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  Subjects -> ELECTRONICS (Total: 186 journals)
Showing 1 - 200 of 277 Journals sorted alphabetically
Acta Electronica Malaysia     Open Access  
Advances in Electrical and Electronic Engineering     Open Access   (Followers: 6)
Advances in Electronics     Open Access   (Followers: 89)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 8)
Advances in Power Electronics     Open Access   (Followers: 35)
Advancing Microelectronics     Hybrid Journal  
Aerospace and Electronic Systems, IEEE Transactions on     Hybrid Journal   (Followers: 330)
American Journal of Electrical and Electronic Engineering     Open Access   (Followers: 26)
Annals of Telecommunications     Hybrid Journal   (Followers: 9)
APSIPA Transactions on Signal and Information Processing     Open Access   (Followers: 9)
Archives of Electrical Engineering     Open Access   (Followers: 14)
Autonomous Mental Development, IEEE Transactions on     Hybrid Journal   (Followers: 8)
Bell Labs Technical Journal     Hybrid Journal   (Followers: 29)
Bioelectronics in Medicine     Hybrid Journal  
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (Followers: 19)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 38)
Biomedical Instrumentation & Technology     Hybrid Journal   (Followers: 6)
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 13)
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   (Followers: 1)
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 47)
China Communications     Full-text available via subscription   (Followers: 8)
Chinese Journal of Electronics     Hybrid Journal  
Circuits and Systems     Open Access   (Followers: 15)
Consumer Electronics Times     Open Access   (Followers: 5)
Control Systems     Hybrid Journal   (Followers: 287)
ECTI Transactions on Computer and Information Technology (ECTI-CIT)     Open Access  
ECTI Transactions on Electrical Engineering, Electronics, and Communications     Open Access  
Edu Elektrika Journal     Open Access   (Followers: 1)
Electrica     Open Access  
Electronic Design     Partially Free   (Followers: 116)
Electronic Markets     Hybrid Journal   (Followers: 7)
Electronic Materials Letters     Hybrid Journal   (Followers: 4)
Electronics     Open Access   (Followers: 96)
Electronics and Communications in Japan     Hybrid Journal   (Followers: 10)
Electronics For You     Partially Free   (Followers: 99)
Electronics Letters     Hybrid Journal   (Followers: 26)
Elkha : Jurnal Teknik Elektro     Open Access  
Embedded Systems Letters, IEEE     Hybrid Journal   (Followers: 55)
Energy Harvesting and Systems     Hybrid Journal   (Followers: 4)
Energy Storage Materials     Full-text available via subscription   (Followers: 3)
EPJ Quantum Technology     Open Access   (Followers: 1)
EURASIP Journal on Embedded Systems     Open Access   (Followers: 11)
Facta Universitatis, Series : Electronics and Energetics     Open Access  
Foundations and Trends® in Communications and Information Theory     Full-text available via subscription   (Followers: 6)
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: 202)
Haptics, IEEE Transactions on     Hybrid Journal   (Followers: 4)
IACR Transactions on Symmetric Cryptology     Open Access  
IEEE Antennas and Propagation Magazine     Hybrid Journal   (Followers: 99)
IEEE Antennas and Wireless Propagation Letters     Hybrid Journal   (Followers: 80)
IEEE Journal of Emerging and Selected Topics in Power Electronics     Hybrid Journal   (Followers: 49)
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: 71)
IEEE Transactions on Antennas and Propagation     Full-text available via subscription   (Followers: 70)
IEEE Transactions on Automatic Control     Hybrid Journal   (Followers: 57)
IEEE Transactions on Circuits and Systems for Video Technology     Hybrid Journal   (Followers: 26)
IEEE Transactions on Consumer Electronics     Hybrid Journal   (Followers: 41)
IEEE Transactions on Electron Devices     Hybrid Journal   (Followers: 19)
IEEE Transactions on Information Theory     Hybrid Journal   (Followers: 26)
IEEE Transactions on Power Electronics     Hybrid Journal   (Followers: 75)
IEEE Transactions on Signal and Information Processing over Networks     Full-text available via subscription   (Followers: 12)
IEICE - Transactions on Electronics     Full-text available via subscription   (Followers: 12)
IEICE - Transactions on Information and Systems     Full-text available via subscription   (Followers: 5)
IET Cyber-Physical Systems : Theory & Applications     Open Access   (Followers: 1)
IET Energy Systems Integration     Open Access  
IET Microwaves, Antennas & Propagation     Hybrid Journal   (Followers: 35)
IET Nanodielectrics     Open Access  
IET Power Electronics     Hybrid Journal   (Followers: 51)
IET Smart Grid     Open Access  
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: 13)
IJEIS (Indonesian Journal of Electronics and Instrumentation Systems)     Open Access   (Followers: 3)
Industrial Electronics, IEEE Transactions on     Hybrid Journal   (Followers: 69)
Industrial Technology Research Journal Phranakhon Rajabhat University     Open Access  
Industry Applications, IEEE Transactions on     Hybrid Journal   (Followers: 35)
Informatik-Spektrum     Hybrid Journal   (Followers: 2)
Instabilities in Silicon Devices     Full-text available via subscription   (Followers: 1)
Intelligent Transportation Systems Magazine, IEEE     Full-text available via subscription   (Followers: 13)
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: 10)
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: 6)
International Journal of Control     Hybrid Journal   (Followers: 11)
International Journal of Electronics     Hybrid Journal   (Followers: 7)
International Journal of Electronics and Telecommunications     Open Access   (Followers: 13)
International Journal of Granular Computing, Rough Sets and Intelligent Systems     Hybrid Journal   (Followers: 3)
International Journal of High Speed Electronics and Systems     Hybrid Journal  
International Journal of Hybrid Intelligence     Hybrid Journal  
International Journal of Image, Graphics and Signal Processing     Open Access   (Followers: 15)
International Journal of Microwave and Wireless Technologies     Hybrid Journal   (Followers: 8)
International Journal of Nanoscience     Hybrid Journal   (Followers: 1)
International Journal of Numerical Modelling: Electronic Networks, Devices and Fields     Hybrid Journal   (Followers: 4)
International Journal of Power Electronics     Hybrid Journal   (Followers: 25)
International Journal of Review in Electronics & Communication Engineering     Open Access   (Followers: 4)
International Journal of Sensors, Wireless Communications and Control     Hybrid Journal   (Followers: 10)
International Journal of Systems, Control and Communications     Hybrid Journal   (Followers: 4)
International Journal of Wireless and Microwave Technologies     Open Access   (Followers: 6)
International Transaction of Electrical and Computer Engineers System     Open Access   (Followers: 2)
JAREE (Journal on Advanced Research in Electrical Engineering)     Open Access  
Journal of Biosensors & Bioelectronics     Open Access   (Followers: 3)
Journal of Advanced Dielectrics     Open Access   (Followers: 1)
Journal of Artificial Intelligence     Open Access   (Followers: 11)
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: 31)
Journal of Electrical Bioimpedance     Open Access  
Journal of Electrical Bioimpedance     Open Access   (Followers: 2)
Journal of Electrical Engineering & Electronic Technology     Hybrid Journal   (Followers: 7)
Journal of Electrical, Electronics and Informatics     Open Access  
Journal of Electromagnetic Analysis and Applications     Open Access   (Followers: 7)
Journal of Electromagnetic Waves and Applications     Hybrid Journal   (Followers: 8)
Journal of Electronic Design Technology     Full-text available via subscription   (Followers: 6)
Journal of Electronics (China)     Hybrid Journal   (Followers: 5)
Journal of Energy Storage     Full-text available via subscription   (Followers: 4)
Journal of Engineered Fibers and Fabrics     Open Access   (Followers: 2)
Journal of Field Robotics     Hybrid Journal   (Followers: 3)
Journal of Guidance, Control, and Dynamics     Hybrid Journal   (Followers: 171)
Journal of Information and Telecommunication     Open Access   (Followers: 1)
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: 10)
Journal of Microelectronics and Electronic Packaging     Hybrid Journal  
Journal of Microwave Power and Electromagnetic Energy     Hybrid Journal  
Journal of Microwaves, Optoelectronics and Electromagnetic Applications     Open Access   (Followers: 10)
Journal of Nuclear Cardiology     Hybrid Journal  
Journal of Optoelectronics Engineering     Open Access   (Followers: 4)
Journal of Physics B: Atomic, Molecular and Optical Physics     Hybrid Journal   (Followers: 29)
Journal of Power Electronics & Power Systems     Full-text available via subscription   (Followers: 11)
Journal of Semiconductors     Full-text available via subscription   (Followers: 5)
Journal of Sensors     Open Access   (Followers: 26)
Journal of Signal and Information Processing     Open Access   (Followers: 9)
Jurnal ELTIKOM : Jurnal Teknik Elektro, Teknologi Informasi dan Komputer     Open Access  
Jurnal Rekayasa Elektrika     Open Access  
Jurnal Teknik Elektro     Open Access  
Jurnal Teknologi Elektro     Open Access  
Kinetik : Game Technology, Information System, Computer Network, Computing, Electronics, and Control     Open Access  
Learning Technologies, IEEE Transactions on     Hybrid Journal   (Followers: 12)
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: 26)
Nanotechnology Magazine, IEEE     Full-text available via subscription   (Followers: 41)
Nanotechnology, Science and Applications     Open Access   (Followers: 6)
Nature Electronics     Hybrid Journal   (Followers: 1)
Networks: an International Journal     Hybrid Journal   (Followers: 5)
Open Electrical & Electronic Engineering Journal     Open Access  
Open Journal of Antennas and Propagation     Open Access   (Followers: 8)
Optical Communications and Networking, IEEE/OSA Journal of     Full-text available via subscription   (Followers: 15)
Paladyn. Journal of Behavioral Robotics     Open Access   (Followers: 1)
Power Electronics and Drives     Open Access   (Followers: 1)
Problemy Peredachi Informatsii     Full-text available via subscription  
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 Advances in Communications and Networking Technology     Hybrid Journal   (Followers: 3)
Recent Advances in Electrical & Electronic Engineering     Hybrid Journal   (Followers: 9)
Research & Reviews : Journal of Embedded System & Applications     Full-text available via subscription   (Followers: 5)
Revue Méditerranéenne des Télécommunications     Open Access  
Security and Communication Networks     Hybrid Journal   (Followers: 2)
Selected Topics in Applied Earth Observations and Remote Sensing, IEEE Journal of     Hybrid Journal   (Followers: 55)
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: 4)
Software Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 77)
Solid State Electronics Letters     Open Access  
Solid-State Circuits Magazine, IEEE     Hybrid Journal   (Followers: 13)
Solid-State Electronics     Hybrid Journal   (Followers: 9)
Superconductor Science and Technology     Hybrid Journal   (Followers: 3)
Synthesis Lectures on Power Electronics     Full-text available via subscription   (Followers: 3)
Technical Report Electronics and Computer Engineering     Open Access  
TELE     Open Access  
Telematique     Open Access  
TELKOMNIKA (Telecommunication, Computing, Electronics and Control)     Open Access   (Followers: 9)
Universal Journal of Electrical and Electronic Engineering     Open Access   (Followers: 6)
Visión Electrónica : algo más que un estado sólido     Open Access   (Followers: 1)
Wireless and Mobile Technologies     Open Access   (Followers: 6)
Wireless Power Transfer     Full-text available via subscription   (Followers: 4)
Women in Engineering Magazine, IEEE     Full-text available via subscription   (Followers: 11)
Електротехніка і Електромеханіка     Open Access  

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Similar Journals
Journal Cover
IEEE Transactions on Power Electronics
Journal Prestige (SJR): 2.215
Citation Impact (citeScore): 9
Number of Followers: 75  
 
  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: Provides a listing of current staff, committee members and society officers.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • IEEE Power Electronics Society
    • Abstract: Provides a listing of current committee members and society officers.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • Administrative committee
    • Abstract: Provides a listing of current committee members and society officers.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • A Fuzzy Logic Based Switching Methodology for a Cascaded H-Bridge
           Multi-Level Inverter
    • Authors: Hadik Azeem;Suresh Yellasiri;Venkatramanaiah Jammala;Banavath Shiva Naik;Anup Kumar Panda;
      Pages: 9360 - 9364
      Abstract: In this letter, an unusual switching technique is implemented using a fuzzy logic approach. The proposed technique simplifies the conventional method by eliminating the traditional logic-gate design. The fuzzy logic pulse generator acts as a lookup table as well as a pulse generator. On the basis of the modulation index as input, controlled membership functions (MFs) and rules of the fuzzy logic controller open various possibilities of producing pulses directly. The proposed technique is evaluated on the cascaded multi-level inverter with symmetric and asymmetric operations using selective harmonic elimination pulsewidth modulation. MFs are designed on the basis of pre-calculated firing conditions for different modulation index values. Hardware verification is carried out to support the proposed switching technique.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • A 34-dB Dynamic Range 0.7-mW Compact Switched-Capacitor Power Detector in
           65-nm CMOS
    • Authors: Chenyang Li;Xiang Yi;Chirn Chye Boon;Kaituo Yang;
      Pages: 9365 - 9368
      Abstract: This letter presents a wide dynamic range low power consumption power detector with a compact area in a 65-nm complementary metal-oxide-semiconductor (CMOS) process. The maximum detectable power of traditional power detector is limited due to the non-linearity of MOSFETs. This problem is solved by using P-type and N-type doped material (PN) junction diodes as switches that have a linear input-output voltage relationship in the proposed power detector. In this structure, the switches work at both the positive and negative cycles to increase the dynamic range. With the increase of input power, the difference between the voltages applied to the two terminals of the diode is also increased. Thus, the current flowing through the diodes and the load resistor is augmented, boosting the output dc voltage. According to the measurement results, the power detector operates from 4 to 6 GHz with a dynamic range of 34 and ±1 dB error at 5 GHz. To the authors' best knowledge, it is the first power detector that has achieved such wide dynamic range with maximum input power of 35 dBm. The core of the power detector occupies an area of 0.0036 mm2 and consumes 0.7-mW static power.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • Full-Duplex High-Speed Simultaneous Communication Technology for Wireless
           EV Charging
    • Authors: Zhongnan Qian;Rui Yan;Jiande Wu;Xiangning He;
      Pages: 9369 - 9373
      Abstract: This letter presents a novel simultaneous wireless power and data transmission (SWPDT) system for wireless electric vehicle (EV) charging. The data carrier is injected and extracted by a plug-and-play toroidal-core inductor. Two data carriers of 5 and 6.25 MHz are adopted to achieve bidirectional and full-duplex communication using frequency-division multiplexing. Differential quadrature phase-shift keying modulation is achieved by a Class-E amplifier in the data transmitter. An analog switch circuit is designed to demodulate the data carrier in the data receiver. The proposed method is verified by a prototype that achieves up to 64 kbps full-duplex data transmission under 3.3 kW power transfer. The bit rate and interference immunity of data transmission are greatly improved compared to the reported SWPDT systems, which makes it possible to realize high-speed simultaneous communication in the kilowatt-level wireless EV charging.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • Computer-Aided Identification of Equivalent Power Electronics Converters
    • Authors: Guipeng Chen;Liping Mo;Yuwei Liu;Xinlin Qing;Yihua Hu;
      Pages: 9374 - 9378
      Abstract: Equivalent power electronics converters (PECs), which have same performance characteristics but dissimilar configurations, are easily mistaken as different converters to be repeatedly studied in the practice, resulting in extra workload. Therefore, it is essential to implement the equivalence identification to avoid the undesired repeated research. In order to accomplish this goal, a computer-aided solution is proposed in this letter, aiming to quickly and precisely identify the equivalent PECs. First, two identification rules are figured out, with which different PECs can be systematically judged to be equivalent or not. Then, software Altium Designer is used to automatically acquire the information of PECs, including the components and the connecting relationships. After that, software MATLAB is utilized to further complete the data process, circuit loop search, and final judgment. Compared with the conventional manual identification method, which is totally dependent on researcher's effort, the proposed computer-aided scheme is more convenient, accurate, and practical, which is beneficial for the topology research in both academic and industrial fields.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • Three-Step Switching Frequency Selection Criteria for Symmetrical
           CLLC-Type DC Transformer in Hybrid AC/DC Microgrid
    • Authors: Jingjing Huang;Xin Zhang;
      Pages: 9379 - 9385
      Abstract: In a hybrid ac/dc microgrid, the symmetrical CLLC-type dc transformer (CLLC-DCT) generally operates at the resonant frequency with the simple and low-cost semi-regulated open-loop scheme to ensure the power transmission (PT). However, more than one resonant frequency may exist, and they feature different characteristics for DCT. Meanwhile, the practical resonant frequencies are varying with temperature and power, which will degrade the PT ability if the switching frequency selection is not considered. Therefore, a switching frequency selection criteria (SFSC) approach is put forward for the symmetrical CLLC-DCT. For convenience, the active PT ratio (APTR) is employed as evaluation index of SFSC. First of all, the number and accurate values of resonant frequency are achieved in Step I. Then, in Step II, the optimal resonant frequency is determined as APTR-based criterion. In Step III, the parameter-variation-based criterion is presented to determine switching frequency. Finally, the experimental results verify that the semiregulated DCT based on the proposed approach not only improves efficiency, but also achieves the approximate PT ability with the relatively high-cost closed-loop controlled DCT.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • A Tunable Power Sharing Control Scheme for the Output-Series DAB DC–DC
           System With Independent or Common Input Terminals
    • Authors: Nie Hou;Yun Wei Li;
      Pages: 9386 - 9391
      Abstract: To connect the low voltage energy storage source equipment and the medium voltage dc (MVdc) bus, the output-series dual-active-bridge (OS-DAB) dc-dc converter system with independent or common input terminals becomes a promising option. For the OS-DAB dc-dc converter system, this letter proposes a simple tunable power sharing control (TPSC) strategy to maintain the voltage of MVdc bus, manage power sharing ratio for each energy storage system. The proposed strategy allows energy storage equipment hot swap as well as converter system black start. Experimental results verify the analysis in this letter and the excellent performance of proposed TPSC strategy.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • A New Hands-On Course in Characterization of Wide-Bandgap Devices
    • Authors: Zheyu Zhang;Leon M. Tolbert;Daniel Costinett;Fei Wang;Benjamin J. Blalock;
      Pages: 9392 - 9403
      Abstract: As wide-bandgap (WBG) devices and applications move from niche to mainstream, a new generation of engineers trained in this area is critical to continue the development of the field. This paper introduces a new hands-on course in characterization of WBG devices, which is an emerging and fundamental topic in WBG-based techniques. First, the lecture-simulation-experiment format based course structure and design considerations, such as safety, are presented. Then, the necessary facilities to support this hands-on course are summarized, including classroom preparation, software tools, and laboratory equipment. Afterward, the detailed course implementation flow is presented to illustrate the approach of close interaction among lecture, simulation, and experiment to maximize students' learning outcomes. Finally, grading for students and course evaluation by students are discussed, highlighting the findings and potential improvements. Detailed course materials are provided via potenntial.eecs.utk.edu/WBGLab for educational use.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • Investigation of Nonlinear Droop Control in DC Power Distribution Systems:
           Load Sharing, Voltage Regulation, Efficiency, and Stability
    • Authors: Fang Chen;Rolando Burgos;Dushan Boroyevich;Juan C. Vasquez;Josep M. Guerrero;
      Pages: 9404 - 9421
      Abstract: Linear droop faces the design tradeoff between voltage regulation and load sharing due to cable resistances and sensing errors. Using a larger droop resistance improves load sharing, but requires a wider droop voltage range. In the nonlinear droop, droop resistance is a function of the converter's output current, and its value increases when the output current increases. As a result, the impacts from sensors and cables are reduced. In this paper, the design of nonlinear droop in dc power distribution systems is studied with special emphasis on load sharing, voltage regulation, system efficiency, and stability. After discussing the piecewise linear and nonlinear droop control, a generic polynomial expression is presented to unify different droop equations. The impact of droop on dc system efficiency is analyzed by evaluating cable and power converter losses. The converter's output impedance using nonlinear droop is modeled to analyze the system stability with constant power loads. The selection and design guidelines of nonlinear droop are summarized, considering both the static performance and interaction with load systems. The analysis is verified in 400-V multi-source dc systems. The nonlinear droop is fully distributed as it only needs local information.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • Modular Parallel Multi-Inverter System for High-Power Inductive Power
           Transfer
    • Authors: Qijun Deng;Pan Sun;Wenshan Hu;Dariusz Czarkowski;Marian K. Kazimierczuk;Hong Zhou;
      Pages: 9422 - 9434
      Abstract: In order to provide high and extendable power levels for inductive power transfer (IPT) system, a parallel multi-inverter system based on modular inverter is presented. Various power requirements can be implemented by an adjustment of the number of paralleled inverters, which provides a high modularity. A master-slave scheme is employed for the switching-driver signals of parallel inverters, where one acts as a leader while others act as followers. Despite the master-slave scheme, the proposed circuit topology has natural robustness because of the equality in terms of the hardware configuration of each modular inverter. For proper parameters, the output phase (current lagging corresponding voltage) of an inverter is lower than the average of output phase of all inverters, when its output voltage lags behind others, and vice versa. Based on this approach, PI controllers are designed to implement phase synchronization for output voltages of all inverters. An IPT prototype supplied by the proposed parallel multi-inverter with three inverters was designed, built, and tested. Experiments show that the proposed parallel multi-inverter system has not only good circulating current suppression capacity but also excellent performance of phase synchronization. The maximum dc-dc efficiency was 94% at a 35.1 kW receiving power. This paper is accompanied by a Matlab/Simulink file demonstrating phase synchronization control.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • Stability Analysis and Auto-Tuning of Interlinking Converters Connected to
           Weak Grids
    • Authors: Qing Liu;Tommaso Caldognetto;Simone Buso;
      Pages: 9435 - 9446
      Abstract: This paper presents an adaptive multi-loop control scheme for inverters interlinking dc voltage sources to single-phase, low-voltage ac grids. Control self-adaptation is particularly useful in the case of weak grids that, due to frequent physical modifications (e.g., network reconfigurations and disconnection of generators/loads) and intrinsic lack of inertia, present strongly time-variant characteristics. The solution presented in this paper is based on a high-performance converter controller with auto-tuning capabilities. It is shown that the applied auto-tuning method can significantly widen the stability region of the interlinking converter, covering a broad range of grid impedance values. In addition, within the stable region, the controller maintains the nominal performance. Experimental results are reported validating the proposed approach in realistic operating conditions, including grid voltage distortion and variations of amplitude and frequency.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • Voltage-Fed Three-Phase Semi-Dual Active Bridge DC–DC Converter
           Utilizing Varying Operating Modes With High Conversion Efficiency
    • Authors: Deshang Sha;Deliang Chen;Salman Khan;Zhiqiang Guo;
      Pages: 9447 - 9458
      Abstract: A novel high-frequency isolated three-phase voltage-fed semi-dual active bridge dc-dc converter is proposed for unidirectional power flow with wide input variations and high voltage interface. A varying operating mode control independently implemented by phase shift and duty cycle control is subsequently raised to handle the stability and improve the conversion efficiency of the converter under the light load conditions. A variety of different operating modes are illustrated and compared in detail. The power expressions and the root mean square expressions of the leakage inductor current of different modes are derived and the optimal modes are consequently selected. The gating signal falling edge compensation of secondary side switches is implemented to further improve the conversion efficiency. The zero voltage switching conditions based on current polarity is also derived. A 1.6 kW prototype was built to verify the effectiveness of the proposed topology and control strategy. The experimental results show that the proposed converter using the proposed control strategy can achieve stability throughout the input and load variations. Moreover, seamless transition can also be achieved, the dynamic performance is good, and high conversion efficiency can be guaranteed.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • A Fault-Tolerant Operation Method for Medium Voltage Modular Multilevel
           Converters With Phase-Shifted Carrier Modulation
    • Authors: Jinyu Wang;Yi Tang;
      Pages: 9459 - 9470
      Abstract: This paper proposes a method for fault-tolerant operation of medium voltage modular multilevel converters (MMCs) with phase-shifted carrier (PSC) modulation. The existing methods need to recalculate and reconfigure all the carriers every time a submodule (SM) fails. However, the proposed method combines the sorting voltage balancing control and the PSC modulation to avoid breaking the symmetry and balance of the carriers. Therefore, the modulation stage in the proposed method can be kept the same and the output voltage of the MMC can remain unchanged without causing voltage mismatch. Moreover, considering the modulation margin and the physical redundancy configuration, two fault SM replacing strategies, i.e., optimal dynamic performance and optimal electrical stress are proposed as well as their respective control structures. Compared with the normal operation of the MMC, the proposed fault-tolerant operation method has only slightly changed the control system and thus the added calculation burden and control complexity can be ignored, which is extremely beneficial for the practical implementation. The effectiveness and performance of the proposed operation method are carefully verified by both simulation and experimental results.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • High-Frequency SiC-Based Inverters With Input Stages Based on
           Quasi-Z-Source and Boost Topologies—Experimental Comparison
    • Authors: Kornel Wolski;Mariusz Zdanowski;Jacek Rabkowski;
      Pages: 9471 - 9478
      Abstract: This paper contains a comparison between three topologies of a three-phase two-level inverter: A quasi-Z-source inverter (qZSI), a voltage-source inverter with a boost converter and a voltage-source inverter with an interleaved boost converter. experimental results obtained from laboratory tests of equivalent 6-kW 100-kHz inverters based on SiC mosfets and Schottky diodes are provided. The following parameters are compared: Quality of input inductor current and output phase voltage as well as total power losses in the inverters. The results for these parameters are obtained for input voltage ranging from 325 V to almost 600 V (where feasible), for two sets of equivalent modulation methods (two regular methods and two reduced-loss methods), for a couple of characteristic values of deadtime and for the operation both at the maximum value of modulation index and at equal values of voltage across the inverter bridge. Results of the experiments show that the qZSI topology may, at certain conditions, surpass the traditional two-stage inverter topologies in the areas of input inductor current quality, output voltage quality and also power losses (at high values of input voltage). What is needed to obtain that is a careful examination of operating conditions, applied modulation method and deadtime value.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • A General Review of Multilevel Inverters Based on Main Submodules:
           Structural Point of View
    • Authors: Mahdi Vijeh;Mohammad Rezanejad;Emad Samadaei;Kent Bertilsson;
      Pages: 9479 - 9502
      Abstract: Multilevel inverters (MLIs) are being used in wide range of power electronic applications. These converters have attracted a lot of attention during recent years and exist in different topologies with similar basic concepts. This paper presents five main submodules (SMs) to be used as the basic structures of MLIs. The paper reviews the common MLI topologies from the structural point of view. The topologies are divided into the different SMs to show conventional MLI configurations and future topologies that can be created from the main SMs. A comparative study between different topologies is performed in detail. The MLIs are categorized and investigated with from different perspectives such as the number of components, the ability to create inherent negative voltage, working in regeneration mode and using single dc source.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • A Family of Ćuk, Zeta, and SEPIC Based Soft-Switching DC–DC
           Converters
    • Authors: Masih Khodabandeh;Ehsan Afshari;Mahshid Amirabadi;
      Pages: 9503 - 9519
      Abstract: In this paper, a new class of dc-dc converter topologies based on capacitive link dc-dc converters-Ćuk, SEPIC, and Zeta converters-that operate under the critical conduction mode has been proposed. The proposed converters are the extensions of quasi-square-wave zero-current-switching converters, which use an auxiliary circuit to provide zero-current and zero-voltage switching for all semiconductor switches at both turn on and turn off transitions and eliminate voltage ringing across the output switch. Using the proposed auxiliary circuit, the value of dv/dt has been diminished; hence, the EMI of the proposed topology is significantly reduced compared to the conventional quasi-square-wave zero-current-switching converters. To verify the operation of the proposed converter and confirm its advantages, an experimental prototype has been implemented, and the experimental results and the efficiency of the proposed converter have been compared with the conventional quasi-square-wave zero-current-switching converters.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • Implications of Capacitor Voltage Imbalance on the Operation of the
           Semi-Full-Bridge Submodule
    • Authors: Stefanie Heinig;Keijo Jacobs;Kalle Ilves;Luca Bessegato;Panagiotis Bakas;Staffan Norrga;Hans-Peter Nee;
      Pages: 9520 - 9535
      Abstract: Future meshed high-voltage direct current grids require modular multilevel converters with extended functionality. One of the most interesting new submodule topologies is the semi-full-bridge because it enables efficient handling of dc-side short circuits while having reduced power losses compared to an implementation with full-bridge submodules. However, the semi-full-bridge submodule requires the parallel connection of capacitors during normal operation, which can cause a high redistribution current in case the voltages of the two submodule capacitors are not equal. The maximum voltage difference and resulting redistribution current have been studied analytically by means of simulations and in a full-scale standalone submodule laboratory setup. The most critical parameter is the capacitance mismatch between the two capacitors. The experimental results from the full-scale prototype show that the redistribution current peaks at 500 A if the voltage difference is 10 V before paralleling and increases to 2500 A if the difference is 40 V. However, neglecting very unlikely cases, the maximum voltage difference predicted by simulations is not higher than 20-30 V for the considered case. Among other measures, a balancing controller is proposed, which reduces the voltage difference safely if a certain maximum value is surpassed. The operating principle of the controller is described in detail and verified experimentally on a down-scaled submodule within a modular multilevel converter prototype. It can be concluded that excessively high redistribution currents can be prevented. Consequently, they are no obstacle for using the semi-full-bridge submodule in future HVdc converters.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • A Novel Segmented Component Injection Scheme to Minimize the Oscillation
           of DC-Link Voltage Under Balanced and Unbalanced Conditions for Vienna
           Rectifier
    • Authors: Wenlong Ding;Han Qiu;Bin Duan;Xiangyang Xing;Naxin Cui;Chenghui Zhang;
      Pages: 9536 - 9551
      Abstract: This paper investigates a Vienna rectifier as a charger for series-connected battery packs. Focusing on carrier-based pulsewidth modulation (CBPWM), the ripple current flowing through the neutral point (NP) results in the voltage oscillation if the loads are resistive. To reduce the ripple of average NP current with mitigated distortion under balanced and unbalanced dc-link voltages conditions, a novel CBPWM with segmented component injection scheme (SCIS) is proposed in this paper. After dc component injection, continuous intervals for optimized component injection and clamping intervals for compensation component injection are identified. Optimized components are calculated originally based on unbalanced factor to make the average NP current zero-size in one switching period. Moreover, unique compensation components generate suitable NP current to shape the sinusoidal input currents according to the circuit analysis. In consequence, the SCIS not only keeps the input current with low-harmonic distortion, but also minimizes the oscillation of dc-link voltage under balanced and unbalanced conditions. In addition, the value of the NP current during the clamping intervals is analyzed under various operating conditions. The effectiveness and the performance of the proposed SCIS are verified by simulation and experiments.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • Design of a Highly Accuracy PSR CC/CV AC–DC Converter Based on a Cable
           Compensation Scheme Without an External Capacitor
    • Authors: Changyuan Chang;Luyang He;Bin Bian;Xiong Han;
      Pages: 9552 - 9561
      Abstract: With the development of portable electronic products, the requirement for chargers is also getting higher. In this paper, a high-accuracy constant output current/constant output voltage (CC/CV) ac-dc flyback converter is proposed and a novel cable compensation method without external capacitor is put forward. The converter adopts primary-side regulation (PSR) scheme, detecting the output voltage through the auxiliary winding, and adjusting switching frequency to achieve output voltage constant in CV mode. Compared to conventional cable compensation module, the proposed circuit applies a method of pre-filtering, averaging, and re-filtering, to obtain the compensation voltage. This method eliminates the need of external capacitor, reducing cost and increasing reliability of the converter. In CC mode, the switching period is adjusted to be fixed multiple of the demagnetization time, thereby realizing the constant current output. The control chip was implemented in NEC 1 μm HVCMOS process, and a 5-V/1-A prototype has been built to verify its feasibility. Experimental results show that the deviations of output voltage and current are within ±0.9% and ±3% under different inputs and loads, while maximum conversion efficiency can reach a level of 78.2%.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • Zero-Voltage Switching Control of an Interleaved Bi-Directional
           Buck–Boost Converter With Variable Coupled Inductor
    • Authors: Milan Pajnić;Predrag Pejović;
      Pages: 9562 - 9572
      Abstract: This paper investigates an approach for achieving zero-voltage switching of an interleaved bi-directional buck-boost converter over a wide input-output voltage operating range by utilizing a coupled inductor with a variable coupling coefficient. The approach is based on regulating the value of the coupling coefficient by means of a direct current depending on the converter conversion ratio, thereby controlling the amplitude and duration of the resonant voltage transition. The impact of the controllable value of the coupling coefficient on the equivalent inductance, the zero-voltage transition period, and the resonant amplitude is analyzed in detail by applying analytical modeling. In comparison to the converter with a fixed coupled inductor operating over a wide input-output voltage span, the variable coupled inductor significantly improves the soft-switching range and reduces the circulating energy. Outside of the controllable resonant amplitude region, the converter with a variable coupled inductor still achieves reduction in the duration of the resonant transition period. To validate theoretical analysis, experimental results are recorded on the gallium nitride interleaved bi-directional buck-boost converter prototype. Improvements in efficiency at both full and half loads in comparison to the prototype with a fixed coupled inductor are achieved.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • A Series Stacked IGBT Switch Based on a Concentrated Clamp Mode Snubber
           for Pulsed Power Applications
    • Authors: Mostafa Zarghani;Sadegh Mohsenzade;Shahriyar Kaboli;
      Pages: 9573 - 9584
      Abstract: Clamp mode snubbers are very well suited for the series structure of the insulated-gate bipolar transistors (IGBTs) in pulsed power applications. They properly meet the necessities expected from them such as the fast operating of the series IGBTs since they have no effect on the gate side. In addition, they can provide safe voltage condition for the IGBTs in short circuit faults, which are very probable in pulsed applications. The clamp mode snubber can perform its voltage balancing task whenever the power capacity of the snubber can support the injected powers due to the voltage unbalancing factors. This paper initially introduces the main factors injecting power to the snubbers. Then, it will be illustrated that the exact injected power to each predetermined snubber cannot be determined due to the uncertainties about the effect of the voltage unbalancing factors. Although it is impossible to determine the exact value of the power injected to each snubber, the total injected powers to the snubbers can be calculated. Therefore, as an effective remedy, this paper proposes a concentrated snubber. Using the proposal, all the injected powers are conducted to a centralized circuit and can be easily managed. In addition, analytical expressions are provided for proper dimensioning of the proposed concentrated snubber elements. Furthermore, the performance of the proposed concentrated snubber is evaluated using simulations and experimental prototyping.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • Novel Bipolar-Type Direct AC–AC Converter Topology Based on
           Non-Differential AC Choppers
    • Authors: Chuang Liu;Dongbo Guo;Renzhong Shan;Guowei Cai;Weichun Ge;Zhezhu Huang;Yibo Wang;Hanwen Zhang;Peng Wang;
      Pages: 9585 - 9599
      Abstract: This paper introduces a novel H-bridge structured ac-ac pulsewidth modulation (PWM) converter topology based on two-level non-differential ac chopper legs, which can work at the non-inverting and inverting modes for the utility voltage compensation. Compared to the traditional bipolar-type H-bridge ac-ac converter, no bidirectional switches are switched in a complementary manner to overcome the commutation problem due to the delayed response of electronic circuits and semiconductor switching devices. The detailed PWM control signals and operational principles are presented to regulate the output voltage in a bipolar manner. Especially the main advantage is that the proposed ac-ac converter has the same buck/boost operation process for non-inverting and inverting modes, which ensures the continuously average current supply to the low-voltage output side without a high-value capacitor to support power. Additionally, due to the common sharing ground of the input and output, the feature that output can reverse or maintain phase angle with input is supported well. Then, the detailed analysis, design conditions, and experimental verification based on a 1 kW experimental prototype are presented.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • Self-Powered 380 V DC SiC Solid-State Circuit Breaker and Fault Current
           Limiter
    • Authors: David Marroquí;José Manuel Blanes;Ausiàs Garrigós;Roberto Gutiérrez;
      Pages: 9600 - 9608
      Abstract: This paper presents a new ultrafast dc solid-state circuit breaker (SSCB) that uses a silicon carbide cascode as the main switching and limiting semiconductor and an isolated photovoltaic driver to control it. The proposed topology is self-powered and fully implemented with discrete parts. The SSCB's cascode can work in three different states-fully on during nominal operation, linear mode for current limitation, and fully off to disconnect the load. The time the SSCB operates in linear mode and the maximum current limit is easily set by discrete components. Control inputs have also been included to reset the SSCB after a fault has been removed or to remotely switch it on or off. This device can be used in dc distribution avoiding deterioration due to the problems associated with electric arcs and mechanical aging of moving parts, limiting inrush currents and also minimizing conduction losses respect other kind of circuit breakers. Functional, thermal, and efficiency tests have been carried out with three different 380 V prototypes. Experimental results show the excellent behavior of the SSCB, it is able to block a 380 V short circuit failure in 570 ns; the authors have not found any faster results in the literature.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • Identifying Electromagnetic Noise-Source Impedance Using Hybrid of
           Measurement and Calculation Method
    • Authors: Feng Zheng;Wugang Wang;Xiaofan Zhao;Mengke Cui;Qiang Zhang;Guqing He;
      Pages: 9609 - 9618
      Abstract: Identifying the noise impedance is a key step to improve the performance of an electromagnetic interference (EMI) filter. This paper proposes an impedance perturbation method to measure and calculate unknowns under a wide frequency range. Not only the differential mode/common mode (DM/CM) impedances but also the magnitude and the phase of impedances will be obtained at the same time. Moreover, the extraneous solution introduced by computation is checked. In addition, the profile of the perturbation infrastructure almost keeps the same under different cases, and it will limit the error of measurement under a very low level, which is also discussed in detail. Finally, the experimental results validate the methods very well.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • A DDS-Based Wait-Free Phase-Continuous Carrier Frequency Modulation
           Strategy for EMI Reduction in FPGA-Based Motor Drive
    • Authors: Yangyang Chen;Ming Yang;Jiang Long;Dianguo Xu;Frede Blaabjerg;
      Pages: 9619 - 9631
      Abstract: In ac motor drives, the fixed-frequency harmonic components of output voltage and current from the inverter with fixed-frequency pulsewidth modulation usually lead to electromagnetic interference (EMI). The spread spectrum clock generation (SSCG) is a widely used solution for this problem. Adjusting the switching frequency to reduce EMI is one kind of practicable scheme among SSCG methods. How to design an optimal or suitable modulation profile is a research emphasis of scholars and has been discussed in depth in many literatures. However, apart from the modulation profile, the mode and quality of carrier are also important and can be improved. In most frequency modulation methods, due to the limitation of the conventional carrier generation mode, the implementation of the new frequency instruction has to wait for the termination of the last switching period. In order to eliminate the waiting state and design a simpler algorithm, this paper has proposed a wait-free phase-continuous carrier frequency modulation (WPCFM) strategy by combining the direct digital frequency synthesizer theory and proper temporal planning of control interruptions. Besides, a theoretical analysis of WPCFM, including quantization error, frequency jitter, phase delay, and voltage distortion, has been finished. Moreover, compared with conventional methods, a more convenient, feasible, and simpler field-programmable gate array based algorithm implementation method and the control structure of WPCFM are also introduced. The analysis shows that, although WPCFM causes a slight increase of the current ripple, it can solve the partial frequency nonuniform distribution problem of the conventional method, and it has a potential value of applications in the wide band gap motor drive systems. The effectiveness of the WPCFM is verified by several sets of EMI reduction experiments where classical periodic carrier frequency modulations are applied.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • Investigation of Radiated Electromagnetic Interference for an Isolated
           High-Frequency DC–DC Power Converter With Power Cables
    • Authors: Yingjie Zhang;Shuo Wang;Yongbin Chu;
      Pages: 9632 - 9643
      Abstract: To analyze the radiated electromagnetic interference generated by isolated power converters, this paper proposes a technique to develop a general radiation model for the converters. The radiated electric field can be predicted from the developed model. The interaction between the impedance of the converter and the undesired antenna in the converter's power delivery paths is explored in detail based on the developed model. Moreover, a dual active bridge converter is taken as an example to demonstrate the developed modeling technique based on the converter's topology. The radiated electric field of the dual active bridge converter is predicted from the developed model. Experiments are conducted to validate the developed model and the predicted interaction between the converter impedance and the undesired antenna impedance in the power delivery paths.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • A Novel Control Scheme for Enhancing the Transient Performance of an
           Islanded Hybrid AC–DC Microgrid
    • Authors: Gopakumar Melath;Sriram Rangarajan;Vivek Agarwal;
      Pages: 9644 - 9654
      Abstract: This paper proposes a novel ancillary feature in bidirectional interlinking converter (BIC) for enhancing the transient performance of an islanded hybrid ac-dc microgrid. The system under consideration includes an ac microgrid with a mix of inertial and non-inertial sources integrated with a dc microgrid through a BIC. The existing BlC control schemes do not judiciously utilize the inertial sources [like the synchronous generator (SG)] as short-term storage for enhancing the transient performance of the system. Since both the microgrids are interfaced through a BIC, this can be achieved by adaptively varying its output frequency during disturbance in the ac microgrid. In the proposed scheme, the BIC is operated as a virtual synchronous generator (VSG) and its output frequency is deliberately increased/decreased during the disturbance. The change in BIC output frequency results in circulating current between the BIC and the SG. Since the BIC voltage phasor leads/lags the SG voltage phasor, it results in the utilization of the inertia of SG as storage. It provides a cost-effective solution by reducing the dependence of the scheme on storage, thereby minimizing the storage requirement while maintaining the transient stability of the system. The proposed control strategy is validated through simulations and experiments.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • An Overview of Assessment Methods for Synchronization Stability of
           Grid-Connected Converters Under Severe Symmetrical Grid Faults
    • Authors: Mads Graungaard Taul;Xiongfei Wang;Pooya Davari;Frede Blaabjerg;
      Pages: 9655 - 9670
      Abstract: Grid-connected converters exposed to weak grid conditions and severe fault events are at risk of losing synchronism with the external grid and neighboring converters. This predicament has led to a growing interest in analyzing the synchronization mechanism and developing models and tools for predicting the transient stability of grid-connected converters. This paper presents a thorough review of the developed methods that describe the phenomena of synchronization instability of grid-connected converters under severe symmetrical grid faults. These methods are compared where the advantages and disadvantages of each method are carefully mapped. The analytical derivations and a detailed simulation model are verified through experimental tests of three case studies. Steady-state and quasi-static analysis can determine whether a given fault condition results in a stable or unstable operating point. However, without considering the dynamics of the synchronization unit, transient stability cannot be guaranteed. By comparing the synchronization unit to a synchronous machine, the damping of the phase-locked loop is identified. For accurate stability assessment, either nonlinear phase portraits or time-domain simulations must be performed. Until this point, no direct stability assessment method is available which consider the damping effect of the synchronization unit. Therefore, additional work is needed on this field in future research.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • An Efficient Power Management Circuit Based on Quasi Maximum Power Point
           Tracking With Bidirectional Intermittent Adjustment for Vibration Energy
           Harvesting
    • Authors: Ge Shi;Yinshui Xia;Huakang Xia;Xiudeng Wang;Libo Qian;Zhidong Chen;Yidie Ye;Qing Li;
      Pages: 9671 - 9685
      Abstract: A power management (PM) circuit based on quasi maximum power point tracking (qMPPT) by maintaining it in maximum power point (MPP) adjacent area is proposed to improve the vibration energy harvesting efficiency. A larger filter capacitor is used to keep the system working in the MPP adjacent area in a long period of time, and the PM circuit can shut down the dc-dc converter for reducing the overall power consumption. When the system deviates from the MPP, a bidirectional buck-boost dc-dc converter turns on to regulate the filter capacitor voltage or extract energy quickly in a short period of time. The experimental results show that the PM circuit can adjust the optimized operating point with the variation of the vibration, the maximum qMPPT efficiency can reach 98.4%, and the maximum end-to-end energy harvesting efficiency can reach 80.6%. The proposed PM circuit can be used in environments permeated with vibration energy to provide energy for the wireless sensor network nodes.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • A Dual-Discrete Model Predictive Control-Based MPPT for PV Systems
    • Authors: Abderezak Lashab;Dezso Sera;Josep M. Guerrero;
      Pages: 9686 - 9697
      Abstract: This paper presents a method that overcomes the problem of the confusion during fast irradiance change in the classical maximum power point tracking (MPPT) as well as in model predictive control (MPC)-based MPPTs available in the literature. The previously introduced MPC-based MPPTs take into account the model of the converter only, which make them prone to the drift during fast environmental conditions. Therefore, the model of the photovoltaic (PV) array is also considered in the proposed algorithm, which allows it to be prompt during rapid environmental condition changes. It takes into account multiple previous samples of power, and based on that is able to take the correct tracking decision when the predicted and measured power differ (in case of drift issue). After the tracking decision is taken, it will be sent to a second part of the algorithm as a reference. The second part is used for following the reference provided by the first part, where the pulses are sent directly to the converter, without a modulator or a linear controller. The proposed technique is validated experimentally by using a buck converter, fed by a PV simulator. The tracking efficiency is evaluated according to EN50530 standard in static and dynamic conditions. The experimental results show that the proposed MPC-MPPT is a quick and accurate tracker under very fast changing irradiance, while maintaining high tracking efficiency even under very low irradiance.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • Mission-Profile-Based Lifetime Prediction for a SiC mosfet Power Module
           Using a Multi-Step Condition-Mapping Simulation Strategy
    • Authors: Lorenzo Ceccarelli;Ramchandra M. Kotecha;Amir Sajjad Bahman;Francesco Iannuzzo;Homer Alan Mantooth;
      Pages: 9698 - 9708
      Abstract: The reliability analysis and lifetime prediction for SiC-based power modules is crucial in order to fulfill the design specifications for next-generation power converters. This paper presents a fast mission-profile-based simulation strategy for a commercial 1.2-kV all-SiC power module used in a photovoltaic inverter topology. The approach relies on a fast condition-mapping simulation structure and the detailed electro-thermal modeling of the module topology and devices. Both parasitic electrical elements and thermal impedance network are extracted from the finite-element analysis of the module geometry. The use of operating conditions mapping and look-up tables enables the simulation of very long timescales in only a few minutes, preserving at the same time the accuracy of circuit-based simulations. The accumulated damage related to thermo-mechanical stress on the module is determined analytically, and a simple consumed lifetime calculation is performed for two different mission profiles and compared in different operating conditions.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • A Sensor Fault Diagnosis Method for a Lithium-Ion Battery Pack in Electric
           Vehicles
    • Authors: Rui Xiong;Quanqing Yu;Weixiang Shen;Cheng Lin;Fengchun Sun;
      Pages: 9709 - 9718
      Abstract: In electric vehicles, a battery management system highly relies on the measured current, voltage, and temperature to accurately estimate state of charge (SOC) and state of health. Thus, the normal operation of current, voltage, and temperature sensors is of great importance to protect batteries from running outside their safe operating area. In this paper, a simple and effective model-based sensor fault diagnosis scheme is developed to detect and isolate the fault of a current or voltage sensor for a series-connected lithium-ion battery pack. The difference between the true SOC and estimated SOC of each cell in the pack is defined as a residual to determine the occurrence of the fault. The true SOC is calculated by the coulomb counting method and the estimated SOC is obtained by the recursive least squares and unscented Kalman filter joint estimation method. In addition, the difference between the capacity used in SOC estimation and the estimated capacity based on the ratio of the accumulated charge to the SOC difference at two nonadjacent sampling times can also be defined as a residual for fault diagnosis. The temperature sensor which is assumed to be fault-free is used to distinguish the fault of a current or voltage sensor from the fault of a battery cell. Then, the faulty current or voltage sensor can be isolated by comparing the residual and the predefined threshold of each cell in the pack. The experimental and simulation results validate the effectiveness of the proposed sensor fault diagnosis scheme.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • DC Substation for DC Grid—Part I: Comparative Evaluation of DC
           Substation Configurations
    • Authors: Jianjun Ma;Miao Zhu;Xu Cai;Yun Wei Li;
      Pages: 9719 - 9731
      Abstract: DC grid has been deemed as the enabling technology for future power systems. Within the dc grid, multi-terminal dc node (MTDN) serves as the key component for voltage/power conversion and fault protection. Configurations of MTDN are explored in this paper. The similarity of MTDN to a classical ac substation is first identified, and three series of “dc substation” have been developed on the basis of classical ac substation structures. To evaluate the influence of different “power conversion technology” and “system structure” on dc substation performance, the proposed configurations are compared under a four-terminal dc node case. Potential applications of dc/dc converters in dc substation are investigated, and each configuration is evaluated in terms of system cost, efficiency, and reliability.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • High-Voltage-Gain DC–DC Step-Up Converter With Bifold Dickson
           Voltage Multiplier Cells
    • Authors: Ahmad Alzahrani;Mehdi Ferdowsi;Pourya Shamsi;
      Pages: 9732 - 9742
      Abstract: This paper presents an interleaved boost converter with a bifold Dickson voltage multiplier suitable for interfacing low-voltage renewable energy sources to high-voltage distribution buses and other applications that require a high-voltage-gain conversion ratio. The proposed converter was constructed from two stages: an interleaved boost stage, which contains two inductors operated by two low-side active switches, and a voltage multiplier cell (VMC) stage, which mainly consists of diodes and capacitors to increase the overall voltage gain. The proposed converter offers a high-voltage-gain ratio with low voltage stress on the semiconductor switches as well as the passive components. This allows the selection of efficient and compact components. Moreover, the required inductance that ensures operation in the continuous conduction mode (CCM) is lower than the one in the conventional interleaved boost converter. The distinction of the proposed converter is that the inductors' currents are equal, regardless of the number of VMCs. Equal sharing of interleaved boost-stage currents reduces the conduction loss in the active switches as well as the inductors and thus improves the overall efficiency, as the conduction power loss is a quadratic function. In this paper, the theory of operation and steady-state analysis of the proposed converter are illustrated and verified by simulation results. A 200-W hardware prototype was implemented to convert a 20-V input source to a 400-V dc load and validate both the theory and the simulation.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • Multi-Period Frame Transient Switching Control for Low-Voltage
           High-Current Buck Converter With a Controlled Coupled Inductor
    • Authors: Zhaoyang Zhao;Weiguo Lu;Weiming Chen;Xiong Du;Herbert Ho-Ching Iu;
      Pages: 9743 - 9757
      Abstract: This paper presents a multi-period frame transient switching control (MP-TSC) scheme for buck converter with a controlled coupled inductor, aiming at improving the load transient response. The proposed buck converter utilizes a controlled coupled inductor as the output inductor. During a load transient, the coupled inductor is controlled as a small equivalent inductance so as to achieve fast transient regulation. While in the steady state, the coupled inductor behaves as a large inductance to reduce the output current ripple. Furthermore, on the basis of the proposed variable inductance circuit, an MP-TSC control scheme is proposed and implemented in a digital form. With the proposed control scheme, the load transient event is divided into n + 1 sub-periods, and in each sub-period, the capacitor-charge balance principle is used to determine the switching time sequence. Moreover, the control principle design and transient response index analysis are provided. Furthermore, its feasibility is validated in simulation and experiment with a 12-3.3V low-voltage high-current synchronous buck converter. Experimental results demonstrate that the voltage deviation of the proposed MP-TSC scheme (coupled coefficient of the controlled coupled inductor is 0.52) has improved by more than 79% compared to that with the auxiliary circuit disabled.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • A Mixed Modeling Approach for Efficient Simulation of PWM Switching Mode
           Power Supplies
    • Authors: Gustavo Migoni;Monica E. Romero;Federico Bergero;Ernesto Kofman;
      Pages: 9758 - 9767
      Abstract: This paper introduces a novel modeling approach that allows to obtain fast simulations of pulsewidth-modulated dc-dc switched-mode power supplies (SMPS). The proposed methodology combines the use of precise switched models during transient evolutions and averaged models during steady-state or slowly varying conditions. In that way, the resulting mixed modeling approach enables to obtain the detailed switching behavior of SMPS in the context of long-term simulations. The commutation between models is automatically performed in runtime by an algorithm that detects the transient or slowly varying condition according to the evolution of some model variables. When the precise switched model is used, the mentioned algorithm also adjusts the averaged model parameters so that its results are accurate irrespective of the operating point. This paper also describes the implementation of the methodology in the Modelica language and reports simulation experiments showing that the results are as accurate as those obtained using precise switched models, but several times faster.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • Voltage-Source Parallel Resonant Class E Inverter
    • Authors: Akinobu Shigeno;Hirotaka Koizumi;
      Pages: 9768 - 9778
      Abstract: This paper proposes a voltage-source parallel resonant Class E inverter. The proposed circuit has a shunt capacitor including parasitic capacitance of a switching device and achieves zero-voltage switching and zero-voltage derivative switching at turning-on like a classical Class E inverter. Therefore, high power conversion efficiency is achieved under high operating frequency. Unlike the other Class E inverters, the proposed circuit has no choke inductor or dc blocking capacitor. Moreover, it has a parallel resonant tank unlike the classical Class E inverter. Thus, a circuit protection is not required in a wireless power transfer system. Circuit analysis, circuit simulations, and circuit experiments were carried out. The experimental circuit performed the desired operation and the power conversion efficiency was 93.2% with the output power 4.76 W at the operating frequency 1 MHz.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • Optimal Design and Experimental Assessment of a Wireless Power Transfer
           System for Home-Cage Monitoring
    • Authors: Jeff Po-Wa Chow;Henry Shu-Hung Chung;Leanne Lai-Hang Chan;Ruihua Shen;Sai Chun Tang;
      Pages: 9779 - 9793
      Abstract: Techniques of long-term in vivo electrophysiological recording play important roles in brain research and neural rehabilitation. To avoid interruption of experiment and risk of infection, use of wireless power transfer (WPT) technique has been suggested to eliminate cumbersome wires and batteries attached to the animals in rodent electrophysiological applications. This paper presents a holistic assessment of the relationships among the physical sizes of the transmitting and receiving coils, power transfer characteristics, and specific absorption rate (SAR) in animals of a simple WPT system using two rectangular coaxial transmitting coils. With given space for the animal and size of the receiving coil, a procedure for designing the minimum driving current, and the transmitting coil dimensions and separation to deliver sufficient power to the receiver, and interactions between the transmitting and receiving coils is derived. A π-capacitor network that can match the impedances of the receiving coil and the load to operate the receiver at the maximum power transfer condition is proposed. It is also optimized for the overall volume. A 100-mW prototype with an operating zone of 400 × 240 × 40 mm3 and a receiving coil with a diameter of 11.45 mm is built and studied. The SAR in the animal is evaluated and compared with the recommended restriction level.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • Review of Power Conversion and Energy Management for Low-Power,
           Low-Voltage Energy Harvesting Powered Wireless Sensors
    • Authors: David Newell;Maeve Duffy;
      Pages: 9794 - 9805
      Abstract: In this paper, state-of-the-art power electronics and energy management solutions utilized in low-power (less than 5 mW), low-voltage (less than 3 V) energy harvesting powered wireless sensors for Internet of things related applications are detailed. All aspects of an energy harvesting powered sensor system are examined, including the challenges of low-power energy harvesting sources, energy management circuits including power converters and energy storage elements, as well as the impact of wireless sensor pulsed power profiles. In particular, this paper focuses on existing voltage step-up energy management techniques, including the issues of cold-start and maximum power point tracking, as well as energy storage which is necessary for wireless sensor operation. Both academic and commercially available energy harvesting powered systems are examined to provide a comprehensive analysis of existing solutions. Issues that are limiting the current system performance are identified to help define future developments needed to enable efficient and effective energy harvesting powered wireless sensor operation.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • A Single-Stage Single-Switch Soft-Switching (S6) Boost-Flyback PFC
           Converter
    • Authors: Alireza Abasian;Hosein Farzanehfard;Sayed Amir Hashemi;
      Pages: 9806 - 9813
      Abstract: This paper presents a single-stage single-switch soft-switching (S6) power factor correction (PFC) converter to enhance the current shaping performance and reduce the total harmonic distortion. This improvement is achieved by the aid of an auxiliary winding which is used to lower the input current harmonics and also achieve soft-switching condition. As a result, the switching losses are reduced and harmonic content of the input current is improved noticeably in comparison to the conventional S6 PFC converter. Also, the total number of semiconductor elements is reduced in the proposed topology which results in lower cost and higher efficiency. The operating modes of the proposed converter are discussed in detail and the design procedure is presented. A 200-kHz prototype of the proposed converter is implemented and the obtained results are provided to verify the converter theoretical analysis and operation.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • An Integrated Step-Up Inverter Without Transformer and Leakage Current for
           Grid-Connected Photovoltaic System
    • Authors: Xuefeng Hu;Penghui Ma;Benbao Gao;Meng Zhang;
      Pages: 9814 - 9827
      Abstract: In this paper, an integrated step-up inverter without transformer is investigated for photovoltaic (PV) power generation. The proposed topology can be derived by combining a traditional boost converter with a single-phase full bridge dc-ac converter. The main features of the integrated inverter are: First, the leakage current caused by the solar cell array-to-ground parasitic capacitance can be theoretically reduced to zero due to the characteristics of the converter configuration, which can improve the efficiency and the reliability of the PV generation system; second, the output ac voltage of the proposed inverter can be higher than the input dc voltage, which is capable of connecting low voltage PV panels to the grid; third, only five active switches are used in the presented inverter, and those switching devices can be synchronously driven by various sinusoidal pulsewidth modulation methods based on the carrier; therefore, the proposed inverter is compact and with curtailed cost. The working principle and analysis of the proposed integrated inverter are elaborated. Finally, simulation and experimental results are obtained in a lab prototype, which agree well with the theoretical analysis.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • Soft-Switching Voltage-Demultiplier-Cell-Based High Step-Down DC–DC
           Converter
    • Authors: Liangzong He;Jiazhe Chen;Xinyong Xu;Bing Cheng;Jiaqing Sun;Dong Guo;Jixiao Nai;
      Pages: 9828 - 9843
      Abstract: A novel high step-down dc-dc converter with voltage demultiplier cell is proposed in this paper, which is widely used in the high step-down applications such as electric vehicle and digital circuits. The combination of switched-capacitor and coupled-inductor is employed to build extended voltage demultiplier in the proposed converter, which makes a quite higher voltage conversion ratio than that of the existing counterparts. Thus, the proposed converter can achieve extremely low output voltage with an appropriate duty ratio, and the extreme duty cycle is avoided. Accordingly, voltage stress on power switches is greatly reduced. Then, mosfets with low conduction resistance could be utilized to reduce conduction loss. Importantly, zero-voltage switching could be achieved for the main switch, which promotes the conversion efficiency further. In addition, the coupled inductor operates not only as a filter inductor, but also as a transformer when the main switch is in the off state, which reduces the volume of the magnetic core and improves the power density of the converter. The operation principle, performance analysis, design considerations of the proposed converter and performance comparison with recent counterparts are discussed in detail, and finally, an experimental prototype is built to verify the theoretical analysis and performance of the proposed converter.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • A Hybrid 7-Level Inverter Using Low-Voltage Devices and Operation With
           Single DC-Link
    • Authors: Apurv Kumar Yadav;K. Gopakumar;Krishna Raj R;Loganathan Umanand;Subhashish Bhattacharya;Wojciech Jarzyna;
      Pages: 9844 - 9853
      Abstract: This paper proposes a new 7-level inverter topology for induction motor drives. It is a hybrid topology formed by cascading a 5-level active neutral-point-clamped inverter with a 3-level T-type converter. It is obtained using low-voltage semiconductor devices with voltage blocking capability of Vdc/3 and Vdc/6. The topology uses three floating capacitors per phase, which are balanced within a pulsewidth modulation (PWM) switching duration using switching-state redundancies for each pole-voltage level. Topology forms two stacks at the front-end, which requires individual symmetrical dc source. The analysis of switching loss and conduction loss is performed and compared with some of the existing 7-level multi-level inverters reported in various literatures to show the advantages of the proposed topology. Furthermore, the single dc source operation with two stacked capacitors and closed-loop control of neutral-point voltage using symmetrical six-phase induction motor is proposed. The voltage-control algorithms for floating capacitors and dc-link stacked capacitors are proposed, which are independent of load power factor and modulation index. Open-loop V/f and closed-loop rotor field oriented control are performed, and various results at steady and transient states are presented to validate the aforementioned claims.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • A Modular Multilevel Series/Parallel Converter for a Wide Frequency Range
           Operation
    • Authors: Zhongxi Li;Ricardo Lizana F.;Zhujun Yu;Sha Sha;Angel V. Peterchev;Stefan M. Goetz;
      Pages: 9854 - 9865
      Abstract: When providing ac output, modular multilevel converters (MMCs) experience power fluctuation in the phase arms. The power fluctuation causes voltage ripple on the module capacitors, which grows with the output power and inversely to the output frequency. Thus, low-frequency operations of MMCs, e.g., for motor drives, require injecting common-mode voltages and circulating currents, and strict dc voltage output relative to ground is impossible. To address this problem, this paper introduces a novel module topology that allows parallel module connectivity in addition to the series and bypass states. The parallel state directly transfers power across the modules and arms to cancel the power fluctuations and hence suppresses the capacitor voltage ripple. The proposed series/parallel converter can operate at a wide frequency range down to dc without common-mode voltages or circulating currents; it also allows sensorless operation and full utilization of the components at higher output frequencies. We present detailed simulation and experiment results to characterize the advantages and limitations of the proposed solution.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • Radial Force Shaping for Acoustic Noise Reduction in Switched Reluctance
           Machines
    • Authors: Alan Dorneles Callegaro;Berker Bilgin;Ali Emadi;
      Pages: 9866 - 9878
      Abstract: Robustness, simple construction, and low cost are some of the advantages of switched reluctance machines (SRMs). These are all desirable characteristics of an electric motor, especially in the automotive sector, where high-temperature and high-speed operation, and low cost are always in demand. However, the acoustic noise generation by conventionally controlled SRMs can prevent its use in applications where acoustic comfort is required. Acoustic noise is radiated by the stator frame when a vibration mode is excited by the respective spatial order at a forcing frequency that is close to the stator's modal natural frequency. The excitation surface wave is the radial force density waveform, which is a function of time and spatial position. In this paper, a phase radial force shaping method is proposed by using harmonic content analysis. A generic function for the radial force shape is identified, whose parameters are calculated by an optimization algorithm to minimize the torque ripple for a given average torque. From the phase radial force profile, a current reference is obtained. The proposed methodology is experimentally validated with a four-phase 8/6 SRM through acoustic noise measurements at different speed and load conditions.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • Impedance Based Stabilization Control Method for Reduced DC-Link
           Capacitance IPMSM Drives
    • Authors: Nannan Zhao;Gaolin Wang;Dawei Ding;Guoqiang Zhang;Dianguo Xu;
      Pages: 9879 - 9890
      Abstract: The instability issue is an important concern in the reduced dc-link capacitance motor drive system, which is caused by the interaction of the LC resonance and the negative impedance of the constant power load (CPL). Harmonics of the grid current also need to be concerned to meet the requirement of the application standards. In this paper, the impedance model of the drive system is established considering the dc-link voltage fluctuation, which is applied to evaluate the drive system stability. The grid current harmonics issue could also be analyzed by the grid input impedance model. A novel grid current feedback based stabilization control method is proposed to stabilize the drive system, which could formulate the Nyquist plot of the drive system. Besides, the grid current harmonics could also be suppressed effectively by adopting the proposed stabilization control method. Experimental results are performed to verify the effectiveness of the proposed method.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • $n$ -Phase+Machines+Including+Antiwindup+and+Distortion-Free+Saturation+With+Full+DC-Bus+Utilization&rft.title=IEEE+Transactions+on+Power+Electronics&rft.issn=0885-8993&rft.date=2019&rft.volume=34&rft.spage=9891&rft.epage=9905&rft.aulast=Toliyat;&rft.aufirst=Alejandro&rft.au=Alejandro+G.+Yepes;Jesús+Doval-Gandoy;Hamid+A.+Toliyat;">Multifrequency Current Control for $n$ -Phase Machines Including
           Antiwindup and Distortion-Free Saturation With Full DC-Bus Utilization
    • Authors: Alejandro G. Yepes;Jesús Doval-Gandoy;Hamid A. Toliyat;
      Pages: 9891 - 9905
      Abstract: Multiphase drives offer important advantages over three-phase ones, e.g., lower per-phase rating and enhanced fault tolerance. For multiphase machines, multifrequency current control (MCC) is often required, e.g., for harmonic cancellation or injection. In certain situations, converter output voltage (OV) saturation occurs, which can cause windup and additional OV distortion. For MCC, obtaining antiwindup and distortion-free OV saturation, with full dc-bus exploitation, entails extra complexity. Recent publications address this problem in three-phase and dual-three-phase (treated as two independent three phases) systems with one and two isolated neutrals, respectively. However, extending such solutions to drives of any phase number n, winding arrangement (symmetrical or asymmetrical), and neutral configuration is not straightforward. This paper proposes a general MCC scheme, including antiwindup and distortion-free OV saturation with full dc-link utilization, for n-phase machines with different winding arrangements (symmetrical or asymmetrical) and neutral configurations. The computational burden required by the proposed antiwindup and saturation strategy is studied; it is concluded that, although it is significant in comparison with the resources needed by the rest of the MCC, the total computational load is acceptable in most of the cases. Experimental results with two multiphase machines are provided, including a comparison with other approaches.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • A Twelve Concentric Multilevel Twenty-Four Sided Polygonal Voltage Space
           Vector Structure for Variable Speed Drives
    • Authors: Krishna Raj R;K. Gopakumar;Apurv Kumar Yadav;L. Umanand;Mariusz Malinowski;Wojciech Jarzyna;
      Pages: 9906 - 9915
      Abstract: Generating dense multilevel voltage space structure using polygons of higher sides is one of the novel and elegant method to suppress low-order harmonics and to obtain refined sinusoidal voltages using voltage source inverters for variable frequency drive application without passive filters. Apart from the advantages of conventional multilevel inverter topologies, schemes generating polygonal voltage space vector structure can equip full dc-bus utilization, low switching frequency strategies to eliminate low-order harmonics, and increased linear modulation range. In this paper, an induction motor drive scheme generating a highly dense multilevel 24-sided polygonal voltage space vector structure using a single dc source, which can eliminate harmonics till 23rd order from phase voltages, is presented. Cascaded power circuit topology with a flying capacitor inverter fed with a dc source and two low voltage floating capacitor fed H-bridge inverters is used. Detailed experimentally validated results, under scalar as well as indirect rotor field oriented control of induction motor are provided. Studies on voltage ripple and reactive energy in various floating capacitors, harmonic performance of output voltage for wide range of speed operation, are also included.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • Weighting Factorless Model Predictive Thrust Control for Linear Induction
           Machine
    • Authors: Wei Xu;Jianqiao Zou;Yi Liu;Jianguo Zhu;
      Pages: 9916 - 9928
      Abstract: Compared with various commonly used control algorithms for linear induction machine, the model predictive thrust control can achieve multiple optimum control objectives, such as high dynamic performance, low power loss, and low flux and thrust ripples, but it is difficult to find suitable weighting factors to balance them. The most commonly used method to tune the weighting factors is by enumerating numerous cases, and then evaluating and comparing each case until the best set of weighting factors is achieved, which can be a very long and tedious procedure. This paper proposes two different methods to solve this problem for minimizing the flux and thrust ripples. One method is to use the variable weighting factor related to flux ripple so that the flux ripple can be seen as a hard constraint without complex tuning process. The other is to replace the flux control term by a variable defined with the same unit as the thrust so that the weighting factor can be equal to one without tuning. These two proposed methods have been successfully applied to a test platform consisting of two 3-kW arc induction motors. The experimental results have shown smaller flux and thrust ripples, as well as tracking errors in comparison with two existing common methods, i.e., the fuzzy decision based method and model predictive flux control.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • Pseudorandom-Frequency Sinusoidal Injection for Position Sensorless IPMSM
           Drives Considering Sample and Hold Effect
    • Authors: Guoqiang Zhang;Gaolin Wang;Hongpeng Zhang;Huiying Wang;Guangdong Bi;Xueguang Zhang;Dianguo Xu;
      Pages: 9929 - 9941
      Abstract: The acoustic noises caused by the fixed-frequency signal injection scheme limit the applications of saliency tracking based sensorless control methods for interior permanent magnet synchronous machine (IPMSM) drives at low-speed operation. In this paper, a pseudorandom-frequency sinusoidal injection (PRFSI) considering the sample and hold effect in practical applications is proposed to reduce the undesired acoustic noises. Since the power spectral density (PSD) of the excited high-frequency (HF) current could be dispersed and continuously distributed with PRFSI, the additional HF acoustic noises can be reduced. Through the comparative analysis of HF response currents PSD results for PRFSI and fixed-frequency sinusoidal injection (FFSI), the principle of acoustic noises reduction with PRFSI is analyzed theoretically. Furthermore, the optimal selection of the injection signals is derived considering the sample and hold effect. Whereby, a comparative evaluation of the proposed PRFSI versus FFSI is carried out on a 2.2-kW position sensorless IPMSM drive, in terms of position estimation and PSD results, which verifies the effectiveness of the proposed scheme.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • Analysis and Suppression of Slotting and Cross-Coupling Effects on Current
           Control in PM Synchronous Motor Drives
    • Authors: Kahyun Lee;Jung-Ik Ha;Dwarakanath V Simili;
      Pages: 9942 - 9956
      Abstract: This paper proposes a d-q cross-coupling current controller for permanent magnet synchronous motor (PMSM) drives. Slotting and cross-coupling effects in PMSMs cause the effective air-gap length to vary with the rotor angle and distort the distribution of the air-gap flux. Such distortions have a significant influence on the current control by changing the relationship between the stator currents and voltages. To investigate their effects, a d-q model is established in this paper, which is suitable for describing the voltage characteristics of the actual PMSMs. The model contains the angle-dependent parameters, the cross-coupling inductance between d-q axes, and the q-axis permanent magnet flux linkage, unlike the ideal d-q model. The transfer function matrix from the d-q currents to d-q voltages of PMSM is newly derived from the model. Based on that, the current controller with the feedback and feedforward terms of 2-by-2 matrix is proposed. It is designed so that the independent gains are in low-pass filter forms and the coupling control gains are zero with eliminating interference between d-q axes. The proposed controller contributes to providing the stable control performance by canceling the slotting and cross-coupling effects. The performance of the proposed current controller is verified by experimental results.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • Independent Speed Control of Two Parallel Connected Split-Phase IM With a
           Common DC Link and Inverter
    • Authors: Sagar Kumar Dash;R. Sudharshan Kaarthik;
      Pages: 9957 - 9965
      Abstract: A novel pulsewidth modulation (PWM) scheme for the decoupled and coordinated control of two parallel connected split-phase induction machines is discussed in this paper for the first time. Both the motors are operated from a single six-phase voltage source inverter which acts as a power source, and two switched capacitor-fed auxiliary inverters to limit the flow of nontorque producing currents in each motor. Both the motors can be operated at its full rated power with low switching frequency, and decoupled control for full power range can be achieved with the proposed topology. This is possible because the individual machines do not carry the load/harmonic currents of other machine (unlike the conventional series or parallel connected systems). The converters can be modulated using sine-triangle PWM or space vector pulsewidth modulation (SVPWM). Furthermore, two different schemes of SVPWM techniques are proposed and compared in this paper. Exhaustive experimental results for all the modulation schemes are provided for steady state and transient operating conditions including start-up to validate the proposed topology and modulation schemes.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • Fuel Economy and EMS for a Series Hybrid Vehicle Based on Supercapacitor
           Storage
    • Authors: Massimiliano Passalacqua;Damiano Lanzarotto;Matteo Repetto;Luis Vaccaro;Andrea Bonfiglio;Mario Marchesoni;
      Pages: 9966 - 9977
      Abstract: The large-scale spread of hybrid electric vehicles (HEVs) in the automotive industry is dominated today by continuous variable transmission parallel powertrain as far as medium size car are concerned. As a matter of fact, the tendency in this sector is to design parallel architectures in that they have provided until now a higher overall powertrain efficiency. However, technological improvements in many electric components and their increased efficiency can reshape this vision and give new outlines on HEV structure design. This paper aims to show the potentials of the series architecture, thanks to the latest electrical improvements especially in storage systems and power electronics. In particular, simulation models and fuel consumption data over different road missions are presented for the series architecture proposed in this study. In addition, a comparison between these results and data available in the scientific literature for state-of-the-art HEVs is reported.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • Dependence of Supercapacitor Peukert Constant on Voltage, Aging, and
           Temperature
    • Authors: Hengzhao Yang;
      Pages: 9978 - 9992
      Abstract: This paper investigates the dependence of the supercapacitor Peukert constant on its terminal voltage, aging condition, and operating temperature. Recent studies show that the charge delivered by a supercapacitor during a constant current discharge process increases when the discharge current decreases if the discharge current is above a certain threshold, i.e., Peukert's law applies. By conducting extensive experiments using three supercapacitor samples with different rated capacitances from different manufacturers, this paper reveals that the Peukert constant increases when the initial voltage of the constant current discharge process is lower, the supercapacitor is more heavily aged, or the operating temperature is lower. The physical mechanisms accounting for the Peukert constant dependence are illustrated by analyzing an RC ladder circuit model. When the supercapacitor terminal voltage is higher, the aging condition is lighter, or the operating temperature is higher, more charge is stored in the supercapacitor. Consequently, when the same discharge current is applied, the discharge time is longer and the branch capacitors are more deeply discharged. Therefore, the relaxation effects of the slow branches are reduced and the supercapacitor behaves more like a single capacitor rather than a distributed capacitor network, which ultimately leads to a lower Peukert constant.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • A Low-Loss Inductor Structure and Design Guidelines for High-Frequency
           Applications
    • Authors: Rachel S. Yang;Alex J. Hanson;Bradley A. Reese;Charles R. Sullivan;David J. Perreault;
      Pages: 9993 - 10005
      Abstract: Operation in the high-frequency (HF) regime (3-30 MHz) has potential for miniaturizing power electronics, but designing small efficient inductors at HF can be challenging. At these frequencies, losses due to skin and proximity effects are difficult to reduce, and gaps needed to keep B fields low in the core add fringing field loss. We propose a low-loss inductor structure with step-by-step design guidelines for HF applications. The structure achieves low loss through double-sided conduction in its single-layer winding and through quasi-distributed gaps. An example ~15 μH inductor designed using the proposed design guidelines achieved an experimental quality factor of 720 at 3 MHz and 2A (peak) of ac current. The inductor also improved a high-current-swing power converter operated at 1-3 MHz; at 250 W, the inductor reduced converter losses by 19%, compared to a conventional inductor design. In some cases, litz wire may further improve the performance of the proposed structure. With litz wire, the example inductor had an improved quality factor of 980. Thus, the proposed inductor geometry and design guidelines are suitable for small highly efficient inductors at HF and can thereby help realize high-frequency miniaturization of power electronics. (This paper is accompanied by an example Python script for generating preliminary designs, available in the online supplementary material).
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • On the Practical Design of a Two-Terminal Active Capacitor
    • Authors: Haoran Wang;Yang Liu;Huai Wang;
      Pages: 10006 - 10020
      Abstract: A two-terminal active capacitor concept has been proposed recently based on an active power electronic circuit with a voltage control method and self-power scheme. It retains the convenience of use as a passive capacitor with two power terminals only without any additional required connections and has the potential to either increase power density or reduce design cost depending on the applications. Based on the previously proof-of-concept study, this paper addresses the design constraints, impedance modeling, and start-up solutions of two-terminal active capacitors. A design method for functionality, efficiency, lifetime, and cost-constraint applications is applied to size the active components and passive elements. A voltage feedforward control scheme is implemented to improve its dynamic response. Two start-up solutions are proposed to overcome the issues brought by the self-power scheme. A case study of an active capacitor for the dc link of a single-phase full-bridge rectifier is presented to demonstrate the theoretical analyses.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • Low Cost High Performance LED Driver Based on a Self-Oscillating Boost
           Converter
    • Authors: David O. Bamgboje;William Harmon;Mohammad Tahan;Tingshu Hu;
      Pages: 10021 - 10034
      Abstract: In this paper, a self-oscillating boost converter with a blocking diode is proposed to meet the desire for simple, cost-effective, high performance, and highly efficient LED drivers. As compared with traditional self-oscillating converters, the proposed converter demonstrates several appealing advantages including design simplicity, robustness, soft-switching characteristics (zero-voltage switching and zero-current switching), tight current regulation, and high efficiency over a wide line/load range. The control stage is implemented with a compact and low-cost industry standard controller, which assumes multiple roles in switching and LED current regulation. A type III compensator with anti-windup is designed to limit the maximum LED current at startup and to achieve tight LED current regulation at steady state. The efficiency and desired transient/steady-state performances are verified with SPICE simulation and a prototype circuit, which demonstrate a maximum efficiency of 95.9% and 2.3% ripple factor for the LED current. The robustness of the proposed driver is verified under a range of power supply voltage and different numbers of LEDs at the load side. In addition, the circuit is modified to implement high efficiency pulsewidth modulation dimming between 5% and 95%.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • A Review on Flicker-Free AC–DC LED Drivers for Single-Phase and
           Three-Phase AC Power Grids
    • Authors: Ignacio Castro;Aitor Vazquez;Manuel Arias;Diego G. Lamar;Marta M. Hernando;Javier Sebastian;
      Pages: 10035 - 10057
      Abstract: Light-emitting diodes (LEDs) are coming strongly into the lighting market due to their advantages over conventional lighting solutions: energy efficient, controllable in both light and color, long lifetime, lack of a warm-up period, and high power density. Some of these advantages will make LED light sources to be more than just a light bulb, being able to transmit data, control light color, hue, and intensity or even detect people in indoor environments. Nevertheless, these advantages attributed to LED capabilities are, in reality, achieved thanks to the LED driver. This paper reviews the current state-of-the-art strategies to drive LEDs from ac power grids with special emphasis into removing the most limiting component from the point of view of the lifetime, which is the electrolytic capacitor, while achieving a flicker-free performance of the light output of the LED driver. Moreover, it focuses on analyzing the required regulations, challenges, and applicability of LED drivers in both single-phase and three-phase ac power grids.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • Dynamic Optical Power Measurements and Modeling of Light-Emitting Diodes
           Based on a Photodetector System and Photo-Electro-Thermal Theory
    • Authors: Huanting Chen;Albert T. L. Lee;Siew-Chong Tan;S. Y. Hui;
      Pages: 10058 - 10068
      Abstract: Optical measurements based on integrating sphere are primary suitable for steady-state measurements and unsuitable for dynamic real-time measurements. This paper presents an alternative method using the combination of a photodetector system and the dynamic photo-electro-thermal theory for real-time optical measurements. It is demonstrated that the voltage output of a photodetector can be correlated to the optical power in real time. Such method has been successfully applied to analyze a phosphor-converted white light-emitting diode (PC white LED) using an extended dynamic model with separate calculations of optical power from the blue LED chips and phosphor layer. Both calculated and practical results are included to confirm the validity of the new method.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • A Turn-off Delay Controlled Bleeder Circuit for Single-Stage TRIAC
           Dimmable LED Driver With Small-Scale Implementation and Low Output Current
           Ripple
    • Authors: Mitsuhiro Kadota;Hiroyuki Shoji;Hiroyuki Hirose;Atsushi Hatakeyama;Keiji Wada;
      Pages: 10069 - 10081
      Abstract: A single-stage TRIAC (TRIode for alternating current switch) dimmable LED (light emitting diode) driver using a buck converter fed through a capacitor input rectifier provides many advantages such as small-scale implementation, low output current ripple, and stable dimming operation. This circuit topology, however, has a serious issue: A large inrush current to the smoothing capacitor. To solve this issue, this paper focuses on a bleeder circuit in the TRIAC dimmable LED driver. This paper presents the mechanism of the large inrush current issue and its relationship to a conventional bleeder circuit. Moreover, this paper proposes a turn-off delay controlled bleeder circuit. The proposed bleeder circuit is analyzed by using its discrete-time state-space model in order to set proper circuit parameters for inrush current reduction. Experimental results demonstrate the inrush current reduction by the proposed method, which leads to a 37% reduction of maximum input current, as well as proper dimming operation and low output current ripple. The proposed method achieves further small-scale implementation, which enhances the advantages of the intended main circuit topology.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • Series-Connected Current-Source-Mode Multiple-Output Converters With High
           Step-Down Ratio and Simple Control
    • Authors: Xiaolu Lucia Li;Zheng Dong;Chi K. Tse;
      Pages: 10082 - 10093
      Abstract: In this paper, a two-stage transformerless multiple-output converter is proposed for applications requiring a high voltage step-down ratio. The proposed circuit transfers power via a current interface and the use of current-source-mode (CSM) converters, resulting in low voltage stress and drastically simplified control. The first stage of this configuration is regulated to provide a constant current to the second stage. The second stage consists of series-connected CSM boost converters. The high step-down ratio of the proposed configuration reduces the voltage stress in the switches of the second stage. The series-connected CSM converters are inherently independent of each other, leading to a very simple control scheme without the need for decoupling of the input voltage of the interconnected converters. Input voltage variation to the system will not affect the input voltage of the second stage. Load variation in one output will not affect the other outputs. If one or more CSM converters are shorted, there is no impact on other converters. These advantages enable a high scalability. Besides, the first stage of the proposed configuration can operate both in continuous conduction mode (CCM) and discontinuous conduction mode (DCM) with the same control strategy. This feature leads to a low control complexity and elimination of inductors. The performance of the proposed converter is illustrated with a laboratory prototype driving light emitting diodes (LEDs).
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • A 2.8-MHz 96.1%-Peak-Efficiency 1.4-μs-Settling-Time Fully Soft-Switched
           LED Driver With 0.08–1 Dimming Range
    • Authors: Yong Qu;Wei Shu;Joseph S. Chang;
      Pages: 10094 - 10104
      Abstract: Present day LED drivers demand both high power efficiency and wide dimming range. However, these two parameters are often a tradeoff, where a wide dimming range requires a high switching frequency, hence the ensuing switching losses. In this paper, we present an LED driver that features both high power efficiency and wide dimming range by means of fully soft switching that substantially eliminates the switching losses, i.e., the switching losses are negligible. We achieve the said fully soft switching by our proposed hysteretic soft-switching controller (HSSC) and the proposed circuits-voltage detector, current sensor, and level shifter. The HSSC enables the fully soft switching, including zero-voltage switching and zero-current switching, by means of turning on/off power switches when their voltage/current is zero. The proposed voltage detector and current sensor, featuring low power, monitor the voltage and current of the power switches. The proposed level shifter, featuring ultra-fast speed, serves to quickly transmit the monitored signal from the said voltage detector and current sensor to the HSSC. The prototype LED driver, realized in a 130-nm BCDLite process, features 6-18 V input voltage range, output current of 0.5-1.3 A, drives 1-3 series-connected LEDs, 12-W maximum output power, 2.8-MHz maximum switching frequency, 96.1% peak power efficiency, 1.4-μs settling time, and 0.08-1 dimming range at 20-kHz dimming frequency. When benchmarked against state-of-the-art LED drivers, our design simultaneously features the widest dimming range, shortest settling time, and requires the smallest inductor. The measurements and benchmark depict the decoupling of the said tradeoff.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • A Multiplexing Ripple Cancellation LED Driver With True Single-Stage Power
           Conversion and Flicker-Free Operation
    • Authors: Peng Fang;Samuel Webb;Yang Chen;Yan-Fei Liu;Paresh C. Sen;
      Pages: 10105 - 10120
      Abstract: Although a single-stage off-line power light-emitting diode (LED) driver can achieve low cost and high efficiency, the notorious double-line-frequency flicker issue with a single-stage LED driver limits its usage in high-quality lighting applications. To solve lighting flicker, as well as maintain a low cost and high efficiency, a multiplexing ripple cancellation (MRC) LED driver is proposed in this paper. One switching cycle is divided into two intervals. During the first interval, the proposed LED driver operates as a conventional LED driver that transfers energy from the ac input to LED output, performs power factor correction, and generates the main output voltage. The main output voltage has a double-line-frequency ripple like in a conventional design. During the second interval, the proposed LED driver transfers energy from the ac input again to generate an opposite ripple voltage to cancel the ripple voltage from the main output. In this way, the voltage across the LED load is a dc to achieve flicker-free LED driving performance. More than 99% of the output power goes through one-time power conversion, while less than 1% goes through two-time power conversion. A 7.5-W experimental prototype is built and tested to verify the design concept.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • Experimental Evaluation and Analysis of Switching Transient's
           Effect on Dynamic on-Resistance in GaN HEMTs
    • Authors: Fei Yang;Chi Xu;Bilal Akin;
      Pages: 10121 - 10135
      Abstract: The dynamic ON-resistance in gallium nitride (GaN) devices is problematic as it can impair the converter's efficiency the increased conduction loss. In this paper, the hard-switching transient's effect on the dynamic ON-resistance is, for the first evaluated experimentally on a commercial high-voltage GaN electron mobility transistor. A new Rdyn_ds,on measurement with fast sensing speed is designed, and an accurate measurement of Rdyn_ds,on can be realized experimentally within 49.6 ns after the device's current reaches to the load current. double-pulse-test setup is designed to comprehensively evaluate switching transient's effect on Rdyn_ds,on under different operating conditions. From the experimental results, it is found turn-ON and turn-OFF gate resistance have a significant on the dynamic ON-resistance whereas the cross-talk effect Rdyn_ds,on is negligible. Specifically, at 400 V/25 A, more (28.2%) increase in Rdyn_ds,on is observed when the external turn-ON (turn-OFF) gate resistance increases from 0 to 20 Ω. Detailed discussion and quantitative analysis are provided to the experimental results. In terms of the turn-ON process, concluded that the Rdyn_ds,on variation is mainly caused different numbers of generated hot electrons. For the turn-OFF transient, it is confirmed the variation of drain current at different slew rate leads to the Rdyn_ds,on difference.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • Junction Temperature Measurement Method for SiC Bipolar Junction
           Transistor Using Base–Collector Voltage Drop at Low Current
    • Authors: Bangbing Shi;Shiwei Feng;Yamin Zhang;Kun Bai;Yuxuan Xiao;Lei Shi;Hui Zhu;Chunsheng Guo;
      Pages: 10136 - 10142
      Abstract: This paper proposes an electrical method for estimation of the vertical junction temperature of silicon carbide bipolar junction transistors (SiC BJTs). This measurement method is based on measurement of the base-collector voltage (VBC) drop at a low current (VBC(low)) during the turn-off process. This voltage shows both good sensitivity and linearity with respect to temperature. The traditional temperature-sensitive electrical parameter VBE(low) (i.e., the base-emitter voltage at a low current) and an infrared camera are used to compare the characteristics of VBC(low). The results show that use of VBC(low) provides more accurate junction temperature and thermal resistance measurement results, which can then be used to extract the vertical junction temperature of the SiC BJT under test.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • Online Junction Temperature Extraction of SiC Power mosfets With
           Temperature Sensitive Optic Parameter (TSOP) Approach
    • Authors: Chengmin Li;Haoze Luo;Chushan Li;Wuhua Li;Huan Yang;Xiangning He;
      Pages: 10143 - 10152
      Abstract: Accurate information of the junction temperature of SiC power mosfets ensures safe operation and helps reliability assessment of the devices. In this paper, an online junction temperature extraction method is proposed based on the electroluminescence phenomenon of the body diode of SiC power mosfets. It is found that during the forward conduction interval of the body diode, visible blue light is emitted around the chip, which ascribes to the radiative recombination in the low doped region of SiC mosfets. Experimental results suggest the light intensity changes linearly with the variation of the temperature and behaves as a temperature sensitive optic parameter (TSOP). Further, an electro-thermal-optic model is proposed to reveal the relationship between the electroluminescence intensity, forward current, and junction temperature. Based on the TSOP, an online junction temperature extraction method is proposed for SiC mosfets and verified in an SiC mosfet based inverter. Compared with state-of-the-art methods, the proposed junction temperature measurement method is contactless and immune from the aging of the package.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • An Online ESR Estimation Method for Output Capacitor of Boost Converter
    • Authors: Lei Ren;Chunying Gong;Yao Zhao;
      Pages: 10153 - 10165
      Abstract: Aluminum electrolytic capacitor (AEC) is one of the most age-affected components in power electronic converters and its reliability has been a major concern. As the growth of service life, the equivalent series resistance (ESR) of AEC increases due to the loss of electrolyte. Therefore, online ESR estimation is critical for condition monitoring of AEC. This paper proposes an online ESR estimation method for output capacitor of boost converter. By analyzing the output voltage ripple, an ESR calculation model is derived. Based on the model, only output voltage and inductor current need to be measured, which can be obtained directly from double closed-loops converter. To implement this proposed method, a detailed extraction scheme based on wavelet transform denoising is presented. Non-ideal factors (noise and voltage spikes) are analyzed and the superiority of the proposed parameter identification scheme is verified. The proposed estimation method can obtain ESR for the converter operating at different working conditions such as resistive loads and converter loads. Effect of temperature on ESR is incorporated for accurate determination of the health of capacitor. Simulation and experimental results are provided to verify the effectiveness of the method.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • Quantitative Model-Based False Turn-on Evaluation and Suppression for
           Cascode GaN Devices in Half-Bridge Applications
    • Authors: Tianhua Zhu;Fang Zhuo;Fangzhou Zhao;Feng Wang;Tong Zhao;
      Pages: 10166 - 10179
      Abstract: Owing to the high operation frequency and fast switching speed, gallium nitride (GaN) devices are prone to the false turn-on phenomenon, causing high switching loss, shoot through, and even sustained oscillation. However, most of research on false turn-on aims at the enhancement-mode GaN devices, whereas there is still little published research on GaN devices in cascode configuration due to the comparatively complicated structure and various parasitic components. This paper conducts a comprehensive and in-depth study for the problem of false turn-on in cascode GaN devices based half-bridge circuits, which has a great guiding significance in the device selection, printed circuit board (PCB) design, and debugging of cascode GaN converters. In this paper, a novel analytical model of the device suffering false turn-on is first developed, with all the parasitic parameters being fully considered. Based on the model, the quantitative and accurate expression of the induced gate-to-source voltage is derived, which can serve as a precise and significant reference for judging and evaluating the false turn-on problems. Then, the influences of device and circuit parameters on the peak value of induced voltage are first investigated in detail, providing a reliable guidance for the usage and PCB design of cascode GaN devices based half-bridge converters. What's more, guidelines to effectively suppress the false turn-on phenomenon are also given, which can be adopted both in the design and debugging process of cascode GaN applications. Finally, all the theoretical calculations and analysis are verified by experiments with satisfying results and performances.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • L- and LCL-Filtered Grid-Tied Single-Phase Inverter Transistor
           Open-Circuit Fault Diagnosis Based on Post-Fault Reconfiguration
           Algorithms
    • Authors: Zhan Li;Borong Wang;Yini Ren;Jun Wang;Zhihong Bai;Hao Ma;
      Pages: 10180 - 10192
      Abstract: This paper presents a transistor open-circuit fault diagnosis method based on an average model and post-fault reconfiguration algorithms for a grid-tied single-phase inverter that transfers power bi-directionally. The transistor open-circuit fault occurrence is detected by comparing the average bridge arm pole-to-pole voltage deviation and threshold first. Then, the exact faulty transistor is identified by developed algorithms based on post-fault reconfiguration of control (PFRC) and of utilizing redundant leg (PFRUR). These two fault identification algorithms are suitable for different situations. Compared with the PFRUR, the PFRC can identify the faulty transistor without the help of redundant leg, but the identification time is longer. For inverters equipped with redundant leg already, the PFRUR can achieve faster identification speed so that inverters in reliability-oriented applications can return to normal operation after fault with short interruption. With average model, this method only requires existing signals sampled for control, thus it can be embedded in system easily without adding extra sensors and diagnosis circuits. The sampling frequency can be as low as switching frequency. Furthermore, this method is suitable for both inverters with L or LCL filters. Finally, experiments are carried out on a 550-W/10-kHz grid-tied single-phase inverter to verify the effectiveness.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • Optimal Phase-Shift Control to Minimize Reactive Power for a Dual Active
           Bridge DC–DC Converter
    • Authors: Shuai Shao;Mingming Jiang;Weiwen Ye;Yucen Li;Junming Zhang;Kuang Sheng;
      Pages: 10193 - 10205
      Abstract: In a dual active bridge (DAB) dc-dc converter, modulating the phase-shift ratios can suppress reactive power and increase the efficiency under non-unity voltage gain conditions. Derivation of the optimal phase-shift ratios to achieve the minimum reactive power is challenging because a DAB can operate in four different scenarios (forward/backward, buck/boost) and each scenario has five operating modes. This paper first introduces a transformation in which different DAB operating scenarios (forward/backward, buck/boost) can be equivalent to one another; then optimization of only one scenario (forward/buck) is required. Next, for the five modes in forward/buck scenario, based on a graphical method, this paper proves that each operating point of Modes 1, 2, and 5 can be mapped into that of Mode 3 with lower conduction losses, and only two modes require detailed analysis. The optimization process of these two modes are derived step-by-step. Global optimal phase-shift signals that minimize the reactive power under four different DAB operating scenarios (forward/backward, buck/boost) are presented. A simple table and control block diagram are presented for practical implementation of global reactive-power minimization control. Experimental comparison with other modulation schemes verifies the efficiency improvement of the proposed control method.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • Sliding-Mode Sensorless Control of PMSM With Inverter Nonlinearity
           Compensation
    • Authors: Yangrui Wang;Yongxiang Xu;Jibin Zou;
      Pages: 10206 - 10220
      Abstract: In this paper, a robust adaptive sliding-mode observer (SMO) is designed based on the surface permanent-magnet synchronous machine (SPMSM) model in rotor reference frame (γδ-axis), and an online inverter nonlinearity identification and compensation method is proposed. In order to reduce the chattering of the SMO, an adaptive law is presented to help estimate the back electromotive forces of an SPMSM; thus, smaller gains can be set for switching functions of the SMO. The small-signal model of the proposed sensorless scheme is derived for analyzing the steady-state and dynamic behavior of the sensorless scheme. Voltage distortion, caused by nonlinear characteristics of switching devices, not only causes (6k ± 1)th harmonics in phase currents but also leads to a rotor position estimation error. The equivalent amplitude of the voltage distortion can be identified based on the derived small-signal model of the proposed sensorless scheme. To improve the accuracy of the estimated voltage distortion, a recursive restricted total least squares is applied to obtain the estimated amplitude of the voltage distortion. Experimental results validate the proposed sensorless control scheme and its effectiveness.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • A Generalized Design Framework for Neutral Point Voltage Balance of
           Three-Phase Vienna Rectifiers
    • Authors: Xing Li;Jian Han;Yao Sun;Mei Su;Jianheng Lin;Shiming Xie;Shoudao Huang;
      Pages: 10221 - 10232
      Abstract: This paper proposes a generalized design framework for three-phase Vienna rectifiers to handle the neutral point voltage balance issue. On the basis of the design framework, it is convenient to construct various neutral point voltage balancing methods with the guarantee of stability. As demonstration, three representative neutral point voltage balance approaches are presented by choosing different zero-sequence voltages. A comprehensive comparison among the three approaches is given in the aspects of input current quality, capacitor voltage fluctuation, and system efficiency. The comparison results provide guidance for constructing the most appropriate approach based on the specific requirement. Finally, simulation and experimental results verify the correctness and effectiveness of the presented approaches and the related performance analysis.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • A Dual-Loop Current Control Structure With Improved Disturbance Rejection
           for Grid-Connected Converters
    • Authors: Srinivas Gulur;Vishnu Mahadeva Iyer;Subhashish Bhattacharya;
      Pages: 10233 - 10244
      Abstract: Increase in renewable energy penetration, in the recent past, has been one of the primary causes for serious issues in power quality of the utility grid. This has ushered in the need for a robust and stable control system for reference tracking and disturbance rejection of grid-connected converters. Conventionally, due to its simplicity and ability to achieve zero steady-state error, a simple proportional integral (PI) controller is used in the synchronous reference frame (dq) for current control of voltage-source based grid-connected systems. However, the PI controller by itself, may not suffice for adequate disturbance rejection, especially when the utility grid voltages contain other harmonics in addition to the fundamental component. This paper introduces and analyzes a dual-loop current control structure, which utilizes two independent controllers, one for reference tracking and the other for disturbance rejection in the dq frame. A small signal model of the dual-loop current control has been presented and its robustness under grid impedance variation, examined. Extensive experimental results are presented to validate the dual-loop control strategy for improved disturbance rejection capability and filtering action during the presence of grid voltage disturbances and grid impedance variations, without compromising the reference tracking performance.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • An Inductive-Power-Transfer Converter With High Efficiency Throughout
           Battery-Charging Process
    • Authors: Zhicong Huang;Siu-Chung Wong;Chi K. Tse;
      Pages: 10245 - 10255
      Abstract: An inductive power transfer (IPT) converter usually has an optimum efficiency only at a matched load. Because of wide load range variation during battery charging, it is challenging for an IPT converter to achieve the required output and maintain high efficiency throughout the charging process. In this paper, a series-series compensated IPT converter with an active rectifier is analyzed and implemented for battery charging. Appropriate operations are employed for constant-current charging and constant-voltage (CV) charging. A novel operation approach is proposed to achieve constant output voltage and to ensure load impedance matching during CV charging without the help of an extra dc-dc converter, which incurs loss. Both a frequency modulated primary inverter and a phase-angle modulated secondary active rectifier can achieve soft switching. High efficiency can be maintained during the whole battery-charging profile.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • Wide-Range ZVS Control Technique for Bidirectional Dual-Bridge
           Series-Resonant DC–DC Converters
    • Authors: Weijian Han;Luca Corradini;
      Pages: 10256 - 10269
      Abstract: For high-voltage and high-power bidirectional dc-dc converters, soft switching of all active power devices is mandatory to ensure the high efficiency and reliability. This paper describes a control technique for wide-range zero-voltage switching (ZVS) implementation of dual-bridge series-resonant dc-dc converters. The proposed control technique integrates variable-frequency modulation (VFM) and phase-shift modulation (PSM), in which the former effectively achieves the ZVS for both step-down and step-up operation, while the latter is employed to further extend the power transmission capability. The proposed technique is built on the time-domain analysis of the ZVS condition. A closed-form solution is formulated that guarantees the sufficient ZVS commutation current at switching instants, accounting for the presence of switches parasitic and/or snubber capacitances, while maintains the rms tank current at near-to-minimum levels. Furthermore, a compensation strategy for the effect of conduction losses is presented achieving better switching behavior and higher efficiency. Compared with the minimum rms current trajectory modulation, lower switching losses, enhanced efficiency, and mitigated voltage ringings are obtained. Effectiveness of the proposed technique is verified by means of a 800 W experimental prototype. Closed-loop operation with the proposed VFM+PSM controller is also implemented and experimentally tested.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • Constant off-Time Digital Current-Mode Controlled Boost Converters With
           Enhanced Stability Boundary
    • Authors: K. Hariharan;Santanu Kapat;Siddhartha Mukhopadhyay;
      Pages: 10270 - 10281
      Abstract: The right-half-plane (RHP) zero in a continuous conduction mode boost converter results in a significantly restricted closed-loop bandwidth (BW) for higher voltage gain and/or load current conditions. A compensating ramp is used for current-mode control (CMC), and a higher ramp slope degrades the BW. Variable-frequency digital CMC offers inherent current-loop stability and real-time tuning scope for higher closed-loop BW. However, the challenges are to select the sampling frequency and sampling instant of the output voltage with discontinuous ripple due to the effective series resistance of the output capacitor, and its impact on stability. This paper shows that an event-based current-mode constant off-time digital modulator achieves superior stability and performance in a boost converter along with the reduced RHP zero effect over other digital CMC techniques. Using a discrete-time framework, the fast-scale stability conditions and small-signal models are analytically derived for various digital CMC techniques, which are validated using SIMPLIS simulation. A boost converter prototype is tested, and the analytical predictions are verified experimentally. Further, the analysis is extended to a non-inverting buck-boost converter.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • An Approach to Suppress Low-Frequency Oscillation by Combining Extended
           State Observer With Model Predictive Control of EMUs Rectifier
    • Authors: Zhigang Liu;Yaqi Wang;Shuang Liu;Zhiyuan Li;Han Zhang;Zhixue Zhang;
      Pages: 10282 - 10297
      Abstract: Recently, low-frequency oscillation (LFO) occurs in electrified railways, which exhibits a synchronous periodic oscillation of about 2-7 Hz in the traction network and electric multiple units (EMUs). To suppress the LFO, an improved model predictive control (MPC) combining with extended state observer (ESO) is proposed. First, for the design of ESO, the changes of system parameters and the unmodeled item in vehicle mathematical model are extended to a new variable and then estimated to compensate the calculated control voltage in real time. Second, the observer stability is analyzed by obtaining the transfer function, and the appropriate gains of observer are chosen through the pole assignment technique. At last, by the combination of the predictive currents, the optimal control voltages can be obtained. The control performance among MPC, dq decoupling control, passivity-based control, and the proposed method is compared. In addition, the system robustness when system parameters change is discussed. At last, to further verify the effectiveness of the proposed method for suppressing LFO, an integrated dSPACE semi-physical experimental platform including eight simulated EMUs and an equivalent traction network is constructed. Simulation and experimental results show that the proposed method not only effectively suppresses LFO but also accelerates the response speed of traction line-side converter, reduces the distortion of grid-side and vehicle-side currents, and overcomes the disadvantages of MPC and dq decoupling control under the mismatching of system parameters.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • Finite-Time Adaptive Fuzzy-Neural-Network Control of Active Power Filter
    • Authors: Shixi Hou;Juntao Fei;Chen Chen;Yundi Chu;
      Pages: 10298 - 10313
      Abstract: In this paper, an adaptive fuzzy-neural-network (AFNN) control using nonsingular terminal sliding mode control is proposed for active power filter (APF) as a current controller to attenuate the effect of unknown external disturbances and modeling uncertainties. First, the dynamic model for APF is built in which both the system parameter variations and external disturbance are considered. Then, a nonsingular terminal sliding mode control based on the backstepping (NTSMB) approach is presented for the current control system to solve singularity point problem and realize the fast and finite-time convergence. Moreover, AFNN is designed to relax the requirement of the prior knowledge of system parameters to improve the robustness of NTSMB. In the AFNN strategy, AFNN framework is designed to mimic the NTSMB, where the parameters are adjusted online by the adaptive law derived from the projection algorithm and the Lyapunov stability analysis, to guarantee tracking performance and stability of the closed-loop system. Simulation studies demonstrate that the proposed control methods exhibit excellent performance in both steady-state and transient operation compared to traditional sliding mode control. Experimental results are provided using a fully digital control system in order to validate the performance of the proposed controller.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • A Low-Cost Phase-Angle Compensation Method for the Indirect Matrix
           Converters Operating at the Unity Grid Power Factor
    • Authors: Zheng Gong;Haijun Zhang;Peng Dai;Ning Sun;Ming Li;
      Pages: 10314 - 10326
      Abstract: Unity grid power factor is essential for the indirect matrix converter (IMC) applications due to the grid-friendly requirement. The existing closed-loop grid power factor control methods usually consist of complex structures, resulting in high requirements both in hardware and software aspects. In this paper, a low-cost phase-angle compensation method is proposed to reduce the costs. Based on the modeling for the IMC, the influences from the system parameters on the grid power factor angle are analyzed. Then, a virtual adaptive resistance model is denoted and calculated with the least mean square algorithm to generate a virtual voltage signal, which is consequently utilized to generate the phase compensation angle by a newly designed proportional-integral closed loop to regulate the grid power factor angle. Compared to the typical existing method, the proposed low-cost phase-angle compensation method requires only one grid current measurement in hardware and reduces 18.9% computational burden in software, while the advantages being adaptive to the system parameters and suitable for a wide load-range are reserved. Simulation and experimental research for the proposed method is carried out to validate its steady-state and dynamic-state compensation effectiveness under various load conditions.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • A High-Performance Shade-Tolerant MPPT Based on Current-Mode Control
    • Authors: Seyedkazem Hosseini;Shamsodin Taheri;Masoud Farzaneh;Hamed Taheri;
      Pages: 10327 - 10340
      Abstract: This paper proposes a high-performance shade-tolerant maximum power point tracking (STMPPT) technique for dc-dc converter stage of photovoltaic (PV) applications. The average current-mode control (ACMC) is utilized to regulate the PV array current using two feedback control loops. The current-mode control is a superior scheme in control of dc-dc power electronic converters. The proposed STMPPT technique operates in two modes. The ACMC with the perturb and observe (P&O) MPPT algorithm functions in a local MPPT mode under normal irradiance condition. When the PV array is likely to be partially shaded, a global MPPT subroutine effectively scans the PV profile to optimize the PV system operation. This is achieved by implementing simple innovations to the ACMC-based P&O algorithm. The innovations benefit from useful observations of I-V characteristics. The idea behind using the I-V characteristics is to significantly reduce the search space, make the algorithm independent of shading conditions and PV array configuration, and inherently recognize the occurrence of partial shading conditions. The proposed STMPPT technique enables very fast and reliable tracking of global maximum power point. In addition, it can stably work under dynamic environmental change without losing correct sense of tracking direction. Its simplicity and independency would offer a viable solution for PV converter products. Simulation and experimental performance assessments are presented under different operating conditions that could happen in outdoor PV installations.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • Control Schemes for Reducing Second Harmonic Current in Two-Stage
           Single-Phase Converter: An Overview From DC-Bus Port-Impedance
           Characteristics
    • Authors: Li Zhang;Xinbo Ruan;
      Pages: 10341 - 10358
      Abstract: The instantaneous input and output power of two-stage single-phase converter are imbalanced, resulting in the second harmonic current (SHC) in the dc-dc converter, dc source, or dc load. This paper revisits the SHC reduction control schemes from the dc-bus port-impedance perspective. The dc-dc converters in two-stage single-phase converters are categorized into two types, namely, bus-voltage-controlled converter (BVCC) and bus-current-controlled converter (BCCC). The dc-bus port impedance of the BVCC is revealed to be approximately inversely proportional to the voltage loop gain. Thus, for reducing the SHC in the BVCC, advanced control schemes are required for increasing the dc-bus port impedance. The dc-bus port impedance of the BCCC is proved to be a negative resistor within the control bandwidth. Hence, for reducing the SHC in the BCCC, the dc-bus voltage ripple should be limited. From the dc-bus port-impedance perspective, the SHC reduction control schemes are reclassified into closed-loop-design-based, virtual-impedance-based, and power-decoupling-based approaches, based on which, different SHC reduction control schemes are carefully reviewed and compared. Finally, potential challenges and issues are discussed.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
  • Modulated Model Predictive Control for Modular Multilevel AC/AC Converter
    • Authors: Zhixing He;Peng Guo;Zhikang Shuai;Qianming Xu;An Luo;Josep M. Guerrero;
      Pages: 10359 - 10372
      Abstract: Modular multilevel converter (MMC) is very popular in high power applications due to its attractive characteristics. The full bridge-based MMC featuring three-phase to single-phase direct ac/ac conversion is a potential solution for ac power supply (ACPS). In this paper, new modulated model predictive control (MMPC) methods are proposed for MMC-ACPS to improve the steady state multi-objective current tracking performance. In the proposed methods, modulated vectors sequence is employed, output voltage levels of upper and lower arms are combined and represented by vectors in the current increments plane first. Then, the plane is divided into eight sectors according to the predictive tracking errors of input current and circulating current. After determining sectors, a modulated vector sequence, consisting of one zero vector and two active vectors, is selected to eliminate these current tracking errors simultaneously at the end of each control period. Duty cycles of the three selected vectors are calculated based on the principle of multiple current tracking errors minimization. Optimized vector selection approaches are illustrated in detail for the proposed MMPC. Since only the adjacent nine vectors are utilized in the proposed methods, the calculation amount is suitable and the dv/dt of the output voltage is also limited. Finally, steady-state and dynamic performances of the proposed control methods are verified by experimental results.
      PubDate: Oct. 2019
      Issue No: Vol. 34, No. 10 (2019)
       
 
 
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