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  Subjects -> ELECTRONICS (Total: 152 journals)
Showing 1 - 200 of 277 Journals sorted alphabetically
Advances in Biosensors and Bioelectronics     Open Access   (Followers: 6)
Advances in Electrical and Electronic Engineering     Open Access   (Followers: 2)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 9)
Advances in Microelectronic Engineering     Open Access   (Followers: 13)
Advances in Power Electronics     Open Access   (Followers: 27)
Aerospace and Electronic Systems, IEEE Transactions on     Hybrid Journal   (Followers: 237)
American Journal of Electrical and Electronic Engineering     Open Access   (Followers: 24)
Annals of Telecommunications     Hybrid Journal   (Followers: 7)
Archives of Electrical Engineering     Open Access   (Followers: 12)
Autonomous Mental Development, IEEE Transactions on     Hybrid Journal   (Followers: 8)
Bell Labs Technical Journal     Hybrid Journal   (Followers: 23)
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (Followers: 17)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 32)
Biomedical Instrumentation & Technology     Hybrid Journal   (Followers: 6)
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 10)
BULLETIN of National Technical University of Ukraine. Series RADIOTECHNIQUE. RADIOAPPARATUS BUILDING     Open Access   (Followers: 1)
Bulletin of the Polish Academy of Sciences : Technical Sciences     Open Access  
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 43)
China Communications     Full-text available via subscription   (Followers: 7)
Circuits and Systems     Open Access   (Followers: 16)
Consumer Electronics Times     Open Access   (Followers: 6)
Control Systems     Hybrid Journal   (Followers: 193)
Edu Elektrika Journal     Open Access  
Electronic Design     Partially Free   (Followers: 83)
Electronic Markets     Hybrid Journal   (Followers: 8)
Electronic Materials Letters     Hybrid Journal   (Followers: 3)
Electronics     Open Access   (Followers: 67)
Electronics and Communications in Japan     Hybrid Journal   (Followers: 9)
Electronics For You     Partially Free   (Followers: 68)
Electronics Letters     Hybrid Journal   (Followers: 26)
Embedded Systems Letters, IEEE     Hybrid Journal   (Followers: 42)
Energy Harvesting and Systems : Materials, Mechanisms, Circuits and Storage     Hybrid Journal   (Followers: 4)
Energy Storage Materials     Full-text available via subscription   (Followers: 2)
EPJ Quantum Technology     Open Access  
EURASIP Journal on Embedded Systems     Open Access   (Followers: 12)
Facta Universitatis, Series : Electronics and Energetics     Open Access  
Foundations and Trends® in Communications and Information Theory     Full-text available via subscription   (Followers: 7)
Foundations and Trends® in Signal Processing     Full-text available via subscription   (Followers: 10)
Frequenz     Hybrid Journal   (Followers: 1)
Frontiers of Optoelectronics     Hybrid Journal   (Followers: 1)
Geoscience and Remote Sensing, IEEE Transactions on     Hybrid Journal   (Followers: 164)
Haptics, IEEE Transactions on     Hybrid Journal   (Followers: 3)
IEEE Antennas and Propagation Magazine     Hybrid Journal   (Followers: 81)
IEEE Antennas and Wireless Propagation Letters     Hybrid Journal   (Followers: 68)
IEEE Journal of Emerging and Selected Topics in Power Electronics     Hybrid Journal   (Followers: 35)
IEEE Journal of the Electron Devices Society     Open Access   (Followers: 9)
IEEE Journal on Exploratory Solid-State Computational Devices and Circuits     Hybrid Journal   (Followers: 1)
IEEE Power Electronics Magazine     Full-text available via subscription   (Followers: 52)
IEEE Transactions on Antennas and Propagation     Full-text available via subscription   (Followers: 59)
IEEE Transactions on Automatic Control     Hybrid Journal   (Followers: 53)
IEEE Transactions on Circuits and Systems for Video Technology     Hybrid Journal   (Followers: 17)
IEEE Transactions on Consumer Electronics     Hybrid Journal   (Followers: 36)
IEEE Transactions on Electron Devices     Hybrid Journal   (Followers: 16)
IEEE Transactions on Information Theory     Hybrid Journal   (Followers: 27)
IEEE Transactions on Power Electronics     Hybrid Journal   (Followers: 60)
IEEE Transactions on Signal and Information Processing over Networks     Full-text available via subscription   (Followers: 9)
IEICE - Transactions on Electronics     Full-text available via subscription   (Followers: 15)
IEICE - Transactions on Information and Systems     Full-text available via subscription   (Followers: 7)
IET Microwaves, Antennas & Propagation     Hybrid Journal   (Followers: 32)
IET Power Electronics     Hybrid Journal   (Followers: 33)
IET Wireless Sensor Systems     Hybrid Journal   (Followers: 18)
IETE Journal of Education     Open Access   (Followers: 4)
IETE Journal of Research     Open Access   (Followers: 11)
IETE Technical Review     Open Access   (Followers: 11)
IJEIS (Indonesian Journal of Electronics and Instrumentation Systems)     Open Access  
Industrial Electronics, IEEE Transactions on     Hybrid Journal   (Followers: 42)
Industry Applications, IEEE Transactions on     Hybrid Journal   (Followers: 11)
Informatik-Spektrum     Hybrid Journal   (Followers: 2)
Instabilities in Silicon Devices     Full-text available via subscription  
Intelligent Transportation Systems Magazine, IEEE     Full-text available via subscription   (Followers: 8)
International Journal of Advanced Research in Computer Science and Electronics Engineering     Open Access   (Followers: 18)
International Journal of Advances in Telecommunications, Electrotechnics, Signals and Systems     Open Access   (Followers: 8)
International Journal of Antennas and Propagation     Open Access   (Followers: 11)
International Journal of Applied Electronics in Physics & Robotics     Open Access   (Followers: 4)
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: 6)
International Journal of Electronics & Data Communication     Open Access   (Followers: 11)
International Journal of Electronics and Telecommunications     Open Access   (Followers: 13)
International Journal of Granular Computing, Rough Sets and Intelligent Systems     Hybrid Journal   (Followers: 2)
International Journal of High Speed Electronics and Systems     Hybrid Journal  
International Journal of Image, Graphics and Signal Processing     Open Access   (Followers: 10)
International Journal of Nano Devices, Sensors and Systems     Open Access   (Followers: 8)
International Journal of Nanoscience     Hybrid Journal   (Followers: 1)
International Journal of Numerical Modelling: Electronic Networks, Devices and Fields     Hybrid Journal   (Followers: 3)
International Journal of Power Electronics     Hybrid Journal   (Followers: 16)
International Journal of Sensors, Wireless Communications and Control     Hybrid Journal   (Followers: 8)
International Journal of Systems, Control and Communications     Hybrid Journal   (Followers: 3)
International Journal of Wireless and Microwave Technologies     Open Access   (Followers: 6)
International Journal on Communication     Full-text available via subscription   (Followers: 14)
International Journal on Electrical and Power Engineering     Full-text available via subscription   (Followers: 8)
International Transaction of Electrical and Computer Engineers System     Open Access   (Followers: 2)
Journal of Biosensors & Bioelectronics     Open Access   (Followers: 3)
Journal of Advanced Dielectrics     Open Access   (Followers: 1)
Journal of Artificial Intelligence     Open Access   (Followers: 9)
Journal of Circuits, Systems, and Computers     Hybrid Journal   (Followers: 4)
Journal of Computational Intelligence and Electronic Systems     Full-text available via subscription   (Followers: 1)
Journal of Electrical and Electronics Engineering Research     Open Access   (Followers: 19)
Journal of Electrical Bioimpedance     Open Access   (Followers: 2)
Journal of Electrical Engineering & Electronic Technology     Hybrid Journal   (Followers: 7)
Journal of Electromagnetic Analysis and Applications     Open Access   (Followers: 7)
Journal of Electromagnetic Waves and Applications     Hybrid Journal   (Followers: 6)
Journal of Electronics (China)     Hybrid Journal   (Followers: 4)
Journal of Energy Storage     Full-text available via subscription   (Followers: 3)
Journal of Field Robotics     Hybrid Journal   (Followers: 2)
Journal of Guidance, Control, and Dynamics     Full-text available via subscription   (Followers: 139)
Journal of Intelligent Procedures in Electrical Technology     Open Access   (Followers: 3)
Journal of Low Power Electronics     Full-text available via subscription   (Followers: 7)
Journal of Low Power Electronics and Applications     Open Access   (Followers: 7)
Journal of Microwaves, Optoelectronics and Electromagnetic Applications     Open Access   (Followers: 9)
Journal of Nuclear Cardiology     Hybrid Journal  
Journal of Optoelectronics Engineering     Open Access   (Followers: 2)
Journal of Physics B: Atomic, Molecular and Optical Physics     Hybrid Journal   (Followers: 31)
Journal of Semiconductors     Full-text available via subscription   (Followers: 4)
Journal of Sensors     Open Access   (Followers: 24)
Journal of Signal and Information Processing     Open Access   (Followers: 9)
Jurnal Rekayasa Elektrika     Open Access  
Learning Technologies, IEEE Transactions on     Hybrid Journal   (Followers: 14)
Magnetics Letters, IEEE     Hybrid Journal   (Followers: 7)
Majalah Ilmiah Teknologi Elektro : Journal of Electrical Technology     Open Access   (Followers: 2)
Metrology and Measurement Systems     Open Access   (Followers: 5)
Microelectronics and Solid State Electronics     Open Access   (Followers: 16)
Nanotechnology Magazine, IEEE     Full-text available via subscription   (Followers: 31)
Nanotechnology, Science and Applications     Open Access   (Followers: 6)
Networks: an International Journal     Hybrid Journal   (Followers: 5)
Open Journal of Antennas and Propagation     Open Access   (Followers: 8)
Optical Communications and Networking, IEEE/OSA Journal of     Full-text available via subscription   (Followers: 14)
Paladyn, Journal of Behavioral Robotics     Open Access   (Followers: 1)
Progress in Quantum Electronics     Full-text available via subscription   (Followers: 7)
Pulse     Full-text available via subscription   (Followers: 5)
Radiophysics and Quantum Electronics     Hybrid Journal   (Followers: 2)
Recent Patents on Electrical & Electronic Engineering     Full-text available via subscription   (Followers: 9)
Recent Patents on Telecommunications     Full-text available via subscription   (Followers: 2)
Security and Communication Networks     Hybrid Journal   (Followers: 3)
Selected Topics in Applied Earth Observations and Remote Sensing, IEEE Journal of     Hybrid Journal   (Followers: 51)
Semiconductors and Semimetals     Full-text available via subscription   (Followers: 1)
Sensing and Imaging : An International Journal     Hybrid Journal   (Followers: 2)
Services Computing, IEEE Transactions on     Hybrid Journal   (Followers: 5)
Software Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 72)
Solid-State Circuits Magazine, IEEE     Hybrid Journal   (Followers: 12)
Solid-State Electronics     Hybrid Journal   (Followers: 8)
Superconductor Science and Technology     Hybrid Journal   (Followers: 2)
Synthesis Lectures on Power Electronics     Full-text available via subscription   (Followers: 3)
Technical Report Electronics and Computer Engineering     Open Access  
Telematique     Open Access  
TELKOMNIKA (Telecommunication, Computing, Electronics and Control)     Open Access   (Followers: 8)
Universal Journal of Electrical and Electronic Engineering     Open Access   (Followers: 6)
Visión Electrónica : algo más que un estado sólido     Open Access  
Wireless and Mobile Technologies     Open Access   (Followers: 5)
Women in Engineering Magazine, IEEE     Full-text available via subscription   (Followers: 13)
Електротехніка і Електромеханіка     Open Access  

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Journal Cover IEEE Transactions on Power Electronics
  [SJR: 3.005]   [H-I: 160]   [60 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0885-8993
   Published by IEEE Homepage  [191 journals]
  • IEEE Power Electronics Society
    • Abstract: Presents a listing of the editorial board, board of governors, current staff, committee members, and/or society editors for this issue of the publication.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • IEEE Power Electronics Society
    • Abstract: Presents a listing of the editorial board, board of governors, current staff, committee members, and/or society editors for this issue of the publication.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Blank page
    • Abstract: This page or pages intentionally left blank.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • A PLL-Based Controller for Three-Phase Grid-Connected Power Converters
    • Authors: Saeed Golestan;Josep M. Guerrero;Juan. C. Vasquez;
      Pages: 911 - 916
      Abstract: The current control of three-phase grid-connected converters is typically carried out by using a proportional-resonant controller or synchronous reference frame (SRF) proportional-integral regulator. The implementation of these controllers often requires knowledge of the grid voltage frequency/phase angle, which is typically provided by a synchronization unit. It implies that dynamics and possible inaccuracies of the synchronization unit have a considerable impact on the current controller performance. The aim of this letter is to design an adaptive current controller by using a conventional SRF phase-locked loop. In this way, the current controller and synchronization part are merged into a single unit, which results in a simpler and more compact structure. The effectiveness of the proposed controller is verified using experimental results.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • A 20-Pulse Asymmetric Multiphase Staggering Autoconfigured Transformer For
           Power Quality Improvement
    • Authors: Saravana Prakash P;R. Kalpana;Bhim Singh;G. Bhuvaneswari;
      Pages: 917 - 925
      Abstract: This letter presents a 20-pulse multiphase staggering autoconfigured transformer (MSAT) for power quality improvement in medium and high power applications. The proposed autoconfigured transformer is a combination of delta and zig-zag transformers. Contrary to the prior art multipulse autoconnected transformers, magnetic rating of the proposed configuration is only 40% of the load rating in addition to improved power quality indices. Moreover, the creation of a neutral point ascribed to inbuilt zig-zag windings supplements as one of the remarkable advantages of the proposed MSAT. Therefore, with this suggested configuration, the performance of zig-zag transformer is accomplished within the autoconfigured transformer. A detailed comparison of the proposed MSAT configuration with that of other multipulse autoconnected transformers in terms of magnetic rating and power quality indices are presented. Further, the feasibility and operability of the proposed MSAT are verified and validated through experimental tests on the laboratory prototype. The test results so obtained complies with the IEEE-519 and IEC 61000-3-2 standards on power quality requirements.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • High-Efficiency Self-Driven Circuit With Parallel Branch For High
           Frequency Converters
    • Authors: Yueshi Guan;Yijie Wang;Qing Bian;Xihong Hu;Wei Wang;Dianguo Xu;
      Pages: 926 - 931
      Abstract: With the development of high frequency converters, driving circuits have gained more and more attention. Self-driven methods can effectively simplify system design and reduce components’ number. A basic self-driven circuit can be achieved by adding a series resonant inductor at the switch gate; however the losses of driving circuit are high. To reduce the corresponding losses, a high efficiency self-driven network with an additional parallel branch is proposed, which can significantly improve the system efficiency. A 13 MHz prototype is built to verify the feasibility of the proposed self-driven circuit. The system efficiency can be improved from 80% to 83.9%.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Hybrid Cascaded Multilevel Inverter (HCMLI) With Improved Symmetrical
           4-Level Submodule
    • Authors: Sze Sing Lee;Michail Sidorov;Chee Shen Lim;Nik Rumzi Nik Idris;Yeh En Heng;
      Pages: 932 - 935
      Abstract: This letter proposes an improved symmetrical 4-level submodule as a basic cell for generating multiple dc voltage levels. A hybrid cascaded multilevel inverter (HCMLI) topology is formed by the combination of n submodules and a full-bridge. A comparative analysis against the recent multilevel inverters reveals that the proposed topology requires less number of switches and dc sources. In addition, the proposed submodule reduces the number of conducting switch and gate driver requirements compared to the widely used half-bridge submodule. To validate the operation of the proposed HCMLI topology, experimental results of a 9-level single-phase inverter controlled by selective harmonic elimination pulse-width-modulation is presented.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • An Enhanced State Observer for DC-Link Voltage Control of Three-Phase
           AC/DC Converters
    • Authors: Jinghang Lu;Saeed Golestan;Mehdi Savaghebi;Juan C. Vasquez;Josep M. Guerrero;Albert Marzabal;
      Pages: 936 - 942
      Abstract: To regulate the dc-link voltage of three-phase ac/dc converters, an enhanced state observer-based controller is presented in this letter. The proposed controller, contrary to the traditional ones, does not require the dc-link current measurement and offers a “plug and play” capability, a rather high disturbance rejection ability and robustness against the dc-link capacitance parameter variation. The design procedure of the suggested controller is discussed, and its effectiveness is verified using experimental results.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Reduced DC-Link Voltage Active Power Filter Using Modified PUC5 Converter
    • Authors: Hani Vahedi;Ali Asghar Shojaei;Louis-A. Dessaint;Kamal Al-Haddad;
      Pages: 943 - 947
      Abstract: In this letter, the five-level packed U-cell (PUC5) inverter is reconfigured with two identical dc links operating as an active power filter (APF). Generally, the peak voltage of an APF should be greater than the ac voltage at the point-of-common coupling (PCC) to ensure the boost operation of the converter in order to inject harmonic current into the system effectively; therefore, full compensation can be obtained. The proposed modified PUC5 (MPUC5) converter has two equally regulated separated dc links, which can operate at no load condition useful for APF application. Those divided dc terminals amplitudes are added at the input of the MPUC5 converter to generate a boosted voltage that is higher than the PCC voltage. Consequently, the reduced dc-links voltages are achieved since they do not individually need to be higher than the PCC voltage due to the mentioned fact that their summation has to be higher than PCC voltage. The voltage balancing unit is integrated into the modulation technique to be decoupled from the APF controller. The proposed APF is practically tested to validate its good dynamic performance in harmonic elimination, ac-side power factor correction, reactive power compensation, and power quality improvement.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Efficiency Improvement of an Adaptive-Energy-Storage Full-Bridge Converter
           by Modifying Turns Ratio of a Coupled Inductor
    • Authors: Lei Zhao;Haoyu Li;Chuanyu Xu;Xuemei Zheng;
      Pages: 948 - 956
      Abstract: This letter proposes a simple and practical way to improve the efficiency of an adaptive-energy-storage (AES) full bridge converter. Since the turns ratio of coupled inductor is 1 in the conventional AES converter, the leading-leg and lagging-leg have the same peak current. By modifying turns ratio of coupled inductor, part of leading-leg current can be steered to the lagging-leg; thus, the peak current of lagging-leg is higher than that of leading-leg and a wider range of zero-voltage switching (ZVS) operation is obtained. In the improved AES converter with modified turns ratio, the energy from primary side can be transferred to the secondary side during freewheeling interval. Both the current ripple of filter inductor and the voltage stress of rectifier diode are reduced. Compared with the conventional AES converter, the improved converter can obtain a wider ZVS range, lower current ripple, and higher conversion efficiency. The detailed theory analysis and experimental results are presented in this letter.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Decoupling Network Design for Inner Current Loops of Stand-Alone Brushless
           Doubly Fed Induction Generation Power System
    • Authors: Lei Sun;Yu Chen;Jingyuan Su;Debin Zhang;Li Peng;Yong Kang;
      Pages: 957 - 963
      Abstract: Brushless doubly fed induction generator (BDFIG) is of high reliability due to its brushless structure. However, brushless structure also results in the complicated d–q vector model, in which the d and q channels are seriously coupled. Traditionally many feedforward (FF) terms were added during control for decoupling purpose. However the FF method features several drawbacks: 1) it requires extra sensors; 2) the rotor position information needs to be known for d–q transformation; and 3) the decoupling effect highly depends on the parameter accuracy. To overcome these problems, this letter proposes a decoupling method based on the decoupling network (DN). With DN method, the BDFIG and the load are first modeled as a dual-input-dual-output system, and then the DN is designed. From control point of view, the DN is in series with the BDFIG and the load, and thus, form a new control plant with highly decoupling feature. As a result, the controllers in d and q channels can be easily designed. The proposed DN method requires neither extra sensors nor rotor position information, and the robustness is enhanced since parameter variations of BDFIG and load can be fully considered during DN design. In this letter, such a DN method is presented and applied on the inner current loops of a stand-alone BDFIG system to obtain the good decoupling feature in the overall operational range, and the design results are verified by the experiments from a stand-alone BDFIG system platform.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Universal Compensation Ramp Auto-Tuning Technique for Current Mode
           Controls of Switching Converters
    • Authors: Pei-Hsin Liu;Yingyi Yan;Fred C. Lee;Paolo Mattavelli;
      Pages: 970 - 974
      Abstract: The conventional slope compensations for current mode controls do not take all the parameters’ changes into account, so the variations on small-signal transfer functions limit the voltage loop bandwidth (BW). In order to optimize the dynamic performance of current-mode control, this letter proposes a universal auto-tuning technique for external ramp slope based on the sensed slope of current feedback signal. The tuning mechanism keeps the quality factor of the double poles unchanged over the duty cycle variation, inductor tolerance, sensing element variation, and topology change, thus a consistent wide BW control is achieved without the limitation from the corner cases. Simple digital and analog implementations are proposed to realize the auto-tuning concept. This method is applicable to digital and analog current-mode controllers with peak current mode, valley current mode, and average current mode operations. The effectiveness of the proposed method is verified by simulation and experimental results.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • A Modular Isolated Topology for Instantaneous Reactive Power Compensation
    • Authors: Hao Chen;Anish Prasai;Deepak Divan;
      Pages: 975 - 986
      Abstract: This paper presents a novel topology for instantaneous reactive power compensation. The topology is derived from the Dynamic-Current or Dyna-C, which is a patented power converter capable of transferring energy for two or multiterminal dc, single- and/or multiphase ac systems. The proposed topology, named dynamic VAr compensator (DVC), has a current source power conversion stage and can provide instantaneous leading or lagging reactive power. The proposed DVC has three individual bridges coupled through a three-winding high-frequency transformer. It has a modular structure that allows it to be series stacked for medium-voltage applications. In addition, the high-frequency Galvanic isolation link provides interphase fault isolation among the three phases. The circuit eliminates the use of electrolytic capacitors for bulk energy storage, which usually lowers life and reliability. Operating principles, theoretical analysis, and design of the proposed topology are described. The converter functionality is validated through simulation as well as experimental results.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • A Square T-Type (ST-Type) Module for Asymmetrical Multilevel Inverters
    • Authors: Emad Samadaei;Abdolreza Sheikholeslami;Sayyed Asghar Gholamian;Jafar Adabi;
      Pages: 987 - 996
      Abstract: This paper introduces a new module for asymmetrical multilevel inverters with a low number of components. The module is a square combination of two back-to-back T-type inverters and some other switches. A square T-type module produces 17 levels by 12 switches and 4 unequal dc sources (two 3VDC and two 1V DC). Also, it can be extended as a cascade connection in two strategies to achieve more levels. The module and its cascade connection are suitable for the applications in several dc sources systems such as photovoltaic farms, which lead to a modular topology with more voltage levels at higher voltages. Inherent creation of the negative voltage levels without any additional circuit (such as H-bridge circuit) is one of the main features of the proposed module. The low total harmonic distortion of the output voltage/current and low number of semiconductors are among the other advantages of the proposed module. A nearest level control method as a switching technique is used to produce high quality output voltage with lower harmonic contents. Simulations have been performed in MATLAB/Simulink and a prototype is implemented in the Power Electronics Laboratory; both the simulation and experimental results show a good performance.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • A Novel Thyristor-Based CSI Topology With Multilevel Current Waveform for
           Improved Drive Performance
    • Authors: Sobhan Mohamadian;Simone Castellan;Alberto Tessarolo;Mohammad Hosein Khanzade;Abbas Shoulaie;
      Pages: 997 - 1006
      Abstract: Load-commutated inverters (LCIs), combined with wound-field synchronous machines (WFSMs), can be an excellent solution for high power drives, but their present technology suffers from important drawbacks related to low power factor, large torque pulsations, and poor starting performance. This paper presents a new LCI design intended to overcome the mentioned limitations. An SCR-based forced-commutation circuit is added to the common inverter topology to obtain a five-level waveform for the stator current. This leads to significantly reduced current harmonics and torque pulsations, in addition to bringing benefits in terms of lower additional losses. As a further advantage, the proposed design allows for a significant power factor enhancement. Finally, it enables the WFSM to be started with a much smoother torque compared to the traditional pulsed operating mode of conventional LCI drives. Simulation studies are conducted on a high-power drive scheme to show the aforementioned improvements. Also, a reduced-scale laboratory prototype of a WFSM drive system is tested to verify the feasibility of the proposed converter.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • A Fixed-Frequency ZVS Integrated Boost Dual Three-Phase Bridge DC–DC
           LCL-Type Series Resonant Converter
    • Authors: Nagendrappa Harischandrappa;Ashoka K. S. Bhat;
      Pages: 1007 - 1023
      Abstract: A new fixed-frequency controlled three-phase dc–dc LCL-type series resonant converter with integrated boost function is proposed for medium to large power applications with wide input voltage variation that is typical of alternate energy sources. The converter includes a dual three-phase LCL-type resonant bridge inverter modules connected in parallel, thus significantly reducing the component stresses when subjected to medium to large power applications. The fixed-frequency control of the output power is achieved by phase shifting the gating signals of one module with respect to the other, while the rectified voltage at the secondary windings of a three-phase high-frequency transformer connected between the two modules is added to the input voltage to boost the supply voltage to the modules. The zero-voltage-switching of all the switches is accomplished by designing the converter to operate in the lagging PF mode for wide variations in the input voltage and the load. Detailed modeling of the three-phase boost section is done and the steady-state analysis of the proposed converter for three-phase LCL-type dc–dc converter modules using complex ac circuit analysis method is presented. For illustration purpose, a dc–dc converter of 600 W is designed, and its performance is verified using PSIM simulations. An experimental model of the converter is built in the laboratory to verify its performance for wide variations in input voltage and load changes.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • An Adaptive Carrier Frequency Optimization Method for Harmonic Energy
           Unbalance Minimization in a Cascaded H-Bridge-Based Active Power Filter
    • Authors: Zezhou Yang;Jianjun Sun;Shangsheng Li;Meng Huang;Xiaoming Zha;Yi Tang;
      Pages: 1024 - 1037
      Abstract: Cascaded H-bridge (CHB) based active power filters (APF) can compensate high-order harmonics in medium and high-voltage systems with relatively low switching frequency. This paper reveals that a severe dc capacitor energy unbalance can be induced by harmonic energy exchange if the frequency of APF output current coincides with the switching harmonic frequency of CHB cells. The mechanism of harmonic energy exchange is analyzed, and it is found that the dc capacitor energy unbalance is essentially affected by the carrier frequency of CHB. A noninteger ratio carrier frequency can be adopted to avoid the divergence of dc voltage, but there is still a significant low-frequency ripple on the dc voltage. This paper proposes an adaptive carrier frequency optimization method. By predicting the dc voltage ripple amplitude under different carrier frequencies, this method can adaptively select the optimal carrier frequency to minimize the dc voltage ripple. The proposed method is also proved to be robust against system parameter variations, and it can be implemented by a practical and simple linear computation method. Results obtained from simulation, experimental prototype, and field test are finally presented to verify the proposed adaptive carrier frequency optimization method.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • A Novel Method Based on Self-Power Supply Control for Balancing Capacitor
           Static Voltage in MMC
    • Authors: Longfei Luo;Yanbin Zhang;Lixin Jia;Ningning Yang;
      Pages: 1038 - 1049
      Abstract: The modular multilevel converter is one of the most attractive converter topologies for high-voltage dc transmission systems, but it needs at least 10 min during the system uncontrolled precharge stage to verify the stability and reliability of submodules (SMs), making the capacitor static voltage balancing a key issue. This paper proposes a novel method based on self-power supply control for balancing capacitor static voltage. Because of the influence of self-power supplies on capacitor voltages, the method can keep the capacitor static voltage balanced by controlling the input characteristic of SMs self-power supplies. The control signals of self-power supplies have a fixed frequency and duty ratio, and they can be determined based on capacitor voltage sorting results and self-power supply output support capacitor. Compared with previous works, this method has less computation, and it does not rely on IGBTs and additional complex circuits except for the self-power supplies. This can save on the software and hardware costs. The proposed method also leads to improved equalizing resistances and reduced active power losses of the SMs. Simulations and experimental studies were conducted, and the results confirm the effectiveness of the proposed method.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Model Predictive Direct Power Control for Single Phase Three-Level
           Rectifier at Low Switching Frequency
    • Authors: Junpeng Ma;Wensheng Song;Shunliang Wang;Xiaoyun Feng;
      Pages: 1050 - 1062
      Abstract: This paper presents a new model predictive direct power control (MP-DPC) to overcome the drawbacks of model predictive control (MPC) for single phase three-level rectifiers in the railway traction drive system, including huge online calculation, poor power control precision at the low switching frequency and variable switching frequency. To do so, an exact analytical solution of instantaneous power estimation is adopted to predict active and reactive powers in next duty cycle updating interval for achieving the deadbeat control and reducing the predictive error at the low switching frequency (below 1 kHz). The optimal d-axis and q-axis components of input voltage within next duty cycle updating interval of the adopted rectifier in rotating coordinate system are directly calculated by minimizing the cost function. And the optimal drive pulses are generated by pulse width modulation stage in the proposed MP-DPC, other than evaluating cost function for each voltage vector in traditional MP-DPC. Finally, the influence of inductance mismatch on control system is analyzed, and an inductance estimation method is shown to improve the control precision. An experimental comparison with other five different DPC schemes has verified the effectiveness of the proposed MP-DPC scheme.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • A Three-Phase Active Rectifier Topology for Bipolar DC Distribution
    • Authors: Yitong Li;Adrià Junyent-Ferré;Joan-Marc Rodriguez-Bernuz;
      Pages: 1063 - 1074
      Abstract: A new three-phase active rectifier topology is proposed for bipolar dc distribution, which can achieve the independent dc-pole control, with only one two-level voltage source converter and an ac-side grounding inductor. The averaged large-signal model and linearized small-signal model of the rectifier are derived in the stationary reference frame. Moreover, a control system is proposed with proper controller parameters. Besides, the rectifier is tested on an experiment platform. Comprehensive experiment results are given and analyzed to validate the function of the proposed rectifier under different operation conditions, including the rectifier start-up performance, rectifier dynamics with unbalanced dc loads for two poles, and rectifier dynamics with asymmetrical dc voltages for two poles. Finally, the proposed rectifier is compared with other two existing ac–dc conversion approaches, in terms of required number and rating of components as well as power losses with different load imbalance levels, which further highlight some potential benefits of the proposed topology.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Investigation and Classification of Short-Circuit Failure Modes Based on
           Three-Dimensional Safe Operating Area for High-Power IGBT Modules
    • Authors: Yuxiang Chen;Wuhua Li;Francesco Iannuzzo;Haoze Luo;Xiangning He;Frede Blaabjerg;
      Pages: 1075 - 1086
      Abstract: Insulated-gate bipolar transistor (IGBT) short-circuit failure modes have been under research for many years, successfully paving the way for device short-circuit ruggedness improvement. The aim of this paper is to classify and discuss recent contributions about IGBT short-circuit failure modes, in order to establish the current state of the art and trends in this area. First, the concept of 3-D safe operating area is proposed as the IGBT's operational boundary to divide the device short-circuit failure modes into short-circuit $V_{{rm{DC}}}/ V_{{rm{rated}}}hbox{--} I_{{rm{SC}}}$ SOA limiting and short-circuit endurance time limiting groups. Then, the discussion is centered on currently reported IGBT short-circuit failure modes in terms of their relationships with the device 3-D short-circuit safe operating area (3D-SCSOA) characteristics. In addition, further investigation on the interaction of 3D-SCSOA characteristics is implemented to motivate advanced contributions in future dependence research of device short-circuit failure modes on temperature. Consequently, a comprehensive and thoughtful review of where the development of short-circuit failure mode research works of IGBT stands and is heading is provided.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • A New Active Output Filter (AOF) for Variable Speed Constant Frequency
           (VSCF) Power System in Aerospace Applications
    • Authors: Fahad M. Alhuwaishel;Ahmed S. Morsy;Prasad N. Enjeti;
      Pages: 1087 - 1093
      Abstract: In this paper a new “active output filter” (AOF) for variable speed constant frequency (VSCF) power system in aerospace applications is proposed. The proposed AOF is envisioned as a power semiconductor filter block. In the proposed system the passive L-C output filter components are replaced by an H-bridge. The H-bridge is operated at high frequency to inject voltage harmonics to achieve a sinusoidal output voltage to the load. Advanced wide band gap devices can be employed in the design of AOF block to obtain high performance with simultaneous reduction in size. The proposed AOF concept offers a significant reduction in size/weight compared to passive L-C. Further, in the presence of AOF the main VSCF inverter can be operated in a six-step and/or at a reduced PWM frequency. An example 250 kVA, 3-phase 400-Hz system with the proposed AOF concept is evaluated via simulation with a corresponding passive L-C filter configuration. Experimental results on reduced kVA laboratory prototype are discussed.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Design, Control, and Analysis of a Fault-Tolerant Soft-Switching DC–DC
           Converter for High-Power High-Voltage Applications
    • Authors: Tao Li;Leila Parsa;
      Pages: 1094 - 1104
      Abstract: A modular isolated soft-switching dc–dc converter that can offer two levels of fault tolerance is proposed. A typical application is the wind energy conversion system used in offshore series-dc wind farm concept. The converter consists of input-parallel-output-series (IPOS) connected modules. Each module is a full-bridge dc–dc converter with an active rectifier, which can achieve zero voltage switching for all primary side switches and zero current switching for all secondary side switches and diodes. Under normal operation, the converter is operated with secondary phase-shifted modulation. When tolerable fault occurs in certain module, reconfiguration method ensures uninterrupted operation for the system. Additionally, modular structure provides another level of fault tolerance. More benefits of IPOS structure include reduced input current and output voltage of each module, module shedding capability, reduced ripple content due to interleaving, intrinsic balancing, and scalable control method. Both normal and faulty operations are simulated and also verified by scaled-down prototype experiment.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • A Branch Current Reallocation Based Energy Balancing Strategy for the
           Modular Multilevel Matrix Converter Operating Around Equal Frequency
    • Authors: Boran Fan;Kui Wang;Pat Wheeler;Chunyang Gu;Yongdong Li;
      Pages: 1105 - 1117
      Abstract: The modular multilevel matrix converter (M3C) is a promising topology for medium-voltage, high-power applications. Due to the modular structure, it is scalable and capable to produce high quality output waveforms and can be fault tolerant. However, the M3C suffers from low frequency capacitor voltage fluctuation if the output frequency is close to the input voltage frequency, which limits its application in adjustable speed drive fields. This paper presents a theoretical analysis in the phasor domain to find the branch-energy equilibrium point of the M3C when operating with equal input and output frequency first. Then, a branch energy balancing control method based on branch current reallocation is proposed to equalize the energy stored in the nine converter branches. With the proposed method, the M3C can effectively suppress the capacitor voltage fluctuation without injecting common-mode voltage or applying reactive power to the input side. Experimental results are presented to validate the proposed method.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Detailed Device-Level Electrothermal Modeling of the Proactive Hybrid HVDC
           Breaker for Real-Time Hardware-in-the-Loop Simulation of DC Grids
    • Authors: Ning Lin;Venkata Dinavahi;
      Pages: 1118 - 1134
      Abstract: This paper proposes a series of proactive hybrid high-voltage direct-current (HVDC) breaker (HHB) electromagnetic transient models that can be implemented in hardware-in-the-loop (HIL) emulation for real-time execution on the field-programmable gate array (FPGA). To achieve high fidelity, an HHB model should have the same configuration as the real one, and three different models for an insulated-gate bipolar transistor (IGBT), i.e., a two-state switch model, a curve-fitting model, and an improved nonlinear behavioral model, are proposed to satisfy different accuracy and simulation speed requirements. Since designing an HHB with hundreds of IGBTs in a massive array would lead to an extremely heavy computational burden as well as to a high FPGA resource utilization, circuit partitioning is applied to each model, which enables decomposition into a number of physically independent subcircuits with smaller matrix dimension to exploit parallel implementation. Meanwhile, low hardware resource demand is achieved by using one of the subcircuits to represent the rest since they are identical. As the IGBTs produce a significant amount of heat, which in turn affects their performance, an electrothermal network is added as part of the model to provide specific information about the device's operation status including the junction temperature. The models are applied to a three-terminal HVDC system, where line faults are simulated to activate HHB protection sequence. Comparison of device-level and system-level performance from HIL emulation with those of commercial offline simulation tools validates the accuracy of the proposed models as well as the efficacy of the solution approach.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Current Shaping in a Hybrid 12-Pulse Rectifier Using a Vienna Rectifier
    • Authors: Ali Reza Izadinia;Hamid Reza Karshenas;
      Pages: 1135 - 1142
      Abstract: This paper presents a hybrid rectifier consisting of a 12-pulse rectifier in parallel with a Vienna rectifier. In the proposed structure, the 12-pulse rectifier supplies the bulk power to the load, whereas the Vienna rectifier shapes the input current to reduce its harmonic distortion. The unidirectional power flow of the Vienna rectifier results in undesirable distortion around the current zero crossing, which deteriorates current shaping in this region. To overcome this problem, besides current shaping, the Vienna rectifier is forced to participate in the active power. In this regard, the share of output power in each rectifier module must be calculated. To shape the input current, the reference current for the Vienna rectifier is generated using instantaneous power theory, and current tracking is carried out using the finite control set model predictive control. A detailed analysis of how to select the output power sharing ratio based on system losses and input current distortion is presented. The theoretical analysis is verified by using simulation and experimental results obtained from a 1 kW laboratory setup.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • An IGBT Turn-ON Concept Offering Low Losses Under Motor Drive dv/dt
           Constraints Based on Diode Current Adaption
    • Authors: Erik Velander;Lennart Kruse;Thomas (Lundström) Wiik;Anders Wiberg;Juan Colmenares;Hans-Peter Nee;
      Pages: 1143 - 1153
      Abstract: In this paper, a new low-loss turn-on concept for the silicon insulated-gate bipolar transistor (Si-IGBT) in combination with silicon p-i-n diode is presented. The concept is tailored for two-level motor converters in the 100 kW to 1 MW range under the constraint that the output voltages slopes are limited in order to protect the motor windings. Moreover, analyses of the IGBT turn-on and diode reverse recovery voltage slopes are presented concluding that the diode reverse recovery is the worst case. The concept includes a low-cost measurement of the free-wheeling diode current and temperature by the gate driver without necessity of acquiring this information from the converter control board. By using this concept, the output dv/dt at the diode turn-off can be kept approximately constant regardless of the commutated current and junction temperature. Hence, the switching losses could be decreased for the currents and temperatures where the voltage slopes are lower when using a conventional gate driver optimized for the worst case. Moreover, results are shown for one such power semiconductor, showing a total switching loss reduction of up to 28% in comparison with a gate driver without current and temperature measurement. Finally, this concept is particularly suitable for high power semiconductor modules in half-bridge configuration which are recently proposed by several suppliers.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • A New Voltage Compensation Philosophy for Dynamic Voltage Restorer to
           Mitigate Voltage Sags Using Three-Phase Voltage Ellipse Parameters
    • Authors: Peng Li;Lili Xie;Jiawei Han;Shilin Pang;Peihao Li;
      Pages: 1154 - 1166
      Abstract: This paper introduces a series compensation philosophy to improve the voltage property of loads using three-phase voltage ellipse parameters intended for optimal utilization of a dynamic voltage restorer. The proposed approach relies on the instantaneous magnitude of voltage signals and functions by inserting a virtual equivalent impedance in series with the distribution feeder during voltage sags, compensating for the difference between faulty and nominal voltages. In addition, the definite mathematical derivations using iterative processes are properly used as an identification mark of the resultant rotating vector tracing an ellipse. The ellipse parameters including major axis, minor axis, and inclination angle are utilized to develop the proposed algorithm and hence, a set of generalized VA loading formulations calculating an optimal sizing with the minimum possible rating are presented. The uniqueness of dual VSCs connected with common dc-side is an attempt to formalize the topological structure keeping a higher level of compensation accuracy. A novel design and the corresponding algorithm are proposed and all possible scenarios concerning sag depth and phase jump are taken into consideration. MATLAB-based simulation results are discussed in detail to support the concept and the test is also performed to verify the effectiveness through real-time experimental laboratory.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Hybrid-DC Electric Springs for DC Voltage Regulation and Harmonic
           Cancellation in DC Microgrids
    • Authors: Ming-Hao Wang;Shuo Yan;Siew-Chong Tan;Shu Yuen (Ron) Hui;
      Pages: 1167 - 1177
      Abstract: DC electric springs (DCES) are emerging technologies for the (i) regulation of mains voltage against the intermittent renewable generations and (ii) harmonic cancellation in dc microgrids. When conventional converter topologies (e.g., half-bridge or full-bridge converter) are adopted as DCES, the battery storage of the DCES has to process both the dc power and the ac harmonic power. The pulsating ac power can severely reduce the lifetime of the battery. To address this issue, a hybrid-DCES (H-DCES) is proposed in this paper to perform (i) and (ii) in a decoupled manner. With a modified topology and control method, the H-DCES can divert the ac current to the ground and retains the function of manipulating noncritical load for dc voltage regulation. The immediate benefits of this H-DCES are the reduction of storage capacity and a prolonged lifetime of the battery. Both the operating principle and the mathematical model of the proposed H-DCES are analyzed in this paper. A prototype of the H-DCES is practically tested in a 48-V dc grid. The experimental results show that the H-DCES can realize the decoupled operation of dc voltage regulation and harmonic cancellation. Simulation studies further demonstrate that the H-DCES requires less storage capacity than its counterparts.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Electromagnetic Noise Mitigation for Ultrafast on-Die Temperature Sensing
           in High-Power Modules
    • Authors: Chengcheng Yao;Pengzhi Yang;Huanyu Chen;Mingzhi Leng;He Li;Ke Zou;Ming Su;Chingchi Chen;Jin Wang;
      Pages: 1178 - 1187
      Abstract: Real-time junction temperature measurements can be very beneficial for improving power converter's design, performance, and reliability. Junction temperature sensing using an on-die diode sensor is a promising solution. However, a strong low-pass filter is usually applied to filter out the sensor's noise during switching transients, which reduces the sensor's bandwidth. This paper aims to improve the sensing system's bandwidth to achieve an ultrafast real-time junction temperature measurement. Three noise coupling mechanisms have been identified and verified by both simulations and experiments. The noise coupling model-based crosstalk capacitances estimation method is proposed and validated. Noise mitigation methods are proposed, thus only a 200-kHz low-pass filter is needed for the noise suppression purpose, which is a significant improvement from the current field implementation of tens of hertz bandwidth.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • New Method for Common Mode Voltage Cancellation in Motor Drives: Concept,
           Realization, and Asymmetry Influence
    • Authors: Di Han;Woongkul Lee;Silong Li;Bulent Sarlioglu;
      Pages: 1188 - 1201
      Abstract: This paper introduces a new concept of common mode voltage cancellation for pulse width modulated motor drives, aiming at solving issues such as ground leakage current, common mode electromagnetic interference, and bearing current. The balanced inverter topology and dual-winding stator configuration are proposed as a practical realization. Implementation considerations on the influence of circuit asymmetry are also investigated. Finally, a gallium nitride HEMT based induction motor drive prototype is built and tested to evaluate the performance of the cancellation concept in a practical situation.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • An Optimized Strategy for PWM Current Source Converter Based Wind
           Conversion Systems With Reduced Cost and Improved Efficiency
    • Authors: Qiang Wei;Bin Wu;Dewei Xu;Navid Reza Zargari;
      Pages: 1202 - 1210
      Abstract: Recently, a series-connected current source converter (CSC) based configuration is proposed for offshore wind conversion systems. However, two problems exist in conventional strategy of such a system. One is increased cost on onshore CSCs, and the other is decreased operation efficiency of onshore CSCs. To solve these issues, this paper proposes an optimized strategy. First, the nominal number of onshore CSCs is optimized that a lower cost and a higher efficiency are achieved. Second, an optimal control scheme is proposed for onshore CSCs with lower operation loss. In addition, it is implemented without any extra components or auxiliary circuits. In summary, the proposed scheme gives a reduced cost and an improved efficiency of the offshore system with all the control objective being ensured simultaneously. Simulation and experiments are finally provided.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Stator Harmonic Currents Suppression for DFIG Based on Feed-Forward
           Regulator Under Distorted Grid Voltage
    • Authors: Chao Wu;Heng Nian;
      Pages: 1211 - 1224
      Abstract: This paper presents a stator harmonic currents suppression method for doubly fed induction generators (DFIGs) under distorted grid voltage. In the proposed control strategy, the feed-forward regulator instead of the resonant regulator is employed to eliminate the negative impacts on the stator current caused by the distorted grid voltage. The leading phase compensator is applied to compensate the system delay when the sampling frequency is low. This approach can provide both the good dynamic response and strong rejection ability against the stator harmonic voltages. Based on the stator current model of DFIG, the feed-forward regulator is designed in detail. The comparison between the resonant controllers and the feed-forward regulator is also made on the basis of Bode diagram. Then, the robustness against the frequency variations and the parameter deviations is analyzed. Finally, the simulation and experimental results are presented to validate the effectiveness of the proposed control strategy.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Lifetime Evaluation of Grid-Connected PV Inverters Considering Panel
           Degradation Rates and Installation Sites
    • Authors: Ariya Sangwongwanich;Yongheng Yang;Dezso Sera;Frede Blaabjerg;
      Pages: 1225 - 1236
      Abstract: Lifetime of Photovoltaic (PV) inverters is affected by the installation sites related to different solar irradiance and ambient temperature profiles (also referred to as mission profiles). In fact, the installation site also affects the degradation rate of the PV panels and, thus, long-term energy production and reliability. Prior-art lifetime analysis in PV inverters has not yet investigated the impact of PV panel degradations. This paper, thus, evaluates the lifetime of PV inverters considering panel degradation rates and mission profiles. Evaluations have been carried out on PV systems installed in Denmark and Arizona. The results reveal that the PV panel degradation rate has a considerable impact on the PV inverter lifetime, especially in the hot climate (e.g., Arizona), where the panel degrades at a faster rate. In that case, the PV inverter lifetime prediction can be deviated by 54%, if the impact of PV panel degradations is not taken into account.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • An Efficiency Comparison of Fuel-Cell Hybrid Systems Based on the
           Versatile Buck–Boost Converter
    • Authors: Harrynson Ramírez-Murillo;Carlos Restrepo;Tine Konjedic;Javier Calvente;Alfonso Romero;Carlos R. Baier;Roberto Giral;
      Pages: 1237 - 1246
      Abstract: This paper extends the use of the versatile buck–boost converter to power manage a parallel hybrid system topology as an alternative to the well-known serial hybrid (SH) topology and the most recent series–parallel hybrid (SPH) topology. These systems utilize a proton exchange membrane fuel cell as the primary source in combination with an auxiliary storage device (ASD), and the selected converter is in charge of the power management between the sources (fuel cell or ASD) and the load. Therefore, the converter has a very important role in the system since it is responsible of ensuring a dc-bus voltage regulation with a safe and reliable operation of the entire system while also guarantee a high power conversion efficiency. Hence, this is the third topology, where the coupled-inductor dc–dc buck–boost converter is studied to demonstrate and exploit its advantages such as noninverting voltage step-up and step-down, high efficiency, regulation of input and output currents and low ripple values, and the ability to change from input to output current regulation loop, suddenly and smoothly, and vice versa. In order to determine which topology (SH, PH, or SPH) exhibits the highest power conversion efficiency under a certain load profile, it is important to ensure a fair efficiency comparison that will only reflect the properties of the topology and not its individual components. Therefore, the same design criteria, the same control, and the same components were used for all the studied topologies. Simulation and experimental results have been validated on a 48-V 1200-W dc bus.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Injected Grid Current Quality Improvement for a Voltage-Controlled
           Grid-Connected Inverter
    • Authors: Xinran Chen;Xinbo Ruan;Dongsheng Yang;Wenxin Zhao;Lei Jia;
      Pages: 1247 - 1258
      Abstract: The injected grid current of the voltage-controlled grid-connected inverter has serious distortion due to the low frequency harmonic components in the output voltage, which is resulted by the dead time of the drive signals of the power switches, and the distortion cannot be eliminated even when an output voltage closed loop is incorporated. This paper introduces a virtual series impedance to increase the output impedance of the grid-connected inverter only at the dominated lower harmonic frequencies; thus, the injected grid current quality can be improved and the dynamic performance of the grid-connected inverter is not deteriorated. Experimental results from a 6-kW single-phase grid-connected inverter confirm the effectiveness of the proposed method.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Single-Switch Single-Magnetic PWM Converter Integrating Voltage Equalizer
           for Partially Shaded Photovoltaic Modules in Standalone Applications
    • Authors: Masatoshi Uno;Akio Kukita;
      Pages: 1259 - 1270
      Abstract: To prevent partial-shading issues in photovoltaic (PV) systems, various kinds of voltage equalizers that virtually unify characteristics of shaded and unshaded modules have been proposed. Although PV string utilization can be dramatically improved, PV systems tend to be complex and costly because, in addition to the main converter for string control, voltage equalizers are separately necessary. This paper proposes the single-switch single-magnetic pulse width modulation (PWM) converter integrating the voltage equalizer using the series-resonant voltage multiplier (SRVM) for standalone PV systems. By utilizing a square wave voltage generated across a filter inductor in a PWM buck converter for driving the SRVM, the main PWM converter and voltage equalizer can be integrated into a single unit with reducing the total switch and magnetic component counts, achieving not only system-level but also circuit-level simplifications. The experimental test using the prototype for three PV modules connected in series was performed emulating a partial-shading condition. The integrated converter effectively precluded the partial-shading issues and significantly improved the power available at a load, demonstrating its efficacy.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Ground Leakage Current Analysis a Suppression in a 60-kW 5-Level T-Type
           Transformerless SiC PV Inverter
    • Authors: Lu Wang;Yanjun Shi;Yuxiang Shi;Ren Xie;Hui Li;
      Pages: 1271 - 1283
      Abstract: In this paper, ground leakage current suppression in a 60-kW 5-level T-type (5LT2) transformerless SiC photovoltaic (PV) inverter has been presented. The common mode (CM) equivalent circuit is analyzed based on a high frequency (HF) CM loop and a low frequency (LF) CM loop, respectively. In the 5LT2 inverter, the derived HF CM voltage (CMV) is found to have 86% reduction compared to that of a 3-level T-type (3LT2) inverter. The simulation and experiment results are provided to demonstrate the advantages of 5LT2 inverter on HF leakage current suppression. In addition, LF CMV caused by neutral point (NP) voltage oscillation has been analyzed in this paper. It is shown that the LF CMV is nearly proportional to the NP voltage oscillation. Furthermore, an LF CMV compensation method is proposed to suppress the LF CMV by 64%, which is verified by simulation and experiment results. Finally, the leakage current shows 79% reduction in the 5LT2 inverter compared to the conventional 3LT2 inverter in the experiment. A further 52% leakage current reduction is achieved by the LF CMV compensation in the 5LT2 inverter.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Design Guidelines for Multiloop Perturbative Maximum Power Point Tracking
           Algorithms
    • Authors: Jyri Kivimäki;Sergei Kolesnik;Moshe Sitbon;Teuvo Suntio;Alon Kuperman;
      Pages: 1284 - 1293
      Abstract: Due to relatively good performance and simple implementation, fixed-step direct maximum power point tracking (MPPT) techniques such as perturb and observe and incremental conductance are the most popular algorithms aimed to maximize the energy yield of photovoltaic energy conversion systems. In order to optimize the MPPT process performance, two design parameters—perturbation frequency and perturbation step size—need to be set a priori , taking into account the properties of both interfacing power converter and photovoltaic generator. While perturbation frequency is limited by the combined energy conversion system settling time, perturbation step size must be high enough to differentiate system response from that caused by irradiation variation. Recent studies have provided explicit design guidelines for single-loop MPPT structures only, where the algorithm directly sets the interfacing converter duty cycle. It was shown that dynamic resistance of the photovoltaic generator, which is both operation point and environmental conditions dependent, significantly affects the combined energy conversion system settling time. On the other hand, no design guidelines were explicitly given for multiloop MPPT structures, where the algorithm sets the reference signal for photovoltaic generator (PVG) voltage and inner-voltage controller performs the regulation task. This paper introduces perturbation frequency and perturbation step size design guidelines for such systems. It is shown that while perturbation step size design is similar to that of single-loop structures, perturbation frequency design is quite different. It is revealed that once the inner-voltage loop is properly closed, the influence of PVG dynamic resistance on settling time (and thus on perturbation frequency design) is negligible. Experimental results are provided to verify the proposed guidelines validity.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Bipolar Operation Investigation of Current Source Converter Based Wind
           Energy Conversion Systems
    • Authors: Qiang Wei;Bin Wu;Dewei Xu;Navid Reza Zargari;
      Pages: 1294 - 1302
      Abstract: A series-connected current source converter (CSC) based configuration has recently been proposed for offshore wind energy conversion systems. A big challenge exists for such a system that its maximum insulation level is the full transmission voltage due to its monopolar operation. This introduces significant burden to the system in terms of cost, reliability, and flexibility. To solve this issue, a bipolar operation giving a half insulation requirement is proposed and investigated in this paper. However, a unique challenge exists for the CSC-based system when operating under bipolar mode, that is, the dc-link current control. There are two equivalent paths for the dc-link current, which introduces a concern for proper operation of the bipolar system. Accordingly, an optimized dc-link current control is developed in this study. In summary, the bipolar system with the help of the optimized dc-link current control features lower insulation requirement, higher reliability, higher efficiency, and higher flexibility. Finally, both simulation and experimental results are provided.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Current Ripple Mechanism with Quantization in Digital LLC Converters for
           Battery Charging Applications
    • Authors: Zhiliang Zhang;Ya-Qi Wu;Dong-Jie Gu;Qianhong Chen;
      Pages: 1303 - 1312
      Abstract: The mechanism of current ripple propagation in a digital controlled LLC converter is investigated from three aspects: battery load, quantization error, and double line frequency perturbation at the input. With conventional frequency modulation (FM), every modulation step is accompanied by quantization error due to limited resolution of digital controllers. Large current ripple is propagated to the output due to poor FM and extremely low internal impedance of batteries, which hurts battery health seriously. The analytical model of output current oscillation is proposed considering the quantization effects and double line frequency input voltage perturbation. The synchronous frequency dither (FD) is proposed to improve quantization resolution and reduce current ripple further. A 2-kW Li-ion battery charger was built to verify the proposed current oscillation model and effectiveness of synchronous FD control. Good agreement is verified between analytical derivations and experimental results. The quantization current ripple is significantly attenuated by around 45% over entire charging range.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • A Sliding-Mode Direct Power Control Strategy for DFIG Under Both Balanced
           and Unbalanced Grid Conditions Using Extended Active Power
    • Authors: Dan Sun;Xiaohe Wang;Heng Nian;Z. Q. Zhu;
      Pages: 1313 - 1322
      Abstract: This paper proposes a sliding-mode direct power control (SMDPC) strategy for doubly fed induction generator (DFIG) under both balanced and unbalanced grid conditions using extended active power. When the traditional power theory is used under unbalanced grid condition, the control strategies usually need to be modified and become more complicated. Therefore, an extended active power is proposed in this paper, which is effective under both balanced and unbalanced grid conditions with a simple control strategy. Based on the extended active power, elaborated analysis of the mathematical model of DFIG is obtained. Furthermore, an SMDPC strategy using the extended active power is proposed, which can obtain sinusoidal stator currents and restrain electromagnetic torque ripples under unbalanced grid condition without the need of decomposition process and phase-locked loop (PLL). Comparative experimental studies of the SMDPC using the extended and traditional active powers for DFIG are conducted to validate the effectiveness of the proposed strategy under both balanced and unbalanced grid conditions. In addition, the dynamic performance and robustness of the proposed SMDPC are also proved to be satisfying by the experimental results.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Current Flow Controlling Hybrid DC Circuit Breaker
    • Authors: Ataollah Mokhberdoran;Oriol Gomis-Bellmunt;Nuno Silva;Adriano Carvalho;
      Pages: 1323 - 1334
      Abstract: This paper proposes a new device by combining features of an interline dual H-bridge current flow controller with the core idea of a hybrid HVdc circuit breaker for meshed HVdc grid application. The proposed device can substitute two dc circuit breakers at a dc bus with at least two adjacent transmission lines. In addition to the current interruption action, the current in one of the adjacent lines can be controlled by the embedded current flow controller. The system-level behavior of the proposed current flow controlling hybrid dc circuit breaker is similar to that of the typical hybrid dc circuit breaker and the interline dual H-bridge current flow controller. The operation principles of the proposed device are introduced and analyzed in this work. The component ratings are compared to the existing solution, and the functionality of the proposed device is verified by simulation.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Active Virtual Ground— Single-Phase Transformerless Grid-Connected
           Voltage Source Inverter Topology
    • Authors: River Tin Ho Li;Carl Ngai Man Ho;Eric-Xu Chen;
      Pages: 1335 - 1346
      Abstract: An efficient single-phase Transformerless grid-connected voltage source inverter topology by using the proposed active virtual ground (AVG) technique is presented. With the AVG, the conventional output L filter can be reconfigured to LCL structure without adding additional inductor. High-frequency differential mode current ripple can be significantly suppressed comparing to the available single-phase grid-connected inverter topologies. Additionally, strong attenuation to the high-frequency common-mode current is achieved. It is particularly important for some applications such as photovoltaic and motor drives. High efficiency can be achieved due to fewer components involved in the conduction loss. Cost of the magnetic device can be reduced since the required inductance of the filter becomes smaller. Performance of the proposed inverter has been evaluated analytically. Experimental verification is performed on a 1-kW, 400-V input, and 110-V/60-Hz output prototype.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • High-Efficiency Current-Fed Dual Active Bridge DC–DC Converter With ZVS
           Achievement Throughout Full Range of Load Using Optimized Switching
           Patterns
    • Authors: Deshang Sha;Xiao Wang;Deliang Chen;
      Pages: 1347 - 1357
      Abstract: For current-fed dual active bridge bidirectional dc–dc converters, all the possible switching patterns are summarized in view of the combinations of both side pulse-width modulation duty cycles and phase-shift angle. A control strategy is proposed for the current-fed dual active bridge converter to operate with the optimized patterns. The equivalent duty cycle of the secondary side is smaller than that of the primary side by a fixed value, which is optimized based on the soft-switching achievement and the circulating current minimization. The closed-loop control is easy to be implemented since there are only two independent variables, one-side duty cycle and the phase-shift angle. With the proposed control, zero-voltage switching can be achieved for all power switches throughout full range of load even at no-load condition. The typical working modes with the proposed control are given. The optimal design of the system parameters including the fixed time delta and dead time is illustrated. The converter has a very good performance, not only under steady states but also in transients. The conversion efficiency is high. The effectiveness of the proposed control is verified by the experimental results of a 1-kW laboratory prototype.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Investigation and Implementation of a Starting and Voltage Spike
           Suppression Scheme for Three-Phase Isolated Full-Bridge Boost PFC
           Converter
    • Authors: Tao Meng;Hongqi Ben;Yilin Song;
      Pages: 1358 - 1367
      Abstract: A starting and voltage spike suppression scheme is proposed and investigated in a three-phase isolated full-bridge boost power factor correction (PFC) converter with the passive flyback auxiliary circuit. In steady state, the auxiliary circuit in the PFC converter is operating as a passive clamp circuit, by which the voltage spike across primary side of the power transformer is suppressed, and the absorbed energy can be transferred to the load during one charging period by the resonance of the inductors and capacitors in the auxiliary circuit. In starting state, the output filter capacitor is charged by the flyback inductor in the auxiliary circuit, and the PFC converter can achieve normal starting-up. The operational processes of the PFC converter are analyzed in both steady and starting states. Furthermore, the design considerations of the key parameters are discussed. Finally, experimental study has been done on a laboratory-made three-phase PFC prototype, and the feasibility of the proposed scheme and the validity of the theoretical analysis are verified by the experimental results.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Study of Wireless Power and Information Transmission Technology Based on
           the Triangular Current Waveform
    • Authors: Zhou Yan;Zhu Xiang;Lin Wu;Baoyun Wang;
      Pages: 1368 - 1377
      Abstract: Wireless power and information transmission (WPIT) technology can realize simultaneous wireless transmission of power and information. In this paper, the fundamental component of the triangular current waveform is employed to transfer power, and its third-order harmonic component is selected to transfer information. The Fourier decomposition method is conducted to analyze the triangular current waveform; two equivalent circuit models of the proposed WPIT system are established based on the relationship between the fundamental component and the third-order harmonic component. Harmonic components have an enlargement effect on the deviation of the fundamental frequency; this feature is used to realize the weakly coupled control between the information transmission and the efficiency of wireless power transfer. Based on the proposed harmonic communication method, the transient process and the maximum communication speed of the circuit are discussed. To achieve the high signal-to-noise ratio (SNR) communication, different space positions of the signal receiving winding are compared. Experimental results show that the proposed method provides a new solution for designing the WPIT system.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Hybrid-Bridge-Based DAB Converter With Voltage Match Control for Wide
           Voltage Conversion Gain Application
    • Authors: Guo Xu;Deshang Sha;Yaxiong Xu;Xiaozhong Liao;
      Pages: 1378 - 1388
      Abstract: This paper proposes a voltage match (VM) control for hybrid-bridge-based dual active bridge (DAB) converter in wide voltage conversion gain applications. With the addition of an auxiliary half-bridge circuit, the topology becomes an integration of a half-bridge and a full-bridge DAB converter. Unlike other pulse width modulation generation method for DAB converters, this converter utilizes four-level voltage at one port of the transformer to obtain matched voltage waveforms within the range of twice the minimum conversion gain. Wide conversion gain, decoupling of the two power control variables and wide zero-voltage switching (ZVS) ranges can be achieved with the proposed VM control. Full load ranges of ZVS for the six main power switches can be achieved and the two auxiliary switches can also operate in a wide ZVS range. In addition, the power control is done only using two control variables and its implementation is very simple, only needing a divider and a conventional voltage regulator. These characteristics and benefits of the proposed control are verified by experimental results from a 1-kw converter prototype.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Isolated Boost DC–DC Converter With Three Switches
    • Authors: Minh-Khai Nguyen;Truong-Duy Duong;Young-Cheol Lim;Yong-Jae Kim;
      Pages: 1389 - 1398
      Abstract: This paper documents a new three-switch, isolated boost dc–dc converter. The major features of the proposed converter are as follows: 1) continuous input current; 2) reduced one active switch, one additional diode, and one additional capacitor; 3) unchanged primary and secondary voltage waveforms of the transformer when the duty cycle is changed; and 4) removal of the snubber circuit. This paper presents the operating principles, analysis, parameter design guidelines, and simulation results for the proposed converter. To verify the performance of the proposed converter, a 400 W prototype was constructed with a 40–60 V dc input. A PID controller was used to maintain the dc output voltage at 400 V. The simulation and experimental results matched those of the theoretical analysis.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Cascaded High Voltage Conversion Ratio Bidirectional Nonisolated DC–DC
           Converter With Variable Switching Frequency
    • Authors: Jianliang Chen;Deshang Sha;Yu Yan;Bin Liu;Xiaozhong Liao;
      Pages: 1399 - 1409
      Abstract: In this paper, a multistage nonisolated high voltage conversion ratio (VCR) bidirectional dc–dc converter is proposed. The VCR is n times of the conventional buck/boost converter using only $n+ {text{2}}$ switches. All the switches can achieve full-range zero voltage switching (ZVS) despite the power flow direction. The operating principle, ZVS condition, and design considerations of a four-stage topology are analyzed in detail. In addition, an improved dynamic switching frequency modulation is proposed to reduce the power loss. Analyses and comparisons between the conventional constant frequency and variable frequency control are made to show the effectiveness. A 500-W experimental prototype interfacing 20–30 V with 270 V is fabricated to verify the performance of the proposed converter and control strategy.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • A New Class of Single-Phase High-Frequency Isolated Z-Source AC–AC
           Converters With Reduced Passive Components
    • Authors: Hafiz Furqan Ahmed;Honnyong Cha;
      Pages: 1410 - 1419
      Abstract: In this paper, a class of single-phase Z-source (ZS) ac–ac converters is proposed with high-frequency transformer (HFT) isolation. The proposed HFT isolated (HFTI) ZS ac–ac converters possess all the features of their nonisolated counterparts, such as providing wide range of buck-boost output voltage with reversing or maintaining the phase angle, suppressing the in-rush and harmonic currents, and improved reliability. In addition, the proposed converters incorporate HFT for electrical isolation and safety, and therefore can save an external bulky line frequency transformer, for applications such as dynamic voltage restorers, etc. The proposed HFTI ZS converters are obtained from conventional (nonisolated) ZS ac–ac converters by adding only one extra bidirectional switch, and replacing two inductors with an HFT, thus saving one magnetic core. The switching signals for buck and boost modes are presented with safe-commutation strategy to remove the switch voltage spikes. A quasi-ZS-based HFTI ac–ac is used to discuss the operation principle and circuit analysis of the proposed class of HFTI ZS ac–ac converters. Various ZS-based HFTI proposed ac–ac converters are also presented thereafter. Moreover, a laboratory prototype of the proposed converter is constructed and experiments are conducted to produce output voltage of 110 Vrms / 60 Hz, which verify the operation of the proposed converters.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Class E/F$_3$ Tuned Power Oscillator
    • Authors: Tsuyoshi Inaba;Hirotaka Koizumi;
      Pages: 1420 - 1427
      Abstract: This paper proposes a Class E/F$_3$ tuned power oscillator based on the Class E/F$_3$ amplifier. The oscillator has a feedback-loop circuit and starts the oscillation in automatic. In addition, the oscillator achieves zero-voltage switching and zero-voltage derivative switching; therefore, the switching losses are reduced under high oscillation frequency. Moreover, the third harmonic tuned by providing a third harmonic series resonant circuit reduces the switch voltage stress of the mosfet sufficiently. The oscillator was designed, built and tested using an IRFR120Z power mosfet. Under the condition of the input voltage 6.003 V, following results were shown: the measured oscillation frequency was 801.6 kHz, the output power was 0.9075 W, and the power conversion efficiency was 86.24%.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Design of a High Efficiency DC–DC Buck Converter With Two-Step Digital
           PWM and Low Power Self-Tracking Zero Current Detector for IoT Applications
           
    • Authors: Sang-Yun Kim;Young-Jun Park;Imran Ali;Truong Thi Kim Nga;Ho-Cheol Ryu;Zaffar Hayat Nawaz Khan;Seong-Mun Park;Young Gun Pu;Minjae Lee;Keum Cheol Hwang;Youngoo Yang;Kang-Yoon Lee;
      Pages: 1428 - 1439
      Abstract: In this paper, a high efficiency dc–dc buck converter with two-step digital pulse width modulation (DPWM) and low power self-tracking zero current detector (ST-ZCD) is proposed for Internet of Things (IoT) and ultralow power applications. The hybrid DPWM core with high linearity and low power consumption is proposed to implement the high efficiency DPWM dc–dc converter. It is composed of a two-step delay control using the counter and delay line. An adaptive window analog to digital converter is proposed to reduce the output voltage ripple within 20 mV. A dead time generator is implemented with the proposed ST-ZCD to minimize the reverse current. The ST-ZCD can improve efficiency by reducing the control loss that accounts for a large proportion of the dc–dc converter. Also, all digital type-III compensator is implemented for the low power and small die area. This chip is fabricated with a 55 nm CMOS process, which uses the standard supply voltage of 1.5–3 V to generate the output voltage of 1.2 V. The total active area is 500 μm × 300 μm. The measured peak efficiency of the DPWM dc–dc buck converter is 91.5% with a quiescent current consuming only 130 μA.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • A Novel Soft-Switching Full-Bridge Converter With a Combination of a
           Secondary Switch and a Nondissipative Snubber
    • Authors: Dai-Duong Tran;Hai-Nam Vu;Sunho Yu;Woojin Choi;
      Pages: 1440 - 1452
      Abstract: In this paper, a novel soft-switching full-bridge converter with an additional secondary switch and a nondissipative energy recovery snubber is proposed. Thanks to the combination of an active switch and the capacitor—diode–diode snubber employed at the secondary side of the converter, the proposed converter can achieve zero-voltage zero-current switching for all of the primary switches and rectifier diodes over the entire load range. As a result, the rectifier diodes have no reverse-recovery problem and their ringing voltage is clamped. In addition, since no phase shift is used for the gate signals of the primary-side switches, the converter control can be implemented easily and it has no circulating current inherently. The converter exhibits a significant improvement in terms of efficiency, especially under light-load conditions, which is difficult to achieve with conventional phase-shift full-bridge converters. A 3-kW prototype circuit is implemented to verify the superior performance of the proposed converter.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • A Three-Winding Coupled-Inductor DC–DC Converter Topology With High
           Voltage Gain and Reduced Switch Stress
    • Authors: Xuefeng Hu;Jianzhang Wang;Linpeng Li;Yongchao Li;
      Pages: 1453 - 1462
      Abstract: This paper presents a dc–dc boost converter topology for low input and high output voltage applications, such as photovoltaic systems, fuel cell systems, high-intensity discharge lamp, and electric vehicles. The suggested configuration consists of a three-winding coupled-inductor, a single switch and two hybrid voltage multiplier cells. Furthermore, two independent hybrid voltage multiplier cells are in parallel when the single switch S is turned on, and they are in series when the switch S is turned off. So, the advantages of the proposed converter structure are summarized as follows: 1) A coupled inductor with three windings is introduced in the presented converter structure. The two secondary windings of the coupled inductor are, respectively, used to form a hybrid multiplier cell on the one hand, on the other hand, it increases the control freedom of the voltage gain, enhances the utility rate of magnetic core and power density, and reduces the stress of power components to provide a stable constant dc output voltage. 2) The two hybrid multiplier cells can absorb synchronously the energy of stray inductance, which not only reduces the current stress of corresponding diodes, but also greatly alleviates the spike voltage of the main switch, which improves the efficiency. 3) The two hybrid multiplier cells are connected in series to supply power energy for the load, so the voltage gain is extended greatly due to this particular structure. Thus, low-voltage low-conduction-loss devices can be selected and the reverse-recovery currents within the diodes are inhibited. The operating principles and the steady state analyses of the proposed converter are discussed in detail. Finally, a test prototype has been implemented in the laboratory, and the simulated and experimental results show satisfactory agreement with the theoretical analysis.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Commutation Torque Ripple Reduction of Brushless DC Motor in Braking
           Operation
    • Authors: Tingna Shi;Xingzhuo Niu;Wei Chen;Changliang Xia;
      Pages: 1463 - 1475
      Abstract: In this paper, the commutation torque ripple is studied in the brushless DC motor (BLDCM) braking operation. As the phase currents flow in the reversed directions in the braking operation, the current circuits in the braking operation are different from those in the motor operation. For this reason, it is found that the commutation torque ripple can be reduced in the speed range from the rated speed to zero just by the common braking pulse width modulation strategies, where the three-phase modulation is not needed. However, it is impossible in motor operation. Under the common braking pulse width modulation strategies, the speed ranges where commutation torque ripple can be reduced are derived and compared. Based on the analysis of these speed ranges, a simple braking method is proposed. With this method, the BLDCM can be slowed down without commutation torque ripple in the whole braking process from the rated speed to zero. Experiment results verify the effectiveness of the method and the correctness of the theory.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Quasi-Z-Source Indirect Matrix Converter Fed Induction Motor Drive for
           Flow Control of Dye in Paper Mill
    • Authors: D. Sri Vidhya;T. Venkatesan;
      Pages: 1476 - 1486
      Abstract: This paper describes a flow control of the dye in the paper mill with the quasi-Z-source indirect matrix converter (QZSIMC) fed induction motor drive. More than a decade the voltage-source inverter (VSI) and current-source inverter (CSI) have been used to control the speed of the induction motor, which in turns controls the flow of dye. Recently, the matrix converter (MC) has been an excellent competitor for the VSI or CSI for its compactness. The voltage transfer ratio of the VSI, CSI, and MC has been limited to 0.866. Thus, the efficiency of these converters is less. To improve the voltage transfer ratio the quasi-Z-source network (QZSN) is to be used between voltage source and indirect MC (IMC). The modification in the shoot-through duty ratio of the QZSN varies the voltage transfer ratio greater than 0.866. Different voltage transfer ratios are needed for different voltage sag conditions. For a variation of the duty ratio of the QZSN, the fuzzy logic controller has been presented. To control the IMC vector control with space vector modulation has been presented. This paper proposes the implementation of QZSIMC adjustable speed drive for the flow control of dye in paper mill during different voltage sag conditions. A 4-kW prototype has been built and the effectiveness of the proposed system is verified with simulation results and experimental setup. Simulation is done in MATLAB, Simulink platform. Experimental setup is done with the aid of a TMS320F2812 (Texas Instrument) processor. The experimental results validate the maintenance of the speed of an induction motor at the set condition, thus controlling the perfect flow of dye in paper manufacturing technology.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • DTC of Three-Level NPC Inverter Fed Five-Phase Induction Motor Drive With
           Novel Neutral Point Voltage Balancing Scheme
    • Authors: Saifullah Payami;Ranjan Kumar Behera;Atif Iqbal;
      Pages: 1487 - 1500
      Abstract: In this paper, direct torque control (DTC) of five-phase induction motor (FPIM) is implemented using three-level neutral point clamped (TL-NPC) inverter. One of the advantages of three-level inverter over two-level one for DTC operation is the low torque ripple. Also TL-NPC inverter through space vector modulation technique gives low $ dv/dt$ transition with better voltage waveform. By applying conventional lookup table for DTC, the TL-NPC inverter does not ensures lower $dv/dt$ transition. In this paper, a novel switching scheme for DTC of FPIM using TL-NPC inverter is proposed that ensures the low $ dv/dt$ transition and balancing of dc-link capacitor voltages of TL-NPC inverter. To form the lookup table for DTC operation, instead of using voltage vectors directly, virtual vectors (VVs) are utilized. Two switching states are used in one sample time to generate a VV in $alpha beta$ plane, which gives zero resultant voltage in $ xy$ plane. The switching strategy ensures low number of transitions to reduce the switching losses. The switching state redundancies are used in a novel way to balance the dc-link capacitor voltages without using any additional hardware. The proposed technique to balance the dc-link capacitor voltage gives lower switching frequency. The MATLAB/Simulink environment is used for the simulation and the results are validated through experiments.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Variable Time Step Control for Six-Step Operation in Surface-Mounted
           Permanent Magnet Machine Drives
    • Authors: Jaeyong Park;Sungho Jung;Jung-Ik Ha;
      Pages: 1501 - 1513
      Abstract: The six-step operation of surface-mounted permanent magnet machine drives in a flux weakening region has many advantages compared to the pulse width modulation mode, such as the reduced switching loss and fully utilized inverter output voltage. However, if the ratio of the sampling frequency to the fundamental frequency is low in fixed sampling system, the low-frequency oscillation in the current can be incurred in the six-step operation. The low-frequency current causes a system stability problem and reduces system efficiency due to an excessive heat and high power loss. Therefore, this paper proposes the variable time step controller for six-step operation. By updating an output voltage, sampling phase currents, and executing the digital controller synchronized with the variable sampling time, the turn on and off switch signals for six-step operation can be generated at the exact moment. As a result, the low-frequency oscillation in the phase current can be eliminated. In addition, the system transfer function of the proposed control method is discussed for the system stability and system dynamic analysis. The effectiveness of the proposed method is verified by the comparative simulation and experimental results.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Disturbances Attenuation of Permanent Magnet Synchronous Motor Drives
           Using Cascaded Predictive-Integral-Resonant Controllers
    • Authors: Zhanqing Zhou;Changliang Xia;Yan Yan;Zhiqiang Wang;Tingna Shi;
      Pages: 1514 - 1527
      Abstract: The performance of a standard model predictive controller (MPC) is directly related to its predictive model. If there are unmodeled periodic disturbances in the actual system, MPC will be difficult to suppress the disturbances, thus causing fluctuations of system output. To solve this problem, this paper proposes an improved MPC named predictive-integral-resonant control (PIRC). Compared with the standard MPC, the proposed PIRC could enhance the suppression ability for disturbances by embedding the internal model composing of the integral and resonant loop. Furthermore, this paper applies the proposed PIRC to PMSM drives, and proposes the PMSM control strategy based on the cascaded PIRC, which could suppress periodic disturbances caused by the dead time effects, current sampling errors, and so on. The experimental results show that the PIRC can suppress periodic disturbances in the drive system, thus ensuring good current and speed performance. Meanwhile, the PIRC could maintain the excellent dynamic performance as the standard MPC.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • High-Precision Sensorless Drive for High-Speed BLDC Motors Based on the
           Virtual Third Harmonic Back-EMF
    • Authors: Xinda Song;Bangcheng Han;Shiqiang Zheng;Jiancheng Fang;
      Pages: 1528 - 1540
      Abstract: In order to improve the performance of the high-speed brushless direct current motor drives, a novel high-precision sensorless drive has been developed. It is well known that the inevitable voltage pulses, which are generated during the commutation periods, will impact the rotor position detecting accuracy, and further impact the performance of the overall sensorless drive, especially in the higher speed range or under the heavier load conditions. For this reason, the active compensation method based on the virtual third harmonic back electromotive force incorporating the SFF-SOGI-PLL (synchronic-frequency filter incorporating the second-order generalized integrator based phase-locked loop) is proposed to precise detect the commutation points for sensorless drive. An experimental driveline system used for testing the electrical performance of the developed magnetically suspended motor is built. The mathematical analysis and the comparable experimental results have been shown to validate the effectiveness of the proposed sensorless drive algorithm.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Direct Torque Control of T-NPC Inverters-Fed Double-Stator-Winding PMSM
           Drives With SVM
    • Authors: Zheng Wang;Xueqing Wang;Jiawei Cao;Ming Cheng;Yihua Hu;
      Pages: 1541 - 1553
      Abstract: This paper studies and proposes the vector space decomposition-based direct torque control (DTC) scheme for the T-type neutral-point-clamping (T-NPC) three-level inverters-fed double-stator-winding permanent magnet synchronous machine (PMSM) drive, which provides an effective solution for high-power high-reliability applications. The key is to propose a simple but effective space vector modulation (SVM) for DTC of T-NPC double-stator-winding drives-based two-step voltage vector synthesis, in such a way that good dynamic response and harmonic performance are obtained. The closed-loop controllers on harmonic subspace are incorporated to suppress the possible harmonics induced from back electromotive force and unbalanced parameters in phase windings of electrical machine. Furthermore, a hybrid current control is proposed for fault-tolerant operation of the T-NPC double-stator-winding PMSM drives under one-phase open-circuit conditions. In the hybrid current controller, the healthy winding still uses the SVM-DTC control while the faulty winding uses the closed-loop current controller to track the optimized current references. Both simulation and experimental results are presented to verify the performance of the proposed switching strategies and control schemes.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Planar Transformers With Near-Zero Common-Mode Noise for Flyback and
           Forward Converters
    • Authors: Mohammad Ali Saket;Martin Ordonez;Navid Shafiei;
      Pages: 1554 - 1571
      Abstract: Flyback and forward converters are two commonly used topologies for isolated low-power applications. These converters are simple and cost effective and provide galvanic isolation, which make them desirable for low-power levels. In order to enhance the performance of these converters, planar transformers (PTs) can be used that feature lower height, considerably lower leakage inductance, excellent thermal characteristics, and repeatability. Selecting a proper winding arrangement for a PT is a significant challenge, in particular given the large capacitances involved in flat structures. While interleaved structures significantly reduce the ac resistance and leakage inductance of PTs, they also lead to very large interwinding capacitance, which produces significant levels of undesired common-mode (CM) noise that causes EMI problems. Reducing interwinding capacitance by using noninterleaved structures is not an ideal solution to the CM noise problem because of its side effects. Instead, this paper tackles the problem by proposing the concept of paired layers. According to this concept, there are layers in the primary and secondary sides that have the same $dv/dt$, and therefore, their overlapping does not generate CM noise. These layers can be used to design highly interleaved structures that not only have very low ac resistance and leakage inductance, but also generate almost zero CM noise, although they may have a very large interwinding capacitance. In addition, a detailed parasitic capacitance model of PTs is proposed, which analytically validates the proposed concept and method. The experimental results show that the proposed PTs not only have very low ac resistance and leakage inductance, but also generate extremely low levels of CM noise. Considering that the proposed PT has interwinding capacitance equal to $text{700 pF}$
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • An Electrolytic Capacitor-Less High Power Factor LED Driver Based on a
           “One-and-a-Half Stage” Forward-Flyback Topology
    • Authors: Hanjing Dong;Xiaogao Xie;Lei Jiang;Zheliang Jin;Xiaodong Zhao;
      Pages: 1572 - 1584
      Abstract: A “one-and-a-half stage” forward-flyback converter for electrolytic capacitor-less light-emitting diode (LED) driver with high power factor (PF), high efficiency, low output ripple current, and long lifetime has been proposed and studied in this paper. The basic topology of the proposed topology is a single-switch forward-flyback converter for achieving high PF. In addition, a buck converter is inserted between the forward subconverter and the load for creating two paralleled power transfer paths. The most of input energy directly reaches the load through flyback subconverter, and only about 1/4 of total energy is transferred to the load through forward subconverter and buck converter. Therefore, the proposed topology is a “one-and-a-half stage” converter and can achieve higher efficiency than the traditional two-stage topologies. At the same time, power decoupling can be realized and the electrolytic capacitor can be eliminated. Optimal control scheme, detailed analysis, and design considerations for this improved converter are presented. Finally, an experimental prototype for 28 V/700 mA LED driver was built up to verify the theoretical analysis.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Instability Analysis and Oscillation Suppression of Enhancement-Mode GaN
           Devices in Half-Bridge Circuits
    • Authors: Kangping Wang;Xu Yang;Laili Wang;Praveen Jain;
      Pages: 1585 - 1596
      Abstract: This paper analyzes the problem of instability in enhancement-mode gallium nitride (GaN) transistors based half-bridge circuits. The instability may cause sustained oscillation, resulting in overvoltage, excessive electromagnetic interference (EMI), and even device breakdown. GaN devices operate in the saturation region when they conduct reversely during the dead time. Under the influence of parasitic parameters, the GaN-based half-bridge circuit exhibits positive feedback under certain conditions, thus, resulting in sustained oscillation. A small-signal model is proposed to study this positive feedback phenomenon. Like the second-order under-damped system, damping ratio is defined to determine the system's stability. Based on the model, the influence of circuit parameters on instability is investigated and guidelines to suppress the oscillation are given. Reducing the common-source inductance, increasing the gate resistance of the inactive switch or connecting a diode in parallel to the inactive switch are some effective ways to suppress the oscillation. Finally, the analyses are verified by both simulation and experiment.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • A Submodule Fault Ride-Through Strategy for Modular Multilevel Converters
           With Nearest Level Modulation
    • Authors: Jun Wang;Hao Ma;Zhihong Bai;
      Pages: 1597 - 1608
      Abstract: The modular multilevel converter (MMC) with nearest level modulation (NLM) is widely used in the high voltage applications for low switching frequency and easy implementation. Existing literature has not provided a complete submodule (SM) fault ride-through scheme for MMC with NLM. In this paper, a strategy including fault detection, localization, redundancy, and recovery is proposed to ensure continuous operation of MMC under IGBT open-circuit faults conditions. It only requires a few hardware and software resources. The features of MMC and SMs with three types of failures are studied, respectively. Based on these, the fault detection method is proposed by using a simple hardware circuit, thus high computation complexity is avoided. Since current fault localization schemes are limited to MMC with carrier phase shifted pulse width modulation, this paper further proposes a strategy for MMC with NLM to locate the faulty SM and identify the fault type. After this, the fault redundancy and the proposed fault recovery method are applied to eliminate the fault and then exit the failure state. Therefore, the ability of SM fault ride-through can be realized. Analysis of failure characteristics are verified in simulation. Experimental results based on a single-phase MMC prototype with 11 SMs per arm are presented to demonstrate the validity of the proposed fault ride-through strategy.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • DC–AC Converter-Fed Induction Motor Drive With Fault-Tolerant Capability
           Under Open- and Short-Circuit Switch Failures
    • Authors: Masoud Farhadi;Majid Tahmasbi Fard;Mehdi Abapour;Mehrdad Tarafdar Hagh;
      Pages: 1609 - 1621
      Abstract: In this paper, a new fault tolerant dc–ac converter-fed induction motor drive is proposed to maintain motor as close as possible to its desired normal operation under open- and short-circuit switch failures. The operational principles for fault detection and isolation schemes are provided. Two control strategies including predictive control and voltage mode-controlled PWM with integral-double-lead controller for two stage of the converter are presented in conjunction with the elaborated discussion. The control strategy determines appropriate switching states for continuous operation of the drive after a fault. The proposed topology makes it possible to integrate the minimal redundant hardware and full tolerance capability which is an important advantage of the proposed topology. Moreover, the most important advantages of the proposed topology are a fast response in a fault condition and low cost of the converter in comparison with the evaluated topologies. A Joule-integral-based method for selecting an appropriate rating of applied fuses has been presented to provide a reliable fault-isolation operation. Also, a comparison with currently available fault-tolerant dc–ac converters is given to show the merits of the proposed topology. Finally, the experimental results are presented to verify the validity of the theoretical analysis and industrial feasibility of the proposed converter.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Degradation Detection and Diagnosis of Inductors in LCL Filter Integrated
           With Active Front End Rectifier
    • Authors: Subash Chandar;Sanjib Kumar Panda;
      Pages: 1622 - 1632
      Abstract: This paper presents an online methodology to detect and diagnose the inductor degradation in LCL filter integrated with Active Front End Rectifier (AFER) for electric drives in marine propulsion system (MPS). The proposed methodology monitors the leakage fluxes of converter-side inductor and compares it with the same under healthy condition to detect and diagnose the inductance degradation. The magnitude of leakage flux's fundamental component is extracted using the Fast Fourier Transform (FFT) and is used for detection of inductance degradation. Hence, inexpensive and low bandwidth magnetic flux sensors along with a simple FFT algorithm are used to detect and diagnose the inductance degradation. The leakage fluxes of the inductor during degradation are analyzed using the developed analytical model and validated on a laboratory prototype of 11.3-kW MPS test-rig. The validation was carried out for different degrees of converter-side inductor degradation from 3% to 19% under 33%, 73%, and 100% of full-load capacity of the MPS test-rig. Both estimated results using the analytical model and experimental results obtained are found to be in good agreement. The proposed online technique can detect and estimate the degraded inductance as low as 3% and is superior to the technique using grid currents in detecting the inductor abnormality.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • A Double-Sided LC-Compensation Circuit for Loosely Coupled Capacitive
           Power Transfer
    • Authors: Fei Lu;Hua Zhang;Heath Hofmann;Chunting Chris Mi;
      Pages: 1633 - 1643
      Abstract: This paper proposes a double-sided LC-compensation circuit for a loosely coupled, long-distance capacitive power transfer (CPT) system. A CPT system usually contains two pairs of metal plates as the capacitive coupler. An LC-compensation circuit resonates with the coupler to generate high voltages, and corresponding electric fields, to transfer power. When the compensation circuit is used on both the primary and secondary sides, it results in a double-sided LC-compensated CPT system. The working principle and frequency properties of the CPT system are analyzed. The results show a similarity with the series–series-compensated inductive power transfer system, which has both constant-voltage (CV) and constant-current (CC) working modes. LC-compensation is also compared with LCLC -compensation in terms of power, frequency properties, and output efficiency. A 150-W double-sided LC -compensated CPT prototype is designed and implemented to demonstrate a loosely coupled CPT system with 2.16% coupling coefficient. For both CC and CV working modes, the experimental results achieve dc–dc efficiencies higher than 70% across an air-gap distance of 180 mm with a switching frequency of 1.5 MHz.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Analysis and Optimization of Variable-Frequency Soft-Switching Peak
           Current Mode Control Techniques for Microinverters
    • Authors: S. Milad Tayebi;Issa Batarseh;
      Pages: 1644 - 1653
      Abstract: This paper presents a detailed power loss model for a microinverter with three different zero voltage switching boundary conduction mode (BCM) current modulation methods. The model is used to calculate the optimum peak current boundaries for each modulation method. Based on the power loss model, a dual-zone modulation method is proposed to further improve the microinverter efficiency. The proposed modulation method provides two main benefits: the addition of one more soft switching transition and low inductor peak current. The additional soft switching transition reduces switching losses by means of zero current switching. The lower peak current boundary reduces inductor rms current and conduction losses as well as allowing the output filter inductor to be smaller and more efficient. An improved BCM peak current control method was proposed and implemented on a microinverter prototype. The control circuit provides a highly accurate representation of the filter inductor current waveform and also provides galvanic isolation that simplifies control circuit design. The experimental results on a 400-W three-phase half-bridge microinverter validate the theoretical analysis of the power loss distribution and demonstrate that further improvement in efficiency can be achieved by using the proposed dual-zone modulation method.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Cell-by-Cell-Based Finite-Control-Set Model Predictive Control for a
           Single-Phase Cascaded H-Bridge Rectifier
    • Authors: Chen Qi;Xiyou Chen;Pengfei Tu;Peng Wang;
      Pages: 1654 - 1665
      Abstract: The traditional finite-control-set model predictive control (FCS-MPC) method for a cascaded H-bridge (CHB) rectifier has two main issues: heavy computational burden and low steady-state current performance. In this paper, a novel FCS-MPC method has been proposed for a single-phase CHB rectifier. The proposed method solves the optimization problem of FCS-MPC for one cell by one cell, like a “pipeline.” In the proposed method, the sampling period is divided into equal intervals by the number of cells. At the beginning of the first interval, the first cell selects its switching state to be applied. Then, the following cell selects its switching state to be applied at the beginning of next interval. Finally, the selected switching state of last cell will be applied at the beginning of the last interval. A cost function presenting the control objectives of common source current error and itself dc-link voltage error is evaluated for each cell. A single-phase three-cell CHB rectifier controlled by a DSpace DS1104 is tested and the experimental results show that a significant reduction in computational time, an improved steady-state current performance, and a comparable dynamic response are achieved in the proposed method in comparison with the traditional FCS-MPC method.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • A PSO-DQ Current Control Scheme for Performance Enhancement of Z-Source
           Matrix Converter to Drive IM Fed by Abnormal Voltage
    • Authors: S. Sina Sebtahmadi;Hanieh Borhan Azad;S. Hr. Aghay Kaboli;Md. Didarul Islam;Saad Mekhilef;
      Pages: 1666 - 1681
      Abstract: A rotational d–q current control scheme is prepared with the particle swarm optimization-PI controller, which drives an induction motor through an ultra-sparse Z-source matrix converter. To minimize the total size of the system, the lowest feasible values of Z-source elements are calculated by considering both timing and circuit aspects. A meta-heuristic method is integrated with the control system in order to find the optimum coefficients values in a single multimodal problem. Henceforth, the effect of all coefficients in minimizing the THD and balancing the stator current are considered simultaneously. By changing the reference point of magnitude or frequency, the modulation index can be automatically adjusted and respond to changes without heavy computational cost. The focus of this research is on having a reliable and lightweight system with no extensive computing time demand. The proposed scheme is validated by the promising simulation and experimental results.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • High Dynamic Performance Solar Array Simulator Based on a SiC MOSFET
           Linear Power Stage
    • Authors: Shanshan Jin;Donglai Zhang;Zhiyun Bao;Xinjun Liu;
      Pages: 1682 - 1695
      Abstract: The power conditioning unit system is a critical part in a spacecraft and is responsible for converting the solar panel energy into a stable bus voltage. This system requires a high dynamic characteristic solar array simulator (SAS) for testing purposes. Space solar array simulators (SSASs) used for testing space power systems generally use a linear power topology because of its fast dynamic performance and good simulation accuracy. However, commercially available SASs are not sufficiently fast for simulating the actual solar array panel output and, therefore are unreliable for terrestrial testing. In this paper, a highly dynamic SSAS is developed with multipath SiC MOSFET linear voltage-controlled current source paralleling for power regulation. The proposed 510 W SSAS, consisting of 20 linear current paths paralleling the power stage and a high-speed FPGA digital controller, can quickly react to a load step between the nominal and short circuit at 50-kHz stepping frequency. It can also react to a step change from a short circuit to an open circuit perfectly at a 1-kHz stepping frequency offering a superior dynamic performance compared to other similar devices.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Voltage Balance Control Based on Dual Active Bridge DC/DC Converters in a
           Power Electronic Traction Transformer
    • Authors: Jianqiang Liu;Jingxi Yang;Jiepin Zhang;Zhao Nan;Qionglin Zheng;
      Pages: 1696 - 1714
      Abstract: In this paper, a voltage balance control strategy based on dual active bridge (DAB) dc/dc converters in a power electronic traction transformer (PETT) is proposed. Based on this strategy, the output-parallel DAB converters can be equivalent to an input-series-output-parallel system. Furthermore, a PETT starting control method is put forward, which can effectively avoid risks of overcurrent and overvoltage in the PETT starting process. In order to carry out the controller design and system stability analysis, three different kinds of mathematical models of DAB converters are set up. The first model is related to a single DAB converter, the second model reflects the equivalent relation between an output-parallel DAB system and a single DAB converter in terms of the output-voltage control loop, and the third model indicates that the voltage balance control system based on DAB converters is a multiinput-multioutput system. Due to the nonzero off-diagonal elements of the controlled plant, there is a mutual effect between different control loops, which is defined as “interaction” in the multivariable feedback control theory. The stability of the voltage balance control system is made up of two parts, including the stability of each single-input-single-output (SISO) control loop and the influence of the interaction on the system stability. The research is carried out to measure the intensity of the interaction in this paper, and a criterion directly based on the controlled plant is proposed to predict the influence of the interaction, which can obviously simplify the system stability analysis. Considering the particular traction onboard application, a new control structure toward the voltage balance controller is introduced. Based on the new structure, the controller is designed and the stability of the SISO system is analyzed. Finally, a five-cell PETT prototype with rated power of 30 kW is taken to carry out further research, and th- experiment results verify the effectiveness and correctness of the proposed algorithms.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Improved Modulated Carrier Control With On-Time Doubler for a Single-Phase
           Shunt Active Power Filter
    • Authors: Gibong Son;Hye-Jin Kim;Bo-Hyung Cho;
      Pages: 1715 - 1723
      Abstract: This paper proposes an improved modulated carrier control with on-time doubler for the single-phase shunt active power filter, which eliminates harmonic and reactive currents drawn by nonlinear loads. This control method directly shapes the line current to be sinusoidal and in phase with the grid voltage by generating a modulated carrier signal with a resettable integrator, comparing the carrier signal to the average line current and making duty ratio doubled. Since the line current compared to the carrier signal is not the peak, but the average value, dc-offset appeared at the conventional control methods based on one-cycle control is effectively addressed. The proposed control technique extirpates the harmonic and reactive currents and solves the dc-offset problem. The operation principle and stability characteristic of the single-phase shunt active power filter with the proposed control method are discussed, and experimental results with laboratory prototype under various load conditions verify its performance.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • One-Cycle Control for Electrolytic Capacitor-Less Second Harmonic Current
           Compensator
    • Authors: Li Zhang;Xinbo Ruan;Xiaoyong Ren;
      Pages: 1724 - 1739
      Abstract: The input power of the single-phase power factor correction ac–dc converter pulsates at twice the line frequency, while the output power of the single-phase dc–ac inverter pulsates at twice the output frequency. The pulsating power will result in second harmonic current (SHC) in the ac–dc converter and dc–ac inverter. In this paper, electrolytic capacitor-less second harmonic current compensator (SHCC) is presented to compensate the SHC. The SHCC has two operating modes, namely, charging mode and discharging mode. To achieve an excellent SHC compensation performance, a hybrid one-cycle control (OCC) is proposed to regulate the port current of the SHCC, and the SHCC can stably operate in both the charging mode and discharging mode. To avoid the mode detection required in the hybrid OCC and ensure seamless transition between the two modes, the OCC with dc bias is further proposed. Besides, a peak voltage control is proposed to regulate the storage capacitor voltage in the SHCC for reducing the power losses of the SHCC at light load. A 1-kW two-stage inverter with the SHCC is fabricated and tested, and the experimental results are provided to verify the effectiveness of the proposed control schemes.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Cascaded Direct Torque Control of Unbalanced PMSM With Low Torque and Flux
           Ripples
    • Authors: Atheer H. Abosh;Zi-Qiang Zhu;Yuan Ren;
      Pages: 1740 - 1749
      Abstract: During operation or manufacturing, the electrical machines are often exposed to parasitic impedance in the phases, causing unbalanced three-phase currents and increased torque and flux ripples. To mitigate the undesired torque and flux ripples, this paper presents a modified cascaded direct torque control strategy for three-phase PMSMs, having asymmetric phase impedances. The proposed method aims to generate the positive and negative reference voltage vectors by extracting the sequential components of the stator flux and current in the stationary αβ frame. Then, these two vectors are combined to produce the modified reference voltage vector for space vector modulation. Moreover, for further torque ripple suppression, a standard proportional-integral regulator has been enhanced by a resonant controller tuning at twice of the fundamental frequency. Various experimental results verify the feasibility of the proposed strategy under dynamic and steady-state conditions.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Virtual Direct Power Control Scheme of Dual Active Bridge DC–DC
           Converters for Fast Dynamic Response
    • Authors: Wensheng Song;Nie Hou;Mingyi Wu;
      Pages: 1750 - 1759
      Abstract: One of the essential requirements for high-performance dual active bridge (DAB) dc–dc converters as the controlled dc voltage sources is to obtain the constant output voltage rapidly and accurately under all working conditions. In order to reach fast dynamic response, combing direct power control with feedforward control strategy, this paper proposes a virtual direct power control (VDPC) scheme with single-phase-shift control for DAB dc–dc converters to face with these following extreme conditions, such as start-up, load step-change, no-load, the input voltage fluctuation, and the desired output voltage step-change. The proposed VDPC scheme of DAB dc–dc converters can achieve no overshoot and fast transient response for the output voltage in load or input voltage disturbances and start-up stage. Dynamic response of the output voltage control has been also improved when the desired value steps up and down. Finally, four control schemes consisting of traditional voltage loop control, load current feed-forward control, model-based phase-shift control, and the proposed VDPC schemes are compared and tested in a scale-down DAB dc–dc converter experimental prototype. Experimental results verify the above excellent performance of the proposed VDPC scheme and the effectiveness of theoretical analysis.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Analysis of the Effects of Operation Voltage Range in Flexible DC Control
           on Railway HPQC Compensation Capability in High-Speed Co-phase Railway
           Power
    • Authors: Keng-Weng Lao;Man-Chung Wong;Ningyi Dai;Chi-Seng Lam;Lei Wang;Chi-Kong Wong;
      Pages: 1760 - 1774
      Abstract: Railway hybrid power quality conditioner (HPQC) is advantageous over conventional railway power quality conditioner (RPC) for its reduction in operation voltage and device ratings in co-phase traction power compensation. In order to further reduce the power loss during operation, flexible dc control has been proposed. However, the operation voltage range for railway HPQC has not yet been discussed. This is important since in contrast to traditional power quality compensation devices, active power compensation is involved in co-phase traction power. Compensation capability in co-phase traction power thus does refer not only to reactive power compensation but also to active power compensation ability. Satisfactory compensation performance can be provided only when railway HPQC can provide enough active and reactive compensation power output at the same time. In this paper, the effects of operation range in flexible dc voltage control on railway HPQC compensation capability is briefly discussed and analyzed. The analysis is verified via PSCAD simulations. A laboratory-scaled hardware prototype is also constructed to obtain experimental results for further verifications.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Unified Impedance Model of Grid-Connected Voltage-Source Converters
    • Authors: Xiongfei Wang;Lennart Harnefors;Frede Blaabjerg;
      Pages: 1775 - 1787
      Abstract: This paper proposes a unified impedance model of grid-connected voltage-source converters for analyzing dynamic influences of the phase-locked loop (PLL) and current control. The mathematical relations between the impedance models in the different domains are first explicitly revealed by means of complex transfer functions and complex space vectors. A stationary (αβ-) frame impedance model is then proposed, which not only predicts the stability impact of the PLL, but also reveals its frequency coupling effect. Furthermore, the impedance shaping effects of the PLL on the current control in the rotating (dq-) frame and the stationary ( αβ-) frame are structurally comapred. The frequency-domain case studies on a three-phase grid-connected converter are next presented, and subsequently validated in time-domain simulations and experimental tests. The close correlations between the measured results and theoretical analysis confirm the effectiveness of the stationary-frame impedance model.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Obtaining Performance of Type-3 Phase-Locked Loop Without Compromising the
           Benefits of Type-2 Control System
    • Authors: Parag Kanjiya;Vinod Khadkikar;Mohamed Shawky El Moursi;
      Pages: 1788 - 1796
      Abstract: A phase-locked loop (PLL) is a closed-loop feedback control system that estimates the frequency as well as phase of an input signal. The most commonly deployed synchronization method in three-phase applications is a type-2 synchronous reference frame PLL. With pre/in-loop selective harmonic filtering stage, type-2 PLLs can obtain good detection speed, decent stability margins, and better disturbance rejection. However, it suffers from the finite steady-state phase error during ramp change in input signal frequency. To tackle this challenge type-3 PLLs have been developed recently, either by adding a feed-forward path to the PLL structure, or by using a second-order controller as the loop filter. However, recent analysis carried out of type-3 PLLs show that they aggravate stability problem and compromise the performance in terms of detection speed and disturbance rejection. A new concept of synchronization is proposed in this paper that obtains the performance of type-3 PLL but retains all the advantages associated with type-2 PLL. Extensive experimental results are provided to validate the proposed work.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Digital Current Sensorless Control of Current-Driven Full-Bridge DC/DC
           Converters
    • Authors: Majid Pahlevani;Suzan Eren;Hamid Pahlevaninezhad;Iman Askarian;Snehal Bagawade;
      Pages: 1797 - 1815
      Abstract: This paper presents a current sensorless technique for current-driven full-bridge dc/dc converters. The proposed technique is able to precisely estimate the transformer current and in turn input/output current of the converter. Since the high-frequency current is estimated, different current-based modulations schemes (e.g., self-sustained oscillating control (SSOC), modulators for synchronous rectifications, etc.) can be implemented using the proposed current sensorless technique. In the proposed technique, the current is estimated using the precise model of dc/dc converters instead of the averaged model. Thus, the accurate current waveform is derived within a switching cycle. The mathematical analysis of the system observability and the practical concerns related to the implementation of the proposed technique are also described in detail. Experimental results on a current-driven dc/dc converter are presented to show the feasibility of the proposed technique and verify its performance.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Analysis and Transmitter Currents Decomposition Based Control for Multiple
           Overlapped Transmitters Based WPT Systems Considering Cross Couplings
    • Authors: Yong Li;Ruikun Mai;Liwen Lu;Tianren Lin;Yeran Liu;Zhengyou He;
      Pages: 1829 - 1842
      Abstract: Multiple transmitters powering a single receiver simultaneously is a good alternative to upgrade the power capacity of the wireless power transfer (WPT) system by using multiple modular inverters manufactured in a larger quantities, since the demand for high power applications is on the rise. A multiple overlapped transmitters based WPT system is presented in this paper. In order to alleviate the effects of the cross couplings between the transmitters, additional capacitors are adopted in the transmitters and the configuration of additional capacitors is provided. Virtual active and reactive powers are defined to decompose the transmitter current into active and reactive components. A transmitter current control scheme based on the proposed current decomposition method consisting of one reactive current control loop and one active current control loop is also presented in this paper. Finally, a low-scale experimental setup using two overlapped transmitters WPT system is provided to verify the proposed approach. The experimental results indicate that the proposed method could improve the stability of output voltage control and achieve minimal current difference amongst transmitters. Besides, the overall system efficiency is improved to 90.34% with the proposed control method at 1.45 kW output power, which demonstrates that the proposed method is a potential solution for high power applications.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Wide-Load-Range Efficiency Improvement for High-Frequency SiC-Based Boost
           Converter With Hybrid Discontinuous Current Mode
    • Authors: Hoai Nam Le;Jun-Ichi Itoh;
      Pages: 1843 - 1854
      Abstract: This paper proposes a hybrid current mode between triangular current mode (TCM) and discontinuous current mode (DCM) in order to improve a wide-load-range efficiency for a high-frequency SiC-based boost converter. At rated load, TCM, where the zero-voltage switching (ZVS) is achieved, is used in order to increase the switching frequency and minimize the boost converter. At light load, the hybrid discontinuous current mode (HDCM), where the TCM current is flown during the zero-current interval of DCM, is applied in order to achieve both ZVS and a reduction of a current ripple. This maintains a high efficiency over a wide load range. A 1-kW prototype is realized to compare HDCM over continuous current mode (CCM), DCM, and TCM. Compared to TCM, the root-mean-square current is reduced up to 56.6% with HDCM. Consequently, the efficiency of HDCM at light load of 0.1 p.u. is improved by 3.1%. Compared to DCM, the average-current ripple in HDCM is reduced by 82.3%, whereas the efficiency of HDCM at light load of 0.1 p.u. is improved by 1.5%. Finally, when the current ripple of CCM is designed to be half of TCM, the efficiency of HDCM at rated load is improved by 0.9% compared to CCM.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
  • Advanced Voltage Support and Active Power Flow Control in Grid-Connected
           Converters Under Unbalanced Conditions
    • Authors: Masoud M. Shabestary;Yasser Abdel-Rady I. Mohamed;
      Pages: 1855 - 1864
      Abstract: Supporting the grid and improving its reliability have recently become major requirements for large distributed generation units. Under most grid faults, the accuracy of the traditional voltage support schemes (VSSs) is dramatically affected due to the existence of the zero-sequence voltage. Also, the traditional VSSs have been used only in the STATCOM applications, where the active power is zero. This paper proposes an advanced VSS in the converter-interfaced units, called zero-sequence compensated voltage support (ZCVS), to accurately regulate the three-phase voltages of the connection point within the pre-set safety limits. The proposed scheme not only compensates the zero-sequence component but also considers the active power injection. Unlike the traditional methods, the proposed VSS is adapted even in resistive distribution systems. The contribution of this paper is, however, ternate. As the second contribution, the limited active power oscillation (LAPO) is proposed to be augmented to the ZCVS. This feature limits the oscillation to a specified value which provides an adjustable dc-link voltage oscillation setting while simultaneously supporting the ac host grid, even under severe unbalanced faults. Third, the maximum active power delivery (MAPD) to the ac grid is also formulated for the ZCVS. The successful results of the proposed support scheme and complementary strategies are verified using selected simulation and experimental test cases.
      PubDate: Feb. 2018
      Issue No: Vol. 33, No. 2 (2018)
       
 
 
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