)
IEEE Consumer Electronics Magazine     Full-text available via subscription   (Followers: 17)
IEEE Journal of Emerging and Selected Topics in Power Electronics     Hybrid Journal   (Followers: 12)
IEEE Journal of the Electron Devices Society     Open Access   (Followers: 3)
IEEE Power Electronics Magazine     Full-text available via subscription   (Followers: 7)
IEEE Transactions on Antennas and Propagation     Full-text available via subscription   (Followers: 10)
IEEE Transactions on Audio, Speech, and Language Processing     Hybrid Journal   (Followers: 13)
IEEE Transactions on Automatic Control     Hybrid Journal   (Followers: 26)
IEEE Transactions on Consumer Electronics     Hybrid Journal   (Followers: 17)
IEEE Transactions on Electron Devices     Hybrid Journal   (Followers: 8)
IEEE Transactions on Information Theory     Hybrid Journal   (Followers: 14)
IEEE Transactions on Power Electronics     Hybrid Journal   (Followers: 21)
IEICE - Transactions on Electronics     Full-text available via subscription   (Followers: 8)
IEICE - Transactions on Information and Systems     Full-text available via subscription   (Followers: 7)
IET Microwaves, Antennas & Propagation     Hybrid Journal   (Followers: 6)
IET Power Electronics     Hybrid Journal   (Followers: 14)
IET Wireless Sensor Systems     Hybrid Journal   (Followers: 10)
IETE Journal of Education     Open Access   (Followers: 2)
IETE Journal of Research     Open Access   (Followers: 9)
IETE Technical Review     Open Access   (Followers: 4)
Industrial Electronics, IEEE Transactions on     Hybrid Journal   (Followers: 13)
Industry Applications, IEEE Transactions on     Hybrid Journal   (Followers: 3)
Informatik-Spektrum     Hybrid Journal  
Instabilities in Silicon Devices     Full-text available via subscription  
Intelligent Transportation Systems Magazine, IEEE     Full-text available via subscription   (Followers: 2)
International Journal of Advanced Electronics and Communication Systems     Open Access   (Followers: 5)
International Journal of Advanced Research in Computer Science and Electronics Engineering     Open Access   (Followers: 20)
International Journal of Advances in Telecommunications, Electrotechnics, Signals and Systems     Open Access   (Followers: 3)
International Journal of Aerospace Innovations     Full-text available via subscription   (Followers: 12)
International Journal of Antennas and Propagation     Open Access   (Followers: 7)
International Journal of Applied Electronics in Physics & Robotics     Open Access   (Followers: 1)
International Journal of Biomedical Nanoscience and Nanotechnology     Hybrid Journal   (Followers: 6)
International Journal of Computational Vision and Robotics     Hybrid Journal   (Followers: 4)
International Journal of Computer & Electronics Research     Full-text available via subscription   (Followers: 2)
International Journal of Control     Hybrid Journal   (Followers: 13)
International Journal of Electronics     Hybrid Journal   (Followers: 2)
International Journal of Electronics & Data Communication     Open Access   (Followers: 4)
International Journal of Electronics and Telecommunications     Open Access   (Followers: 3)
International Journal of Granular Computing, Rough Sets and Intelligent Systems     Hybrid Journal   (Followers: 1)
International Journal of High Speed Electronics and Systems     Hybrid Journal  
International Journal of Microwave and Wireless Technologies     Hybrid Journal   (Followers: 1)
International Journal of Nano Devices, Sensors and Systems     Open Access   (Followers: 4)
International Journal of Nanoscience     Hybrid Journal  
International Journal of Numerical Modelling:Electronic Networks, Devices and Fields     Hybrid Journal   (Followers: 2)
International Journal of Power Electronics     Hybrid Journal   (Followers: 8)
International Journal of Review in Electronics & Communication Engineering     Open Access   (Followers: 2)
International Journal of Sensors, Wireless Communications and Control     Hybrid Journal   (Followers: 3)
International Journal of Superconductivity     Open Access  
International Journal of Systems, Control and Communications     Hybrid Journal   (Followers: 2)
International Journal on Communication     Full-text available via subscription   (Followers: 9)
International Journal on Electrical and Power Engineering     Full-text available via subscription   (Followers: 10)
International Transaction of Electrical and Computer Engineers System     Open Access  
Journal of Biosensors & Bioelectronics     Open Access   (Followers: 2)
Journal of Advanced Dielectrics     Open Access   (Followers: 1)
Journal of Artificial Intelligence     Open Access   (Followers: 5)
Journal of Circuits, Systems, and Computers     Hybrid Journal   (Followers: 1)
Journal of Computational Intelligence and Electronic Systems     Full-text available via subscription  
Journal of Electrical and Electronics Engineering Research     Open Access   (Followers: 4)
Journal of Electrical Bioimpedance     Full-text available via subscription   (Followers: 2)
Journal of Electrical Engineering & Electronic Technology     Hybrid Journal   (Followers: 2)

        1 2 | Last

Journal Cover   IEEE Transactions on Power Electronics
  [SJR: 2.866]   [H-I: 128]   [21 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0885-8993
   Published by Institute of Electrical and Electronics Engineers (IEEE) Homepage  [176 journals]
  • IEEE Power Electronics Society Information
    • Abstract: Provides a listing of board members, committee members and society officers.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Blank page
    • Abstract: This page or pages intentionally left blank.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Table of Contents
    • Pages: 6471
      Abstract: Presents the table of contents for this issue of the publication.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • IEEE Transactions on Power Electronics publication information
    • Abstract: Provides a listing of the editors, board members, and current staff for this issue of the publication.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Analysis and Implementation of Parallel Connected Two-Induction Motor
           
    • Authors: Gunabalan; R.;Sanjeevikumar, P.;Blaabjerg, F.;Ojo, O.;Subbiah, V.;
      Pages: 6472 - 6475
      Abstract: Sensorless-based direct vector control techniques are widely used for three-phase induction motor drive, whereas in case of multiple-motor control, it becomes intensively complicated and very few research articles in support to industrial applications were found. A straight-forward direct vector control with sensorless operation for parallel connected two similar-rated induction motors driven by single three-phase inverter is proposed and verified numerically by simulation software test under balanced and unbalanced conditions. The proposed control algorithm adapts the natural observer to estimate the rotor speed, rotor flux, and load torque of both motors. Simulation results along with theoretical background provided in this paper confirm the feasibility of operation of the ac motors and proves reliability for industrial applications.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Novel High Step-Up DC–DC Converter With an Active Coupled-Inductor
           Network for a Sustainable Energy System
    • Authors: Liu; H.;Li, F.;
      Pages: 6476 - 6482
      Abstract: In this letter, a novel high step-up dc–dc converter with an active coupled-inductor network is presented for a sustainable energy system. The proposed converter contains two coupled inductors which can be integrated into one magnetic core and two switches. The primary sides of coupled inductors are charged in parallel by the input source, and both the coupled inductors are discharged in series with the input source to achieve the high step-up voltage gain with appropriate duty ratio, respectively. In addition, the passive lossless clamped circuit not only recycles leakage energies of the coupled inductor to improve efficiency but also alleviates large voltage spike to limit the voltage stresses of the main switches. The reverse-recovery problem of the output diode is also alleviated by the leakage inductor and the lower part count is needed; therefore, the power conversion efficiency can be further upgraded. This letter shows the key waveforms of the proposed converter and the detailed derivation of the steady-state operation principle. The voltage conversion ratio, the effect of the leakage inductance and the parasitic parameters on the voltage gain are discussed. The voltage stress and current stress on the power devices are illustrated and the comparisons between the proposed converter and other converters are given. Finally, a prototype circuit rated 200-W output power is implemented in the laboratory, and the experimental results show the satisfactory agreement with the theoretical analysis.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • A Converter for Bipolar DC Link Based on SEPIC-Cuk Combination
    • Authors: Ferrera; M.B.;Litran, S.P.;Duran Aranda, E.;Andujar Marquez, J.M.;
      Pages: 6483 - 6487
      Abstract: This letter describes a new application of single-ended primary converter (SEPIC) and Cuk converter for dc bipolar network. A dc–dc converter configuration based on a combination of both converters is proposed. In the resulting topology, the switching node is shared by the SEPIC and Cuk converter since they have the same instantaneous duty cycle. The main advantage of this topology is that synchronization of various switches is not required and control terminal is connected to ground which simplifies the design of the gate drive. On the other hand, this configuration allows the connection of renewable energy sources to microgrids (MG)-type bipolar dc link and to cover the current needs of new distributed generation units with efficient, economical, and easy way. To verify its performance, a prototype was designed. Experimental results show as this combination of two converter topologies with appropriated modulation schemes are adequate to use in dc MG.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Universal High-Frequency-Link Characterization and Practical
           Fundamental-Optimal Strategy for Dual-Active-Bridge DC-DC Converter Under
           PWM Plus Phase-Shift Control
    • Authors: Zhao; B.;Song, Q.;Liu, W.;Liu, G.;Zhao, Y.;
      Pages: 6488 - 6494
      Abstract: This letter first develops a universal steady-state model to simply and accurately describe the analytical expressions for the high-frequency-link (HFL) electrical quantities of isolated dual-active-bridge (DAB) dc–dc converter under PWM plus phase-shift control. Second, a universal reactive power interaction among the HFL electrical quantities is present; using this interaction, the circulating current characteristic of DAB can be described accurately by HFL power factor. On this basis, a practical HFL fundamental-optimal strategy is proposed to decrease the circulating current and increase the efficiency. At last, experimental results verify the correctness of the universal model and the effectiveness of the fundamental-optimal strategy.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Superjunction MOSFETs in Voltage-Source Three-Level Converters:
           Experimental Investigation of Dynamic Behavior and Switching Losses
    • Authors: Yuan; X.;Oswald, N.;Mellor, P.;
      Pages: 6495 - 6501
      Abstract: The superjunction MOSFETs with low R DS(on) and fast-switching speed are expected to achieve high efficiency and high-switching-frequency operation in three-phase voltage-source converters. In this letter, experimental measurements of MOSFET switching behavior and losses in a mixed-technology (silicon MOSFET, silicon superjunction-MOSFET, and silicon carbide diode) three-level neutral-point-clamped phase-leg circuit are presented. The effects of superjunction MOSFETs’ nonlinear output capacitance and silicon MOSFET intrinsic diode reverse recovery are identified, acting to limit the achievable switching speed and efficiency. A significant high voltage is observed across the superjunction MOSFET occurring under no-load conditions. This letter has revealed that the superjunction MOSFETs cannot be directly used in voltage-source converters (e.g., to replace IGBTs) to achieve higher switching speed due to its nonlinear output capacitance, which creates significant high voltage across the inner device and extra losses.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • DC-Link Voltage Measurement Method Suitable for Power Converter Systems
           Controlled by a μ-Controller
    • Authors: Kim; K.;
      Pages: 6502 - 6505
      Abstract: A dc-link voltage measurement method is proposed in this letter. The proposed method is suitable for a power converter with μ-processor control. The dc-link voltage is directly measured so that the measurement error caused by the resistive voltage divider can be removed. The circuit is designed as simply as possible to avoid errors caused by inaccuracies in the components. DC-link voltage sampling and A/D conversion are synchronized with the timing of the PWM modulator to avoid instances where power-converter switching generates strong electromagnetic noise. The validity of the proposed method is verified through an experiment.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Permanent Magnet Flux Online Estimation Based on Zero-Voltage Vector
           Injection Method
    • Authors: Xie; G.;Lu, K.;Dwivedi, S.K.;Riber, R.J.;Wu, W.;
      Pages: 6506 - 6509
      Abstract: In this paper, a simple and accurate method is proposed for online estimation of the rotor permanent magnet (PM) flux linkage for surface mounted PM synchronous machines. By advantageously utilizing an injected zero-voltage vector, the effects of inductance in estimating the PM flux linkage is eliminated. The inverter voltage error and phase resistive voltage drop effects are minimized by repeating the test at different speeds. Therefore, as a result, only the voltage commands are needed for PM flux linkage estimation, resulting in great simplicity. Filtering the current ripple caused by the zero-voltage vector injection is not necessary. The proposed method can be used with sensored or sensorless field-oriented control strategies. The experimental results have shown a good accuracy of the proposed new method.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Implementation of Wavelet-Based Robust Differential Control for Electric
           Vehicle Application
    • Authors: Daya; J.L.F.;Sanjeevikumar, P.;Blaabjerg, F.;Wheeler, P.W.;Ojo, J.O.;
      Pages: 6510 - 6513
      Abstract: This research letter presents the modeling and simulation of electronic differential, employing a novel wavelet controller for two brushless dc motors. The proposed controller uses discrete wavelet transform to decompose the error between actual and reference speed. Error signal that is actually given by the electronic differential based on throttle and steering angle is decomposed into frequency components. Numerical simulation results are provided for both wavelet and proportional-integral-derivate controllers. In comparison, the proposed wavelet control technique provides greater stability and ensures smooth control of the two back driving wheels.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Quasi-Y-Source Boost DC–DC Converter
    • Authors: Siwakoti; Y.P.;Blaabjerg, F.;Loh, P.C.;
      Pages: 6514 - 6519
      Abstract: In this letter, a new topology called “quasi-Y-source dc–dc converter” is presented. It inherits all the advantages of the original Y-source converter. In addition, the new topology draws a continuous current from the source, which is definitely more appropriate for most renewable sources. It also has dc-current-blocking capacitors, which will definitely help to prevent the coupled inductor core from saturation. Experimental testing has proven the validity of the proposed network and its application as a high boost dc–dc converter.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Realization of Digital Differentiator Using Generalized Integrator For
           Power Converters
    • Authors: Xin; Z.;Wang, X.;Loh, P.C.;Blaabjerg, F.;
      Pages: 6520 - 6523
      Abstract: In power converters, the digital implementation of a differentiator is challenged by noise amplification and phase error. For example, the backward Euler differentiator loses its effectiveness at high frequency due to an introduced large-phase error. The Tustin differentiator, on the other hand, yields unacceptable noise amplification even though it produces the phase of an ideal differentiator perfectly. For an even more accurate performance, this letter proposes a new digital differentiator based on generalized integrator (GI). It will specifically be shown that the differentiation characteristic of a GI is an optimized compromise between those of backward Euler and Tustin differentiators. Several discretization techniques are then investigated for discretizing the GI-based differentiator. The effectiveness of the proposed differentiator has been verified by experimental results obtained with an LCL-filtered grid converter damped by feeding back the derivative of its capacitor voltage.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Family of Bridgeless Buck-Boost PFC Rectifiers
    • Authors: Zhao; B.;Abramovitz, A.;Smedley, K.;
      Pages: 6524 - 6527
      Abstract: Family of single-phase single-stage bridgeless power factor correctors based on tapped-inductor buck-boost converters is introduced. The converters’ family has the merits of reduced component count and alleviated losses in the conduction path. The feasibility of the proposed topologies was verified by simulation and experimental results.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • An Analysis of Modified Demodulation-Based Grid Voltage Parameter
           Estimator
    • Authors: Golestan; S.;Guerrero, J.M.;
      Pages: 6528 - 6533
      Abstract: The estimation of the grid voltage fundamental parameters, i.e., the phase, frequency, and amplitude, is required for a wide variety of applications, particularly for synchronization and control of grid-connected converters and for monitoring and protection purposes in power systems. To accomplish this task, many approaches have been proposed in the literature. Recently, a modified demodulation-based technique (MDT) has been presented, which aims to accurately extract the grid voltage fundamental parameters under harmonically distorted and frequency-varying conditions. In this letter, it is shown that the MDT is actually a phase-locked loop. The MDT small-signal modeling and stability analysis are then conducted, and some modifications to enhance its performance are suggested. The effectiveness of these modifications is finally confirmed using numerical results.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Multistructure Power Converter With H-Bridge Series Regulator Suitable for
           High-Current High-Precision-Pulsed Current Source
    • Authors: Penovi; E.;Retegui, R.G.;Maestri, S.;Uicich, G.;Benedetti, M.;
      Pages: 6534 - 6542
      Abstract: This study presents a novel multistructure power converter capable of generating high current pulses with short rise and fall times, and high precision in the flat-top. The proposed topology is based on the use of three conversion structures operated with current, voltage and switching frequency ratings in line with the different requirements of each pulse stage. In order to achieve the required precision, a switched-mode compensation structure in series with the load is used. Though this structure must handle a high load current, it is designed to deviate most of the load current to an auxiliary inductor; thus reducing the semiconductor devices requirements. Moreover, the use of this compensation strategy results in a first-order model of the circuit, which leads to an oscillation-free response during structures interconnection. This feature minimizes the required flat-top time, which in turn decreases the power losses on the load. Experimental results based on a scaled-down laboratory prototype validate the capability of the proposed topology to produce current pulses according to the specifications of high-precision applications.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • A Dual-Active Bridge Topology With a Tuned CLC Network
    • Authors: Twiname; R.P.;Thrimawithana, D.J.;Madawala, U.K.;Baguley, C.A.;
      Pages: 6543 - 6550
      Abstract: This paper proposes a resonant dual-active bridge (DAB) converter, which uses a tuned capacitor–inductor–capacitor network. In comparison to the conventional DABs, the proposed topology significantly reduces the bridge currents, lowering both conduction and switching losses and improving the bridge power factors. A mathematical model, which predicts the behavior of the proposed system, is presented to show that both the magnitude and direction of the power flow can be controlled through either relative phase angle or pulse width modulation of voltages produced by the bridges. The viability of the proposed concept is verified through simulation. Experimental results of a 4- kW prototype converter, which has an efficiency of 95% at rated power, are also presented with discussions to demonstrate the improved performance of this topology.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • CCM and DCM Operation of the Interleaved Two-Phase Boost Converter With
           Discrete and Coupled Inductors
    • Authors: Barry; B.C.;Hayes, J.G.;Rylko, M.S.;
      Pages: 6551 - 6567
      Abstract: Coupled-inductor interleaved boost converters are under development for high-current, high-power applications ranging from automotive to distributed generation. The operating modes of these coupled-inductor converters can be complex. This paper presents an investigation of the various continuous-current (CCM) and discontinuous-current (DCM) modes of operation of the coupled-inductor interleaved two-phase boost converter. The various CCM and DCM of the converter are identified together with their submodes of operation. The standard discrete-inductor interleaved two-phase boost can be seen as a subset of the coupled-inductor converter family with zero mutual coupling between the phases. The steady-state operating characteristics, equations and waveforms for the many CCM and DCM will be presented for the converter family. Mode maps will be developed to map the converter operation across the modes over the operating range. Experimental validation is presented from a 3.6 kW laboratory prototype. Design considerations and experimental results are presented for a 72 kW prototype.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • New Multilevel Converter Based on Cascade Connection of Double Flying
           Capacitor Multicell Converters and Its Improved Modulation Technique
    • Authors: Sadigh; A.K.;Dargahi, V.;Corzine, K.A.;
      Pages: 6568 - 6580
      Abstract: This paper proposes a new multilevel converter based on the cascade connection of double flying capacitor multicell (DFCM) converters, as multilevel modules, to decrease the voltage diversity of the flying capacitors. Furthermore, a new switching pattern based on the phase-shifted pulse-width modulation technique is proposed to reduce the voltage ripple across the flying capacitors. Moreover, the proposed modulation technique reduces the rms value of the current flowing through flying capacitors. This results in an increase in the life time of flying capacitors and a decrease in the capacitance of the flying capacitors, to keep the same amount of the ripple, meaning a reduction in the physical size of the converter. In addition, this paper presents an analytical approach to calculate the average and rms currents of the insulated gate bipolar transistors (IGBTs)/diodes in the DFCM converter in a closed-form expression. The derived closed-form equations to calculate the average and rms currents of the IGBTs/diodes are utilized to investigate the conduction power losses in a DFCM converter and the proposed multilevel converter. Numerical results of the derived closed-form equations match the simulation results well, which validates the derived equations. Furthermore, simulation results and experimental measurements of the proposed multilevel power converter, configured by cascading two two-cell five-level DFCM converters, are presented to validate the performance of the proposed converter as well as the suggested modulation technique.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • A Groebner Bases Theory-Based Method for Selective Harmonic Elimination
    • Authors: Yang; K.;Yuan, Z.;Yuan, R.;Yu, W.;Yuan, J.;Wang, J.;
      Pages: 6581 - 6592
      Abstract: An algebraic method is proposed for selective harmonic elimination PWM (SHEPWM). By computing its Groebner bases under the pure lexicographic monomial order, the nonlinear high-order SHE equations are converted to an equivalent triangular form, and then a recursive algorithm is used to solve the triangular equations one by one. Based on the proposed method, a user-friendly software package has been developed and some computation results are given. Unlike the commonly used numerical and intelligent methods, this method does not need to choose the initial values and can find all the solutions. Also, this method can give a definite answer to the question of whether the SHE equations have solutions or not, and the accuracy of the solved switching angles are much higher than that of the reference method. Compared with the existing algebraic methods, such as the resultant elimination method, the calculation efficiency is improved. Experimental verification is also shown in this paper.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • A New Center-Tapped Half-Bridge Zeta Converter With Small Transformer
           DC-Offset Current and Low Voltage Stress
    • Authors: Lee; J.;Park, K.;Kim, J.;Youn, H.;Moon, G.;
      Pages: 6593 - 6603
      Abstract: In this paper, an asymmetrical half-bridge (AHB) converter employing a new center-tapped zeta rectifier (CTZR) is proposed to achieve a high efficiency in wide-input-voltage and low-output-current applications. Due to the proposed CTZR with high dc conversion ratio and extended maximum duty cycle above 0.5, the transformer turns ratio of the proposed converter can be increased, which decreases the transformer dc-offset current compared with that of the AHB converter. Therefore, its transformer core size is decreased. Moreover, it has a wide zero-voltage-switching range with small transformer leakage inductor, which improves light and medium load efficiency. Furthermore, since it has low voltage stress on the secondary diode, its conduction loss can be reduced. In addition, due to the elimination of a diode, the snubber loss in the secondary side is reduced compared with the AHB converter. Therefore, the proposed converter can achieve a higher efficiency compared with the AHB converter without additional devices. To confirm the operation, features, and validity of the proposed converter, a 250–400 V input and 50 V/250 W output laboratory prototype is built and tested.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Soft Switching PWM Cascaded Three-Level Combined DC–DC Converters
           With Reduced Filter Size and Wide ZVS Load Range
    • Authors: Shi; Y.;Yang, X.;
      Pages: 6604 - 6616
      Abstract: Two soft switching cascaded three-level (TL) combined dc–dc converters are proposed in this paper. The first converter is composed of a half-bridge cascaded TL dc–dc converter (CTLC) and a full-bridge (FB) CTLC, and the other one is composed of two FB CTLCs. The presented topologies have following common advantages: off-state voltage on all switches is only half of the input voltage; the structure of the primary circuit is simple and compact; all primary switches are directly clamped by the input capacitors and no added clamping devices are required; and the voltage across the output LC filter is a TL waveform, which results lower output filter volume and faster system dynamic response. In addition, the input filter can also be minimized. All power switches in the proposed converters can obtain zero-voltage switching in wide load range; furthermore, less conduction loss is added. The operation and technical analysis of the proposed converters are given. Experiments are carried out to validate the proposed converters, and efficiency curves are tested and given.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • DCM Analysis of Single-Switch-Based ZVZCS Converters With a Tapped
           Inductor
    • Authors: Choi; B.H.;Lee, E.S.;Kim, J.H.;Rim, C.T.;
      Pages: 6617 - 6627
      Abstract: The analysis of a novel single-active-switch-based zero voltage and zero current switching (ZVZCS) tapped boost converter in the discontinuous conduction mode (DCM) is proposed in this paper. The ZVZCS converter includes a lossless snubber composed of three diodes and two capacitors and exhibits novel ZVZCS operation for wide operating ranges of duty cycles, load currents, and input voltages. The voltage stress of the active switch is always less than the load voltage, and soft switching turn-on and turn-off are achieved without cumbersome current or voltage sensing, which could not have been obtained from quasi-resonant converters that also have an active switch. Detailed analyses of the DCM and the component stresses of the proposed converter are presented. Experiments for a 450-W prototype exhibited 99.0% of the maximum efficiency with a SiC JFET at the switching frequency of 50 kHz, and the ZVZCS operation is guaranteed, even for the DCM under the experimental conditions. Moreover, the proposed ZVZCS principle has been applied to a tapped buck–boost converter case, which was also experimentally verified.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Hybrid Three-Level and Half-Bridge DC–DC Converter With Reduced
           Circulating Loss and Output Filter Inductance
    • Authors: Guo; Z.;Sha, D.;Liao, X.;
      Pages: 6628 - 6638
      Abstract: A hybrid three-level (TL) and half-bridge (HB) dc–dc converter is proposed in this paper. The TL dc–dc converter and HB converter have their own transformers, respectively. Compared with conventional TL dc–dc converters, the proposed one has no additional switch at the primary side of the transformer, where the TL converter shares the lagging switches with the HB converter. In order to reduce the circulating current in the primary side, a blocking capacitor is used to reset the primary winding current of the TL converter. Moreover, the rectifier stage is composed of four diodes in the center-tap rectification, forcing the circulating current at the primary side to stay zero during the freewheeling period. The magnetizing inductor of the HB transformer can extend the zero voltage switching operation range of the lagging switches even at light loads. Furthermore, the proposed converter can reduce the output filter inductance. Due to the advantages mentioned above, the efficiency of the converter is improved dramatically. The features and design guidelines of the proposed converter are given in the paper. Finally, the performance of the converter is verified by a 1-kW experimental prototype.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • A 80-kW Isolated DC–DC Converter for Railway Applications
    • Authors: Baars; N.H.;Everts, J.;Huisman, H.;Duarte, J.L.;Lomonova, E.A.;
      Pages: 6639 - 6647
      Abstract: This paper provides an analysis of a three-phase dual active bridge (DAB) topology used as high-power-density dc–dc converter for railway applications. The three-phase DAB is analyzed concerning the current intervals, the output power, and soft-switching region, including the impact of zero-voltage switching capacitors. Furthermore, two measures are proposed to achieve soft-switching in the entire operating range, being auxiliary inductors and a straightforward switching strategy called the burst mode. Optimal component values are calculated to minimize losses in the complete operating range and to assess which measure is best suited. A prototype with the specifications acquired from the application has been built, yielding an efficiency of 95.6% at a nominal output power of 80, {\rm kW} .
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Multiport DC–DC Autotransformer for Interconnecting Multiple
           High-Voltage DC Systems at Low Cost
    • Authors: Lin; W.;Wen, J.;Cheng, S.;
      Pages: 6648 - 6660
      Abstract: This paper proposes a multiport dc–dc autotransformer (multiport dc auto) that is used to interconnect multiple HVDC systems with different voltage levels. The multiport dc auto is able to reduce 50–80% the converter cost compared with conventional dc–ac–dc technology. Different from the conventional dc–ac–dc technology using magnetic coupling at the ac sides of the converters, there is direct electrical connection between the interconnected dc systems in the multiport dc auto. Such direct electrical interconnection significantly reduces the used power converters in the multiport dc auto. Taking interconnecting a ±250, ±320, and ±400 kV dc system with the rated exporting/importing dc power at each of the dc system being 500, 1000, and 1500 MW as an example, the conventional multiport dc–ac–dc technology requires a total of 3000 MW power converters while only 775 MW power converter is required in the multiport dc–dc autotransformer. The required power converter in the multiport dc–dc autotransformer is only 26% of the converter used in the conventional multiport dc–ac–dc technology. Cost and operating power loss is therefore significantly reduced.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Shunt Compensator Based on Interconnected Three-Phase Converter
    • Authors: Fabricio; E.L.L.;Jacobina, C.B.;de Menezes, A.V.G.;de Rossiter Correa, M.B.;de Almeida Carlos, G.A.;
      Pages: 6661 - 6671
      Abstract: This paper presents a shunt power compensator based on the interconnection of three-phase two-level converters, and its comparison with two-level- and multilevel-based topologies. The shunt power compensator based on interconnected three-phase converter (ITC) is compared with compensators based on the two-level converter, three-level neutral-point clamped converter, and five-level modular multilevel converter. The comparisons were done in terms of components ratings, harmonic distortion, and semiconductor losses. Control strategies suitable to control the compensator and circulating currents, as well as the three-dc-link voltages are presented. The PWM strategy to generate the control reference voltages of the converter command is designed. Simulation and experimental results are presented.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Islanding Detection in Three-Phase and Single-Phase Systems Using
           Pulsating High-Frequency Signal Injection
    • Authors: Reigosa; D.D.;Briz, F.;Charro, C.B.;Guerrero, J.M.;
      Pages: 6672 - 6683
      Abstract: This paper analyzes the use of pulsating high-frequency signal injection for islanding detection purposes. Active islanding detection using high-frequency signal injection is an appealing option due to its reduced nondetection zone, reduced cost, and ease of implementation. The use of a rotating high-frequency signal has been reported and analyzed. However, this method can only be applied to three-phase systems. In this paper, the use of a pulsating high-frequency signal injection is proposed. While it uses the same principles as rotating signal injection, it can be applied to both three-phase and single-phase systems.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • A Common Mode Inductor With External Magnetic Field Immunity, Low-Magnetic
           Field Emission, and High-Differential Mode Inductance
    • Authors: Chu; Y.;Wang, S.;Zhang, N.;Fu, D.;
      Pages: 6684 - 6694
      Abstract: This paper proposes a stacked common-mode (CM) inductor for electromagnetic interference (EMI) attenuation. The proposed stacked CM inductor consists of two CM inductors with identical cores and the same number of winding turns but with opposite winding directions. The proposed stacked CM inductor has three advantages. First, it is much less susceptible to external magnetic field interference than conventional CM inductors. This suppresses the EMI due to the near-magnetic-field coupling to the CM inductor. Second, the proposed winding structure effectively increases the leakage inductance of the CM inductor, which enhances its ability to suppress differential-mode (DM) noise. Third, the magnetic field generated by the DM current in the stacked CM inductor is partially canceled outside of the inductor. As a result, the stacked CM inductor has lower magnetic field emission than that of a conventional CM inductor. Simulation and experimental results validate the advantages of the proposed CM inductor, which show the proposed technique greatly improves the performance of CM inductors.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Improved Demagnetization Control of a Doubly-Fed Induction Generator Under
           Balanced Grid Fault
    • Authors: Zhou; L.;Liu, J.;Zhou, S.;
      Pages: 6695 - 6705
      Abstract: Doubly-fed induction generators are one of the most popular machines for variable-speed wind turbine. However, they are very sensitive to grid fault since the stator is directly connected to the grid. This paper analyzes the low-voltage ride-through performance of a doubly-fed induction generator-based wind turbine under balanced grid fault. An improved demagnetization control, immune to system parameter variation, is proposed to shorten the dynamic process. The investigation shows that the proposed method increases the probability of a successful ride-through at the recovery moment of balanced grid fault. Feasibility region for a representatively sized system is also investigated for balanced grid fault. In order to verify the proposed control method, laboratory experiments are carried out and the results demonstrate the analysis.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • A Wireless Load Sharing Strategy for Islanded Microgrid Based on Feeder
           Current Sensing
    • Authors: Zhu; Y.;Zhuo, F.;Wang, F.;Liu, B.;Zhao, Y.;
      Pages: 6706 - 6719
      Abstract: To solve the reactive power sharing issue in droop control application, many solutions have been developed based on the basic wireless manner. However, existing wireless methods cannot eliminate reactive power sharing errors effectively, especially in load change situations. In this paper, a wireless reactive power sharing method that employs feeder current sensing and adaptive virtual impedance control is proposed for islanded microgrid. To improve reactive power sharing accuracy of virtual impedance method, an equivalent feeder concept is introduced, which can reflect the mismatch in connecting circuits equivalently. Through fast feeder current sensing, distributed generation units can calculate their respective equivalent feeders in real time. With the cooperation between real-time calculation and virtual impedance control, the proposed method achieves both accurate and fast performance in reactive power sharing. Compared with communication-based methods, the proposed wireless control provides the same high accuracy in reactive power sharing; meanwhile, its response speed to load change is much faster than that of other methods. Moreover, the proposed method can work as normal even though load changes during the transient process. Matlab simulation and real-time digital simulator test are used to validate the feasibility of this method.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • A Practical Supercapacitor Model for Power Management in Wireless Sensor
           Nodes
    • Authors: Chai; R.;Zhang, Y.;
      Pages: 6720 - 6730
      Abstract: In this paper, a new practical method is presented to estimate supercapacitor state for wireless sensor nodes. The self-discharge process of supercapacitor, as an energy storage device in sensor nodes, is usually considered as the main factor that needs to be taken into account for power management. Recent studies have demonstrated that a supercapacitor charge-redistribution process may also have significant impact on power management. To consider charge redistribution in power management of a real-time system, a practical method is presented to estimate the state of a supercapacitor. The accuracy of the method is validated by experiments. The impact of time step on the proposed model is also investigated. The results indicate that the proposed model can achieve good accuracy with relatively large time step. Moreover, the model is easy to implement, and has low memory usage and computational cost for practical applications in a real-time system. Based on the practical model, estimations of charge and energy transferred during the redistribution process are presented, which provide important information toward developing energy aware algorithms in wireless sensor networks.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Online Interturn Fault Diagnosis of Permanent Magnet Synchronous Machine
           Using Zero-Sequence Components
    • Authors: Hang; J.;Zhang, J.;Cheng, M.;Huang, J.;
      Pages: 6731 - 6741
      Abstract: This paper develops an online interturn fault diagnosis method for permanent magnet synchronous machine (PMSM). The mathematical model of the PMSM with interturn fault is established. The zero-sequence voltage component and zero-sequence current component are analyzed in the PMSM, respectively. Then, the new fault indicators are defined to remove the influence of the variation of the rotor speed and an effective frequency tracking algorithm is presented to extract fault indicators. In this proposed method, not only the interturn fault can be effectively detected, but also the phase in which this fault occurs can be accurately identified. The experiments are carried out and the experiment results verify the effectiveness of the proposed method.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Direct MPPT Algorithm for PV Sources With Only Voltage Measurements
    • Authors: Dallago; E.;Liberale, A.;Miotti, D.;Venchi, G.;
      Pages: 6742 - 6750
      Abstract: This paper presents a direct maximum power point tracking method, based on an easy and robust way of identifying the maximum power point (MPP) of a photovoltaic (PV) source that needs the measurement of the PV generator voltage only. The algorithm accurately detects the MPP and can rapidly track it in presence of irradiance variations, with no erratic behavior. An interface for a PV inverter that employs the proposed algorithm is described. The converter, called double capacitor interface (DCI), is designed to charge the dc link of the inverter and follow the MPP of the PV generator. Numerical simulations of the system operation, in different irradiance conditions, are discussed and evaluation of the tracking efficiency is reported. Finally, experimental results of a prototype breadboard built to test on the field the MPP tracking capability are presented.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Sinusoidal Output Current Implementation of DFIG Using Repetitive Control
           Under a Generalized Harmonic Power Grid With Frequency Deviation
    • Authors: Song; Y.;Nian, H.;
      Pages: 6751 - 6762
      Abstract: The paper presents the control strategy of stator current harmonic distortion performance improvement for doubly fed induction generator (DFIG) using bandwidth-based repetitive control (BRC) under generalized harmonic grid voltage. The control target is to eliminate the DFIG stator current 6n \pm 1 harmonic components; thus, sinusoidal stator output current can be injected into the power grid. Considering that the frequency deviation always occurs in the practical grid, the BRC regulator is designed on the basis of conventional repetitive control regulator with the introduction of control bandwidth. The closed-loop operation stability considering different bandwidth and gain parameter is also analyzed. Finally, the availability of the proposed BRC control strategy under generalized harmonic grid voltage is verified by experimental results.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • A Broadband Bistable Piezoelectric Energy Harvester With Nonlinear
           High-Power Extraction
    • Authors: Singh; K.A.;Kumar, R.;Weber, R.J.;
      Pages: 6763 - 6774
      Abstract: This paper presents a nonlinear vibration energy harvester, which combines a nonlinear bistable broadband piezoelectric cantilever used to transduce ambient vibration energy, with synchronized capture for efficient harvesting over broadband sources. An accurate model of the bistable transducer, that augments the Butterworth van Dyke model to capture the external magnetic force added as a bias to the external vibrations, is presented. Its validity has been demonstrated through physical implementation and experimental validation against simulation of the mathematical model. For efficient extraction of the transduced energy, nonlinear extraction circuits, namely synchronous charge extraction (SCE) and parallel synchronized switch harvesting on inductor (SSHI), are employed. The switching in these circuits is implemented using a fully self-propelled, low-power electronic breaker circuit, capable of detecting extrema in the waveform to perform switching. Both simulated and experimental power outputs from the bistable harvester have been presented, with the SCE and parallel-SSHI providing average outputs with more than 100-fold increase over the harvested power reported in the literature for the same input, and further, even more significant gains are observed for broadband excitations.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Line Filter Design of Parallel Interleaved VSCs for High-Power Wind Energy
           Conversion Systems
    • Authors: Gohil; G.;Bede, L.;Teodorescu, R.;Kerekes, T.;Blaabjerg, F.;
      Pages: 6775 - 6790
      Abstract: The voltage source converters (VSCs) are often connected in parallel in a wind energy conversion system to match the high power rating of the modern wind turbines. The effect of the interleaved carriers on the harmonic performance of the parallel connected VSCs is analyzed in this paper. In order to achieve low-switching losses, the 60^\circ clamp discontinuous pulsewidth modulation (DPWM1) is used to modulate the VSCs. A step-by-step design procedure of the line filter, which ensures the desired harmonic performance under all operating conditions, is presented. The analytical harmonic solution for the two parallel interleaved VSCs is derived in order to obtain the worst case voltage magnitude of the individual harmonic components. The required value of the filter admittance for the specific harmonic component is obtained by using the worst case voltage magnitude and the allowable harmonic injection limit. In order to achieve the desired filter performance with optimal values of the filter parameters, the use of an LC trap branch with the conventional LCL filter is proposed. The expressions for the resonant frequencies of the proposed line filter are derived and used in the design to selectively choose the values of the line filter components. The analysis and design methodology are also verified experimentally.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Metaheuristic Optimization Methods Applied to Power Converters: A Review
    • Authors: De Leon-Aldaco; S.E.;Calleja, H.;Aguayo Alquicira, J.;
      Pages: 6791 - 6803
      Abstract: Power converters systems aimed at renewable energy applications have become a common option for sustainable electricity and distributed generation, since their performance has improved, and prices have steadily been reduced in the last years. However, there are still several drawbacks that hinder their widespread installation, such as the simultaneous minimization of cost and volume, efficiency maximization, size reduction, etc. Quite often, accomplishing these goals requires dealing with complicated optimization problems, which are difficult to solve by classical methods. Metaheuristic techniques provide a viable alternative to solve complex intricate optimization problems, such as those encountered in the development of power electronics converters. This paper presents a comprehensive coverage of metaheuristic methodologies applied in the area of power converters. The review includes a classification of the methodologies and main objective functions in each paper surveyed. An aim for this paper is to highlight the importance of the optimization tools, and the many benefits they provide to tackle the challenges encountered in the design, operation, and control of power converters.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Analysis of Class DE Current Driven Low
           
    • Authors: Minami; Y.;Koizumi, H.;
      Pages: 6804 - 6816
      Abstract: Class DE current driven low di/dt rectifier satisfies Class E switching condition and low diode current stress, which is no more than the output current. Thus, the switching loss is decreased extremely. In this paper, the Class DE current driven low di/dt rectifier is analyzed for any diode-on-duty-ratio. The initial phase angle of the input current, the current and voltage transfer functions, the normalized input resistance and inductance, the normalized diode voltage stress, and the power-output capability are obtained, and clarified as the functions of the diode-on-duty ratio and those of R/wL . Moreover, the power conversion efficiency and the circuit design method are shown. The circuit performance has been confirmed by the simulation results and the experimental results. In the simulation and the experiment, the characteristics of the output voltage and the power conversion efficiency against the amplitude of the input current, the load resistance, and the operation frequency have been obtained. In addition, the relationship between the equations, simulation results, and experimental results have been obtained. Theoretical, simulation, and experimental results were in good agreement with each other.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Enabling High-Frequency High-Efficiency Non-Isolated Boost Converters With
           Quasi-Square-Wave Zero-Voltage Switching and On-Chip Dynamic
           Dead-Time-Controlled Synchronous Gate Drive
    • Authors: Xue; J.;Lee, H.;
      Pages: 6817 - 6828
      Abstract: This paper presents techniques to enable non-isolated boost converters to achieve high power efficiencies under high switching frequency and high-voltage conditions. A quasi-square-wave zero-voltage switching (QSW-ZVS) boost converter topology is proposed to achieve high-frequency soft switching without any coupled inductors in the power stage and, thus, minimize the switching power loss of the converter. An on-chip dynamic dead-time controller is developed to provide near-optimum dead time for power FETs during switching transitions under different output voltage and load current conditions in order to achieve ZVS with minimal body diode conduction loss of power FETs. A synchronous gate driver is also proposed to provide fast propagation delays and output signal rise/fall time, enabling megahertz operation of the converter. A hardware boost converter prototype is built with the synchronous gate driver circuitry implemented in a 0.5-μm high-voltage CMOS process. The proposed QSW-ZVS boost converter provides an output voltage of 150 V and delivers an output power of 130 W. The peak power efficiency of the proposed converter achieves 92.7% at the switching frequency of 1 MHz. Compared with state-of-the-art gate drivers, the worst-case propagation delay of the proposed synchronous gate driver is improved by at least 7.6 times. The operation frequency of the proposed non-isolated boost converter is also improved by at least 15 times compared with other state-of-the-art counterparts.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Bidirectional Operation of High Step-Down Converter
    • Authors: Yau; Y.T.;Jiang, W.Z.;Hwu, K.I.;
      Pages: 6829 - 6844
      Abstract: In this paper, a high step-down bidirectional converter, utilizing one coupled inductor and two energy-transferring capacitors, is presented. In the step-down mode, the capacitor is connected between input voltage and coupled inductor, which plays a role to step down the input voltage. Therefore, the corresponding voltage conversion ratio is much lower than that of the traditional buck converter and also can be lower than that of the tapped-inductor buck converter. Moreover, the output voltage varies with the duty cycle linearly, making control easier. In the step-up mode, one capacitor is first charged by the coupled inductor, and then releases the energy along with the coupled inductor and the other capacitor connected in series. Therefore, a higher voltage gain can be obtained. Furthermore, the leakage inductance energy can be recycled. Therefore, the switching losses can be reduced and the efficiency can be improved. In this study, the operating principles and experimental results are provided to verify the effectiveness and performance of the proposed converter.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Steep-Gain Bidirectional Converter With a Regenerative Snubber
    • Authors: Yao; J.;Abramovitz, A.;Ma Smedley, K.;
      Pages: 6845 - 6856
      Abstract: This paper introduces a SEPIC-derived bidirectional dc–dc converter. The proposed converter utilizes tapped inductor and charge pump techniques to achieve steep voltage conversion ratio and an active lossless regenerative snubber to attain lossless switching and high efficiency. The paper presents the principle of operation, steady-state analyses, and experimental results obtained from a 400-W, 48-V/380-V prototype. The efficiency of the proposed topology is demonstrated to peak at 96.4% for boost mode and 95.0% for buck mode.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Investigation and Experimental Test of Fault-Tolerant Operation of a
           Mutually Coupled Dual Three-Phase SRM Drive Under Faulty Conditions
    • Authors: Ding; W.;Hu, Y.;Wu, L.;
      Pages: 6857 - 6872
      Abstract: The mutually coupled dual three-phase switched reluctance motor (DTPSRM) is a new type of special 12/8 SRMs, which possesses high-reliability and fault-tolerant feature. In the past researches, the model, analysis, and fault-tolerant operation were mainly focused on the classical single three- and four-phase SRMs. This paper is mainly to analyze and investigate the fault-tolerant performances of a 12/8-pole mutually coupled DTPSRM drive under various open-circuit operations. First, the static magnetic characteristics of DTPSRM with single- and two-phase excitations are calculated by finite-element analysis. Then, the mathematic model of the DTPSRM drive under open-circuit condition is developed with a combination of state and fault functions. The simulation model of the DTPSRM drive system with a fault-tolerant control strategy is established for dynamic analysis. The faulty characteristics and fault-tolerant performances of the DTPSRM with diverse open circuits are predicted. Finally, a 12/8 DTPSRM is prototyped and an experimental setup is built for verification. The experimental normal results and diverse open-circuit operations and self-starting capability under lack of phases are presented, validating the accuracy of the analysis and simulation as well as fault-tolerant characteristics of the DTPSRM drive system.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Carrier-Based Pulse Width Modulation for Symmetrical Six-Phase Drives
    • Authors: Glose; D.;Kennel, R.;
      Pages: 6873 - 6882
      Abstract: Modulating the output of a voltage source inverter (VSI) inherently causes current distortions on the load side due to the switching behavior of the inverter. This paper describes a method to reduce these distortions for a drive setup with six phases. The setup consists of a six-phase machine connected to two three-leg two-level VSIs. The phases within the machine are symmetrically arranged and spatially shifted by 60^\circ . The phases are grouped so that two conventional three-phase sets are formed, each fed by one inverter. The output of each inverter leg is modulated by comparing a triangle carrier waveform with the desired fundamental wave. Arranged in this way, the drive setup offers an additional degree of freedom, the phase shift of the two carrier waveforms. It is shown that, depending on the machine parameters, there exists an optimal angle, which reduces the harmonic losses of the drive for a certain amplitude of the fundamental wave. The resulting overall current distortion can even be lower compared to a conventional three-phase drive with a two- or three-level inverter topology. For three different modulation techniques, the optimal phase shift angles are derived in an exact form, naturally, symmetrical regular and asymmetrical regular sampled pulse width modulation. An approximation with reasonable accuracy is achieved out of the exact solution. Simulations and experimental tests validate the theoretical considerations.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Pulse Magnetic Properties Measurement and Characterization of Fe-Based
           Nanocrystalline Cores for High-Voltage Pulse Magnetics Applications
    • Authors: Liu; Y.;Han, Y.;Liu, S.;Lin, F.;
      Pages: 6883 - 6896
      Abstract: Fe-based nanocrystalline (FE-N) cores are widely used in power electronics and pulsed power applications. In pulsed power applications, it always requires high excitation current (up to tens of kiloampere) to excite large-volume cores (up to hundreds of cubic centimeter) with fewer number of winding turns, and it is hard to use the traditional test scheme to obtain the pulse magnetic properties in this case. The principles and scopes for the application of pulse magnetic properties measurement circuits, including the single-winding test circuit and double-winding test circuit, are analyzed and presented. Although the double-winding test circuit is classical to test the hysteresis loop, the single-winding test circuit is not totally useless in some cases. Based on the double-winding test circuit, the initial magnetization curves and maximum hysteresis loops of toroidal FE-N cores with high and low remanence are obtained under a relative constant magnetization rate with the order of 0.7–7 T/μs, and an equivalent frequency from 49 to 650 kHz. The unsaturated permeability is calculated based on the experimental results and fitted with the magnetization rate. The loss densities and permeability are fitted and compared. A design procedure of the saturable pulse transformer is illustrated for the application of the testing results. It is proved that the initial energy loss and unsaturated permeability are used for the design of the pulse transformer, and the traditional core loss is suitable for the estimation of power loss under the repetitive operation condition.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Design Procedure for Racetrack Microinductors on Silicon in Multi-MHz
           DC–DC Converters
    • Authors: Feeney; C.;Wang, N.;Cian O Mathuna, S.;Duffy, M.;
      Pages: 6897 - 6905
      Abstract: Inductor-on-silicon research to date has focused on optimizing technologies for maximum power density and efficiency, with most design procedures based on computationally intensive methods. In this paper, a simple and intuitive method for designing microinductors based on a given dc–dc converter specification, which includes accurate models for all loss components, is presented. A detailed examination of variations in designs to realise the same circuit performance is presented. Finally, finite element analysis simulations demonstrating the accuracy of the models are given, along with measured results.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Design Space Analysis and
            $rho$
            $eta$ Pareto
           Optimization of $LC$
           
    Output Filters for Switch-Mode AC Power
           Sources
    • Authors: Boillat; D.O.;Krismer, F.;Kolar, J.W.;
      Pages: 6906 - 6923
      Abstract: In this study, the design space (DS) concept is refined and utilized to design the output filter of a {\rm 10} - {\rm kW} , four-quadrant, three-phase, switch-mode controllable AC power source (CPS). The DS concept is based on the simultaneous consideration of multiple criteria that are derived from application-oriented specifications for the CPS regarding quality and transient response of the output voltage, and limited reactive power demand of the output filter. In this paper, the output filter of the studied CPS needs to satisfy six different criteria, which, in the case of a single-stage LC filter, leads to bounds on the values of L and C that can be indicated by boundary curves in an L\hbox {-}C plane. The intersection set of all boundary curves defines the DS, in which all six specifications can be fulfilled. For the considered requirements, it is shown that the DS is empty for a single-stage LC filter, but exists for a two-stage LC filter, which is therefore employed as an output filter of the CPS. To fully exploit the 4D DS of the two-stage LC filter, a multi objective optimization, resulting in the power density–efficiency Pareto front, is performed to determine the most compact and/or most efficient filter design among all possible filter realizations with parameters in the DS. From the outcome of this optimization, the filter design with the highest power density of {14.6}, {\rm kW} / {\rm dm}^{3} ( {239}, {\rm W} /{\rm \in}^{3} ), for an efficiency of 99.4% , is realized in hardware. Finally, all six specifications for the CPS are successfully verified by experimental measurements.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Develop Parasitic Inductance Model for the Planar Busbar of an IGBT H
           Bridge in a Power Inverter
    • Authors: Zhang; N.;Wang, S.;Zhao, H.;
      Pages: 6924 - 6933
      Abstract: This paper first analyzes the current paths on a planar busbar based on insulated-gate bipolar transistor bridge switching states and dc-link capacitor configurations. The busbar's circuit models which include both self- and mutual inductances are developed based on the identified current paths. The inductance circuit models are analyzed and reduced for different switching states, transition states, and dc-link capacitor configurations. Inductance and current sharing is analyzed based on circuit theory. Both simulations and measurements are conducted to verify the developed technique.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Nonlinear Dimming and Correlated Color Temperature Control of Bicolor
           White LED Systems
    • Authors: Chen; H.;Tan, S.;Hui, S.Y.R.;
      Pages: 6934 - 6947
      Abstract: This paper proposes a nonlinear approach of controlling the luminous intensity and correlated color temperature (CCT) of white light-emitting diode (LED) systems with dual color temperatures. This LED system is made up of a warm color LED source (2700 K) and a cool color LED source (5000 K). The luminous intensity of each of these LED sources is individually controlled by pulsewidth modulation. The overall intensity of the LED system is due to the combined emitted flux of both LED sources. Its overall CCT is the mixed average CCT of both LED sources. This proposed method is based on the nonlinear empirical luminous and CCT models of the LEDs, which take into consideration the thermal effect of LEDs on its luminance and CCT properties. With reasonable approximation, the theoretical models are simplified into practical solutions, which are translatable into real-life applications. It is experimentally validated that the proposed approach is considerably more accurate than the existing linear approaches that do not consider color variations of LED sources. The idea is applicable to LED systems with multiple color temperatures and is not limited to white LEDs.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • A Ring Diode–Capacitor Network for Current-Balancing Multiple LED
           Strings
    • Authors: Zhang; R.;Chung, H.S.;
      Pages: 6948 - 6965
      Abstract: A ring diode–capacitor network for current-balancing multiple LED strings is presented. The concept is based on utilizing the charge-balance property of capacitors to balance the currents of two adjacent LED strings in each switching cycle. Such current-balancing mechanism propagates over a ring network. The network has several merits, including 1) high current-balancing accuracy, 2) a simple structure, 3) modular and scalable, 4) current-balancing property being less dependent on the string voltages and the values of the capacitors, 5) inherent galvanic isolation between the driver and the LED strings, and 6) operation of the healthy LED(s) being unaffected by the failure LED(s). In addition, the capacitors in the network can be used as resonant tank components for the front-stage driver. An 80-W prototype for balancing the currents of ten LED strings has been built and evaluated. Each string has eight pieces of 1-W LED connected in series. The prototype is driven by a series-resonant converter. Results reveal that the string current variation is less than ±0.5%, irrespective to the variation of the string voltages and capacitor values. The total LED power can be dimmed to 10% of the rated output by a hybrid switching frequency and duty-cycle control scheme. The overall efficiency from the driver input to all LED strings is around 95% over the operating range. Modeling, design, and analysis of four possible configurations will be given.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Resonant-Switched Capacitor Converters for Chip-Scale Power Delivery:
           Design and Implementation
    • Authors: Kesarwani; K.;Sangwan, R.;Stauth, J.T.;
      Pages: 6966 - 6977
      Abstract: There is an increasing need for power management systems that can be fully integrated in silicon to reduce cost and form factor in mobile applications, and provide point-of-load voltage regulation for high-performance digital systems. Switched-capacitor (SC) converters have shown promise in this regard due to relatively high energy-density of capacitors and favorable device utilization figures of merit. Resonant switched-capacitor (ReSC) converters show similar promise as they benefit from many of the same architectures and scaling trends, but also from ongoing improvements in mm-scale magnetic devices. In this study, we explore the design and optimization of 2:1 step-down topologies, based on representative capacitor technologies, CMOS device parameters, and air-core inductor models. We compare the SC approach to the ReSC approach in terms of efficiency and power density. Finally, a chip-scale ReSC converter is presented that can deliver over 4 W at 0.6 W/mm2 with 85% efficiency. The two-phase, nominally 2:1 converter supports input voltages from 3.6–6.0 V, and is implemented in 180-nm bulk CMOS with die-attached air-core solenoid inductors.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Compact Electrothermal Reliability Modeling and Experimental
           Characterization of Bipolar Latchup in SiC and CoolMOS Power MOSFETs
    • Authors: Bonyadi; R.;Alatise, O.;Jahdi, S.;Hu, J.;Ortiz Gonzalez, J.A.;Ran, L.;Mawby, P.A.;
      Pages: 6978 - 6992
      Abstract: In this paper, a compact dynamic and fully coupled electrothermal model for parasitic BJT latchup is presented and validated by measurements. The model can be used to enhance the reliability of the latest generation of commercially available power devices. BJT latchup can be triggered by body-diode reverse-recovery hard commutation with high dV/dt or from avalanche conduction during unclamped inductive switching. In the case of body-diode reverse recovery, the base current that initiates BJT latchup is calculated from the solution of the ambipolar diffusion equation describing the minority carrier distribution in the antiparallel p-i-n body diode. For hard commutation with high dV/dt, the displacement current of the drain-body charging capacitance is critical for BJT latchup, whereas for avalanche conduction, the base current is calculated from impact ionization. The parasitic BJT is implemented in Simulink using the Ebers–Moll model and the temperature is calculated using a thermal network matched to the transient thermal impedance characteristic of the devices. This model has been applied to CoolMOS and SiC MOSFETs. Measurements show that the model correctly predicts BJT latchup during reverse recovery as a function of forward-current density and temperature. The model presented, when calibrated correctly by device manufacturers and applications engineers, is capable of benchmarking the robustness of power MOSFETs.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • A Current-Sensorless Online ESR and C Identification
           Method for Output Capacitor of Buck Converter
    • Authors: Yao; K.;Tang, W.;Hu, W.;Lyu, J.;
      Pages: 6993 - 7005
      Abstract: As electrolytic capacitor is apt to fail in power circuits, it is very important to identify its electrical parameters, mainly the equivalent series resistance (ESR) and capacitance (C). A noninvasive online identification method of capacitor's ESR and C for continuous-conduction-mode (CCM) buck converter is proposed in this paper. Based on the ac component of capacitor voltage, the calculation model is founded. By sampling the pulse width modulation signal and output voltage, the method needs no current sensor and is effective for the CCM buck converter operating at different conditions. Implementation of the identification system is presented. The tests are carried out for different aged capacitors and ambient temperatures. The experimental results validate the effectiveness of the method.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Cascaded H-Bridge Multilevel Inverter System Fault Diagnosis Using a PCA
           and Multiclass Relevance Vector Machine Approach
    • Authors: Wang; T.;Xu, H.;Han, J.;Elbouchikhi, E.;Benbouzid, M.E.H.;
      Pages: 7006 - 7018
      Abstract: Multilevel inverters, for their distinctive performance, have been widely used in high voltage and high-power applications in recent years. As power electronics equipment reliability is very important and to ensure multilevel inverter systems stable operation, it is important to detect and locate faults as quickly as possible. In this context and to improve fault diagnosis accuracy and efficiency of a cascaded H-bridge multilevel inverter system (CHMLIS), a fault diagnosis strategy based on the principle component analysis and the multiclass relevance vector machine (PCA-mRVM), is elaborated and proposed in this paper. First, CHMLIS output voltage signals are selected as input fault classification characteristic signals. Then, a fast Fourier transform is used to preprocess these signals. PCA is used to extract fault signals features and to reduce samples dimensions. Finally, an mRVM model is used to classify faulty samples. Compared to traditional approaches, the proposed PCA-mRVM strategy not only achieves higher model sparsity and shorter diagnosis time, but also provides probabilistic outputs for every class membership. Experimental tests are carried out to highlight the proposed PCA-mRVM diagnosis performances.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Virtual-Impedance-Based Control for Voltage-Source and Current-Source
           Converters
    • Authors: Wang; X.;Li, Y.W.;Blaabjerg, F.;Loh, P.C.;
      Pages: 7019 - 7037
      Abstract: The virtual impedance concept is increasingly used for the control of power electronic systems. Generally, the virtual impedance loop can either be embedded as an additional degree of freedom for active stabilization and disturbance rejection, or be employed as a command reference generator for the converters to provide ancillary services. This paper presents an overview of the virtual-impedance-based control strategies for voltage-source and current-source converters. The control output impedance shaping attained by the virtual impedances is generalized first using the impedance-based models. Different virtual impedances and their implementation issues are then discussed. A number of practical examples are demonstrated to illustrate the feasibility of virtual impedances. Emerging applications and future trends of virtual impedances in power electronic systems conclude this paper.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Operating Point Optimization of Auxiliary Power Unit Based on Dynamic
           Combined Cost Map and Particle Swarm Optimization
    • Authors: Wang; Y.;Shen, Y.;Yuan, X.;Yang, Y.;
      Pages: 7038 - 7050
      Abstract: Series hybrid electric vehicles improvements in fuel consumption and emissions directly depend on the operating point of the auxiliary power unit (APU). A new APU operating point optimization approach based on dynamic combined cost map (DCM) and particle swarm optimization (PSO) is presented in this paper. The influence of coolant temperature, catalyst temperature, and air/fuel (A/F) ratio on fuel consumption characteristics and HC, CO, NOx emission characteristics are quantitatively analyzed first. Then, the DCM is derived by combining the individual cost maps with predefined weighting factors, so as to balance the potentially conflicting goals of fuel consumption and emissions reduction in the choice of operating point. The PSO is utilized to search the optimum APU operating point in the DCM. Finally, bench experiments under three typical driving cycles show that, compared with the results of the traditional static steady-state fuel consumption map-based APU operating point optimization approach, the proposed DCM and PSO-based approach shows significant improvements in emission performance, at the expense of a slight drop in fuel efficiency.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Power Control of Asymmetrical Frequency Modulation in a Full-Bridge Series
           Resonant Inverter
    • Authors: Hu; J.;Bi, C.;Jia, K.;Xiang, Y.;
      Pages: 7051 - 7059
      Abstract: The traditional power control schemes for induction heating device mainly focus on the pulse frequency modulation (PFM) and the pulse density modulation. But they cannot solve the problems of power control, efficiency, and load-adaption well. This paper presents and analyzes the asymmetrical frequency modulation (AFM) control scheme used in the full-bridge series resonant inverter. With the proposed AFM control technique, the output power is controlled by two variables: the operation frequency and the division factor. Better efficiency performance can be achieved in the medium and low output power range when compared with PFM. The principles as well as the zero-voltage switching condition of the AFM are explained and the power losses of switches are analyzed. A control algorithm that schedules the three control modes of AFM is experimentally verified with a digital signal processor based induction heating prototype. The load-adaption, noise and thermal distribution problem of switches are also analyzed.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • A Dual Voltage Control Strategy for Single-Phase PWM Converters With Power
           Decoupling Function
    • Authors: Tang; Y.;Qin, Z.;Blaabjerg, F.;Loh, P.C.;
      Pages: 7060 - 7071
      Abstract: The inherent double line ripple power in single-phase systems is adverse to the performance of power electronics converters, e.g., limited lifetime due to the requirement of large electrolytic capacitors and low voltage control bandwidth due to harmonic disturbance. In this paper, an active converter topology based on a symmetrical half-bridge circuit is proposed to decouple the ripple power so that balanced instantaneous power flow is assured between source and load, and the required dc-link capacitance can be dramatically reduced. For proper closed-loop regulation, the small signal modeling of the proposed system is presented, and a dual voltage control strategy is then proposed, which comprises one voltage loop implemented in the synchronous reference frame for active power balancing, and another one implemented in the stationary reference frame for ripple power compensation. Special attention is given to the bandwidth of voltage control loops because the variation of dc-link voltage should be kept within an acceptable range during load transients. This is particularly important for systems with reduced dc-link capacitance because they are of lower energy capacity, and the dc-link voltage is therefore very sensitive to step load changes. Comprehensive simulation and experimental results are presented to show the effectiveness of the proposed circuit and control algorithm.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Overview of Power Management Strategies of Hybrid AC/DC Microgrid
    • Authors: Nejabatkhah; F.;Li, Y.W.;
      Pages: 7072 - 7089
      Abstract: Today, conventional power systems are evolving to modern smart grids, where interconnected microgrids may dominate the distribution system with high penetration of renewable energy and energy storage systems. The hybrid ac/dc systems with dc and ac sources/loads are considered to be the most possible future distribution or even transmission structures. For such hybrid ac/dc microgrids, power management strategies are one of the most critical operation aspects. This paper presents an overview of power management strategies for a hybrid ac/dc microgrid system, which includes different system structures (ac-coupled, dc-coupled, and ac–dc-coupled hybrid microgrids), different operation modes, a thorough study of various power management and control schemes in both steady state and transient conditions, and examples of power management and control strategies. Finally, discussion and recommendations of power management strategies for the further research are presented.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Table-Based Direct Power Control for Three-Phase AC/DC Converters Under
           Unbalanced Grid Voltages
    • Authors: Zhang; Y.;Qu, C.;
      Pages: 7090 - 7099
      Abstract: This paper proposes a simple but effective direct power control (DPC) strategy for three-phase ac/dc converters operating under unbalanced grid voltage conditions. An extended instantaneous power theory is adapted and applied in the proposed DPC, where the reactive power is expressed in the form of dot product of grid currents and delayed grid voltages. Neither complicated positive/negative sequence extraction of grid voltage/current nor power compensation is required. The switching table suitable to control both active power and reactive power is constructed by analyzing the influence of each converter voltage vector on power slopes. Compared to conventional table-based DPC using original pq theory, the proposed DPC achieves constant active power and reactive power as well as sinusoidal grid currents, while maintaining the simplicity and robustness as much as possible. The presented simulation and experimental results confirm the theoretical study and the effectiveness of the proposed method.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Predictive Instantaneous Torque Control for Disc Coreless Permanent Magnet
           Synchronous Motor With the Current Source Chopper
    • Authors: Wang; X.;Wang, X.;Fu, T.;Wang, J.;
      Pages: 7100 - 7112
      Abstract: The disc coreless permanent magnet synchronous motor has several advantages, such as strong overload capacity, zero cogging torque, sinusoidal back EMF, and linear parameters. The motors tend to have low inductance because of the coreless structure. There is a stringent current ripple in the motor winding that produces unacceptable torque ripple if driven from conventional drivers with a pulse width modulation control method based on voltage source inverter. To solve this problem, a predictive instantaneous torque control method based on a current source chopper is proposed in this paper. As electromagnetic torque depends on the stator current magnitude and rotor angle, the relationship between these two variables is discussed. The current amplitude and switch state of the inverter are computed according to the rotor position, and the stator current magnitude can be regulated in real time by the current source chopper. The proposed control system can dramatically reduce the current ripple caused by low inductance and the validity of the proposed control method is verified by simulation and experimental results.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Analysis and Parameter Optimization of Start-Up Process for
           LLC Resonant Converter
    • Authors: Zheng; R.;Liu, B.;Duan, S.;
      Pages: 7113 - 7122
      Abstract: There is a current spike in LLC resonant converter during start-up and frequency modulation method is adopted to limit the resonant current usually, which controls switching frequency decreasing from specific high frequency to steady-state frequency in exponential pattern with a time constant tau. However, it is hard to determine the crucial parameter of time constant of the exponential switching frequency sweep curve, due to the complexity in analyzing dynamic process of the converter. In this paper, the operation modes and characteristics under continued conductive mode and discontinued conductive mode are analyzed based on state-plane analysis and the boundary of two conductive modes is figured out. Then, the iteration calculation model of the LLC converter is proposed to predict the resonant current during start-up progress, and time constant of the existing soft start method is optimized using iteration algorithm. Using the proposed iterative design method, the current stress of LLC resonant converter is limited, as well as guaranteeing the response speed of output voltage.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Performance Comparison of PI and P Compensation in DSP-Based
           Average-Current-Controlled Three-Phase Six-Switch Boost PFC Rectifier
    • Authors: Huber; L.;Kumar, M.;Jovanovic, M.M.;
      Pages: 7123 - 7137
      Abstract: In this paper, it is shown that in the three-phase six-switch boost power factor correction rectifier with average-current control with mismatched input-voltage and input-current sensing gains as well as offset errors in input-voltage and input-current sensing, the current controller with proportional (P) compensation exhibits lower total harmonic distortion (THD) and higher power factor compared with that of proportional and integral compensation. It is also shown that P compensation with input-voltage feedforward is effective in improving output-voltage transient response with respect to input-voltage changes only if duty-cycle feedforward is also implemented. Finally, it is shown that zero-sequence-signal injection, in addition to enabling the output-voltage regulation in a wider input-voltage range, also improves the THD of the input currents.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Variable-Frequency Phase Shift Modulation of a Dual Active Bridge
           Converter
    • Authors: Hiltunen; J.;Vaisanen, V.;Juntunen, R.;Silventoinen, P.;
      Pages: 7138 - 7148
      Abstract: In this paper, a variable-frequency modulation method for a dual active bridge converter is introduced. The proposed method ensures zero-voltage switching over a wide power range with a minimal circulating current. Unlike previously presented modulation schemes, this modulation method can also be used for half-bridge variants of a traditional dual active bridge converter. The modulation method is given in a closed form, which makes it easy to apply in practice. Further, the phase drift phenomenon is discussed, and a simple phase drift compensation scheme is presented. Finally, a detailed analysis of the proposed modulation method is provided and its feasibility is verified by measurements.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • A Comprehensive Study on Equivalent Modulation Waveforms of the SVM
           Sequence for Three-Level Inverters
    • Authors: Chen; J.;He, Y.;Hasan, S.U.;Liu, J.;
      Pages: 7149 - 7158
      Abstract: According to the number of segments, the space vector modulation (SVM) can divide into conventional SVM sequence (CSVMS) and special SVM sequence (SSVMS). It is well known that SVM can be equivalently realized by carrier-based pulse width modulation (CBPWM) with a zero component injection in both two-level and three-level inverters. For eight segment CSVMS in three-level inverters, many papers have ever got the injected zero component equation. But similar approach does not work for SSVMS, which has more than eight segments, e.g., 10, 12, or 14. What more, the accurate injected zero component has never been achieved so far. To solve above problems, therefore, a generated decomposition method of modulation wave has been proposed in this paper. By strict theoretical derivation, the same correlation can be extended to SSVMS and the corresponding zero component expression can be acquired. Based on this method, this paper puts a lot attention on the essential feature explanation, mathematical proof, and gives a detailed process to get the zero component equation, using it can realize SSVMS by CBPWM. The simulation and experimental results illustrate that the generated decomposition method of modulation wave is correct, and the unified theory of CBPWM and SVM is verified.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Steady-State Analysis of Electric Springs With a Novel
           δ Control
    • Authors: Wang; Q.;Cheng, M.;Chen, Z.;
      Pages: 7159 - 7169
      Abstract: A novel control strategy is proposed for the recent proposed electric springs (ESs), which are connected in series with noncritical loads to form smart loads for enhancing stability of smart grid with renewable energy sources. δ control is the key concept in this paper, which is realized by controlling the phase angle of the predefined reference in a proportional resonant controller. Four critical operating functions of the ESs are analyzed with different critical loads such as resistive, inductive and capacitive types, where vector diagrams and geometric relationships are explored for δ calculation with which the ac mains voltage is regulated to the predefined value and the phase angle between the ES voltage and current is determined. With the proposed δ control, the operating modes of the ES can also be determined automatically as the input voltage varies. Operating limitations and constraints of the ESs and guidelines on how to distribute the ESs in the distributed systems are provided with δ control. Both simulation and experiment are carried out to verify the effectiveness of the proposed control strategy and theoretical analysis for the ESs.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Load Adaptability of Active Harmonic Reduction for 12-Pulse Diode Bridge
           Rectifier With Active Interphase Reactor
    • Authors: Meng; F.;Yang, W.;Zhu, Y.;Gao, L.;Yang, S.;
      Pages: 7170 - 7180
      Abstract: In order to improve the harmonic reduction ability of 12-pulse rectifier, an active interphase reactor (AIPR) and corresponding auxiliary circuit are often used to produce circulating current resulting in harmonic reduction. This paper analyzes the load adaptability of 12-pulse rectifier with AIPR. The loads are classified into three types, RL-type load, RC-type load, and RLC-type load. Load currents and circulating currents are calculated under different load types. According to the calculation results, the THD of input line current and ripple coefficient of load voltage are also described by figures under RL-type load and RLC-type load. The appropriate amplitude of the circulating current under RL -type load and the LC filter under RLC-type load are presented. Simulation and experimental results validate the theoretical analysis.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Variable Modulation Offset SPWM Control to Balance the Neutral-Point
           Voltage for Three-Level Inverters
    • Authors: Lyu; J.;Hu, W.;Wu, F.;Yao, K.;Wu, J.;
      Pages: 7181 - 7192
      Abstract: In order to solve the neutral-point voltage unbalancing problem for three-level inverters, this paper proposes a method to balance the neutral-point voltage for three-level inverters with variable modulation wave offset sinusoidal pulse-width modulation (SPWM) control. Based on the mathematical expressions of neutral-point voltage unbalancing, the factors are studied, which affect the fluctuation of neutral-point voltage. Theoretically the mathematical expressions of the neutral-point voltage with the proposed method are derived, and the mathematical relationship between the fluctuation of neutral-point voltage and the adjusting offset of modulation wave is studied. This proposed method realizes controlling the neutral-point voltage balance by dynamically calculating the offset superimposed to the modulation wave based on SPWM (DCOSPWM). This DCOSPWM method is very simple, which has good steady-state performance and is easy for digital implementation. The simulation results verify the correctness of the theoretical analysis in this paper, and the feasibility and effectiveness of this method is verified by the experiments in the experimental platform of neutral point clamped three-level inverters based on digital signal processor (DSP)-complex programmable logic device (CPLD).
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Nonlinear Control of a Buck Converter Which Feeds a Constant Power Load
    • Authors: Solsona; J.A.;Jorge, S.G.;Busada, C.A.;
      Pages: 7193 - 7201
      Abstract: In this paper, a nonlinear control strategy for controlling a dc/dc buck converter feeding a constant power load is proposed. The main objective of the proposed controller is to improve the transient performance when in presence of unknown power disturbances. A feedback controller is combined with a feedforward strategy. A nonlinear reduced order observer is used for estimating the value of the power load and its time derivative. These estimated values are fed forward to the nonlinear feedback controller whose design is based on feedback linearization method. The proposed controller is tested via simulation and experimental results.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Ripple Minimization Through Harmonic Elimination in Asymmetric Interleaved
           Multiphase DC–DC Converters
    • Authors: Schuck; M.;Pilawa-Podgurski, R.C.N.;
      Pages: 7202 - 7214
      Abstract: Symmetric multiphase dc–dc converters are widely used in power electronics, as they enable the processing of high power through splitting the overall load-current into multiple phases. Distributing the processed power symmetrically between the phases and performing ripple minimization through interleaving is well understood. However, in recent applications such as maximum power point tracking for solar photovoltaic, converters are forced to operate under asymmetric conditions, due to differences in the sources or loads of each converter. This study presents a control technique, based on harmonic elimination, that allows for ripple minimization under asymmetric conditions. The mathematical derivations are outlined and simulations are used to evaluate the performance of the proposed technique. Measurements taken from an experimental prototype, consisting of three dc–dc buck converters, demonstrate significant improvements in ripple reduction over conventional interleaving techniques. When the multiphase converter is operated at the optimum asymmetric phase-shift found through the techniques presented here, a more than 3x reduction in net current ripple is observed under realistic operating conditions. Additionally, the undesirable first harmonic ripple component is reduced by 14.8 dB with the proposed technique.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Decentralized Power Management of a PV/Battery Hybrid Unit in a
           Droop-Controlled Islanded Microgrid
    • Authors: Mahmood; H.;Michaelson, D.;Jiang, J.;
      Pages: 7215 - 7229
      Abstract: In this paper, a control strategy is proposed to achieve decentralized power management of a PV/battery hybrid unit in a droop-controlled islanded microgrid. In contrast to the common approach of controlling the PV unit as a current source, in the proposed strategy, the PV unit is controlled as a voltage source that follows a multi-segment adaptive power/frequency characteristic curve. The proposed power/frequency characteristics, of the hybrid unit and of the whole microgrid, adapt autonomously to the microgrid operating conditions so that the hybrid unit may supply the maximum PV power, match the load, and/or charge the battery, while maintaining the power balance in the microgrid and respecting the battery state-of-charge limits. These features are achieved without relying on a central management system and communications, as most of the existing algorithms do. The control strategy is implemented using multi-loop controllers, which provide smooth and autonomous transitions between the operating scenarios. Small-signal stability of the proposed control loops is investigated, and the system performance is experimentally validated on a 3.5 kVA microgrid.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • A Cell-Level Differential Power Processing IC for Concentrating-PV Systems
           With Bidirectional Hysteretic Current-Mode Control and Closed-Loop
           Frequency Regulation
    • Authors: Zaman; M.S.;Wen, Y.;Fernandes, R.;Buter, B.;Doorn, T.;Dijkstra, M.;Bergveld, H.J.;Trescases, O.;
      Pages: 7230 - 7244
      Abstract: This paper describes an integrated power management IC with bidirectional current capability, aimed at compensating differences in output current between series-connected cells in concentrating photovoltaic (CPV) systems. The integrated 3.6-MHz power stage allows building a small-form-factor converter per cell. A hysteretic current-mode controller regulates the bidirectional converter's current to equalize neighboring cell voltages. A phase-locked loop controls the inductor current ripple around the average value to stabilize the switching frequency. The use of hysteretic current-mode control with a novel bidirectional senseFET scheme provides inherent current protection and high reliability. The converter can operate from an input voltage as low as 1.8 V and with an inductor current up to \pm 1.5 A, while achieving a system efficiency above 90% for current mismatches between cells up to 60%. Measurement results show that the converter maximizes the output power of series-connected CPV cells with mismatched output currents.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • A Method for Identification of the Equivalent Inductance and Resistance in
           the Plant Model of Current-Controlled Grid-Tied Converters
    • Authors: Vidal; A.;Yepes, A.G.;Freijedo, F.D.;Lopez, O.;Malvar, J.;Baneira, F.;Doval-Gandoy, J.;
      Pages: 7245 - 7261
      Abstract: Precise knowledge of the plant time constant L/R is essential to perform a thorough analysis and design of the current control loop in voltage source converters (VSCs). From the perspective of the current controller dynamics in the low-frequency range, such plant time constant is also suitable for most cases in which an LCL filter is used. As the loop behavior can be significantly influenced by the VSC working conditions, the effects associated to converter losses should be included in the model, through an equivalent series resistance. In addition, the plant inductance may also present important uncertainties with respect to the value of the VSC L/LCL interface filter measured at rated conditions. Thus, in this paper, a method is presented to estimate both parameters of the plant time constant, i.e., the equivalent inductance and resistance in the plant model of current-controlled VSCs. The proposed technique is based on the evaluation of the closed-loop transient responses of both axes of the synchronous reference frame when a proportional-integral current controller is implemented. The method gives a set of resistance and inductance values that should be employed for a rigorous design of the current controllers. Experimental results validate the approach.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Finite Control-Set Model Predictive Control (FCS-MPC) of Nested Neutral
           Point-Clamped (NNPC) Converter
    • Authors: Narimani; M.;Wu, B.;Yaramasu, V.;Reza Zargari, N.;
      Pages: 7262 - 7269
      Abstract: This paper proposes a model predictive control (MPC) strategy for a nested neutral point-clamped (NNPC) converter to control output currents and voltages of flying capacitors. The NNPC converter is a four-level converter topology for medium-voltage applications with interesting properties such as operating over a wide range of voltages (2.4–7.2 KV) without the need for connecting power semiconductor in series, high quality output voltage, less number of components compared to other classical four-level topologies. A discrete-time model of the converter is presented and all the control objectives are formulated in terms of the switching states. During each sampling interval, the predicted variables are assessed by the cost function and the best switching state which gives minimum value for the cost function is selected and applied to the converter gating terminals. The performances of the NNPC converter and predictive control scheme are verified through MATLAB/Simulink simulations and their feasibility is evaluated experimentally.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • On the Feasibility of Integrated Battery Charger Utilizing Traction Motor
           and Inverter in Plug-In Hybrid Electric Vehicles
    • Authors: Woo; D.;Joo, D.;Lee, B.;
      Pages: 7270 - 7281
      Abstract: For the practical use of an integrated battery charger (IBC), this paper proposes an improved IBC based on a detailed analysis of the conventional IBC with respect to the inherent limitations such as switching frequency, motor inductance, common-mode noise, power loss, and input current and voltage sensing. Moreover, battery charging performance according to pulse-width-modulated switching schemes is mathematically analyzed and explained. The informative simulation and experimental results are provided with the traction motor/inverter hardware of an actual plug-in hybrid vehicle.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Design of Adaptive Fuzzy-Neural-Network Control for a Single-Stage Boost
           Inverter
    • Authors: Wai; R.;Lin, Y.;Liu, Y.;
      Pages: 7282 - 7298
      Abstract: This study mainly focuses on the development of an adaptive fuzzy-neural-network control (AFNNC) system for a single-stage boost inverter. First, the dynamic model of a single-stage boost inverter is analyzed and is built for the later control manipulation. Then, a total sliding-mode control (TSMC) framework without the reaching phase in conventional SMC is developed for enhancing the system robustness during the transient response of the voltage tracking control. In order to alleviate the control chattering phenomena caused by the sign function in the TSMC design and relax the requirement of detailed system dynamics, an AFNNC system is further investigated to imitate the TSMC law for the boost inverter. In the AFNNC system, online learning algorithms are derived in the sense of Lyapunov stability theorem and projection algorithm to ensure the stability of the controlled system without the requirement of auxiliary compensated controllers despite the existence of uncertainties. The output of the AFNNC system can be easily supplied to the duty cycle of the power switch in the boost inverter without strict constraints on control parameters selection in conventional control strategies. In addition, the effectiveness of the proposed AFNNC scheme is verified by realistic experiments, and its advantages are indicated in comparison with a traditional double-loop proportional-integral control scheme and the TSMC framework.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Dual Active Bridge-Based Battery Charger for Plug-in Hybrid Electric
           Vehicle With Charging Current Containing Low Frequency Ripple
    • Authors: Xue; L.;Shen, Z.;Boroyevich, D.;Mattavelli, P.;Diaz, D.;
      Pages: 7299 - 7307
      Abstract: Manufacturers want high power density for the on-board battery chargers of plug-in hybrid electric vehicles. Wide bandgap devices can be used to shrink other passive components by increasing the switching frequency, but the bulk dc link capacitor of the ac–dc power factor correction stage, becomes one of the major barriers to higher power density, because its volume depends on the ripple power at the double line frequency in a dc current charging system. However, if this double line frequency ripple flows into the battery, the dc link capacitance can be significantly reduced. This charging scheme, named as sinusoidal charging in this paper, is analyzed and implemented based on a two-stage battery charging system, which is comprised of one full bridge ac–dc stage and one dual active bridge dc–dc stage. We further find that converter loss causes ripple power imbalance and bigger dc link capacitance. Therefore, the impact of converter loss on the ripple power balance is analyzed, and a feedback control on the dc link voltage ripple is proposed based on this analysis in order to further reduce the dc link capacitance. The effectiveness of the proposed solutions is verified in both Si-based and GaN-based charging systems.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
  • Discussion and Comments on “L-Z Source Inverter”
    • Authors: Mostaan; A.;Baghramian, A.;Zeinali, H.;
      Pages: 7308 - 7308
      Abstract: In this correspondence, it is shown that there are some problems when an inductive load is considered in Figs. 2–5 of the original paper [1]. The objective of this correspondence is to point out these problems using analysis and detailed computer simulation.
      PubDate: Dec. 2015
      Issue No: Vol. 30, No. 12 (2015)
       
 
 
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