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  Subjects -> ELECTRONICS (Total: 139 journals)
Advances in Biosensors and Bioelectronics     Open Access   (Followers: 1)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 4)
Advances in Microelectronic Engineering     Open Access   (Followers: 1)
Advances in Power Electronics     Open Access   (Followers: 7)
Aerospace and Electronic Systems, IEEE Transactions on     Hybrid Journal   (Followers: 49)
American Journal of Electrical and Electronic Engineering     Open Access   (Followers: 7)
Annals of Telecommunications     Hybrid Journal   (Followers: 4)
APL : Organic Electronics and Photonics     Hybrid Journal   (Followers: 1)
APSIPA Transactions on Signal and Information Processing     Open Access   (Followers: 2)
Archives of Electrical Engineering     Open Access   (Followers: 8)
Autonomous Mental Development, IEEE Transactions on     Hybrid Journal   (Followers: 5)
Bell Labs Technical Journal     Hybrid Journal   (Followers: 8)
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (Followers: 14)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 11)
Biomedical Instrumentation & Technology     Full-text available via subscription   (Followers: 4)
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 5)
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: 12)
China Communications     Full-text available via subscription   (Followers: 1)
Circuits and Systems     Open Access   (Followers: 7)
Consumer Electronics Times     Open Access   (Followers: 3)
Control Systems     Hybrid Journal   (Followers: 18)
Electronic Markets     Hybrid Journal   (Followers: 5)
Electronic Materials Letters     Hybrid Journal   (Followers: 2)
Electronics     Open Access   (Followers: 3)
Electronics and Communications in Japan     Hybrid Journal   (Followers: 4)
Electronics Letters     Hybrid Journal   (Followers: 15)
Embedded Systems Letters, IEEE     Hybrid Journal   (Followers: 14)
EPJ Quantum Technology     Open Access  
EURASIP Journal on Embedded Systems     Open Access   (Followers: 8)
Foundations and TrendsĀ® in Communications and Information Theory     Full-text available via subscription   (Followers: 5)
Foundations and TrendsĀ® in Signal Processing     Full-text available via subscription   (Followers: 4)
Frequenz     Full-text available via subscription   (Followers: 1)
Frontiers of Optoelectronics     Hybrid Journal   (Followers: 1)
Geoscience and Remote Sensing, IEEE Transactions on     Hybrid Journal   (Followers: 19)
Haptics, IEEE Transactions on     Hybrid Journal   (Followers: 4)
IEEE Consumer Electronics Magazine     Full-text available via subscription   (Followers: 7)
IEEE Journal of Emerging and Selected Topics in Power Electronics     Hybrid Journal   (Followers: 3)
IEEE Journal of the Electron Devices Society     Open Access   (Followers: 1)
IEEE Power Electronics Magazine     Full-text available via subscription  
IEEE Transactions on Audio, Speech, and Language Processing     Hybrid Journal   (Followers: 9)
IEEE Transactions on Automatic Control     Hybrid Journal   (Followers: 19)
IEEE Transactions on Consumer Electronics     Hybrid Journal   (Followers: 10)
IEEE Transactions on Electron Devices     Hybrid Journal   (Followers: 6)
IEEE Transactions on Information Theory     Hybrid Journal   (Followers: 13)
IEEE Transactions on Power Electronics     Hybrid Journal   (Followers: 11)
IEICE - Transactions on Electronics     Full-text available via subscription   (Followers: 7)
IEICE - Transactions on Information and Systems     Full-text available via subscription   (Followers: 7)
IET Power Electronics     Hybrid Journal   (Followers: 7)
IET Wireless Sensor Systems     Hybrid Journal   (Followers: 5)
IETE Journal of Education     Open Access   (Followers: 2)
IETE Journal of Research     Open Access   (Followers: 4)
IETE Technical Review     Open Access   (Followers: 1)
Industrial Electronics, IEEE Transactions on     Hybrid Journal   (Followers: 9)
Industry Applications, IEEE Transactions on     Hybrid Journal   (Followers: 5)
Informatik-Spektrum     Hybrid Journal  
Instabilities in Silicon Devices     Full-text available via subscription  
Intelligent Transportation Systems Magazine, IEEE     Full-text available via subscription   (Followers: 1)
International Journal of Advanced Electronics and Communication Systems     Open Access   (Followers: 3)
International Journal of Advanced Research in Computer Science and Electronics Engineering     Open Access   (Followers: 18)
International Journal of Advances in Telecommunications, Electrotechnics, Signals and Systems     Open Access   (Followers: 1)
International Journal of Aerospace Innovations     Full-text available via subscription   (Followers: 10)
International Journal of Applied Electronics in Physics & Robotics     Open Access  
International Journal of Biomedical Nanoscience and Nanotechnology     Hybrid Journal   (Followers: 4)
International Journal of Computational Vision and Robotics     Hybrid Journal   (Followers: 4)
International Journal of Computer & Electronics Research     Full-text available via subscription   (Followers: 2)
International Journal of Control     Hybrid Journal   (Followers: 9)
International Journal of Electronics     Hybrid Journal   (Followers: 2)
International Journal of Electronics & Data Communication     Open Access   (Followers: 3)
International Journal of Electronics and Telecommunications     Open Access   (Followers: 3)
International Journal of Granular Computing, Rough Sets and Intelligent Systems     Hybrid Journal   (Followers: 1)
International Journal of High Speed Electronics and Systems     Hybrid Journal  
International Journal of Microwave and Wireless Technologies     Hybrid Journal   (Followers: 1)
International Journal of Nano Devices, Sensors and Systems     Open Access   (Followers: 1)
International Journal of Nanoscience     Hybrid Journal   (Followers: 1)
International Journal of Numerical Modelling:Electronic Networks, Devices and Fields     Hybrid Journal   (Followers: 2)
International Journal of Power Electronics     Hybrid Journal   (Followers: 3)
International Journal of Power Management Electronics     Open Access  
International Journal of Review in Electronics & Communication Engineering     Open Access   (Followers: 1)
International Journal of Sensors, Wireless Communications and Control     Hybrid Journal   (Followers: 2)
International Journal of Systems, Control and Communications     Hybrid Journal   (Followers: 2)
International Journal on Communication     Full-text available via subscription   (Followers: 7)
International Journal on Electrical and Power Engineering     Full-text available via subscription   (Followers: 11)
ISRN Electronics     Open Access   (Followers: 1)
ISRN Signal Processing     Open Access  
Journal of Advanced Dielectrics     Open Access   (Followers: 1)
Journal of Artificial Intelligence     Open Access   (Followers: 5)
Journal of Circuits, Systems, and Computers     Hybrid Journal   (Followers: 1)
Journal of Electrical and Electronics Engineering Research     Open Access   (Followers: 1)
Journal of Electrical Bioimpedance     Full-text available via subscription   (Followers: 2)
Journal of Electrical Engineering & Electronic Technology     Full-text available via subscription   (Followers: 1)
Journal of Electromagnetic Analysis and Applications     Open Access   (Followers: 2)
Journal of Electromagnetic Waves and Applications     Hybrid Journal   (Followers: 1)
Journal of Electronic Design Technology     Full-text available via subscription   (Followers: 1)
Journal of Electronics (China)     Hybrid Journal   (Followers: 2)
Journal of Field Robotics     Hybrid Journal   (Followers: 2)
Journal of Guidance, Control, and Dynamics     Full-text available via subscription   (Followers: 49)
Journal of Intelligent Procedures in Electrical Technology     Open Access  
Journal of Low Power Electronics     Full-text available via subscription   (Followers: 4)

        1 2 | Last

IEEE Transactions on Power Electronics
   [13 followers]  Follow    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
     ISSN (Print) 0885-8993
     Published by Institute of Electrical and Electronics Engineers (IEEE) Homepage  [172 journals]   [SJR: 3.308]   [H-I: 111]
  • IEEE Power Electronics Society Information
    • Pages: C3 - C3
      Abstract: Provides a listing of current committee members and society officers.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • Table of contents
    • Pages: C1 - C2
      Abstract: Presents the table of contents/front cover of this publication.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • IEEE Transactions on Power Electronics publication information
    • Pages: C2 - C2
      Abstract: Provides a listing of current staff, committee members and society officers.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • Steady-State Analysis of Switching Power Converters Via Augmented
           Time-Invariant Equivalents
    • Authors: Trinchero; R.;Stievano, I.S.;Canavero, F.G.;
      Pages: 5657 - 5661
      Abstract: This letter addresses the simulation of the steady-state response of switching power converters. The proposed approach is based on the interpretation of the voltage and current variables of a periodically switched linear circuit in terms of a series expansion and on the generation of augmented time-invariant constitutive relations of the circuit elements. The circuit solution is obtained from an augmented time-invariant nodal equation generated from topological information and circuit inspection only. The feasibility and strength of the approach are demonstrated on a dc–dc boost converter.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • Effects of Leakage Inductances on Magnetically Coupled Y-Source Network
    • Authors: Siwakoti; Y.P.;Loh, P.C.;Blaabjerg, F.;Town, G.E.;
      Pages: 5662 - 5666
      Abstract: Coupled inductors have been used with impedance-source networks, extended from the earlier Z-source network, to keep their shoot-through times short, while providing high-voltage gains. A commonly stated requirement for these networks is that their magnetic couplings must be strong or their leakage inductances must be small. This is often difficult to achieve in practice especially at high switching frequencies. It is therefore necessary to understand the effects that leakage inductances have on the performance of these converters. In this letter, we address these issues for the latest Y-source network, showing in particular that voltage spikes will appear across its switching devices in some, but not all, cases. Experimental results verifying the findings have been obtained and presented at the end of this letter.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • Thermography-Based Virtual MPPT Scheme for Improving PV Energy Efficiency
           Under Partial Shading Conditions
    • Authors: Hu; Y.;Cao, W.;Wu, J.;Ji, B.;Holliday, D.;
      Pages: 5667 - 5672
      Abstract: This paper proposes a new thermography-based maximum power point tracking (MPPT) scheme to address photovoltaic (PV) partial shading faults. Solar power generation utilizes a large number of PV cells connected in series and in parallel in an array, and that are physically distributed across a large field. When a PV module is faulted or partial shading occurs, the PV system sees a nonuniform distribution of generated electrical power and thermal profile, and the generation of multiple maximum power points (MPPs). If left untreated, this reduces the overall power generation and severe faults may propagate, resulting in damage to the system. In this paper, a thermal camera is employed for fault detection and a new MPPT scheme is developed to alter the operating point to match an optimized MPP. Extensive data mining is conducted on the images from the thermal camera in order to locate global MPPs. Based on this, a virtual MPPT is set out to find the global MPP. This can reduce MPPT time and be used to calculate the MPP reference voltage. Finally, the proposed methodology is experimentally implemented and validated by tests on a 600-W PV array.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • Design of A, B, and C Pulse Forming Networks Using the VINPFN Application
    • Authors: Clementson; J.;Rahbarnia, K.;Grulke, O.;Klinger, T.;
      Pages: 5673 - 5679
      Abstract: A set of MATLAB scripts are presented for transient modeling of voltage-fed pulse-forming networks (PFNs). The VINPFN program has been written to design and simulate PFNs connected to loads that can be described as resistive or inductive. The application allows for free variation of network parameters and includes some simple optimization routines. The implementation of Guillemin voltage-fed Type A, B, and C PFN network models are described and the calculated waveform from a Type B PFN is compared to experimental data. The VINPFN program has been employed to investigate PFN generator designs for pulsed-power applications at the Max-Planck VINETA facility. The scripts are available online.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • A Novel Soft-Switching Boost Converter With Magnetically Coupled Resonant
    • Authors: Zhan; T.;Zhang, Y.;Nie, J.;Zhang, Y.;Zhao, Z.;
      Pages: 5680 - 5687
      Abstract: A novel soft-switching boost converter with a magnetically coupled resonant snubber is presented in this paper. The passive snubber circuit, which is composed of two diodes, two capacitors, and one coupled inductor, ensures a zero current turn-on and zero voltage turn-off conditions for the power switch, and alleviates the reverse-recovery problem for the output diode. Moreover, with the proper design of the snubber circuit, the power switch and output diode can be softly switched in a wide load range. The operating principle and performance analysis of the proposed converter are described in detail. The experiment from a 400 W prototype has been carried out and the results show that the proposed converter has the advantages of simple structure, low complexity control, and the highest efficiency is more than 95%.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • A DC–DC Multiport Module for Integrating Plug-In Electric Vehicles
           in a Parking Lot: Topology and Operation
    • Authors: Rezaee; S.;Farjah, E.;
      Pages: 5688 - 5695
      Abstract: Today's life and industry are intimately dependent on the electric energy. This dependence in future will be still intensified, especially due to the appearance of electric-dependent vehicles overriding conventional fossil-fuel-based vehicles in the societies. Electric and hybrid electric vehicles (EVs) carry battery storages to store the electrical energy they need. The batteries have recharging and discharging capabilities. A parking lot hosting multiple EVs could be considered as important aggregators for them. In this paper, a novel dc–dc multiport (MP) bidirectional converter (MPBC) is suggested to function in a parking lot integrating EVs as either electric load or source of energy. The switching strategies of MPBC and power sharing flowchart are presented and then its operation in the presence of three plug-in EV batteries is studied through simulation and verified through experimental testbench.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • Impact of Modulation Schemes on the Power Capability of High-Power
           Converters with Low Pulse Ratios
    • Authors: Shen; J.;Schroder, S.;Stagge, H.;De Doncker, R.W.;
      Pages: 5696 - 5705
      Abstract: The design of modulation schemes at low pulse ratios is a known topic. However, most of previous work has focused on optimized pulse patterns, e.g., selective harmonic elimination. For industrial applications, standard carrier modulators are still highly attractive in many cases. Unfortunately, few papers presented insightful studies on carrier modulators at extremely low pulse ratios. This paper covers this gap. At extremely low pulse ratios, several special phenomena of carrier modulators are introduced for the first time. For example, a significant performance variation effect can be observed when carrier modulators are used. Moreover, the thermal unbalance of the hotspot devices in the converter may lead to significant power capability degradation of the converter unit. In this paper, the mechanisms behind this are explored and explained in detail for the first time. A quantitative comparison between different carrier-based modulation schemes is presented. Based on that, several design instruction for modulators at low pulse ratios are summarized at the end.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • The Single-Stage Taipei Rectifier—Design Consideration and
           Performance Evaluation
    • Authors: Jang; Y.;Jovanovic, M.M.;
      Pages: 5706 - 5714
      Abstract: A new three-phase, single-stage, isolated zero-voltage-switching (ZVS) rectifier that achieves less than 5% input-current total harmonic distortion (THD) and provides tightly regulated output voltage is introduced. The proposed circuit is obtained by integrating the three-phase, two-switch, ZVS, discontinuous-current-mode, boost power-factor-correction rectifier, for short named the TAIPEI rectifier, with the ZVS full-bridge phase-shift dc/dc converter. The performance was evaluated on a three-phase 2.7-kW prototype designed for high voltage direct current (HVDC) distribution applications with the line-to-line voltage range from 180 to 264 $V_{rm RMS}$ and with a tightly regulated variable dc output voltage from 200 to 300 V. The prototype operates with ZVS over the entire input-voltage and load-current range and achieves less than 5% input-current THD with the efficiency in the 95% range.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • A Near-State Three-Dimensional Space Vector Modulation for a Three-Phase
           Four-Leg Voltage Source Inverter
    • Authors: Zhang; M.;Atkinson, D.J.;Ji, B.;Armstrong, M.;Ma, M.;
      Pages: 5715 - 5726
      Abstract: A near-state three-dimensional space-vector modulation (NS 3-D SVM) switching scheme, which aims to reduce the common-mode noise in a three-phase four-leg voltage source inverter, is proposed. The impact of common-mode noise, which is related to electromagnetic interference issues for a high-voltage level four-leg system, is investigated first. Identification of the section in a 3-D space, selection of the near-state switching vectors, and sequence of the selected switching vectors are then introduced in steps to describe the proposed switching scheme. The proposed switching scheme is based on classical 3-D SVM, producing higher dc-link utilization, less harmonic content, and reduced switching loss compared to sinusoidal PWM. Theory, simulation, and experimental results show that the near-state 3-D SVM can work under both balanced and unbalanced load conditions.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • Physical Model Analysis During Transient for Series-Connected HVIGBTs
    • Authors: Ji; S.;Lu, T.;Zhao, Z.;Yu, H.;Yuan, L.;Yang, S.;Secrest, C.;
      Pages: 5727 - 5737
      Abstract: Obvious differences are observed between simulation and experimental results for series-connected insulated-gate bipolar transistors (IGBTs) using current IGBT models. Here, the cause of these errors is analyzed in detail. A physical model based on more effective assumptions for a 2-D structure is proposed in this paper. The relationship between carrier concentration and lifetime is considered in the model in order to achieve an accurate description for excess carrier distribution. Testing was performed in a buck converter using series-connected non-punch-through (NPT) planar-gate 6500 V/600 A high-voltage IGBTs (HVIGBTs) at various bus voltages using an asynchronous control signal. The accuracy of HVIGBT transient model is verified by comparing experimental and simulation results in buck converters using two and three series-connected IGBTs. The function of the RC snubber circuit is also evaluated using the proposed model.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • Improved ADC Model of Voltage-Source Converters in DC Grids
    • Authors: Mu; Q.;Liang, J.;Zhou, X.;Li, Y.;Zhang, X.;
      Pages: 5738 - 5748
      Abstract: Due to a large number of converters in dc grids, the simulation speed using traditional electromagnetic simulation tools becomes very slow. An associated discrete circuit (ADC) switch model can improve the simulation efficiency greatly by avoiding the modification of system matrix during switching. However, existing ADC switches induce virtual power losses due to simulation errors during switching transients. The mechanism of the virtual power loss is analyzed, and a power loss model is established. An improved ADC switch model is designed by adding compensation sources to mitigate the simulation errors. Theoretical analyses are carried out to prove this improvement. A fast algorithm to obtain the initial values of the compensation sources is proposed by utilizing the complementary operation of IGBTs. The improved ADC switch provides fast simulation speed and high accuracy. The modeling is particularly suitable for investigating long term system dynamics of dc grids with multiple converters and fast converter transients at the same time.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • High Switches Utilization Single-Phase PWM Boost-Type PFC Rectifier
           Topologies Multiplying the Switching Frequency
    • Authors: Ortmann; M.S.;Soeiro, T.B.;Heldwein, M.L.;
      Pages: 5749 - 5760
      Abstract: Decades of research have seen single-phase boost-type pulse-width modulation converters be employed as front-end power factor correction (PFC) rectifiers in commercial power supplies. The benefits of employing this technology to comply with power quality standards while assuring high efficiency, low volume, and weight have been observed. However, this paper shows that further efforts can be driven toward new topologies. In this context, novel single-phase rectifier circuits are introduced. These are able to double or triple the ripple frequency present at the input components. Furthermore, a high utilization of the switches is observed during both positive and negative grid half-cycles. The theoretical analysis of the proposed topologies as well as their operation in PFC applications are presented and different operation modes are proposed and a comparison with a state-of-the-art PFC rectifier is presented. Finally, experimental verification of a PFC rectifier doubling the switching frequency is presented in a 1-kW prototype employing a current self-control strategy.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • Isolated Double-Twin VSC Topology Using Three-Phase IPTs for High-Power
    • Authors: Laka; A.;Barrena, J.A.;Chivite-Zabalza, J.;Rodriguez, M.A.;Izurza-Moreno, P.;
      Pages: 5761 - 5769
      Abstract: This paper presents a voltage source converter (VSC) topology for high power applications. The presented topology combines four three-phase converters by using two three-phase coupled inductances or three-phase interphase transformers (IPTs). By using the three-phase IPTs in the proposed converter configuration, the number of magnetic elements is reduced comparing to other existing topologies that combine four three-phase converters. The output power of the proposed VSC is four times the power rating of each converter. Due to the use of three-phase IPTs the power is naturally balanced between the converters without any control action. Hence, the proposed VSC works as a single three-phase high power converter. In order to validate the good performance of the proposed VSC topology, it has been simulated using the simulation tool Saber and the results have been validated experimentally in a test bench of 80 kVA.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • Generalized Active EMF Cancel Methods for Wireless Electric Vehicles
    • Authors: Choi; S.Y.;Gu, B.W.;Lee, S.W.;Lee, W.Y.;Huh, J.;Rim, C.T.;
      Pages: 5770 - 5783
      Abstract: In the inductive power transfer systems (IPTSs) of wireless electric vehicles (WEV), the electromagnetic field (EMF) should be lowered for the safety of pedestrians. In general, the EMF should be canceled for every space, time, and load condition of interest. Three generalized design methods for cancelling the EMF of WEV are proposed in this paper. By adding active EMF cancel coils to each primary main coil and secondary main coil, respectively, the EMF generated from each main coil can be independently cancelled by their corresponding cancel coils. Moreover, the EMF can be successfully mitigated if a dominant EMF source only is cancelled with 3-dB margin, which can be applied to any resonant type wireless power transfer systems. Furthermore, no significant power drop may occur if the cancel coils are placed aside from magnetic coupling path. Design examples are shown for U-type and W-type IPTS as well as a wireless stationary EV charger. Experimental verifications are shown for a recently developed I-type IPTS, which has a narrow rail width structure with alternating magnetic polarity along with a roadway. The proposed design methods have been demonstrated, without the loss of generality, to only the secondary coil where relatively large EMF is generated due to high ampere turns. An optimum spacing for cancel coils from main coils and an optimum number of turns are determined. Through experiments, additional EMF mitigation techniques such as the magnetic mirror method, separating pick-up rectifiers, and passive Al plate are provided. Thus, the EMF at 1 m distance from the center of a pick-up becomes under 44 mG even for the maximum power of 12 kW.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • Mathematical Modeling and Analysis of a Very Low Frequency HV Test System
    • Authors: Eberharter; S.;Kemmetmuller, W.;Kugi, A.;
      Pages: 5784 - 5794
      Abstract: This paper presents a new type of very low frequency (VLF) high-voltage test system for on-site cable tests up to 200 kV rms. The VLF system is based on a so called differential resonance technology (DRT), which enables a light-weight and compact construction of cable test systems. A mathematical model of the test system is presented, which is used for a detailed analysis and optimization of the DRT system. Measurement results on a prototype for 200 kV rms and loads up to 0.75 μF are used to validate the mathematical model and to show the feasibility of the test system.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • Impedance Shaping of the Grid-Connected Inverter with LCL Filter to
           Improve Its Adaptability to the Weak Grid Condition
    • Authors: Yang; D.;Ruan, X.;Wu, H.;
      Pages: 5795 - 5805
      Abstract: The current-controlled grid-connected inverter with LCL filter is widely used in the distributed generation system (DGS), due to its fast dynamic response and better power quality features. However, with the increase of power injected into the grid, control performances of the inverter will be significantly influenced by the nonideal grid conditions. Specifically, the possible wide variation of the grid impedance challenges the system stability. Meanwhile, background harmonics of the grid can greatly distort the injected current. Therefore, the control of the inverter should be designed with strong stability-robustness and high harmonic-rejection-ability, both of which correlate closely with the inverter output impedance. However, it is difficult to shape the output impedance into the one with a desirable characteristic simply by adjusting the current loop gain. In this paper, an impedance shaping method is proposed with virtual impedances, and the current control loop can be designed independently. The implementation and parameter design of the virtual impedances are studied under the practical considerations. With this proposed method, the grid-connected inverter can work stably over a wide range of the typical inductive-resistive grid impedance and exhibit strong rejection ability of grid-voltage harmonics. Experimental results from a 6-kW single-phase grid-connected inverter confirm the effectiveness of the proposed method.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • Power Converter-Based Three-Phase Nonlinear Load Emulator for a Hardware
           Testbed System
    • Authors: Kesler; M.;Ozdemir, E.;Kisacikoglu, M.C.;Tolbert, L.M.;
      Pages: 5806 - 5812
      Abstract: A three-phase nonlinear load emulator using a power electronic converter is presented in this study. The proposed nonlinear load emulator is intended to be used in an ultrawide-area grid transmission network emulator, also called hardware testbed (HTB). The emulator converter is controlled in rectifier mode to act as the real nonlinear three-phase diode rectifier load. This paper presents an accurate controller for the nonlinear load emulator based on a three-phase diode rectifier system to be used in the HTB. This study also demonstrates simulation and experimental results for verification of the proposed controller.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • Line Loss Minimization in Isolated Substations and Multiple Loop
           Distribution Systems Using the UPFC
    • Authors: Sayed; M.A.;Takeshita, T.;
      Pages: 5813 - 5822
      Abstract: This paper presents the line loss minimum condition in isolated substations and same substation multiple loop distribution systems by using the unified power flow controller (UPFC). In each case, the mathematical model is presented and the line loss minimum conditions are obtained based on the line parameters of the distribution feeders. Since multiple loop distribution system is fed from same substation, the line loss minimization can be achieved by compensating the summation of the line reactance voltage drop. In an isolated substation loop distribution system, the line loss minimization can be achieved by compensating the summation of the line reactance voltage drop in addition to the voltage difference of the substations. Realization of both cases can be achieved if the loop current is eliminated from the loop system. The series compensation technique applied by the UPFC is used to eliminate the loop current from the loop distribution system and hence minimize the total line loss. The effectiveness of the proposed control schemes of the UPFC have been verified experimentally.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • Integration of Both EMI Filter and Boost Inductor for 1-kW PFC Converter
    • Authors: Deng; C.;Xu, D.;Chen, P.;Hu, C.;Zhang, W.;Wen, Z.;Wu, X.;
      Pages: 5823 - 5834
      Abstract: In order to increase the power density of the power factor correction converter, a novel integrated structure for both the electromagnetic interference (EMI) filter and the boost inductor is proposed with the flexible multilayer foil integration technique, which can reduce the volume of these passive components. Also, the performance of the proposed integrated structure is investigated based on the distributed electromagnetic component model. Furthermore, the design procedure for the integrated structure is detailed. Finally, a prototype of the integrated structure for both the EMI filter and the boost inductor has been built and the experiments demonstrate the validity of the integrated structure.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • Analytical Approach for Determining the Frequency-Dependent
           Characteristics of Multipath Conductive Structures
    • Authors: Brink; E.A.;Hofsajer, I.W.;
      Pages: 5835 - 5845
      Abstract: An analysis technique is presented that can be used to determine the current density, as well as the electric field and magnetic field distributions, within multipath conductive structures. A multipath conductor has several different conductive materials that are configured in parallel and carry a total known terminal current at a known frequency. The conductivity and permeability of the materials in the multipath conductor may take on arbitrary values. Knowledge of the different field and current distributions is important as it then becomes possible to determine the resistance and internal inductance of the multipath conductor as a function of frequency. The technique is initially developed for an arbitrary number of stacked planar conductors; however, it is also extended to multilayer coaxially arranged cylindrical conductors. Verification of the proposed technique is achieved through comparison against finite element method eddy current simulations as well as experimental structures and demonstrates excellent agreement.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
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           + Z$
    Type Cascade System in Hybrid Energy Storage System
    • Authors: Liu; F.;Liu, J.;Zhang, H.;Xue, D.;
      Pages: 5846 - 5859
      Abstract: Stability issues in hybrid energy storage systems (HESSs) are the major concern, in addition to the control design challenges of individual modules. In this paper, the stability issues of $Z + Z$ type cascade systems in HESS are focused. The stability issues of cascade systems have been studied for many years. Impedance ratio type criterions in the form of $Z_{S}$ / $Z_{L}$ or $Z_{L}$ / $Z_{S}$ have been proposed to solve these stability issues. However, existing ratio type criteria still have problems in some cascade systems. The terminal characteristics of submodule are studied and the different types of cascade system are defined in this paper. The validity of conventional impedance ratio type criterion would be influenced by the right-half-plane zeros (RHZ) in terminal impedance of submodules in the $Z + Z$ type cascade system. Two improved criteria are proposed for the $Z + Z$ type cascade system: one is improved ratio type criterion considering the RHZ in the terminal impedance of the submodule; the other one is sum type criterion which does not need the information about RHZ in terminal impedance of each submodule. Experimental evidences are provided to prove the validity of these two improved criteria.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • A Modified SEPIC Converter With High Static Gain for Renewable
    • Authors: Gules; R.;dos Santos, W.;dos Reis, F.;Romaneli, E.;Badin, A.;
      Pages: 5860 - 5871
      Abstract: Two high static gain step-up dc–dc converters based on the modified SEPIC converter are presented in this paper. The proposed topologies present low switch voltage and high efficiency for low input voltage and high output voltage applications. The configurations with magnetic coupling and without magnetic coupling are presented and analyzed. The magnetic coupling allows the increase of the static gain maintaining a reduced switch voltage. The theoretical analysis and experimental results show that both structures are suitable for high static gain applications as a renewable power sources with low dc output voltage. Two experimental prototypes were developed with an input voltage equal to 15 V and an output power equal to 100 W. The efficiency at nominal power obtained with the prototype without magnetic coupling was equal to 91.9% with an output voltage of 150 V. The prototype with magnetic coupling operating with an output voltage equal to 300 V, presents an efficiency at nominal power equal to 92.2%.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • Antiislanding Protection Based on Signatures Extracted From the
           Instantaneous Apparent Power
    • Authors: Saleh; S.A.;Aljankawey, A.S.;Meng, R.;Meng, J.;Diduch, C.P.;Chang, L.;
      Pages: 5872 - 5891
      Abstract: This paper proposes a new passive antiislanding method for three-phase ( $3phi$ ) distributed generation units (DGUs). The proposed method is based on extracting signatures from the instantaneous $3phi$ apparent powers determined at the point of common coupling (PCC). This new method is found on the fact that the instantaneous $3phi$ apparent powers have components continuously exchanged between loads and sources. The islanding condition creates transient high-frequency components in the instantaneous $3phi$ apparent powers.These high-frequency components contain signature information capable of identifying the islanding condition. These transient high-frequency components can be extracted using the wavelet packet transform (WPT), when applied to the direct and quadrature ( $d-q$ -axis) components of the instantaneous $3phi$ apparent powers. The $d-q$ WPT-based antiislanding method is implemented for testing on a $3phi$ permanent magnet generator-based wind energy conversion system. Test results demonstrate an accurate, fast, and reliable response to the islanding condition occurring when supplying different load types at different levels of power delivery to the host grid.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • Generalized Technique of Compensating Low-Frequency Component of Load
           Current With a Parallel Bidirectional DC/DC Converter
    • Authors: Dusmez; S.;Khaligh, A.;
      Pages: 5892 - 5904
      Abstract: The first stage of a battery charger in electric vehicles is a power factor correction (PFC) circuit, which creates a second harmonic in the dc link. This harmonic is typically filtered through a bulky dc-link capacitor. In the conventional battery chargers, another dc/dc stage is utilized to regulate the battery current. In this paper, the second harmonic in the dc link is analyzed in detail and a new load current compensation technique is proposed. The proposed technique replaces the second stage dc/dc converter with a bidirectional dc/dc converter connected in parallel with the load, and requires a secondary energy source, i.e., a small-size capacitor. The capacitor injects 180° phase-shifted second harmonic current to the dc link. Thus, the dc-link capacitor can be reduced significantly as it is only sized for high-frequency ripples rather than being sized for low-frequency content. The proposed method is generalized for resistive and battery loads with voltage- and current-source PFC circuits. A 360 W prototype is developed to experimentally verify the proposed technique. A 72 V/10 A·h battery module is charged by filtering an oscillating power of 360 W using a two-quadrant bidirectional dc/dc converter and an UC module, demonstrating a peak charging current of 16 A.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • Near-Real-Time Parameter Estimation of an Electrical Battery Model With
           Multiple Time Constants and SOC-Dependent Capacitance
    • Authors: Wang; W.;Shu-Hung Chung, H.;Zhang, J.;
      Pages: 5905 - 5920
      Abstract: A modified particle swarm optimization algorithm for conducting near-real-time parameter estimation of an electrical model for lithium batteries is presented. The model comprises a dynamic capacitance for characterizing the nonlinear relationship between the battery electromotive force and the state-of-charge, and a resistor–capacitor network for characterizing the static and transient responses. The algorithm is confirmed by successfully determining all parameters in a predefined simulation model. It is also evaluated on a hardware test bed with two samples of 3.3-V, 40-Ah, Lithium Iron Phosphate (LiFePO $_{4}$ ) battery driven under six different loading patterns. The intrinsic parameters are estimated by first processing 15-min samples of the battery terminal voltage and current. The whole process takes 2 min. Then, the voltage–current characteristics in the following 15 min are predicted. Results show that the extracted parameters can fit the first 15-min voltage samples with a maximum error of 16 mV and an average error of 3.8 mV. With the extracted parameters, the electrical model can predict voltage–current characteristics in the following 15 min with a maximum error of 31 mV and an average error of 15 mV. The algorithm is further verified by successfully determining the emulated variation of the output resistance.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • Analysis and Implementation of Phase Synchronization Control Strategies
           for BCM Interleaved Flyback Microinverters
    • Authors: Zhang; Z.;Chen, M.;Chen, W.;Jiang, C.;Qian, Z.;
      Pages: 5921 - 5932
      Abstract: A flyback converter that operates in the boundary conduction mode or discontinuous conduction mode has been widely used in microinverters. Placing two flyback converters in parallel and utilizing interleaving can extend the power range of microinverters. Interleaving phases between the two converters should be carefully regulated in order to reduce the switching current ripple. In this paper, two open-loop phase synchronization methods are put forward and compared for the interleaved flyback microinverters utilizing the master–slave control principle. The comparison result shows that stable phase regulation can be achieved if synchronization is triggered at the instant when the master converter's primary switch is turned OFF. However, the switching loss will be increased with the transformers’ magnetizing inductances mismatch between the two interleaved converters. To solve this problem, a novel closed-loop interleaving phase synchronization control method is proposed in this paper to guarantee high efficiency and stable operation at the same time. Simulation platform together with a 200-W prototype have been built to verify the proposed control methods. These results demonstrate that the proposed closed-loop interleaving phase synchronization control method can achieve high efficiency while maintaining stable phase synchronization for the interleaved flyback microinverter.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • Design of a Two-Phase Buck Converter With Fourth-Order Output Filter for
           Envelope Amplifiers of Limited Bandwidth
    • Authors: Sebastian; J.;Fernandez-Miaja, P.;Ortega-Gonzalez, F.J.;Patino, M.;Rodriguez, M.;
      Pages: 5933 - 5948
      Abstract: The use of techniques such as envelope tracking (ET) and envelope elimination and restoration (EER) can improve the efficiency of radio frequency power amplifiers (RFPA). In both cases, high-bandwidth DC/DC converters called envelope amplifiers (EA) are used to modulate the supply voltage of the RFPA. This paper addresses the analysis and design of a modified two-phase Buck converter optimized to operate as EA. The effects of multiphase operation on the tracking capabilities are analyzed. The use of a fourth-order output filter is proposed to increase the attenuation of the harmonics generated by the PWM operation, thus allowing a reduction of the ratio between the switching frequency and the converter bandwidth. The design of the output filter is addressed considering envelope tracking accuracy and distortion caused by the side bands arising from the nonlinear modulation process. Finally, the proposed analysis and design methods are supported by simulation results, as well as demonstrated by experiments obtained using two 100-W, 10-MHz, two-phase Buck EAs capable of accurately tracking a 1.5-MHz bandwidth OFDM signal.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • A Bridgeless Resonant Pseudoboost PFC Rectifier
    • Authors: Fardoun; A.A.;Ismail, E.H.;Al-Saffar, M.A.;Sabzali, A.J.;
      Pages: 5949 - 5960
      Abstract: In this paper, a new bridgeless single-phase ac–dc converter with a natural power factor correction (PFC) is proposed. Compared with existing single-phase bridgeless topologies, the proposed topology has the merits of less component counts. The absence of an input diode bridge and the presence of only one diode in the current path during each stage of the switching cycle result in higher power density and less conduction losses; hence, improved thermal management compared to existing PFC rectifiers is obtained. The proposed topology is designed to work in resonant mode to achieve an automatic PFC close to unity in a simple and effective manner. The resonant mode operation gives additional advantages such as zero-current turn-on in the active power switches, zero-current turn-off in the output diode and reduces the complexity of the control circuitry. Principle of operation and the feasibility of the proposed converter are provided. Detailed experimental and simulation results are presented.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • A Pseudo Cross-Coupled Switch-Capacitor Based DC-DC Boost Converter for
           High Efficiency and High Power Density
    • Authors: Das; T.;Prasad, S.;Dam, S.;Mandal, P.;
      Pages: 5961 - 5974
      Abstract: In this paper, we propose a fully-integrated switch-capacitor (SC) dc–dc boost converter having high power efficiency, low output ripple, and high power density. It uses a switching scheme called nonoverlapped rotational time-interleaving (NORI) which eliminates shoot-through loss as well mitigates the adverse effect of dead times between successive charging and discharging phases which results into a small ripple. A basic cross-coupled voltage doubler has been adopted to implement the NORI scheme working over a wide range of switching frequencies. Dynamic adjustment of the frequency provides high power density as well as maintains high power efficiency over a wide load current range. The proposed converter has been fabricated in 0.18- $mu$ m CMOS thick gate process for 3.3 to 5.5 V conversion and output ripple not more than 0.5% of the output voltage. The converter uses only 440 pF to deliver up to 25 mA at 5.3 V regulated output. The measured peak power efficiency is 89% at 20 mA for unregulated output. With mixed mode regulations, the measured efficiency of the converter including analog blocks is 83.5% at 15 mA, while the overall efficiency is 75%. Power density of the designed converter is more than 0.85 W/mm $^2$ considering the capacitor area.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • Electronic Tuning of Misaligned Coils in Wireless Power Transfer Systems
    • Authors: Aldhaher; S.;Luk, P.C.-K.;Whidborne, J.F.;
      Pages: 5975 - 5982
      Abstract: The misalignment and displacement of inductively coupled coils in a wireless power transfer system (WPT) can degrade the power efficiency and limit the amount of power that can be transferred. Coil misalignment leads the primary coil driver to operate in an untuned state which causes nonoptimum switching operation and results in an increase in switching losses. This paper presents a novel method to electronically tune a Class-E inverter used as a primary coil driver in an inductive WPT system to minimize the detrimental effects of misalignment between the inductively coupled coils which may occur during operation. The tuning method uses current-controlled inductors (saturable reactors) and a variable switching frequency to achieve optimum switching conditions regardless of the misalignment. Mathematical analysis is performed on a Class-E inverter based on an improved model of a resonant inductive link. Experimental results are presented to confirm the analysis approach and the suitability of the proposed tuning method.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • Commutation Control for the Low-Commutation Torque Ripple in the Position
           Sensorless Drive of the Low-Voltage Brushless DC Motor
    • Authors: Jung; S-.Y.;Kim, Y-.J.;Jae, J.;Kim, J.;
      Pages: 5983 - 5994
      Abstract: This paper discusses a commutation control method aimed at reducing the commutation torque ripple in sensorless drive of brushless direct current motors. These motors are generally used for low-cost applications because of relatively high efficiency and low manufacturing cost. On the other hand, they show a high torque ripple characteristic caused by nonideal commutation currents. This limits their application area, especially for low-voltage applications. In order to minimize torque ripple for the entire speed range, a comprehensive analysis of commutation torque ripple was made according to three commutation control methods whereupon an optimal current vector trajectory for low torque ripple was devised. The effectiveness of the proposed method was verified through simulation and experimental results.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • Multifrequency Inductive Power Transfer
    • Authors: Pantic; Z.;Lee, K.;Lukic, S.M.;
      Pages: 5995 - 6005
      Abstract: This paper presents a generalized analysis of an inductive power transfer system where multiple frequencies are used to transfer power through the magnetic link. Specifically, we consider a system that amplifies both the fundamental and the third harmonic generated by a full-bridge inverter in order to transfer power to a receiver at both frequencies. The system is analyzed in a generalized manner, by looking at the transconductance function at the transmitter and the receiver for each of the harmonics. Using this approach, the emitted field strength, inverter losses, combined transmitter and receiver coil conduction losses, and VA ratings are compared to a reference single-frequency system. The analysis shows that the dual-frequency system can outperform the single-frequency equivalent for all metrics considered; however, in practice, a tradeoff between the performance criteria is necessary, since the optimal operation points for each criterion cannot be attained with a single design.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • Families of Forward Converters Suitable for Wide Input Voltage Range
    • Authors: Wu; H.;Xing, Y.;
      Pages: 6006 - 6017
      Abstract: A topology approach is proposed to derive forward converters suitable for wide voltage range applications. A unified forward switching cell concept from the core principle of forward conversion is proposed with three cells given, named as forward positive cell, forward negative cell, and forward composite cell. All cells consist of active switch, diode, transformer, and comprehensive demagnetizing voltage source. By utilizing different subcircuit to balance the voltage of the comprehensive demagnetizing voltage source, various types of forward switching cells, including RCD type, active-clamping type, LCDD type, flyback-integrated type, and independent-circuit type, are deduced from the traditional forward converters with topology derivation rules given. Families of forward converters, including existing ones and novel ones, are constructed as examples. The forward converters built in such a way illustrates features such as recycle of leakage and magnetizing energy, low voltage stress on devices, etc. The proposed method is extended to flyback converter family to further justify the feasibility. An input-series interleaved RCD forward converter and an active-clamping forward converter are analyzed in detail and verified with experimental results.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • New Three-Phase Multilevel Inverter With Reduced Number of Power
           Electronic Components
    • Authors: Masaoud; A.;Ping, H.;Mekhilef, S.;Taallah, A.;
      Pages: 6018 - 6029
      Abstract: In this paper, a new configuration of a three-phase five-level multilevel voltage-source inverter is introduced. The proposed topology constitutes the conventional three-phase two-level bridge with three bidirectional switches. A multilevel dc link using fixed dc voltage supply and cascaded half-bridge is connected in such a way that the proposed inverter outputs the required output voltage levels. The fundamental frequency staircase modulation technique is easily used to generate the appropriate switching gate signals. For the purpose of increasing the number of voltage levels with fewer number of power electronic components, the structure of the proposed inverter is extended and different methods to determine the magnitudes of utilized dc voltage supplies are suggested. Moreover, the prototype of the suggested configuration is manufactured as the obtained simulation and hardware results ensured the feasibility of the configuration and the compatibility of the modulation technique is accurately noted.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • Analysis and Design of Energy Regenerative Snubber for Transformer
           Isolated Converters
    • Authors: Vartak; C.;Abramovitz, A.;Ma Smedley, K.;
      Pages: 6030 - 6040
      Abstract: An energy regenerative passive snubber for transformer isolated converters is proposed. The snubber is implemented on the transformer's primary and secondary windings. The proposed snubber significantly reduces the voltage spike across the switch caused by the transformer's primary inductance upon switch turn-off and facilitates the fast ramping up of the transformer secondary current. In addition, the proposed snubber provides lossless zero voltage turn off and zero current turn on conditions for the power switch. Experimental example of a flyback converter has shown measured efficiency exceeding 90%. This paper describes the principle of operation and presents approximate theoretical analysis and design guidelines of the proposed snubber. Simulation and experimental results are also reported. The proposed energy regenerating snubber is best suited for flyback and SEPIC converters and can also be adapted to other transformer isolated topologies.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • Current-Fed Soft-Switching Push–Pull Front-End Converter-Based
           Bidirectional Inverter for Residential Photovoltaic Power System
    • Authors: Xuewei; P.;Rathore, A.;
      Pages: 6041 - 6051
      Abstract: Photovoltaic (PV) residential power system is an important application of renewable energy. The parallel-connected configuration of PV modules rather than the series-connected configuration become popular considering the safety requirements and making full use of the PV generated power for the PV residential generation system. In this paper, a novel soft-switching current-fed push–pull front-end converter-based inverter is proposed. Push–pull converter has only two primary devices with common ground to supply and results in simple and reduced gating requirement. The device voltage is clamped naturally by secondary modulation without active clamping circuit or passive snubbers. Zero-current switching of primary devices and zero-voltage switching of secondary devices is achieved. Soft-switching is inherent owing to proposed secondary modulation, load independent, and is maintained during wide variation of input voltage and power transfer capacity, and thus is suitable for PV applications. A 250-W laboratory prototype of the converter is built and tested to demonstrate the converter performance over wide variations in input voltage and output power for PV applications.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • A Micromachined Wiring Board With Integrated Microinductor for Chip-Scale
           Power Conversion
    • Authors: Meyer; C.D.;Bedair, S.S.;Morgan, B.C.;Arnold, D.P.;
      Pages: 6052 - 6063
      Abstract: This paper presents a multilayer wiring board that integrates a copper air-core microinductor to enable a highly compact, chip-scale power converter module. The wiring board is wafer-level fabricated with three 30-μm-thick electroplated copper layers and is subsequently detached from the fabrication wafer to yield a board that is only 90 μm thick for minimum overall module volume. Within this platform, a stacked-spiral air-core microinductor is designed for high-switching-frequency power conversion and yields high inductance density of 128 nH/mm $^{2}$ (100 nH/mm $^{3}$ by volume, including 600 μm clearances both above and below the inductor to minimize coupling with external conductors). Although this technology is anticipated to be more appropriate for emerging, experimental converters with switching frequencies >30 MHz, a proof-of-concept, ultraminiature (9 mm $^{2}$ footprint, 0.7 mm thick) power converter module is presented that utilizes the microinductor wiring board in conjunction with a commercially available surface-mount boost regulator (∼4 MHz switching frequency). The converter module yielded a maximum output power of 153 mW at 60% efficiency for a volumetric power density of 24 mW/mm $^{3}$ based on the physical volume occupied by the module (13 mW/mm $^{3}$ based on the volume needing to be kept clear from external conductors).
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • Fluctuating Current Control Method for a PMSM Along Constant Torque
    • Authors: Kim; J.;Jeong, I.;Lee, K.;Nam, K.;
      Pages: 6064 - 6073
      Abstract: The dc-link voltage fluctuation problem is more serious for an inverter system which utilizes a single phase ac source. As an effort to reduce the dc-link capacitance, there is a tendency to make torque oscillate in synchronism with the input power. Then, the fluctuating motor power matches the converter power. The key idea is to enforce current oscillation along a constant torque line which only affects the reactive power of the motor. In other words, the proposed method uses the motor as inductive energy storage by controlling the motor flux by the reactive current component. Analytic method for obtaining the current bounds was derived. Also, a practical recursive algorithm was proposed. Simulation and experimental results support the effectiveness of the proposed method.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • Effect of Static Power Supply in Alternator Used for Short-Circuit
           Testing-Observation of Shaft Voltage
    • Authors: Datta; A.;Dubey, M.;Jain, S.;
      Pages: 6074 - 6080
      Abstract: All electrical power equipment, before putting into service, have to pass through numbers of tests to prove their functional performance. In this context, short-circuit test is one of the vital performance tests. A high power alternator used in short-circuit test laboratory is taken as a study object in this paper. Normally, a motor is used as the prime mover for this type of alternator. In this system, the driving motor is eliminated and a thyristor-based static drive is placed to run the machine. The benefit with the static drive is that the single machine can be operated in dual mode, either as a motor or as an alternator. But the negative side of this system is the generation of voltages in the machine shaft. Machine bearings are susceptible to failure if these unwanted shaft voltages cause a high level of bearing currents and persist for a prolonged period. Very little studies were carried out on the power generators related to shaft voltages with perspective to static power supply. This paper explains the details of the static drives applied on this machine for different operational modes. Various causes of generation of shaft voltages are analyzed in view of this special alternator. The outcome of this paper can also be applicable to other large synchronous machines.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • Acoustic Emission in Power Semiconductor Modules—First Observations
    • Authors: Karkkainen; T.J.;Talvitie, J.P.;Kuisma, M.;Hannonen, J.;Strom, J-.P.;Mengotti, E.;Silventoinen, P.;
      Pages: 6081 - 6086
      Abstract: Traditionally, condition monitoring of power semiconductor modules has been based on electrical measurements. Acoustic emission has been utilized for condition monitoring in many other applications, but is an unknown phenomenon in power semiconductor modules. In this paper, the authors present an experimental setup used to show that acoustic emission does occur because of the switching of power semiconductor components. An analysis based on propagation delays is used to determine the source of the acoustic emission.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • High-Performance Fault Diagnosis in PWM Voltage-Source Inverters for
           Vector-Controlled Induction Motor Drives
    • Authors: Zhang; J.;Zhao, J.;Zhou, D.;Huang, C.;
      Pages: 6087 - 6099
      Abstract: This paper proposes a simple method for single switch and double switches open-circuit fault diagnosis in pulsewidth-modulated voltage-source inverters (PWM VSIs) for vector-controlled induction motor drives, which also applies to secondary open-circuit fault diagnosis. According to the phase angle of one phase current, the repetitive operation process of VSI is evenly divided into six operating stages by certain rules. At each stage, only three of the six power switches exert a vital influence on this operation and the others make a negligible influence. An open-circuit fault of power switches introduces the repetitive current distortions, whose period is identical to that of the three-phase currents. The current distortions appear at faulty stages and disappear at healthy stages. The stage is determined by recalculating the current vector rotating angle. The $d$ - and $q$ -axis current repetitive distortions are applied to the detection of faulty switches due to its simplicity and fair robustness, while the faulty stages are used for the identification of faulty switches. The simulations and experiments are carried out and the results show the effectiveness of the proposed method.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • A Novel Three-Level Hysteresis Current Regulation Strategy for Three-Phase
           Three-Level Inverters
    • Authors: Davoodnezhad; R.;Holmes, D.;McGrath, B.P.;
      Pages: 6100 - 6109
      Abstract: This paper presents a new hysteresis current regulation strategy for the neutral point clamped and flying capacitor (FC) three-level inverters. The strategy uses the measured average of the switched phase leg output voltage to adjust the controller hysteresis band as the load back EMF varies to maintain a near constant phase leg switching frequency. The phase leg switchings are then fine tuned to a fixed frequency clock to further improve frequency regulation. Next, the zero-crossings of the measured phase leg average voltages are used to select between positive and negative switched output voltage levels, so that only one hysteresis current regulator is required for the full inverter switched output voltage range. For the FC inverter, a state machine is then added to select between redundant switching states to maintain balanced capacitor voltages. Finally, the controller is extended to a three-phase system by subtracting the common mode interacting current from the total phase leg current error before making any switching decision. The resulting controller achieves a line-to-line harmonic performance that is very close to open-loop phase disposition pulse width modulation, while retaining all of the dynamic benefits of hysteresis current regulation.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • Principles and Efficient Implementation of Charge Replacement in Hybrid
           Electrical Energy Storage Systems
    • Authors: Xie; Q.;Kim, Y.;Wang, Y.;Kim, J.;Chang, N.;Pedram, M.;
      Pages: 6110 - 6123
      Abstract: Hybrid electrical energy storage systems (HEES) are comprised of multiple banks of inhomogeneous EES elements with difference characteristics. They have been proposed to achieve desired performance metrics of an ideal energy storage device, i.e., high energy capacity, high output power level, low self-discharge, low cost, and long service life. Implementation of appropriate charge management policies enables efficient storage and retrieval of the electrical energy, attaining performance metrics that are close to the respective best values across the constituent EES elements in the HEES system. This paper addresses a global charge replacement problem in HEES systems, namely, how to dynamically select a subset of the EES banks and discharge them to meet the load power demand in a prespecified amount of time. Precisely, the global charge replacement optimization problem is formulated as a mixed-integer nonlinear programming problem, and a hierarchical algorithm is presented to efficiently solve this problem. At the top level the proposed algorithm considers the complete discharging process and allocates the load demand among all available EES banks, whereas at the bottom level it employs convex optimization methods to solve for discharging currents and the voltage level of a shared charger transfer interconnect. A prototype HEES system has been built to demonstrate the energy benefits brought by HEES systems and the efficacy of the proposed charge replacement algorithm.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • Synchronization of Parallel Single-Phase Inverters With Virtual Oscillator
    • Authors: Johnson; B.B.;Dhople, S.V.;Hamadeh, A.O.;Krein, P.T.;
      Pages: 6124 - 6138
      Abstract: A method to synchronize and control a system of parallel single-phase inverters without communication is presented. Inspired by the phenomenon of synchronization in networks of coupled oscillators, we propose that each inverter be controlled to emulate the dynamics of a nonlinear dead-zone oscillator. As a consequence of the electrical coupling between inverters, they synchronize and share the load in proportion to their ratings. We outline a sufficient condition for global asymptotic synchronization and formulate a methodology for controller design such that the inverter terminal voltages oscillate at the desired frequency, and the load voltage is maintained within prescribed bounds. We also introduce a technique to facilitate the seamless addition of inverters controlled with the proposed approach into an energized system. Experimental results for a system of three inverters demonstrate power sharing in proportion to power ratings for both linear and nonlinear loads.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • Modeling and Design of Voltage Support Control Schemes for Three-Phase
           Inverters Operating Under Unbalanced Grid Conditions
    • Authors: Castilla; M.;Miret, J.;Camacho, A.;Garcia de Vicuna, L.;Matas, J.;
      Pages: 6139 - 6150
      Abstract: Three-phase inverters equipped with voltage support control schemes have been successfully used to alleviate the negative impact of voltage imbalance on electric power systems. With these schemes, dc-link voltage ripple and current harmonics are significantly reduced by processing the positive and negative sequence components separately. However, the design methods for tuning the parameters of these control schemes have one or more of the following limitations: 1) the design is a very time-consuming task, 2) it is conservative, 3) it does not guarantee the specifications for all the considered situations, and 4) the system can be unstable in some abnormal conditions. As an alternative, this paper presents a design method based on the analysis of oscillations in nonlinear systems. The method proceeds by first developing simple and accurate models of the power system, second it reveals the system features through an in deep analysis of the derived models, and third it introduces a systematic design procedure for tuning the parameters of the control schemes. As an example, a voltage support control scheme for a three-phase inverter operating under an unbalanced voltage sag is designed and validated experimentally.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • Flexible-Voltage DC-Bus Operation for Reduction of Switching Losses in
           All-Electric Ship Power Systems
    • Authors: Farasat; M.;Arabali, A.;Trzynadlowski, A.M.;
      Pages: 6151 - 6161
      Abstract: The multizonal medium voltage dc architecture of all-electric ship shipboard power systems (SPSs) includes a variety of distributed energy resources, energy storage devices, and power electronic voltage source converters. Due to the limited fuel supply and tight space, control of the converters should be aimed at increasing their efficiency and compactness. In this paper, a novel approach to voltage control in all-electric ship power systems is proposed to fulfill these goals. In contrast to the traditional SPSs that emulate the land-based electricity grid, maintaining a steady bus voltage is no longer an objective here. On the contrary, the voltage is compelled to fluctuate in order to minimize switching losses in the converters. A method for calculation of the minimum required dc voltage level is described, and results of computer simulations of an SPS with a flexible-voltage dc bus are presented. The minimum-voltage operation of the system results in a significant efficiency increase.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • A Nonlinear-Disturbance-Observer-Based DC-Bus Voltage Control for a Hybrid
           AC/DC Microgrid
    • Authors: Wang; C.;Li, X.;Guo, L.;Li, Y.;
      Pages: 6162 - 6177
      Abstract: DC-bus voltage control is an important task in the operation of a dc or a hybrid ac/dc microgrid system. To improve the dc-bus voltage control dynamics, traditional approaches attempt to measure and feedforward the load or source power in the dc-bus control scheme. However, in a microgrid system with distributed dc sources and loads, the traditional feedforward-based methods need remote measurement with communications. In this paper, a nonlinear disturbance observer (NDO) based dc-bus voltage control is proposed, which does not need the remote measurement and enables the important “plug-and-play” feature. Based on this observer, a novel dc-bus voltage control scheme is developed to suppress the transient fluctuations of dc-bus voltage and improve the power quality in such a microgrid system. Details on the design of the observer, the dc-bus controller and the pulsewidth-modulation (PWM) dead-time compensation are provided in this paper. The effects of possible dc-bus capacitance variation are also considered. The performance of the proposed control strategy has been successfully verified in a 30 kVA hybrid microgrid including ac/dc buses, battery energy storage system, and photovoltaic (PV) power generation system.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • Predictive-Control-Based Direct Power Control With an Adaptive Parameter
           Identification Technique for Improved AFE Performance
    • Authors: Kwak; S.;Moon, U.-C.;Park, J.-C.;
      Pages: 6178 - 6187
      Abstract: This paper proposes predictive-control-based direct power control (DPC) with an adaptive online parameter identification technique for ac–dc active front ends (AFEs) to overcome model mismatch and parameter uncertainty. Based on least-squares estimation, the input inductance and input resistance of the AFE are calculated every sampling period using sampled input currents and input voltages. Because the online-tuned input inductance and resistance are updated for the controller, the proposed predictive-control-based DPC with the adaptive parameter identification technique can mitigate performance degradation resulting from the model uncertainty of the model predictive controller without any additional sensors. Therefore, the AFE generates sinusoidal input currents with a unity power factor despite parameter uncertainty.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • $N$ +-level+Flying+Capacitor+Multilevel+Inverter+With+Capacitor+Voltage+Balancing+Capability&rft.title=IEEE+Transactions+on+Power+Electronics&rft.issn=0885-8993&;">An Effortless Space-Vector-Based Modulation for        formulatype="inline"> $N$ -level
           Flying Capacitor Multilevel Inverter With Capacitor Voltage Balancing
    • Authors: Amini; J.;
      Pages: 6188 - 6195
      Abstract: Although inverters with high number of levels offer many merits, their utilization is hindered mainly by their complicated control. Overcoming this barrier gives them the opportunity to find more practical applications. This paper presents an effective closed-loop space-vector-based modulation algorithm to control flying capacitor multilevel inverters with linearly distributed flying capacitor voltages. This modulation technique drastically reduces the computational load. Besides, it is able to balance capacitor voltages more simply and effectively than other methods presented so far. It does not require any stored information from memory or a lookup table. Therefore, it permits online computation of the switching sequence. Moreover, due to the closed-loop structure of this method, the effect of system nonlinearity and capacitor voltage deregulation on performance of the modulation is reduced. Other advantages of the proposed algorithm are: low number of instructions, level-independent number of instructions, and simple extendibility to an arbitrary number of levels without considerable modification.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • Variable-Structure-Based Nonlinear Control for the Master VSC in
           DC-Energy-Pool Multiterminal Grids
    • Authors: Davari; M.;Mohamed, Y.A.-R.I.;
      Pages: 6196 - 6213
      Abstract: DC-energy-pool-based multiterminal grids are gaining widespread acceptance under the super- and smart-grid vision. DC-link voltage control via a master voltage-source converter (VSC) is essential to ensure stable and reliable operation of the overall multiterminal system. In such a demanding application, conventional dc-link voltage controllers, however, suffer from stability and performance issues, mainly attributed to the small-signal-based control design approach and the use of a cascaded control structure based on the power-balance framework which yields unmodeled nonlinear dynamics. To overcome these issues, this paper presents a natural-frame variable-structure-based nonlinear control system for the master VSC applied in dc-energy pool multiterminal grids. The proposed controller accounts for the complete nonlinear dynamics of the master VSC without any cascaded control structure and globally stabilizes the nonlinear dynamics via a passivity-based design approach. Analysis and comparative simulation as well as experimental results are presented to show the effectiveness of the proposed controller.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • An Approach to Bumpless Control for LPV Modeled Inverters in a Microgrid
    • Authors: Steenis; J.;Tsakalis, K.;Ayyanar, R.;
      Pages: 6214 - 6223
      Abstract: Recent papers have shown advantages of robust controllers compared to the controllers based on classical control theory. Further improvements in performance and stable operating range may be realized through the use of multiple robust controllers, but these are typically complicated to synthesize and implement. The complexity is somewhat relaxed for bumpless-transfer controllers, which have appeared in the literature as an ad hoc gain-scheduling control scheme. The approach is less conservative, easier to synthesize, and easier to implement than a gain-scheduled polytopic controller or other interpolation scheme, and has a larger operating range than a nominal controller. In this paper, an inverter connected to a microgrid is modeled as a linear parameter varying system and bumpless controllers are scheduled using polytopic coordinates and applied to inverters in a microgrid.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • Reactive Power Control for Distributed Generation Power Plants to Comply
           With Voltage Limits During Grid Faults
    • Authors: Camacho; A.;Castilla, M.;Miret, J.;Guzman, R.;Borrell, A.;
      Pages: 6224 - 6234
      Abstract: Grid faults are one of the most severe problems for network operation. Distributed generation power plants can help to mitigate the adverse effects of these perturbations by injecting the reactive power during the sag and the postfault operation. Thus, the risk of cascade disconnection and voltage collapse can be reduced. The proposed reactive power control is intended to regulate the maximum and minimum phase voltages at the point of common coupling within the limits established in grid codes for continuous operation. In balanced three-phase voltage sags, the control increases the voltage in each phase above the lower regulated limit by injecting the positive sequence reactive power. In unbalanced voltage sags, positive and negative sequence reactive powers are combined to flexibly raise and equalize the phase voltages; the maximum phase voltage is regulated below the upper limit and the minimum phase voltage just above the lower limit. The proposed control strategy is tested by considering a distant grid fault and a large grid impedance. Selected experimental results are reported in order to validate the behavior of the control scheme.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
  • AC–AC Converter With Controllable Phase and Amplitude
    • Authors: Zhang; Y.;Ruan, X.;
      Pages: 6235 - 6244
      Abstract: By adopting the concept of virtual quadrature source (VQS), a novel method for power transmission control—ac–ac converter with controllable phase and amplitude (ACCPA) was proposed, which has two control variables and is able to continuously regulate the phase and the amplitude of its output voltage independently. The operation principle was studied in detail, and the relationship with the optimization of control parameters of ACCPA's two duty ratios was analyzed for regulating the phase and amplitude of its output voltage. The phase is regulated in the front part, and the amplitude is regulated in the back part. For phase regulation, two methods were proposed to select optimal control parameters dynamically. The curves followed by two methods are crossed at the reference phase angle and have the same initial control parameters. It is necessary to adjust two independent control parameters for method 1 and one parameter for method 2. So method 2 is simple, easy to implement and has high control stability in comparison with method 1. The control strategy of ACCPA was presented and a prototype of single-phase ACCPA was manufactured. The experimental results verified the correctness of the theory and the feasibility of the control strategy.
      PubDate: Nov. 2014
      Issue No: Vol. 29, No. 11 (2014)
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