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  Subjects -> ELECTRONICS (Total: 155 journals)
Showing 1 - 200 of 277 Journals sorted alphabetically
Advances in Biosensors and Bioelectronics     Open Access   (Followers: 6)
Advances in Electrical and Electronic Engineering     Open Access   (Followers: 2)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 9)
Advances in Microelectronic Engineering     Open Access   (Followers: 11)
Advances in Power Electronics     Open Access   (Followers: 24)
Aerospace and Electronic Systems, IEEE Transactions on     Hybrid Journal   (Followers: 214)
American Journal of Electrical and Electronic Engineering     Open Access   (Followers: 24)
Annals of Telecommunications     Hybrid Journal   (Followers: 7)
Archives of Electrical Engineering     Open Access   (Followers: 12)
Autonomous Mental Development, IEEE Transactions on     Hybrid Journal   (Followers: 8)
Bell Labs Technical Journal     Hybrid Journal   (Followers: 23)
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (Followers: 17)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 32)
Biomedical Instrumentation & Technology     Hybrid Journal   (Followers: 6)
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 10)
BULLETIN of National Technical University of Ukraine. Series RADIOTECHNIQUE. RADIOAPPARATUS BUILDING     Open Access   (Followers: 1)
Bulletin of the Polish Academy of Sciences : Technical Sciences     Open Access  
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 41)
China Communications     Full-text available via subscription   (Followers: 7)
Circuits and Systems     Open Access   (Followers: 14)
Consumer Electronics Times     Open Access   (Followers: 6)
Control Systems     Hybrid Journal   (Followers: 175)
Edu Elektrika Journal     Open Access  
Electronic Design     Partially Free   (Followers: 75)
Electronic Markets     Hybrid Journal   (Followers: 8)
Electronic Materials Letters     Hybrid Journal   (Followers: 2)
Electronics     Open Access   (Followers: 58)
Electronics and Communications in Japan     Hybrid Journal   (Followers: 8)
Electronics For You     Partially Free   (Followers: 62)
Electronics Letters     Hybrid Journal   (Followers: 24)
Embedded Systems Letters, IEEE     Hybrid Journal   (Followers: 40)
Energy Harvesting and Systems : Materials, Mechanisms, Circuits and Storage     Hybrid Journal   (Followers: 3)
Energy Storage Materials     Full-text available via subscription   (Followers: 1)
EPJ Quantum Technology     Open Access  
EURASIP Journal on Embedded Systems     Open Access   (Followers: 12)
Facta Universitatis, Series : Electronics and Energetics     Open Access  
Foundations and Trends® in Communications and Information Theory     Full-text available via subscription   (Followers: 7)
Foundations and Trends® in Signal Processing     Full-text available via subscription   (Followers: 5)
Frequenz     Hybrid Journal   (Followers: 1)
Frontiers of Optoelectronics     Hybrid Journal   (Followers: 1)
Geoscience and Remote Sensing, IEEE Transactions on     Hybrid Journal   (Followers: 135)
Haptics, IEEE Transactions on     Hybrid Journal   (Followers: 3)
IEEE Antennas and Propagation Magazine     Hybrid Journal   (Followers: 54)
IEEE Antennas and Wireless Propagation Letters     Hybrid Journal   (Followers: 47)
IEEE Journal of Emerging and Selected Topics in Power Electronics     Hybrid Journal   (Followers: 32)
IEEE Journal of the Electron Devices Society     Open Access   (Followers: 8)
IEEE Journal on Exploratory Solid-State Computational Devices and Circuits     Hybrid Journal   (Followers: 1)
IEEE Power Electronics Magazine     Full-text available via subscription   (Followers: 49)
IEEE Transactions on Antennas and Propagation     Full-text available via subscription   (Followers: 46)
IEEE Transactions on Automatic Control     Hybrid Journal   (Followers: 49)
IEEE Transactions on Circuits and Systems for Video Technology     Hybrid Journal   (Followers: 17)
IEEE Transactions on Consumer Electronics     Hybrid Journal   (Followers: 32)
IEEE Transactions on Electron Devices     Hybrid Journal   (Followers: 14)
IEEE Transactions on Information Theory     Hybrid Journal   (Followers: 26)
IEEE Transactions on Power Electronics     Hybrid Journal   (Followers: 55)
IEEE Transactions on Signal and Information Processing over Networks     Full-text available via subscription   (Followers: 7)
IEICE - Transactions on Electronics     Full-text available via subscription   (Followers: 14)
IEICE - Transactions on Information and Systems     Full-text available via subscription   (Followers: 7)
IET Microwaves, Antennas & Propagation     Hybrid Journal   (Followers: 16)
IET Power Electronics     Hybrid Journal   (Followers: 29)
IET Wireless Sensor Systems     Hybrid Journal   (Followers: 17)
IETE Journal of Education     Open Access   (Followers: 4)
IETE Journal of Research     Open Access   (Followers: 11)
IETE Technical Review     Open Access   (Followers: 11)
Industrial Electronics, IEEE Transactions on     Hybrid Journal   (Followers: 38)
Industry Applications, IEEE Transactions on     Hybrid Journal   (Followers: 9)
Informatik-Spektrum     Hybrid Journal   (Followers: 2)
Instabilities in Silicon Devices     Full-text available via subscription  
Intelligent Transportation Systems Magazine, IEEE     Full-text available via subscription   (Followers: 8)
International Journal of Advanced Research in Computer Science and Electronics Engineering     Open Access   (Followers: 16)
International Journal of Advances in Telecommunications, Electrotechnics, Signals and Systems     Open Access   (Followers: 7)
International Journal of Antennas and Propagation     Open Access   (Followers: 11)
International Journal of Applied Electronics in Physics & Robotics     Open Access   (Followers: 4)
International Journal of Computational Vision and Robotics     Hybrid Journal   (Followers: 4)
International Journal of Control     Hybrid Journal   (Followers: 13)
International Journal of Electronics     Hybrid Journal   (Followers: 3)
International Journal of Electronics & Data Communication     Open Access   (Followers: 11)
International Journal of Electronics and Telecommunications     Open Access   (Followers: 12)
International Journal of Granular Computing, Rough Sets and Intelligent Systems     Hybrid Journal   (Followers: 2)
International Journal of High Speed Electronics and Systems     Hybrid Journal  
International Journal of Image, Graphics and Signal Processing     Open Access   (Followers: 10)
International Journal of Nano Devices, Sensors and Systems     Open Access   (Followers: 6)
International Journal of Nanoscience     Hybrid Journal   (Followers: 1)
International Journal of Numerical Modelling: Electronic Networks, Devices and Fields     Hybrid Journal   (Followers: 3)
International Journal of Power Electronics     Hybrid Journal   (Followers: 14)
International Journal of Review in Electronics & Communication Engineering     Open Access   (Followers: 4)
International Journal of Sensors, Wireless Communications and Control     Hybrid Journal   (Followers: 7)
International Journal of Systems, Control and Communications     Hybrid Journal   (Followers: 4)
International Journal of Wireless and Microwave Technologies     Open Access   (Followers: 5)
International Journal on Communication     Full-text available via subscription   (Followers: 12)
International Journal on Electrical and Power Engineering     Full-text available via subscription   (Followers: 8)
International Transaction of Electrical and Computer Engineers System     Open Access   (Followers: 2)
Journal of Biosensors & Bioelectronics     Open Access   (Followers: 3)
Journal of Advanced Dielectrics     Open Access   (Followers: 1)
Journal of Artificial Intelligence     Open Access   (Followers: 8)
Journal of Circuits, Systems, and Computers     Hybrid Journal   (Followers: 3)
Journal of Computational Intelligence and Electronic Systems     Full-text available via subscription   (Followers: 1)
Journal of Electrical and Electronics Engineering Research     Open Access   (Followers: 16)
Journal of Electrical Bioimpedance     Open Access   (Followers: 2)
Journal of Electrical Engineering & Electronic Technology     Hybrid Journal   (Followers: 7)
Journal of Electromagnetic Analysis and Applications     Open Access   (Followers: 6)
Journal of Electromagnetic Waves and Applications     Hybrid Journal   (Followers: 5)
Journal of Electronic Design Technology     Full-text available via subscription   (Followers: 6)
Journal of Electronics (China)     Hybrid Journal   (Followers: 4)
Journal of Energy Storage     Full-text available via subscription  
Journal of Field Robotics     Hybrid Journal   (Followers: 2)
Journal of Guidance, Control, and Dynamics     Full-text available via subscription   (Followers: 131)
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: 6)
Journal of Microwaves, Optoelectronics and Electromagnetic Applications     Open Access   (Followers: 9)
Journal of Nuclear Cardiology     Hybrid Journal  
Journal of Optoelectronics Engineering     Open Access   (Followers: 2)
Journal of Physics B: Atomic, Molecular and Optical Physics     Hybrid Journal   (Followers: 31)
Journal of Power Electronics & Power Systems     Full-text available via subscription   (Followers: 9)
Journal of Semiconductors     Full-text available via subscription   (Followers: 3)
Journal of Sensors     Open Access   (Followers: 21)
Journal of Signal and Information Processing     Open Access   (Followers: 8)
Jurnal Rekayasa Elektrika     Open Access  
Learning Technologies, IEEE Transactions on     Hybrid Journal   (Followers: 14)
Magnetics Letters, IEEE     Hybrid Journal   (Followers: 7)
Majalah Ilmiah Teknologi Elektro : Journal of Electrical Technology     Open Access   (Followers: 1)
Metrology and Measurement Systems     Open Access   (Followers: 4)
Microelectronics and Solid State Electronics     Open Access   (Followers: 14)
Nanotechnology Magazine, IEEE     Full-text available via subscription   (Followers: 31)
Nanotechnology, Science and Applications     Open Access   (Followers: 4)
Networks: an International Journal     Hybrid Journal   (Followers: 5)
Open Journal of Antennas and Propagation     Open Access   (Followers: 5)
Optical Communications and Networking, IEEE/OSA Journal of     Full-text available via subscription   (Followers: 14)
Paladyn, Journal of Behavioral Robotics     Open Access  
Progress in Quantum Electronics     Full-text available via subscription   (Followers: 7)
Pulse     Full-text available via subscription   (Followers: 5)
Radiophysics and Quantum Electronics     Hybrid Journal   (Followers: 2)
Recent Patents on Electrical & Electronic Engineering     Full-text available via subscription   (Followers: 9)
Recent Patents on Telecommunications     Full-text available via subscription   (Followers: 2)
Research & Reviews : Journal of Embedded System & Applications     Full-text available via subscription   (Followers: 4)
Security and Communication Networks     Hybrid Journal   (Followers: 3)
Selected Topics in Applied Earth Observations and Remote Sensing, IEEE Journal of     Hybrid Journal   (Followers: 48)
Semiconductors and Semimetals     Full-text available via subscription   (Followers: 1)
Sensing and Imaging : An International Journal     Hybrid Journal   (Followers: 2)
Services Computing, IEEE Transactions on     Hybrid Journal   (Followers: 5)
Software Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 62)
Solid-State Circuits Magazine, IEEE     Hybrid Journal   (Followers: 11)
Solid-State Electronics     Hybrid Journal   (Followers: 7)
Superconductor Science and Technology     Hybrid Journal   (Followers: 2)
Synthesis Lectures on Power Electronics     Full-text available via subscription   (Followers: 3)
Technical Report Electronics and Computer Engineering     Open Access  
Telematique     Open Access  
TELKOMNIKA (Telecommunication, Computing, Electronics and Control)     Open Access   (Followers: 7)
Universal Journal of Electrical and Electronic Engineering     Open Access   (Followers: 6)
Visión Electrónica : algo más que un estado sólido     Open Access  
Wireless and Mobile Technologies     Open Access   (Followers: 5)
Women in Engineering Magazine, IEEE     Full-text available via subscription   (Followers: 12)
Електротехніка і Електромеханіка     Open Access  

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Journal Cover IEEE Transactions on Power Electronics
  [SJR: 3.005]   [H-I: 160]   [55 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0885-8993
   Published by IEEE Homepage  [191 journals]
  • IEEE Power Electronics Society
    • PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • IEEE Power Electronics Society
    • PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • A Series Resonant Filament Power Supply with Variable Structure and
           Oscillation-Free Switching Strategy for High-Voltage Accelerator
    • Authors: Yu Chen;Ni Zhang;Kai Wang;Jun Yang;Yong Kang;
      Pages: 8229 - 8236
      Abstract: Filament in a high-voltage accelerator needs to be fed by a power supply (PS) to emit electron beam. Rather than using traditional regulated transformer, power electronics converter is a better solution for such a PS. This letter proposes an optimized power electronics solution for such a PS. The primary side of the PS is placed far away from the filament to facilitate the assembly; and the high-frequency transformer is placed very close to the filament to reduce the conduction loss on the secondary-side wires. The PS is designed as a series resonant converter, so that the parasitic inductances and resistances of the wires, transformer, and filament can be fully utilized as resonant components. The H-bridge with zero-voltage switching is used, so that the thermal problem can be alleviated in the vacuum environment. The H-bridge is proposed to be operated in either half-bridge or full-bridge structure to narrow the switching frequency range. A special switching strategy is also proposed to eliminate the oscillation of voltage and current during structure switching, ensuring the safety operation of the converter and the stable vacuum environment around the filament. The designs are experimentally verified by a prototype.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • A High-Efficiency Asymmetrical Half-Bridge Converter With Integrated Boost
           Converter in Secondary Rectifier
    • Authors: Jung-Kyu Han;Jong-Woo Kim;Gun-Woo Moon;
      Pages: 8237 - 8242
      Abstract: A conventional asymmetrical half-bridge (AHB) converter is one of the most promising topologies in low-to-medium power applications because of zero-voltage switching of all switches and small number of components. However, when the converter is designed taking a hold-up time into consideration, it has a large DC offset current in a transformer and a small transformer turns-ratio. To solve these problems, a new AHB converter with an integrated boost converter is proposed in this letter. Because the proposed converter compensates for the hold-up time using the integrated boost converter without additional loss in the nominal state, it can achieve the optimized efficiency regardless of the hold-up time. The effectiveness and feasibility are verified with a 250–400-V input and 45 V/3.3 A output prototype.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • Comparison of Postfault Strategies for Current Reference Generation for
           Dual Three-Phase Machines in Terms of Converter Losses
    • Authors: Fernando Baneira;Jesús Doval-Gandoy;Alejandro G. Yepes;Óscar López;D. Pérez-Estévez;
      Pages: 8243 - 8246
      Abstract: Dual three-phase machines are attractive due to advantages such as inherent fault tolerance. Several strategies for current reference generation have been proposed to improve the postfault performance under open-phase fault. However, for the development and analysis of these strategies, only the stator winding losses were considered, but not the converter ones. In fact, there are no studies so far evaluating the converter losses during postfault operation. Aiming to fill this gap, this letter addresses this topic. Namely, it compares the main postfault control strategies in terms of converter losses for dual three-phase machines with sinusoidally distributed windings under single open-phase fault.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • Online Advanced Angle Adjustment Method for Sinusoidal BLDC Motors with
           Misaligned Hall Sensors
    • Authors: Joon Sung Park;Ki-Doek Lee;
      Pages: 8247 - 8253
      Abstract: This letter presents an improved approach for high performance operation of brushless dc (BLDC) motors with hall sensors. The hall sensors in BLDC motors are ideally placed 120 electrical degrees apart. However, hall sensor placement may be significantly incorrect, particularly in high-pole and small-sized motors. These misaligned hall sensors can cause serious torque ripple, and it can be difficult to apply advanced angle control. Therefore, a position error compensator is needed before an advanced angle control method is applied. In this letter, on the basis of the position error compensator, an online advanced angle adjustment method using input voltage and input current is proposed. Using the proposed method, balanced hall sensor signals can be obtained and the high-performance operation can be achieved. The effectiveness of the proposed approach is verified through experimental results.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • Errors of a Linear Current Approximation in High-Speed PMSM Drives
    • Authors: Leszek Jarzebowicz;
      Pages: 8254 - 8257
      Abstract: Current sampling techniques and predictive algorithms used in the digital control of electric drives rely on a simple mathematical model that assumes linear current changes upon constant supplying voltages. This paper identifies rotor movement as a factor that makes this assumption invalid when the rotor covers an angular distance of a few tens of degrees during the control interval duration. The errors of the linear current approximation were quantified both by simulation and by experiment for an exemplary high-speed permanent magnet synchronous motor drive.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • Six Degrees of Freedom Wide-Range Ubiquitous IPT for IoT by DQ Magnetic
    • Authors: Eun S. Lee;Jin S. Choi;Ho S. Son;Seung H. Han;Chun T. Rim;
      Pages: 8258 - 8276
      Abstract: Direct and quadrature (DQ) rotating magnetic-field-based transmitting (Tx) coils for wireless charging of multiple internet of things (IoT), which are broadly distributed over three-dimensional (3D) spaces, are newly proposed in this paper. The proposed Tx coils provide a uniformly distributed DQ magnetic field environment so that numerous IoT, such as active radio frequency identification (RFID) tag, electric shelf label (ESL), appliances, and various sensors connected to internet, are charged with 3-D omnidirectional wireless charging. By virtue of the generated DQ magnetic field, six degrees of freedom (6-DoF), regardless of their three-axes positions and directions, are achieved by the proposed Tx coils with plane receiving (Rx) coils, which is essential for the proposed ubiquitous wireless power environment. Therefore, the proposed wide-range ubiquitous inductive power transfer (IPT) is highly recommended for adoption in practical applications, where volumetric structures with large size of core are not allowed. The optimum distance between the DQ lines of the proposed Tx coils $d_{w}$ was found by magnetic field analysis to deliver maximum magnetic field $B_{t}$ at a target distance of $z_{{1}}$. To generate DQ currents and guarantee zero-voltage-switching operation of the main switches, detailed static analysis of the proposed DQ Class D inverter based on an imaginary gyrator model is presented. The effective area ratio of an Rx coil having a ferrite core is derived and experimentally found in this evenly distributed magnetic field condition. 1:20 and 1:1 scaled-prototypes for $d_{l}\,= \,{\text{10}}\;\text{m}$ and 5 m DQ line cases, respectively, were install-d on the ceiling and experimentally verified for the uniformity of magnetic field and the highest wireless power delivery freedom. Experimental results showed that the proposed IPT has 78% of uniformity for magnetic field and Rx coils are freely charged with a 6-DoF characteristic. Two hundred of Rx coils, which are arbitrarily distributed over 3-D space, can be simultaneously charged with 16.2 W of total received load power and 9.3% of power efficiency.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • An Approach for Switched Reluctance Generator in a Wind Generation System
           With a Wide Range of Operation Speed
    • Authors: Tárcio André dos Santos Barros;Pedro José dos Santos Neto;Paulo Sergio Nascimento Filho;Adson Bezerra Moreira;Ernesto Ruppert Filho;
      Pages: 8277 - 8292
      Abstract: This paper presents a complete approach for switched reluctance generator (SRG) in variable wind energy conversion systems. Two forms of direct power control (DPC) and a commutative system that allows SRG performance at a wide range of speed variations are proposed. Thus, more mechanical energy can be captured in wind generation. In the proposed structure, the SRG operates in a self-excited mode using a common dc bus system of a voltage source inverter connected to an electrical grid. DPCs are proposed by hysteresis of the SRG phase current for low-speed operation (DPC-LS) and by a single pulse of current for high-speed operation (DPC-HS). The low-pass filter employed to obtain the average power generated may slow down the response of the control system of the DPC applied to SRG. To improve the system performance, sliding mode controllers in DPCs were used. For operation throughout a wide speed range, the DPC-LS and DPC-HS controls should be joined. Therefore, a commutative system with smooth transition between DPC modes is proposed. Finally, simulations and experimental tests were conducted to verify the behavior of the proposed arrangement. The results confirmed correct operation of the proposed system.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • Boost-Type Power Factor Corrector With Power Semiconductor Filter for
           Input Current Shaping
    • Authors: Chung-pui Tung;Henry Shu-hung Chung;Ken Kuen-Faat Yuen;
      Pages: 8293 - 8311
      Abstract: This paper extends the application of a solid-state input current harmonic filtering technique, named as power semiconductor filter (PSF), for boost-type power factor corrector (PFC). The filtering technique is based on connecting an active device, namely, series pass device (SPD), in series with the input of the boost converter. By adjusting the control signal to the SPD, the input current of the PFC is profiled to be in phase with the supply voltage and regulate the output voltage. The power dissipation of the SPD is maintained at a low level by operating the SPD at the boundary between the linear and saturation regions. Modeling of the static and dynamical characteristics, design, and analysis of the entire system will be given. A 100 W, 85–265 Vac/400 Vdc PFC with the boost converter operating in discontinuous conduction mode has been built and evaluated. Experimental results reveal that the PSF can reduce the input current harmonics and improve the input power factor. They are in close agreement with the theoretical predictions. Finally, the conducted electromagnetic interference under different supply voltages will also be reported.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • A Transformerless Bipolar Modular Multilevel DC–DC Converter With
           Wide Voltage Ratios
    • Authors: Sixing Du;Bin Wu;
      Pages: 8312 - 8321
      Abstract: This paper presents a transformerless bipolar dc–dc converter based on series-connected submodules. It is intended for transforming dc voltage and managing power flow for medium/high-voltage dc grids. The dc–dc converter is composed of positive-pole and negative-pole subsystems, each of which consists of six arms/branches. Every two arms and one branch are constructed into a T-type circuit with the outer terminals interface to primary- and secondary-side dc buses. The two T-type circuits in one subsystem are connected in parallel to transmit power between primary and secondary sides. The transformerless structure (none bulky coupled inductors as well) solves the challengeable insulation and cooling issues of the extremely high-power magnetics in prior arts, while not sacrificing the power efficiency and system reliability. A $ \pm $ 10-kV 2-MW simulation model performed in MATLAB/Simulink verifies the feasibility of the bipolar dc–dc converter. Experimental results obtained from a laboratory setup also confirm the validation of the proposal.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • Class-E Half-Wave Zero dv/dt Rectifiers for Inductive Power Transfer
    • Authors: George Kkelis;David C. Yates;Paul D. Mitcheson;
      Pages: 8322 - 8337
      Abstract: This paper analyses and compares candidate zero dv/dt half-wave Class-E rectifier topologies for integration into multi-MHz inductive power transfer (IPT) systems. Furthermore, a hybrid Class-E topology comprising advantageous properties from all existing Class-E half-wave zero dv/dt rectifiers is analyzed for the first time. From the analysis, it is shown that the hybrid Class-E rectifier provides an extra degree of design freedom that enables optimal IPT operation over a wider range of operating conditions. Furthermore, it is shown that by designing both the hybrid and the current-driven rectifiers to operate below resonance provides a low deviation input reactance and inherent output voltage regulation with duty cycle allowing efficient IPT operation over wider dc load range than would otherwise be achieved. A set of case studies demonstrated the following performances: First, for a constant dc load resistance, a receiving end efficiency of 95% was achieved when utilizing the hybrid rectifier, with a tolerance in required input resistance of 2.4% over the tested output power range (50–200 W). Second, for a variable dc load in the range of 100–10%, the hybrid and current-driven rectifiers presented an input reactance deviation less than 2% of the impedance of the magnetizing inductance of the inductive link respectively and receiving end efficiencies greater than 90%. Third, for a constant current in the receiving coil, both the hybrid and the current-driven rectifier achieve inherent output voltage regulation in the order of 3% and 8% of the nominal value, respectively, for a variable dc load range from 100% to 10%.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • Passive Reactor Compensated Cascaded H-Bridge Multilevel LC-StatCom
    • Authors: Glen Farivar;Christopher David Townsend;Branislav Hredzak;Josep Pou;Vassilios G. Agelidis;
      Pages: 8338 - 8348
      Abstract: The cascaded H-bridge (CHB) low-capacitance StatCom (LC-StatCom) has a limited operating area in the inductive region compared to a conventional StatCom's V–I characteristic. This limitation for operation in the inductive region is considered to be the biggest disadvantage of CHB LC-StatCom. In this paper, the effect of adding parallel and series reactors on the LC-StatCom system's V–I characteristic is analyzed. Then, a new configuration, which fully compensates for the lost operating area of the LC-StatCom, is introduced. A scaled down single-phase seven-level laboratory prototype is used to confirm practicability of the proposed system.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • Ferrite-Less Circular Pad With Controlled Flux Cancelation for EV Wireless
    • Authors: Abiezer Tejeda;Claudio Carretero;John T. Boys;Grant A. Covic;
      Pages: 8349 - 8359
      Abstract: In this paper, a new ferrite-less wireless charging pad, called circular nonferrite pad, for roadway applications is introduced. The pad is characterized by having the ability to control leakage flux to reduce the electromagnetic fields outside the charging region. In addition, the pad shows low sensitivity to changes in the self-inductance due to secondary pad misalignment. A comparison of this new pad with similar-sized ferrite pads and single spiral couplers is presented. A formal mathematical description of the pad is shown here with finite element method simulations along with lab measurements to verify the validity of the models. The costs, advantages, and limitations of the new pad are also investigated.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • A Frequency Adaptive Phase Shift Modulation Control Based LLC Series
           Resonant Converter for Wide Input Voltage Applications
    • Authors: S. M. Showybul Islam Shakib;Saad Mekhilef;
      Pages: 8360 - 8370
      Abstract: This paper presents an isolated LLC series resonant DC/DC converter with novel frequency adaptive phase shift modulation control, which suitable for wide input voltage (200–400 V) applications. The proposed topology integrates two half-bridge in series on the primary side to reduce the switching stress to half of the input voltage. Unlike the conventional converter, this control strategy increases the voltage gain range with zero-voltage-switching (ZVS) to all switches under all operating voltage and load variations. Adaptive frequency control is used to secure ZVS in the primary bridge with regards to load change. To do so, the voltage gain becomes independent of the loaded quality factor. In addition, the phase shift control is used to regulate the output voltage as constant under all possible inputs. The control of these two variables also significantly minimizes the circulating current, especially from the low-voltage side, which increases the efficiency as compared to a conventional converter. Experimental results of a 1-Kw prototype converter with 200–400-V input and 48-V output are presented to verify all theoretical analysis and characteristics.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • A Simplified Space-Vector Modulation Algorithm for Four-Leg NPC Converters
    • Authors: Félix Rojas;Roberto Cárdenas;Ralph Kennel;Jon C. Clare;Matías Díaz;
      Pages: 8371 - 8380
      Abstract: To interface generation sources and loads to four-wire distribution networks it is important to use power converters and modulation methods, which provide high performance, flexibility, and reliability. To achieve these goals, this paper proposes a simple and efficient space vector modulation (SVM) algorithm in $\alpha \beta \gamma$ coordinates for neutral point clamped (NPC) converters. The proposed SVM method reduces a 3-D ($\alpha \beta \gamma$) search amongst modulating vectors into a simple 2-D ( $\alpha \beta$) problem. Moreover, the algorithm provides full utilization of the dc-link voltage and full utilization of the redundant vectors, and it can be applied to any other four-leg converter topology. The proposed SVM has been successfully validated using a 6-kW three-level four-leg NPC converter, achieving control over the voltages of the dc-link capacitors and a simple definition of the switching patterns for shaping the frequency spectrum.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • Control of Modular Multilevel Converter With Parallel
           Connectivity—Application to Battery Systems
    • Authors: Stefan M. Goetz;Zhongxi Li;Xinyu Liang;Chengduo Zhang;Srdjan M. Lukic;Angel V. Peterchev;
      Pages: 8381 - 8392
      Abstract: This paper presents a multiobjective real-time controller for a modular multilevel converter capable of parallel module connectivity, the so-called modular multilevel series parallel converter (MMSPC). The MMSPC topology allows the batteries to be dynamically rewired in various series–parallel configurations, generating a wide range of output voltage levels. The novel control method parallelizes the modules to balance their voltages without the need for individual module voltage monitoring. Additionally, the controller optimizes across the large number of feasible system configurations to minimize switching and conduction losses. Finally, the controller efficiently encodes the system configuration with module interconnection states rather than the module switch states, which substantially simplifies control. Furthermore, this work experimentally validates the MMSPC topology and concept. In the prototype, the parallel mode reduced the system losses at 5 kW output power by 18% and 24% for load power factors of 1.0 and 0.8, respectively. Sensorless balancing via parallelization maintained well-matched module voltages (standard deviation = 0.045 V) over a 5-h battery discharge with highly variable load current. The reduced conduction losses and simple balancing capability of the MMSPC can enable new applications at medium and low voltages that benefit from its high-quality output, elimination of filtering magnetics, fast response, and modularity.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • A Primary Full-Integrated Active Filter Auxiliary Power Module in
           Electrified Vehicles With Single-Phase Onboard Chargers
    • Authors: Ruoyu Hou;Ali Emadi;
      Pages: 8393 - 8405
      Abstract: In single-phase ac high-voltage (HV) battery chargers, as the input current is enforced to be varying sinusoidally in phase with the input voltage, the pulsating power at two times of the line frequency will be seen on the dc-link. Bulky capacitor bank or extra active filter (AF) circuits are needed to assimilate this harmonic current, which become a major barrier in terms of power density and cost. Sinusoidal charging method can be applied, while this might affect the charging efficiency and a deep study is still needed to further investigate on the impact to the Lithium-ion battery. An active filter auxiliary power module (AFAPM) based dual-mode dual-voltage charging system for vehicle application has been proposed. The AFAPM converter has two modes: the HV active filtering mode, in which the vehicle is connected to the grid and the converter assimilates the significant second-order harmonic current; and the low-voltage (LV) battery charging mode, in which the vehicle is running and the converter charges the LV battery from HV battery. However, a relay and inductors are still required in that converter to achieve the dual-mode operation. This paper proposes a primary full-integrated AFAPM for electrified vehicle applications with single-phase onboard chargers. The proposed AFAPM converter is composed of a two-phase bidirectional buck converter to work as an AF and a dual-active-bridge to operate as a LV battery charger auxiliary power module (APM). With the proposed converter, only an extra active energy storage capacitor is needed to achieve the active filtering. All the switches and inductors on the primary stage are shared between the AF and APM. Therefore, the use of a bulky capacitor bank or an additional AF circuit is avoided and, thus, the cost, size, and weight of the dual-voltage charging system in the electrified vehicle applications can be reduced. A 720-W prototype has been built to confirm the effectiveness of the proposed converter.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • Dynamic Voltage Restorer Using Switching Cell Structured Multilevel
           AC–AC Converter
    • Authors: Sanghun Kim;Heung-Geun Kim;Honnyong Cha;
      Pages: 8406 - 8418
      Abstract: Dynamic voltage restorer (DVR) technology has become a mature power quality product. In high-power applications, DVR using a multilevel converter is commonly used. However, DVR using a multilevel direct pulse width modulation (PWM) ac–ac converter has not been well studied. This paper presents a new DVR topology using a cascaded multilevel direct PWM ac–ac converter. In the proposed scheme, the unit cell of the multilevel converter consists of a single-phase PWM ac-ac converter using switching cell structure with coupled inductors. Therefore, the multilevel converter can be short- and open-circuited without damaging the switching devices. Neither lossy RC snubber nor a dedicated soft commutation strategy is required in the proposed DVR. This improves the reliability of the DVR system. The output voltage levels of the multilevel converter increase with the number of cascaded unit cells, and a high ac output voltage is obtained by using low-voltage-rating switching devices. Furthermore, a phase-shifted PWM technique is applied to significantly reduce the size of the output filter inductor. A 1-kW prototype of single-phase DVR is developed, and its performance is experimentally verified. Finally, the simulation results are shown for a three-phase DVR system.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • A Robust DC-Split-Capacitor Power Decoupling Scheme for Single-Phase
    • Authors: Wenli Yao;Poh Chiang Loh;Yi Tang;Xiongfei Wang;Xiaobin Zhang;Frede Blaabjerg;
      Pages: 8419 - 8433
      Abstract: Instead of bulky electrolytic capacitors, active power decoupling circuit can be introduced to a single-phase converter for diverting second harmonic ripple away from its dc source or load. One possible circuit consists of a half-bridge and two capacitors in series for forming a dc-split capacitor, instead of the usual single dc-link capacitor bank. Methods for regulating this power decoupler have earlier been developed, but almost always with equal capacitances assumed for forming the dc-split capacitor, even though it is not realistic in practice. The assumption should, hence, be evaluated more thoroughly, especially when it is shown in the paper that even a slight mismatch can render the power decoupling scheme ineffective and the IEEE 1547 standard to be breached. A more robust compensation scheme is, thus, needed for the dc-split capacitor circuit, as proposed and tested experimentally in the paper.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • Passive Islanding Detection Using Inverter Nonlinear Effects
    • Authors: David Díaz Reigosa;Fernando Briz;Cristian Blanco Charro;Juan M. Guerrero;
      Pages: 8434 - 8445
      Abstract: This paper analyzes the use of the voltage distortions in pulse width modulation voltage-source inverters caused by the inverter switching for islanding detection purposes. The nonideal characteristics of the inverters, mainly due to the dead time needed to have safe commutations, produce fundamental frequency-dependent harmonics (−5th, 7th, …) in the output voltage. These harmonic order are, in principle, an unwanted effect, as they reduce the power quality. However, they can potentially be used for islanding detection purposes. The physical principles of the method would be the same as for high-frequency signal injection methods that have already been proposed, but without the need of injecting a high-frequency signal, behaving, therefore, as a passive islanding detection technique.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • An Integrated Trap-LCL Filter With Reduced Current Harmonics for
           Grid-Connected Converters Under Weak Grid Conditions
    • Authors: Jingyang Fang;Xiaoqiang Li;Xu Yang;Yi Tang;
      Pages: 8446 - 8457
      Abstract: High-frequency current harmonics injected into the point of common coupling, mainly at the switching frequency and its multiples introduced by the modulation of grid-connected converters, should be limited to comply with grid codes. This requirement can be satisfied by using trap filters with LC-traps tuned at the switching frequency and its multiples in replacement of conventional L filters. However, all existing trap filters are subject to certain problems, e.g., sensitivity to grid impedance variation and decreased high-frequency roll-off rate. In view of this, this paper presents a trap-LCL filter with its parallel resonant LC-trap located on the converter side, named as LT-C-L filter. The modeling and analysis presented in this paper show that the LT-C-L filter can be the most promising trap filter due to its advantages such as high roll-off rate, robustness against parametric variations of grid impedance and passive damper, satisfactory harmonic attenuation at the switching frequency, reduction of converter current total-harmonic-distortion, and flexible design of filter components through magnetic integration. A single-phase ac/dc grid-connected converter prototype has been built and tested in the laboratory, and experimental results are presented to verify the superiority of the proposed filter.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • Two-Capacitor Transformer Winding Capacitance Models for Common-Mode EMI
           Noise Analysis in Isolated DC–DC Converters
    • Authors: Huan Zhang;Shuo Wang;Yiming Li;Qinghai Wang;Dianbo Fu;
      Pages: 8458 - 8469
      Abstract: For isolated dc–dc power converters, the interwinding parasitic capacitance of the transformer is usually one of the main paths for common-mode (CM) noise. In order to simplify the CM noise analysis, this paper proposes a two-capacitor transformer winding capacitance model. The model is derived based on general conditions so it can be applied to different isolated converter topologies. A measurement technique is also proposed to obtain the lumped capacitance for the model. The CM noise models of several isolated converter topologies are analyzed with the proposed two-capacitor transformer winding capacitance model to achieve simplicity. Finally, the proposed transformer winding capacitance model and measurement technique are verified by simulations and experiments.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • Improved PV Inverter Operating Range Using a Miniboost
    • Authors: Emanuel Serban;Francisco Paz;Martin Ordonez;
      Pages: 8470 - 8485
      Abstract: In the past two decades, the operating voltage of photovoltaic (PV) installation has increased in order to reduce current ratings and system installation costs. Such a large number of PV panels in series (e.g., 1000–1500 V systems) lead to wide variations of PV voltage due undesirable effects such as shading, soiling/dust, aging, and hot surface temperature. A partial shade would normally shut down solar inverters, unless a boost stage is added to the system input to ensure a proper dc-link operating voltage for the inverter. A boost input stage can double the input voltage operating range to extract maximum power under any possible shading and temperature condition. In this paper, a new PV string boost topology arrangement is proposed in the form of a miniboost used for three-phase grid-connected converters. The string miniboost increases the dc voltage range to extend power extraction under shading and low irradiance conditions and only requires to process a fraction of the rated power. The proposed cost-effective solution is further improved by using the inverter peak power envelope at boundary operation, resulting in expanded energy extraction beyond existing techniques. A design procedure to optimally size the miniboost and the peak-power envelope is presented along with a comparative analysis, under different irradiance levels, to illustrate the advantages in energy extraction obtained with the proposed PV string miniboost solution under low voltage and boundary operation. Furthermore, improved efficiency operation schemes and issues of common-mode current are discussed, and three mitigation design techniques intended for three-phase, three-level inverter transformerless topology are presented. Simulations and experimental results using a dual miniboost dc–dc stage and three-phase three-level neutral point clamped inverter are presented to validate the proposed dc-bus extension range and system design.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • A Novel Flower Pollination Based Global Maximum Power Point Method for
           Solar Maximum Power Point Tracking
    • Authors: J. Prasanth Ram;N. Rajasekar;
      Pages: 8486 - 8499
      Abstract: To maximize solar photovoltaic (PV) output under dynamic weather conditions, maximum power point tracking (MPPT) controllers are incorporated in solar PV systems. However, the occurrence of multiple peaks due to partial shading adds complexity to the tracking process. Even though conventional and soft computing techniques are widely used to solve MPPT problem, conventional methods exhibit limited performance due to fixed step size, whereas soft computing techniques are restricted by insufficient randomness after reaching the vicinity of maximum power. Hence, in this paper, a new flower pollination algorithm (FPA) with the ability to reach global peak is proposed. Optimization process in FPA method performs global and local search in single stage and it is a key tool for its success in MPPT application. The ruggedness of the algorithm is tested with zero, weak, and strong shade pattern. Further, comprehensive performance estimation via simulation and hardware are carried out for FPA method and are quantified with conventional perturb and observe and particle swarm optimization (PSO) methods. Results obtained with FPA method show superiority in energy saving and proved to be economical.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • PWM Converter Integrating Switched Capacitor Converter and Series-Resonant
           Voltage Multiplier as Equalizers for Photovoltaic Modules and
           Series-Connected Energy Storage Cells for Exploration Rovers
    • Authors: Masatoshi Uno;Akio Kukita;
      Pages: 8500 - 8513
      Abstract: Power systems for exploration rovers tend to be complex as three separate converters are necessary; in addition to a main dc–dc converter and cell equalizer for rechargeable energy storage cells, an equalizer for photovoltaic (PV) modules is desirably equipped in order to preclude negative impacts of partial shading. This paper proposes the pulse width modulation (PWM) converter integrating voltage equalizers for PV modules and energy storage cells. The proposed integrated converter comprises a switched capacitor converter, PWM buck converter, and series-resonant voltage multiplier that perform PV equalization, power conversion from the PV modules to the load, and cell equalization, respectively. Three converters can be integrated into a single unit with reducing the total switch counts, achieving not only system-level but also circuit-level simplifications. The derivation procedure of the integrated converter is explained, followed by the operation analysis. Experimental tests were performed using series-connected supercapacitor (SC) modules and solar array simulators to emulate a partial shading condition. With the integrated converter, the extractable maximum power from the PV modules significantly increased while voltage imbalance of SC modules was adequately eliminated, demonstrating the integrated performance of the proposed converter.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • Inductance-Emulating Control for DFIG-Based Wind Turbine to Ride-Through
           Grid Faults
    • Authors: Donghai Zhu;Xudong Zou;Lu Deng;Qingjun Huang;Shiying Zhou;Yong Kang;
      Pages: 8514 - 8525
      Abstract: For doubly fed induction generator (DFIG)-based wind turbines, the rotor side of DFIG is prone to suffering from overcurrent during grid faults, due to large electromotive force (EMF) induced in the rotor circuit. To solve this problem, this paper proposes an inductance-emulating control strategy for DFIG-based wind turbine to suppress the postfault rotor current, thereby enhancing its low-voltage ride through capability. Under the proposed control strategy, once the grid fault is detected, the rotor side converter (RSC) is controlled to emulate an inductance. Furthermore, with proper inductance value, both the required rotor voltage and postfault rotor current can be reduced within the permissible ranges of RSC, thus the controllability of control system can be maintained during transient process. Moreover, the oscillation of electromagnetic torque can be effectively suppressed during transient state of both grid fault and fault recovery. Finally, the simulation and experimental results are presented to demonstrate the effectiveness of the proposed method.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • Incorporation of Harmonic Injection in an Interleaved Flyback Inverter for
           the Implementation of an Active Anti-Islanding Technique
    • Authors: Dionisis Voglitsis;Nick Papanikolaou;Anastasios Ch. Kyritsis;
      Pages: 8526 - 8543
      Abstract: Over recent years, the output power of micro-inverters [module-incorporated inverter (MIC)] is progressively pushed to higher levels, following the current photovoltaic (PV) modules market trends. The interleaved Flyback inverter—under discontinuous conduction mode of operation (DCM)—is an appealing solution for PV applications which are based on MIC technology. This topology provides increased power level for distributed PV generation exploitation with simple control configuration, high efficiency, and reduced filter size. In this paper, the harmonic injection capability is incorporated into the interleaved Flyback inverter for the implementation of an active anti-islanding scheme. A suitable technical solution is proposed that bypasses the unfolding H-bridge, without affecting the active power generation of the inverter and without requiring any hardware modification. In addition, a mathematical model based on the instantaneous power balance theory is presented, being a powerful analysis tool for inverters operating under complete magnetic discharge such as the Flyback inverter (either conventional or interleaved) under DCM or boundary conduction mode of operation. The proposed model predicts accurately the steady-state operational behavior of the Flyback inverter under current harmonic injection, either in grid-tied or islanding operation. The proposed technical implementation method and mathematical model are verified through simulation and experimental results. Finally, an anti-islanding set-up based on the proposed harmonic injection technique is presented and implemented into the Flyback micro-inverter. The proposed set-up is verified through experimental results on various quality factor values, as well as for weak grid conditions.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • Single Switch Nonisolated Ultra-Step-Up DC–DC Converter With an
           Integrated Coupled Inductor for High Boost Applications
    • Authors: Yam P. Siwakoti;Frede Blaabjerg;
      Pages: 8544 - 8558
      Abstract: This paper introduces a new single-switch nonisolated dc–dc converter with very high voltage gain and reduced semiconductor voltage stress. The converter utilizes an integrated autotransformer and a coupled inductor on the same core in order to achieve a very high voltage gain without using extreme duty cycle. Furthermore, a passive lossless clamp circuit recycles the leakage energy of the coupled magnetics and alleviates the voltage spikes across the main switch. This feature along with low stress on the switching device enables the designer to use a low voltage and low RDS-on MOSFET, which reduces cost, as well as conduction and turn on losses of the switch. The principle of operation, theoretical analysis, and comparison supported by some key simulation and experimental results of a 500 W prototype are presented.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • A Sensorless Power Reserve Control Strategy for Two-Stage Grid-Connected
           PV Systems
    • Authors: Ariya Sangwongwanich;Yongheng Yang;Frede Blaabjerg;
      Pages: 8559 - 8569
      Abstract: Due to the still increasing penetration of grid-connected photovoltaic (PV) systems, advanced active power control functionalities have been introduced in grid regulations. A power reserve control, where namely the active power from the PV panels is reserved during operation, is required for grid support. In this paper, a cost-effective solution to realize the power reserve for two-stage grid-connected PV systems is proposed. The proposed solution routinely employs a maximum power point tracking control to estimate the available PV power and a constant power generation (CPG) control to achieve the power reserve. In this method, the solar irradiance and temperature measurements that have been used in conventional power reserve control schemes to estimate the available PV power are not required, and thereby, being a sensorless approach with reduced cost. Experimental tests have been performed on a 3-kW two-stage single-phase grid-connected PV system, where the power reserve control is achieved upon demands.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • A 2-kW Single-Phase Seven-Level Flying Capacitor Multilevel Inverter With
           an Active Energy Buffer
    • Authors: Yutian Lei;Christopher Barth;Shibin Qin;Wen-Chuen Liu;Intae Moon;Andrew Stillwell;Derek Chou;Thomas Foulkes;Zichao Ye;Zitao Liao;Robert C. N. Pilawa-Podgurski;
      Pages: 8570 - 8581
      Abstract: High-efficiency and compact single-phase inverters are desirable in many applications such as solar energy harvesting and electric vehicle chargers. This paper presents a 2-kW, 60-Hz, 450-V $ _{\text{DC}}$-to-240-V $_{\text{AC}}$ power inverter, designed and tested subject to the specifications of the Google/IEEE Little Box Challenge. The inverter features a seven-level flying capacitor multilevel converter, with low-voltage GaN switches operating at 120 kHz. The inverter also includes an active buffer for twice-line-frequency power pulsation decoupling, which reduces the required capacitance by a factor of 8 compared to conventional passive decoupling capacitors, while maintaining an efficiency above 99%. The inverter prototype is a self-contained box that achieves a high power density of 216 W/in $^3$ and a peak overall efficiency of 97.6%, while meeting the constraints including input current ripple, load transient, thermal, and FCC Class B EMC specifications.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • A High-Switching-Frequency Flyback Converter in Resonant Mode
    • Authors: Jianting Li;Frank B. M. van Horck;Bobby J. Daniel;Henk Jan Bergveld;
      Pages: 8582 - 8592
      Abstract: The demand of miniaturization of power systems has accelerated the research on high-switching-frequency power converters. A flyback converter in resonant mode that features low switching losses, less transformer losses, and low switching noise at high switching frequency is investigated in this paper as an alternative to a conventional quasi-resonant (QR) flyback topology to increase power density. In order to find a compromise between magnet size, electromagnetic interference (EMI), and efficiency, the concept utilizes the resonant behavior between transformer leakage inductance and snubber capacitor to achieve near-zero-voltage switching at both turn-on and turn-off of the primary switch, low core loss due to a continuous transformer magnetizing current, and reduced EMI due to low di/dt and dv/dt values. Meanwhile, the concept uses the regenerative snubber to recycle the transformer leakage energy with two snubber diodes and one snubber capacitor. The proposed concept has been validated on a 340-kHz 65-W prototype. Compared to the conventional QR flyback converter operating at the same switching frequency, the proposed concept has 2% efficiency improvement and better EMI performance.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • Confined Band Variable Switching Frequency Pulse Width Modulation (CB-VSF
           PWM) for a Single-Phase Inverter With an LCL Filter
    • Authors: Hussain A. Attia;Tan Kheng Suan Freddy;Hang Seng Che;Wooi Ping Hew;Ahmad H. El Khateb;
      Pages: 8593 - 8605
      Abstract: Variable switching frequency pulse width modulation (VSF PWM) has been proposed in the past to optimize the total harmonic distortion (THD) performance and switching losses of an inverter. Nevertheless, such VSF PWMs give rise to switching harmonics which vary across a wide frequency spectrum, where the lower frequencies could resonate with the filter while the upper frequency could exceed the maximum switching frequency. This complicates VSF PWM design, restricting their practical uses. In this paper, a confined band VSF PWM (CB-VSF PWM) for a single-phase inverter with an LCL filter is presented. By confining the switching frequencies within a practical band, the design of the filter becomes easier while maintaining low current THD with low switching losses. The choices of the upper and lower bands of the proposed VSF are defined and the design criterion is introduced. It is found that the proposed method allows reduction in switching losses as well as reduction in current THD when the effect of the LCL filter is taken into consideration. The performance analysis is validated through simulation and experimental results in a 1 kW inverter.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • Hybrid Dual and NPC Six-Phase Drive Systems
    • Authors: Victor Felipe Moura Bezerra Melo;Cursino Brandão Jacobina;Nady Rocha;Reuben Palmer Rezende de Sousa;Edgar Roosevelt Braga-Filho;
      Pages: 8606 - 8617
      Abstract: This paper presents two hybrid six-phase machine drive systems. The topologies are considered to be hybrid because two three-phase groups of the machine are fed by different types of converters. The purpose of these topologies is to be alternative configurations, being midway between the conventional six-leg two-level (2L) inverter, composed of 12 switches, and more complex structures, such as the six-leg three-level neutral point clamped (3L-NPC) inverter, composed of 24 switches and 12 clamping diodes, or the conventional 12-leg dual inverter, composed of 24 switches. One of the hybrid topologies is composed of 18 switches and the other is composed of 18 switches and 6 clamping diodes. A comparative study of harmonic distortion, semiconductor losses, and machine torque ripple is performed. Compared with the conventional 2L inverter, the proposed systems provide better performance in terms of harmonic distortion, overall semiconductor losses, and machine torque ripple and are less complex than dual and NPC inverters. Pulse width modulation (PWM) strategy is discussed and simulated. A modification in PWM strategy of the hybrid configurations is performed in order to obtain similar torque ripple to the cases when dual and 3L-NPC converters are used, even with lower number of semiconductor devices. Experimental results are also presented in order to validate the PWM strategy.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • An Asymmetric Three-Level Neutral Point Diode Clamped Converter for
           Switched Reluctance Motor Drives
    • Authors: Fei Peng;Jin Ye;Ali Emadi;
      Pages: 8618 - 8631
      Abstract: An asymmetric three-level neutral point diode clamped converter for switched reluctance motor drives is proposed in this paper. The modulation method, the dc-link voltage balancing algorithm, and the current control scheme of this converter are presented. The proposed three-level converter is compared with the conventional two-level asymmetric half-bridge converter in terms of cost, current ripple, noise, and power losses. Compared to the conventional two-level converter, the proposed three-level converter has much lower current ripple, lower noise, and higher efficiency. The effectiveness of the proposed converter is verified by both simulation and experimental results.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • Characterization of Input Current Interharmonics in Adjustable Speed
    • Authors: Hamid Soltani;Pooya Davari;Firuz Zare;Poh Chiang Loh;Frede Blaabjerg;
      Pages: 8632 - 8643
      Abstract: This paper investigates the interharmonic generation process in the input current of double-stage adjustable speed drives (ASDs) based on voltage-source inverters and front-end diode rectifiers. The effects of the inverter output-side low order harmonics, caused by implementing the double-edge symmetrical regularly sampled space vector modulation technique, on the input current interharmonic components are presented and discussed. Particular attention is also given to the influence of the asymmetrical regularly sampled modulation technique on the drive input current interharmonics. The developed theoretical analysis predicts the drive interharmonic frequency locations with respect to the selected sampling strategies. Simulation and experimental results on a 2.5 kW ASD system verify the effectiveness of the theoretical analysis.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • Direct Torque Control of Five-Phase Induction Motor With Common-Mode
           Voltage and Current Harmonics Reduction
    • Authors: Yogesh N. Tatte;Mohan V. Aware;
      Pages: 8644 - 8654
      Abstract: This paper proposes two direct torque control (DTC) strategies to reduce the common-mode voltage (CMV) in the five-phase induction motor driven by three-level five-phase inverter. In each technique, 31 voltage vectors consisting of 30 nonzero voltage vectors, and a zero voltage vector are selected out of available 243 voltage vectors. The selection of these voltage vectors are based on their capabilities of reducing the CMV, eliminating the x–y stator flux and maintaining the torque ripple under control. The ten large, ten small, and a zero voltage vector are same in both schemes, however only difference in designing the control strategy for the two schemes is the utilization of different ten medium voltage vectors. First proposal (DTC-I) reduces the CMV to $3V_{{\rm{dc}}}\,/ 10$ and second proposal (DTC-II) reduces to $V_{{\rm{dc}}}\,/ 10$. These schemes are compared with DTC technique of five-phase induction motor fed by two-level five-phase inverter in order to judge the capabilities of proposed schemes in context of reducing the CMV. The simulation and experimental results validate the proposed DTC techniques.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • Modulation Techniques for Enhanced Reduction in Common-Mode Voltage and
           Output Voltage Distortion in Indirect Matrix Converters
    • Authors: Varsha Padhee;Ashish Kumar Sahoo;Ned Mohan;
      Pages: 8655 - 8670
      Abstract: This paper targets the reduction of common-mode voltage in an indirect matrix converter (IMC) through an intelligent space-vector-based modulation technique. This mode of control results in lower dV/dt at the motor terminals, thereby, reducing voltage stress to windings; and reduced output voltage distortion resulting in lower machine losses. The conventional indirect space vector pulse-width modulation method of controlling matrix converters involves independent control of either the rectifying stage or the inverting stage of the converter. However, in this paper, by suitable selection of space vectors, the rectifying stage of the matrix converter generates different levels of virtual dc-link voltage. Therefore, the responsibility of formulating output voltages with a particular magnitude and frequency, which can be translated to different machine speeds, has been transferred solely to the rectifying stage of the IMC. Estimation of the degree of distortion in the three-phase output voltage is another facet discussed in this paper, which aids the sizing and designing of output passive filters. The analysis of output voltage distortion and the proposed modulation strategies have been substantiated by simulations in MATLAB/Simulink and experimentally verified on a scaled down laboratory prototype.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • Instantaneous Torque Control Method With Rated Torque-Sharing Ratio for
           Cascaded DFIMs
    • Authors: Ghasem Esfandiari;Mohammad Ebrahimi;Ahmadreza Tabesh;
      Pages: 8671 - 8680
      Abstract: This paper presents an instantaneous torque control method for cascaded doubly fed induction machines (CDFIMs) with a rated torque-sharing ratio feature under steady-state operation. A CDFIM includes two coupled main and auxiliary doubly fed induction machines, and the rated torque-sharing ratio herein means that the machine torques are proportional to the machine ratings. The proposed method is established based on transferring the torque equations of the two machines into the rotor-flux reference frame of the auxiliary machine. Then, the instantaneous torque and the rated torque-sharing ratio are controlled via the stator current components of the auxiliary machine, while machine fluxes are within allowable ranges. To verify the method and evaluate its capabilities, the suggested method is used for the speed control of a CDFIM experimental setup including two 4-kW doubly fed induction machines and a 4-kW dc machine to apply a sudden mechanical load change to the CDFIM. Further, a case study including 12-kW and 4-kW DFIMs is also simulated to evaluate the performance of the torque control method for a CDFIM with different machine ratings. The test results confirm that the proposed control schemes achieve the desired performances without exceeding the ratings of the machines under various test scenarios.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • From Chip to Converter: A Complete Cost Model for Power Electronics
    • Authors: Gabriel Domingues-Olavarría;Pontus Fyhr;Avo Reinap;Mats Andersson;Mats Alaküla;
      Pages: 8681 - 8692
      Abstract: The unified knowledge on power converter design and manufacturing technology establishes a powerful tool, where the cost and topology realization can be analyzed simultaneously. This paper collects the design practice and cost estimation of various components in a power electronics converter and unites that to a choice of the assembling and manufacturing processes and resulting cost of the complete converter. The outcome of this work specifies the power converter at predefined power level and cooling condition and demonstrates the cost drivers of the complete unit depending on production volumes. As a case study, the cost of an inverter for a full electric or hybrid vehicle application is estimated and the results are compared with figures available in the literature, yielding the conclusion that the validity of such figures is highly dependent on production volumes and power levels. The essence of this paper is a set of general, reliable, and fast design models and production charts, in accordance with realistic cost estimates for the sake of system optimization and development of cost effective electric drives from small series to large volumes.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • Energy Efficient Heat Sink Design: Natural Versus Forced Convection
    • Authors: Daniel Christen;Milos Stojadinovic;Juergen Biela;
      Pages: 8693 - 8704
      Abstract: In highly efficient converter systems, the power consumption of the cooling system (fans) significantly influences the total system efficiency as well as the power density. This paper investigates the potential of free convection cooled heat sinks and compares their performance to forced convection cooled heat sinks on the basis of their volume and power consumption. Underlying theoretical concepts for both types of cooling systems are summarized and their application in an optimization procedure is presented. The theoretical concepts are validated with prototype heat sinks. Finally, at an example of a half-bridge converter, it is shown that by free convection cooling, not only the efficiency but also the power density can be increased. In this case, by paralleling semiconductor devices the losses decrease approximately by a factor of three while simultaneously the heat sink volume can be reduced by approximately 50%.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • Very High Frequency IVR for Small Portable Electronics With High-Current
           Multiphase 3-D Integrated Magnetics
    • Authors: Dongbin Hou;Fred C. Lee;Qiang Li;
      Pages: 8705 - 8717
      Abstract: As today's small portable electronics (smartphones, tablets, e-readers, etc.) becomes lighter, thinner, quicker, and smarter, the voltage regulator for the processor is expected to be efficient, miniaturized, integrated, and placed closer to the processor. In this paper, a concept of a very high frequency [tens of megahertz (MHz)] three-dimensional integrated voltage regulator (IVR) for small portable electronics is proposed. The magnetic characterization technique at tens of MHz is investigated, and the issues of and solutions for permeability and loss measurement are demonstrated. The LTCC and NEC flake materials are characterized and compared for the IVR inductor development. Both single-phase and five-phase integrated inductors are designed, fabricated, and experimentally tested at 20 MHz, featuring a simple single-via winding structure, small size, ultralow profile, ultralow DC resistance (DCR), high current-handling ability, air-gap-free magnetics, multiphase integration within one magnetic core, and lateral nonuniform flux distribution.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • A Lifetime Prediction Method for LEDs Considering Real Mission Profiles
    • Authors: Xiaohui Qu;Huai Wang;Xiaoqing Zhan;Frede Blaabjerg;Henry Shu-Hung Chung;
      Pages: 8718 - 8727
      Abstract: The light-emitting diode (LED) has become a very promising alternative lighting source with the advantages of longer lifetime and higher efficiency than traditional ones. The lifetime prediction of LEDs is important to guide the LED system designers to fulfill the design specifications and to benchmark the cost-competitiveness of different lighting technologies. However, the existing lifetime data released by LED manufacturers or standard organizations are usually applicable only for some specific temperature and current levels. Significant lifetime discrepancies may be seen in the field operations due to the varying operational and environmental conditions during the entire service time (i.e., mission profiles). To overcome the challenge, this paper proposes an advanced lifetime prediction method, which takes into account the field operation mission profiles and also the statistical properties of the life data available from accelerated degradation testing. The electrical and thermal characteristics of LEDs are measured by a T3Ster system, used for the electrothermal modeling. It also identifies key variables (e.g., heat sink parameters) that can be designed to achieve a specified lifetime and reliability level. Two case studies of an indoor residential lighting and an outdoor street lighting application are presented to demonstrate the prediction procedures and the impact of different mission profiles on the lifetime of LEDs.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • Topology and Control Innovation for Auxiliary Power Supply in Dimmable LED
    • Authors: Liang Jia;Yan-Fei Liu;
      Pages: 8728 - 8742
      Abstract: In this paper, a cost-effective architecture based on Flyback topology is proposed for both constant current (CC) output for LED drive and constant voltage (CV) output for auxiliary (AUX) supply. A novel nonlinear ramp-based control scheme is proposed to decouple the main CC power train from the CV AUX supply and avoid LED output flickering. Small signal modeling is presented to highlight the advantages of this control scheme over conventional peak current mode control. This scheme has been implemented successfully for a 40-W dimmable LED driver with a 12-V 3-W AUX supply.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • All-GaN-Integrated Cascode Heterojunction Field Effect Transistors
    • Authors: Sheng Jiang;Kean Boon Lee;Ivor Guiney;Pablo F. Miaja;Zaffar H. Zaidi;Hongtu Qian;David J. Wallis;Andrew J. Forsyth;Colin J. Humphreys;Peter A. Houston;
      Pages: 8743 - 8750
      Abstract: All-GaN-integrated cascode heterojunction field effect transistors were designed and fabricated for power switching applications. A threshold voltage of +2 V was achieved using a fluorine treatment and a metal–insulator–semiconductor gate structure on the enhancement mode part. The cascode device exhibited an output current of 300 mA/mm by matching the current drivability of both enhancement and depletion mode parts. The optimization was achieved by shifting the threshold voltage of the depletion mode section to a more negative value with the addition of a dielectric layer under the gate. The switching performance of the cascode was compared to the equivalent GaN enhancement-mode-only device by measuring the hard switching speed at 200 V under an inductive load in a double pulse tester. For the first time, we demonstrate the switching speed advantage of the cascode over equivalent GaN enhancement-mode-only devices, due to the reduced Miller-effect and the unique switching mechanisms. These observations suggest that practical power switches at high power and high switching frequency will benefit as part of an integrated cascode configuration.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • Impact of PWM Duty Cycle Jitter on Switching-Mode Power Converter
    • Authors: Feng-Yu Wu;Yaow-Ming Chen;
      Pages: 8751 - 8762
      Abstract: The objective of this paper is to propose an efficiency model to evaluate the impact of the pulse width modulation (PWM) duty cycle jitter on the efficiency of switching-mode power converter. By taking the product of two perturbation terms into consideration, which is ignored in the conventional average small-signal model, the average efficiency model is proposed first. Due to the nonlinear characteristic of the PWM generator, the multifrequency efficiency model is also developed by considering the sideband frequency. Three different perturbation waves are induced to the control loop of the converter to generate the jitter to observe its impact on the efficiency. The mathematical expression of the efficiency drop based on the proposed multifrequency model is derived. The reason of control-to-output gain's magnitude spike on the Bode plot can be explained by the derived equations. Eventually, the methods to reduce the efficiency drop caused by the jitter are suggested. In spite of various perturbation frequencies, amplitudes, and waveforms, the mathematical calculation, the computer simulation, and the hardware measurement of the efficiency drop are consistent which validate the accuracy of the proposed multifrequency efficiency model.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • Sensor-Less Current Sharing Over Wide Operating Range for
           Extended-Duty-Ratio Boost Converter
    • Authors: Jinia Roy;Raja Ayyanar;
      Pages: 8763 - 8777
      Abstract: An extended-duty-ratio (EDR) boost converter is studied extensively in this paper for high voltage gain applications with a wide input (and/or output) voltage range. The EDR is a unique combination of an interleaved, multiphase boost converter and switched capacitor configuration that achieves high voltage gain with significantly lower switch voltage stress and switching losses compared to conventional high-gain solutions. Most of the switches in the multiphase EDR experience only a fixed fraction of the output voltage ($1/M, 2/M$ , etc., where $M$ is the number of phases). Through extensive analysis over a wide operating range, it is shown here that the EDR boost converter has inherent current sharing among the phases only in a limited range of duty ratio— $(M-1)/M \leq D \leq 1$. As the duty ratio reduces beyond this range as required in wide input voltage applications, inherent current sharing property is lost. In this paper, techniques to ensure current sharing under all operating zones without requiring current sensors are presented. Instead of having equal duty ratio for each phase, it is adjusted for each phase according to the operating region of the converter. Extensive analysis is presented to derive the required duty ratio changes for the different phases. The proposed concept is validated with experimental results from a 250 W, 3-phase EDR boost, and GaN-based hardware prototype.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • Capacitive Power Transfer System With a Mixed-Resonant Topology for
           Constant-Current Multiple-Pickup Applications
    • Authors: Yu-Gang Su;Shi-Yun Xie;Aiguo Patrick Hu;Chun-Sen Tang;Wei Zhou;Liang Huang;
      Pages: 8778 - 8786
      Abstract: Capacitive power transfer (CPT) systems based on high-frequency electric field coupling have attracted much attention recently due to their simplicity and low eddy-current losses. This paper proposes a mixed-resonant topology consisted of a Π-CLC resonant circuit on the primary side and a T-CLC circuit on the secondary side for multiple pickups constant current output applications. The voltage gain, current gain, and zero phase angle frequency at different operating modes of Π-CLC and T-CLC circuits are analyzed by fundamental frequency approximation, and the conditions leading to a constant output current independent of loads are determined. Based on the analysis, a design method to determine the resonant network parameters is proposed according to the required output current of each pickup. A prototype with three pickups has been designed and built, and both simulation and experimental results have demonstrated that the proposed multiple-pickup CPT system can output a constant current at each operating power pickup against the load variations of itself and others.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • Bilinear Discrete-Time Modeling and Stability Analysis of the Digitally
           Controlled Dual Active Bridge Converter
    • Authors: Ling Shi;Wanjun Lei;Zhuoqiang Li;Jun Huang;Yao Cui;Yue Wang;
      Pages: 8787 - 8799
      Abstract: Dual active bridge (DAB) converters have been widely used in distributed power systems and energy storage equipment. However, the inherent nonlinearity of the DAB converters can cause stability problem, such as output voltage oscillation. In this paper, the dynamic behavior and stability of a digitally controlled DAB converter with a closed-loop controller are studied. First, to accurately study the nonlinear dynamics and stability in a DAB converter, a bilinear discrete-time model considering the output capacitor equivalent series resistance (ESR) and the digital control delay in circuit is established. Based on the model, the nonlinear dynamic characteristic and stability of the DAB converter versus the control parameter are studied. Furthermore, extensive analyses are performed to study the effect of the transformer leakage inductance and the output capacitor ESR on the stability boundaries of the control parameter. The accuracy of the model and the theoretical analyses are validated by simulation and experimental results. The proposed model of the digitally controlled DAB converter can accurately predict the stability boundaries, which can be effectively applied to the design of the system parameters and guarantee stable operation of the converter.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • Sinusoidal Input Current Discontinuous Conduction Mode Control of the
           VIENNA Rectifier
    • Authors: Michael Leibl;Johann W. Kolar;Josef Deuringer;
      Pages: 8800 - 8812
      Abstract: During light load conditions unidirectional power factor correction rectifiers, such as the VIENNA rectifier, enter discontinuous conduction mode, causing the relationship between average half-bridge voltage and duty cycle to become nonlinear and synchronously sampled current measurements not equaling the switching period average. Combined, these measurement and actuation errors result in distorted input currents at light load if no additional measures are taken. This work presents a control scheme that leads to low total harmonic distortion of the input currents in discontinuous conduction mode without relying on current measurements. The analytic expressions for the duty cycles and the threshold between discontinuous and continuous conduction mode are derived, the capability of supplying asymmetric loads is investigated and the effect on the noise spectrum relevant for the electromagnetic interference filter design is studied. Measurements of efficiency, total harmonic distortion, and conducted electromagnetic interference in discontinuous and continuous conduction mode are obtained on a 65 kW prototype operating at 290 to 530 V line-to-line RMS mains voltage range and supplying 800 V dc output voltage. The prototype, which is optimized for pulse load applications, achieves a power density of 9.56 kW/dm3 (157 W/in3) and 97.2 % efficiency at full load using 650 V Si insulated gate bipolar transistor (IGBTs) with 28 kHz switching frequency.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • SiC-Based Z-Source Resonant Converter With Constant Frequency and Load
           Regulation for EV Wireless Charger
    • Authors: Hulong Zeng;Fang Z. Peng;
      Pages: 8813 - 8822
      Abstract: Traditional load regulation methods for a resonant converter mainly rely on frequency modulation. It is always a tradeoff between the design of the resonant network and the range of load. Especially for wireless power transfer (WPT) systems, the resonant network usually has a high quality factor. Small variation on frequency leads to huge drop in gain and efficiency. Due to this problem, many WPT systems are unregulated and they need one or two more front-end stages to regulate the dc bus voltage and perform power factor correction (PFC). In order to lower the cost and complexity of two- or three-stages structure, a single-stage solution with a silicon carbide (SiC) based Z-source resonant converter (ZSRC) was recently proposed. The Z-source network provides high reliability as being immune to shoot-through problems. Additionally, a ZSRC can boost the dc bus voltage while the traditional voltage-source inverter can only produce a lower voltage. However, the load regulation of this new topology has not been addressed. Two effective load regulation methods with constant frequency are presented for this SiC-based ZSRC specifically. Operation principle of the two load regulation methods are described in this paper. Experimental results based on a 200-W scale-down prototype with a full-bridge series resonant dc–dc converter are presented to illustrate the mechanism of these two methods.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • Single-Step Current Control for Voltage Source Inverters With Fast
           Transient Response and High Convergence Speed
    • Authors: Lanhua Zhang;Hongbo Ma;Rachael Born;Xiaonan Zhao;Jih-Sheng Lai;
      Pages: 8823 - 8832
      Abstract: Current control loop response in voltage source inverters impacts the quality of output current and output voltage waveforms. Parabolic current control provides a fast transient response with approximate-constant switching frequency, solving the frequency variation problem of hysteresis current control. This makes it a good candidate for the current control loop of voltage source inverters to achieve a good system performance. Yet, parabolic current control is often implemented with digital-to-analog converters, analog comparators, and field-programmable gate array circuits where increasing switching frequency pushes update speed and bandwidth requirements. Concurrently, even if the transient response of parabolic current control is fast, it can still take up several switching cycles converging to steady state. In order to solve both problems, a new current control strategy, motivated by the convergence analysis of parabolic current control but with a convergence process that takes just one switching operation, is proposed: single-step current control. Since single-step current control samples two data points in a switching cycle instead of using continuous parabolic carriers, it can be easily implemented in a digital microcontroller then high switching frequency can be achieved. The small signal model, dead-time compensation, and stability analysis are also studied in this paper. The convergence speed of the algorithm is verified with experimental hardware prototype and the transient performance of the designed voltage source inverter meets expectation.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • Model-Based Dead Time Optimization for Voltage-Source Converters Utilizing
           Silicon Carbide Semiconductors
    • Authors: Zheyu Zhang;Haifeng Lu;Daniel J. Costinett;Fred Wang;Leon M. Tolbert;Benjamin J. Blalock;
      Pages: 8833 - 8844
      Abstract: Dead time significantly affects the reliability, power quality, and efficiency of voltage-source converters. For silicon carbide (SiC) devices, considering the high sensitivity of turn-off time to the operating conditions (> 5× difference between light load and full load) and characteristics of inductive loads (> 2× difference between motor load and inductor), as well as large additional energy loss induced by the freewheeling diode conduction during the superfluous dead time (∼15% of the switching loss), then the traditional fixed dead time setting becomes inappropriate. This paper introduces an approach to adaptively regulate the dead time considering the current operating condition and load characteristics via synthesizing online monitored turn-off switching parameters in the microcontroller with an embedded preset optimization model. Based on a buck converter built with 1200-V SiC MOSFETs, the experimental results show that the proposed method is able to ensure reliability and reduce power loss by 12% at full load and 18.2% at light load (8% of the full load in this case study).
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • Sensorless Control of BLDCM Drive for a High-Speed Maglev Blower Using
           Low-Pass Filter
    • Authors: Shaohua Chen;Gang Liu;Shiqiang Zheng;
      Pages: 8845 - 8856
      Abstract: This paper develops the brushless dc motor sensorless control strategy for a high-speed maglev blower. The sensorless techniques are based on a phase voltage comparator and a nonlinear offline compensator. The nonlinear offline compensator is used to compensate for the phase delay of the back electromotive force due to a low-pass filter; the phase voltage comparator is used to compensate for variations of the phase due to changes in the load, calculation error, and unbalance of three-phase motor stator. The commutation mode based on the transition between “$60 - \phi $,” “ $120 - \phi $,” and “ $180 - \phi $” by detecting the total delay angle, the process of start-up, and the antidisturbance capability is described in detail. Some experiments are implemented on a single-chip DSP controller to demonstrate the feasibility of the suggested sensorless and the good anti-interference property.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • Active Suppression of Selected DC Bus Harmonics for Dual Active Bridge
           DC–DC Converters
    • Authors: Jan Riedel;Donald G. Holmes;Brendan P. McGrath;Carlos Teixeira;
      Pages: 8857 - 8867
      Abstract: AC coupled dual active bridge (DAB) dc–dc converters typically use phase shifted square wave (PSSW) modulation to manage the power flow between two dc sources. With this scheme, the current flowing between the converter bridges injects high-magnitude current harmonics into each dc port at multiples of the primary switching frequency, which can excite resonances in the $LC$ circuits created by parasitic second-order impedances such as wiring inductances in the dc-link connections. This can cause substantial dc bus voltage and current oscillations, particularly with the higher switching frequencies that are used with wide bandgap devices, leading to excessive electromagnetic interference, significant filter stress, and eventual component operational failure. Conventionally, a relatively large dc bus filter capacitor (or inductor) helps to suppress these dc bus harmonic dynamics. However, the use of adaptive three-level modulation for a single phase DAB provides a much greater solution space to achieve a desired power transfer condition, with the three PSSW control angles that are available. This paper now explores the additional use of these angles to selectively suppress particular dc bus current harmonics across the entire operating range of the converter and thus allow the size of the DAB dc bus bridge capacitors to be minimized. This new active harmonic suppression (AHS) strategy is validated by theory, simulation, and matching experimental results.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • Bifurcation and Large-Signal Stability Analysis of Three-Phase Voltage
           Source Converter Under Grid Voltage Dips
    • Authors: Meng Huang;Yu Peng;Chi K. Tse;Yushuang Liu;Jianjun Sun;Xiaoming Zha;
      Pages: 8868 - 8879
      Abstract: Three-phase voltage source converters (VSCs) are commonly used as power flow interface in ac/dc hybrid power systems. The ac power grid suffers from unpredictable short-circuit faults and power flow fluctuations, causing undesirable grid voltage dips. The voltage dips may last for a short time or a long duration, and vary the working conditions of VSCs. Due to their nonlinear characteristics, VSCs may enter abnormal operating mode in response to voltage dips. In this paper, the transient response of three-phase VSCs under practical grid voltage dips is studied and a catastrophic bifurcation phenomenon is identified in the system. The converter will exhibit an irreversible instability after the dips. The expanded magnitude of ac reactive current may cause catastrophic consequence for the system. A full-order eigenvalue analysis and a reduced-order mixed-potential-theory-based analysis are adopted to reveal the physical origin of the large-signal instability phenomenon. The key parameters of the system are identified and the boundaries of instability are located. The bifurcation phenomenon and a set of design-oriented stability boundaries in some chosen parameter space are verified by cycle-by-cycle simulations and experimental measurement on a practical grid-connected VSC prototype.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • Experimental Evaluation of Internal Model Control Scheme on a DC–DC
           Boost Converter Exhibiting Nonminimum Phase Behavior
    • Authors: Tarakanath Kobaku;Sachin C. Patwardhan;Vivek Agarwal;
      Pages: 8880 - 8891
      Abstract: In this work, an internal model controller (IMC) with two-degree-of-freedom has been implemented as a voltage mode controller for the output voltage regulation of a boost-type dc–dc converter that exhibits nonminimum phase behavior due to occurrence of a right-half plane (RHP) zero. The IMC structure provides an alternate parameterization of the conventional feedback controller and is comparatively simple to tune to achieve satisfactory servo and regulatory behavior that are close to the performance limits set by the RHP zero. An internal model controller was designed using a linear model developed in the neighborhood of a nominal operating point for the converter. To assess the efficacy of the IMC scheme, simulation studies and experimental evaluations were carried. In majority of the problems investigated, the IMC was found to perform significantly better than a PID designed using the conventional approach. The responses obtained using the experimental setup were found to match closely with the responses obtained using the nonlinear dynamic model based closed-loop simulations, which corroborated the conclusions reached through the simulations. Thus, the simulation as well as experimental studies indicated that the IMC scheme is ideally suited for controlling a boost-type dc–dc converter exhibiting the nonminimum phase behavior.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • Lifetime-Based Power Routing of a Quadruple Active Bridge DC/DC Converter
    • Authors: Giampaolo Buticchi;Markus Andresen;Mathias Wutti;Marco Liserre;
      Pages: 8892 - 8903
      Abstract: Medium-voltage dc/dc converters have recently acquired importance in the smart grid and dc distribution framework. However, several open issues remain with regard to the reliability of such systems. This paper proposes a modular isolated dc/dc converter with multiple quadruple active bridge building blocks. This design, in combination with a virtual resistor-based control, weights the paths depending on the components wear-out and can balance the stress of the semiconductors in the attempt of extending overall system lifetime. The effectiveness of the approach is demonstrated in simulations and supported with measurements on a small-scale demonstrator with open modules, built in order to verify in real time the capability of controlling the thermal stress of the semiconductors.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • DQ Current Control of Voltage Source Converters With a Decoupling Method
           Based on Preprocessed Reference Current Feed-forward
    • Authors: Sizhan Zhou;Jinjun Liu;Linyuan Zhou;Yan Zhang;
      Pages: 8904 - 8921
      Abstract: Axes cross-coupling in dq-frame will deteriorate the current control performance, especially for applications with low switching/sampling frequency. Decoupling methods based on inductor current state feedback and complex vector proportional-integrator controllers are usually performed to solve this problem. In this paper, an alternative decoupling method based on preprocessed reference current feed-forward is proposed, which can provide excellent decoupling performance even with considerable control delay. The current control of grid-connected voltage source converters is analyzed with complex-coefficient transfer functions. It is revealed that the decoupling performance of current control schemes is closely related to the symmetry of current closed-loop transfer function bode diagrams. The current closed-loop transfer function should show a standard symmetrical bode diagram with respect to 0 Hz, if axes cross-coupling is well decoupled. A quantitative index named cross-coupling function is then proposed to analyze and comprehensively compare the decoupling performance of the proposed method and existing ones in terms of the influence of the control delay, inductance estimation error, grid frequency deviation, and voltage disturbance. Experimental tests are implemented to validate the performance of the proposed method and comparison results.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • Passivity-Based Stability Analysis and Damping Injection for
           Multiparalleled VSCs with LCL Filters
    • Authors: Xiongfei Wang;Frede Blaabjerg;Poh Chiang Loh;
      Pages: 8922 - 8935
      Abstract: This paper addresses the harmonic stability resulting from the current-control interactions of the multiparalleled, LCL-filtered voltage-source converters. First, an alternative impedance model is proposed for the single-loop current control. The control output admittance of the converter is decomposed into a passive filter output admittance in series with an active admittance, which is dependent on the current controller and the time delay. The frequency-domain passivity theory is then applied to the active admittance for system stability analysis. It reveals that the stability region of the single-loop grid current control is not only dependent on the time delay, but affected also by the resonance frequency of the converter-side filter inductor and filter capacitor. Further on, the damping injection based on the discrete derivative controller is proposed to enhance the passivity of individual converters and thereby stabilizing the paralleled converters. Finally, simulation studies and laboratory tests validate the effectiveness of theoretical analysis and controller design.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
  • Principle and Application of the Contactless Load Detection Based on the
           Amplitude Decay Rate in a Transient Process
    • Authors: Sideng Hu;Zipeng Liang;Yujie Wang;Jing Zhou;Xiangning He;
      Pages: 8936 - 8944
      Abstract: For maximizing the power transfer in an inductive power transfer system, the operating frequency of the system is normally designed to be the same as the resonant frequency of the secondary power pick-up. But the load deviation reflected from secondary side to primary side will result in the frequency mismatch issue. Therefore, the contactless load detection technique is significant to ensure the power transfer efficiency and capacity. The emerging technique taking advantages of the amplitude decay rate in a transient process is promising. The robustness and practicability can get enhanced and the complicated steady circuit model is avoided. However, the accuracy for the small resistance application is still a challenge even with sophisticated compensation algorithms. This paper classified the system detectable region through the root locus method. The transient process in different subregions is excavated mathematically. It is revealed that the variation of the system from the second order to fourth order is the key issue for the detection error in the small load resistance application. The analysis brings out a novel automatic contactless load detection method to extend the detection range. Both simulation and experimental results verified the effectiveness of the proposed theory and detection method.
      PubDate: Nov. 2017
      Issue No: Vol. 32, No. 11 (2017)
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
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