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  Subjects -> ELECTRONICS (Total: 154 journals)
Advances in Biosensors and Bioelectronics     Open Access   (Followers: 1)
Advances in Electronics     Open Access   (Followers: 1)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 5)
Advances in Microelectronic Engineering     Open Access   (Followers: 2)
Advances in Power Electronics     Open Access   (Followers: 7)
Aerospace and Electronic Systems, IEEE Transactions on     Hybrid Journal   (Followers: 75)
American Journal of Electrical and Electronic Engineering     Open Access   (Followers: 11)
Annals of Telecommunications     Hybrid Journal   (Followers: 4)
APL : Organic Electronics and Photonics     Hybrid Journal   (Followers: 2)
APSIPA Transactions on Signal and Information Processing     Open Access   (Followers: 6)
Archives of Electrical Engineering     Open Access   (Followers: 9)
Autonomous Mental Development, IEEE Transactions on     Hybrid Journal   (Followers: 5)
Bell Labs Technical Journal     Hybrid Journal   (Followers: 9)
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (Followers: 16)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 14)
Biomedical Instrumentation & Technology     Hybrid Journal   (Followers: 5)
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 5)
BULLETIN of National Technical University of Ukraine. Series RADIOTECHNIQUE. RADIOAPPARATUS BUILDING     Open Access   (Followers: 2)
Bulletin of the Polish Academy of Sciences : Technical Sciences     Open Access  
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 13)
China Communications     Full-text available via subscription   (Followers: 4)
Circuits and Systems     Open Access   (Followers: 9)
Consumer Electronics Times     Open Access   (Followers: 4)
Control Systems     Hybrid Journal   (Followers: 24)
Electronic Design     Partially Free  
Electronic Markets     Hybrid Journal   (Followers: 5)
Electronic Materials Letters     Hybrid Journal   (Followers: 3)
Electronics     Open Access   (Followers: 9)
Electronics and Communications in Japan     Hybrid Journal   (Followers: 5)
Electronics Letters     Hybrid Journal   (Followers: 19)
Embedded Systems Letters, IEEE     Hybrid Journal   (Followers: 23)
Energy Harvesting and Systems : Materials, Mechanisms, Circuits and Storage     Hybrid Journal   (Followers: 1)
EPJ Quantum Technology     Open Access  
EURASIP Journal on Embedded Systems     Open Access   (Followers: 9)
Facta Universitatis, Series : Electronics and Energetics     Open Access  
Foundations and TrendsĀ® in Communications and Information Theory     Full-text available via subscription   (Followers: 6)
Foundations and TrendsĀ® in Signal Processing     Full-text available via subscription   (Followers: 4)
Frequenz     Hybrid Journal   (Followers: 2)
Frontiers of Optoelectronics     Hybrid Journal   (Followers: 2)
Geoscience and Remote Sensing, IEEE Transactions on     Hybrid Journal   (Followers: 21)
Haptics, IEEE Transactions on     Hybrid Journal   (Followers: 4)
IEEE Antennas and Propagation Magazine     Hybrid Journal   (Followers: 15)
IEEE Antennas and Wireless Propagation Letters     Hybrid Journal   (Followers: 14)
IEEE Consumer Electronics Magazine     Full-text available via subscription   (Followers: 17)
IEEE Journal of Emerging and Selected Topics in Power Electronics     Hybrid Journal   (Followers: 12)
IEEE Journal of the Electron Devices Society     Open Access   (Followers: 2)
IEEE Power Electronics Magazine     Full-text available via subscription   (Followers: 6)
IEEE Transactions on Antennas and Propagation     Full-text available via subscription   (Followers: 11)
IEEE Transactions on Audio, Speech, and Language Processing     Hybrid Journal   (Followers: 12)
IEEE Transactions on Automatic Control     Hybrid Journal   (Followers: 26)
IEEE Transactions on Consumer Electronics     Hybrid Journal   (Followers: 17)
IEEE Transactions on Electron Devices     Hybrid Journal   (Followers: 8)
IEEE Transactions on Information Theory     Hybrid Journal   (Followers: 14)
IEEE Transactions on Power Electronics     Hybrid Journal   (Followers: 21)
IEICE - Transactions on Electronics     Full-text available via subscription   (Followers: 8)
IEICE - Transactions on Information and Systems     Full-text available via subscription   (Followers: 7)
IET Microwaves, Antennas & Propagation     Hybrid Journal   (Followers: 7)
IET Power Electronics     Hybrid Journal   (Followers: 13)
IET Wireless Sensor Systems     Hybrid Journal   (Followers: 10)
IETE Journal of Education     Open Access   (Followers: 2)
IETE Journal of Research     Open Access   (Followers: 9)
IETE Technical Review     Open Access   (Followers: 4)
Industrial Electronics, IEEE Transactions on     Hybrid Journal   (Followers: 13)
Industry Applications, IEEE Transactions on     Hybrid Journal   (Followers: 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: 2)
International Journal of Advanced Electronics and Communication Systems     Open Access   (Followers: 5)
International Journal of Advanced Research in Computer Science and Electronics Engineering     Open Access   (Followers: 20)
International Journal of Advances in Telecommunications, Electrotechnics, Signals and Systems     Open Access   (Followers: 3)
International Journal of Aerospace Innovations     Full-text available via subscription   (Followers: 11)
International Journal of Antennas and Propagation     Open Access   (Followers: 8)
International Journal of Applied Electronics in Physics & Robotics     Open Access   (Followers: 1)
International Journal of Biomedical Nanoscience and Nanotechnology     Hybrid Journal   (Followers: 7)
International Journal of Computational Vision and Robotics     Hybrid Journal   (Followers: 4)
International Journal of Computer & Electronics Research     Full-text available via subscription   (Followers: 2)
International Journal of Control     Hybrid Journal   (Followers: 13)
International Journal of Electronics     Hybrid Journal   (Followers: 2)
International Journal of Electronics & Data Communication     Open Access   (Followers: 4)
International Journal of Electronics and Telecommunications     Open Access   (Followers: 3)
International Journal of Granular Computing, Rough Sets and Intelligent Systems     Hybrid Journal   (Followers: 1)
International Journal of High Speed Electronics and Systems     Hybrid Journal  
International Journal of Microwave and Wireless Technologies     Hybrid Journal   (Followers: 1)
International Journal of Nano Devices, Sensors and Systems     Open Access   (Followers: 6)
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: 8)
International Journal of Review in Electronics & Communication Engineering     Open Access   (Followers: 2)
International Journal of Sensors, Wireless Communications and Control     Hybrid Journal   (Followers: 2)
International Journal of Superconductivity     Open Access  
International Journal of Systems, Control and Communications     Hybrid Journal   (Followers: 2)
International Journal on Communication     Full-text available via subscription   (Followers: 9)
International Journal on Electrical and Power Engineering     Full-text available via subscription   (Followers: 11)
International Transaction of Electrical and Computer Engineers System     Open Access  
Journal of Biosensors & Bioelectronics     Open Access   (Followers: 2)
Journal of Advanced Dielectrics     Open Access   (Followers: 1)
Journal of Artificial Intelligence     Open Access   (Followers: 5)
Journal of Circuits, Systems, and Computers     Hybrid Journal   (Followers: 1)
Journal of Computational Intelligence and Electronic Systems     Full-text available via subscription  
Journal of Electrical and Electronics Engineering Research     Open Access   (Followers: 4)

        1 2 | Last

Journal Cover   IEEE Transactions on Power Electronics
  [SJR: 2.866]   [H-I: 128]   [21 followers]  Follow
    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Print) 0885-8993
   Published by Institute of Electrical and Electronics Engineers (IEEE) Homepage  [176 journals]
  • Table of contents
    • Abstract: Presents the cover/table of contents for this issue of the periodical.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • IEEE Transactions on Power Electronics publication information
    • Abstract: Provides a listing of current staff, committee members and society officers.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • IEEE Power Electronics Society Information
    • Abstract: Provides a listing of current committee members and society officers.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • Decentralized Inverse-Droop Control for
           Input-Series–Output-Parallel DC–DC Converters
    • Authors: Guo Xu;Deshang Sha;Xiaozhong Liao;
      Pages: 4621 - 4625
      Abstract: Input-series-output-parallel dc-dc converters are suited for high-input voltage and low output voltage applications. This letter presents a decentralized inverse-droop control for this configuration. Each module is self-contained and no central controller is needed; thus, improving the system modularity, reliability, and flexibility. With the proposed inverse-droop control, the output voltage reference rises as the load becomes heavy. Even though the input voltages are not used in the inverse-droop loop, the power sharing including input voltage sharing and output current sharing can still be well achieved. Besides, the output voltage regulation characteristic is not affected by the variation of input voltage. The operation principle is introduced, and stability of the strategy is also revealed based on small signal modeling. Finally, the experiment is conducted to verify the effectiveness of the control strategy.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • A Self-Sustainable Power Management System for Reliable Power Scaling Up
           of Sediment Microbial Fuel Cells
    • Authors: Nghia Tang;Wookpyo Hong;Ewing; T.;Beyenal, H.;Jong-Hoon Kim;Deukhyoun Heo;
      Pages: 4626 - 4632
      Abstract: Sediment microbial fuel cells (SMFCs) are considered a promising renewable power source for remote monitoring applications. However, existing SMFCs can only produce several milliwatts of power, and the output power is not scaled linearly with the size of SMFCs. An effective alternative method to increase the output power is to independently operate multiple SMFCs, each of which has an optimal size for maximum power density. Independently operated SMFCs have electrically isolated electrodes (anodes/cathodes), which complicates the design of a suitable power management system (PMS). This paper describes the challenges in designing a PMS that can harvest energy from multiple independently operated (mio) SMFCs and accordingly proposes a design solution. From experimental results, the proposed PMS demonstrates reliable output power scaling up of mio-SMFC. The proposed PMS is self-sustainable because it is powered entirely from harvested energy without requiring additional external power sources.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • An Online Frequency-Domain Junction Temperature Estimation Method for IGBT
           Modules
    • Authors: Ze Wang;Wei Qiao;
      Pages: 4633 - 4637
      Abstract: This letter proposes a new frequency-domain thermal model for online junction temperature estimation of insulated-gate bipolar transistor (IGBT) modules. The proposed model characterizes the thermal behavior of an IGBT module by a linear time-invariant (LTI) system, whose frequency response is obtained by applying the fast Fourier transform (FFT) to the time derivative of the transient thermal impedance from junction to a reference position of the IGBT module. The junction temperature of the IGBT is then estimated using the frequency responses of the LTI system and the heat sources of the IGBT module. Simulation results show that the proposed method is computationally efficient for an accurate online junction temperature estimation of IGBT modules in both steady-state and transient loading conditions.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • Characterization of a Silicon IGBT and Silicon Carbide MOSFET Cross-Switch
           Hybrid
    • Authors: Rahimo; M.;Canales, F.;Minamisawa, R.A.;Papadopoulos, C.;Vemulapati, U.;Mihaila, A.;Kicin, S.;Drofenik, U.;
      Pages: 4638 - 4642
      Abstract: A parallel arrangement of a silicon (Si) IGBT and a silicon carbide (SiC) MOSFET is experimentally demonstrated. The concept referred to as the cross-switch (XS) hybrid aims to reach optimum power device performance by providing low static and dynamic losses while improving the overall electrical and thermal properties due to the combination of both the bipolar Si IGBT and unipolar SiC MOSFET characteristics. For the purpose of demonstrating the XS hybrid, the parallel configuration is implemented experimentally in a single package for devices rated at 1200 V. Test results are obtained to validate this approach with respect to the static and dynamic performance when compared to a full Si IGBT and a full SiC MOSFET reference devices having the same power ratings as for the XS hybrid samples.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • Performance of a 1-kV, Silicon Carbide Avalanche Breakdown Diode
    • Authors: Urciuoli; D.;Ryu, S.;Capell, D.C.;Ibitayo, D.;Koebke, G.;Tipton, C.W.;
      Pages: 4643 - 4645
      Abstract: A SiC avalanche breakdown diode (ABD) having a nominal 1-kV breakdown voltage was fabricated to provide improved suppression of voltage transients induced during hard-switched turn-off of solid-state devices. Three SiC ABDs were pulsed 1000 times in an inductive load circuit at peak currents of over 100 A. Superior performance in peak pulse current, clamping voltage, and peak pulse power was seen, compared to the results of two series-connected commercial TVS devices, collectively having a comparable breakdown voltage. The transient thermal response of the SiC ABDs was calculated using a model for energy dissipation in short pulses. SiC ABD design parameters and test data were used to show that the reported performance of these devices was not related to package thermal impedance.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • Detailed Analysis of DC-Link Virtual Impedance-Based Suppression Method
           for Harmonics Interaction in High-Power PWM Current-Source Motor Drives
    • Authors: Ye Zhang;Yun Wei Li;
      Pages: 4646 - 4658
      Abstract: For high-power PWM current-source motor drive systems, due to the low converter switching frequency and the relative small dc choke for reduced cost/weight, the converters' switching harmonics may interact through dc link and produce interharmonics in the entire system. Such harmonics interaction phenomenon may give rise to the system resonance at certain motor speeds, which degrades the grid-side power quality and generates excessive torque ripples on the motor side. The resonance caused by the harmonics interaction in high-power PWM current-source motor drives is investigated in previous study. In addition, to actively suppress such resonance, the basic idea of a dc-link virtual impedance-based suppression method has also been proposed. This paper extends the previous study to thoroughly analyze the mechanism and realization of resonance suppression by the dc-link virtual impedance-based method. The in-depth analysis shows that the dc-link virtual impedance-based method successfully enables the active interharmonics compensation capability of high-power PWM current-source drives, which is not addressed in previous researches. Moreover, simulations and experiments demonstrate that, by following the selection of coefficient in the suppression method discussed in this paper, the dc-link virtual impedance-based method can effectively enhance the attenuation effect of dc link in high-power PWM current-source drive systems so as to suppress the resonance due to the harmonics interaction under all resonance conditions.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • LCL Filter Design and Inductor Current Ripple Analysis for a Three-Level
           NPC Grid Interface Converter
    • Authors: Yang Jiao;Lee; F.C.;
      Pages: 4659 - 4668
      Abstract: The harmonic filter for a three-level neutral-point-clamped (NPC) grid interface converter is designed in this paper with good filtering performance and small component size. LCL topology is selected because of the attenuation and size tradeoff. The design of the inverter-side inductor L1 is emphasized due to its cost. A detailed inductor current ripple analysis is given based on the space vector modulation. The analysis derives the inductor volt-second and the maximum current ripple equation in line cycle. It also reveals the switching cycle current ripple distribution over a line cycle, with the consideration of power factor. The total system loss is calculated with different ripple current. Inductor L1 is determined by the loss and size tradeoff. Also the capacitor- and grid-side inductor L2 is designed based on attenuation requirement. Different damping circuits for LCL filter are compared and investigated in detail. The filter design is verified by both simulation and 200-kVA three-level NPC converter hardware.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • Indirect Matrix Converter-Based Topology and Modulation Schemes for
           Enhancing Input Reactive Power Capability
    • Authors: Yao Sun;Xing Li;Mei Su;Hui Wang;Hanbing Dan;Wenjing Xiong;
      Pages: 4669 - 4681
      Abstract: A new topology based on indirect matrix converter (IMC) is proposed to enhance the input reactive power capability. This topology consists of a conventional IMC and an auxiliary switching network (ASN), which is connected to the dc-link of the IMC in parallel. With the aid of ASN, an implicit current source converter-based static synchronous compensator can be embedded into an IMC, which lays a foundation for the input reactive power control. Based on the proposed topology, two modulation schemes are presented, and the formations of the output voltage and input reactive current are decoupled in both of them. To minimize power loss and improve input current quality, a double closed-loop control algorithm is introduced, in which the current through the dc inductor in ASN is controlled to be minimum. Different from the conventional IMC, the input reactive power of the topology is independent of its load condition without considering the practical constraints. The effectiveness of the proposed topology and modulation scheme is confirmed by experimental results.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • On Reducing Power Losses in Stack Multicell Converters with Optimal
           Voltage Balancing Method
    • Authors: Ghias; A.M.Y.M.;Pou, J.;Agelidis, V.G.;
      Pages: 4682 - 4695
      Abstract: This paper proposes a voltage balancing method for stacked multicell converters (SMCs) based on phase-disposition pulse-width modulation (PD-PWM). In order to reduce the switching transitions of the power devices, only optimal transitions between consecutive voltage levels are used. Selection of the optimal transition sequence is performed by evaluating a cost function. Significant reductions in the switching transitions and power losses of the power devices are achieved as compared to the optimal-state voltage balancing method where nonoptimal transitions are allowed. Simulation and experimental results from a seven-level 3×2 SMC verifies that the proposed PD-PWM voltage balancing method is robust under linear/nonlinear loads and transients.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • High Step-Up Interleaved Forward-Flyback Boost Converter With
           Three-Winding Coupled Inductors
    • Authors: Kuo-Ching Tseng;Jyun-Ze Chen;Jang-Ting Lin;Chi-Chih Huang;Tzu-Hsiang Yen;
      Pages: 4696 - 4703
      Abstract: A novel high step-up interleaved converter for high-power high-voltage applications is proposed in this paper. Through three-winding coupled inductors, a high step-up conversion with high efficiency is obtained. The proposed converter not only reduces the current stress, but also constrains the input current ripple, which decreases the conduction losses and lengthens the life time of input source. In addition, due to the lossless passive clamp performance, leakage energy is recycled to the output terminal. Hence, large voltage spikes across the main switches are alleviated and the efficiency is improved. Even, the low-voltage stresses on semiconductor components are substantially lower than the output voltage. Finally, the prototype circuit with input voltage 48 V, output voltage 380 V, and output power 2 kW is operated to verify its performance. The highest efficiency is 96.5%, and the full-load efficiency is 92.6%.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • Functional Modeling of Symmetrical Multipulse Autotransformer Rectifier
           Units for Aerospace Applications
    • Authors: Tao Yang;Bozhko; S.;Asher, G.;
      Pages: 4704 - 4713
      Abstract: This paper aims to develop a functional model of symmetrical multipulse autotransformer rectifier units (ATRUs) for more-electric aircraft (MEA) applications. The ATRU is seen as the most reliable way readily to be applied in the MEA. Interestingly, there is no model of ATRUs suitable for unbalanced or faulty conditions at the moment. This paper is aimed to fill this gap and develop functional models suitable for both balanced and unbalanced conditions. Using the fact that the dc voltage and current are strongly related to the voltage and current vectors at the ac terminals of ATRUs, a functional model has been developed for the asymmetric ATRUs. The developed functional models are validated through simulation and experiment. The efficiency of the developed model is also demonstrated by comparing with corresponding detailed switching models. The developed functional model shows significant improvement of simulation efficiency, especially under balanced conditions.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • Closed-Loop Discontinuous Modulation Technique for Capacitor Voltage
           Ripples and Switching Losses Reduction in Modular Multilevel Converters
    • Authors: Picas; R.;Ceballos, S.;Pou, J.;Zaragoza, J.;Konstantinou, G.;Agelidis, V.G.;
      Pages: 4714 - 4725
      Abstract: In this paper, a new discontinuous modulation technique is presented for the operation of the modular multilevel converter (MMC). The modulation technique is based on adding a zero sequence to the original modulation signals so that the MMC arms are clamped to the upper or lower terminals of the dc-link bus. The clamping intervals are controlled according to the absolute value of the output current to minimize the switching losses of the MMC. A significant reduction in the capacitor voltage ripples is achieved, especially when operating with low modulation indices. Furthermore, a circulating current control strategy suitable for this modulation technique is also proposed. Simulation and experimental results under various operating points are reported along with evaluation and comparison results against a conventional carrier-based pulse width modulation method.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • Virtual RC Damping of LCL-Filtered
           Voltage Source Converters With Extended Selective Harmonic Compensation
    • Authors: Xiongfei Wang;Blaabjerg; F.;Poh Chiang Loh;
      Pages: 4726 - 4737
      Abstract: Active damping and harmonic compensation are two common challenges faced by LCL-filtered voltage source converters. To manage them holistically, this paper begins by proposing a virtual RC damper in parallel with the passive filter capacitor. The virtual damper is actively inserted by feeding back the passive capacitor current through a high-pass filter, which indirectly, furnishes two superior features. They are the mitigation of phase lag experienced by a conventional damper and the avoidance of instability caused by the negative resistance inserted unintentionally. Moreover, with the virtual RC damper, the frequency region, within which the harmonic compensation is effective, can be extended beyond the gain crossover frequency. This is of interest to some high-performance applications, but has presently not been achieved by existing schemes. Performance of the proposed scheme has been tested in the laboratory with results obtained for demonstrating stability and harmonic compensation.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • Versatile Control of Unidirectional AC–DC Boost Converters for
           Power Quality Mitigation
    • Authors: Sung Min Park;Sung-Yeul Park;
      Pages: 4738 - 4749
      Abstract: This paper introduces a versatile control scheme for unidirectional ac-dc boost converters for the purpose of mitigating grid power quality. Since most power factor correction circuits available in the commercial market utilize unidirectional ac-dc boost converter topologies, this is an almost no-cost solution for compensating harmonic current and reactive power in residential applications. Harmonic current and reactive power compensation methods in the unidirectional ac-dc boost converter are investigated. The additional focus of this paper is to quantify the input current distortions by the unidirectional ac-dc boost converter used for supplying not only active power to the load but also reactive power. Due to input current distortions, the amount of reactive power injected from an individual converter to the grid should be restricted. Experimental results are presented to validate the effectiveness of the proposed control method.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • Modulation Scheme Analysis for High-Efficiency Three-Phase Buck-Type
           Rectifier Considering Different Device Combinations
    • Authors: Ben Guo;Wang; F.F.;Burgos, R.;Aeloiza, E.;
      Pages: 4750 - 4761
      Abstract: The three-phase buck-type rectifier features a step-down ac-dc conversion function, smaller filter size, inrush current limiting capability, and potential for high efficiency, where its switching loss is dependent on the modulation scheme and the specific semiconductors used. In this paper, three different device combinations are compared through experiments on their switching characteristics for the buck rectifier application. It is shown that the switching performance of two series-connected devices becomes worse than a single device due to the superposition of the nonideal semiconductor characteristics. Moreover, the switching loss in the commutation between two switches is usually higher than the one in the commutation between a switch and the freewheeling diode. Taking into consideration both types of commutations, the switching loss of the buck rectifier is then modeled and the analytical equations are derived for four space vector modulation schemes. According to the analysis, each modulation scheme has its own field for high-efficiency application. The most advantageous modulation scheme is identified in this paper for each of the device combinations investigated.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • Alleviation of Electromagnetic Interference Noise Using a Resonant Shunt
           for Balanced Converters
    • Authors: Yu Zhang;Feng Zheng;Yue Wang;
      Pages: 4762 - 4773
      Abstract: Balanced converter is an effective way to reduce the CM noise. However, the parasitic capacitance between the switch and heat sink leads to resonant problems, resulting in high noise in certain frequency range. This paper proposes a novel coupled inductor structure based on the balanced technique for the Boost converter to further reduce the CM noise at certain frequency range. A shunt resonant path is adopted to offer a maximum suppression. The analytical estimation for shunt winding's performaPnce is provided for better design. Some simulation and experimental results of this new technique are presented to validate its effectiveness. The experiments about the capacitance unbalance, different load current, and reduction of the CM inductor size are also discussed for better understanding of this technique.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • State-of-Charge Estimation of Lithium-Ion Battery Using Square Root
           Spherical Unscented Kalman Filter (Sqrt-UKFST) in Nanosatellite
    • Authors: Aung; H.;Low, K.S.;Shu Ting Goh;
      Pages: 4774 - 4783
      Abstract: State-of-charge (SOC) estimation is an important aspect for modern battery management system. Dynamic and closed loop model-based methods such as extended Kalman filter (EKF) have been extensively used in SOC estimation. However, the EKF suffers from drawbacks such as Jacobian matrix derivation and linearization accuracy. In this paper, a new SOC estimation method based on square root unscented Kalman filter using spherical transform (Sqrt-UKFST) with unit hyper sphere is proposed. The Sqrt-UKFST does not require the linearization for nonlinear model and uses fewer sigma points with spherical transform, which reduces the computational requirement of traditional unscented transform. The square root characteristics improve the numerical properties of state covariance. The proposed method has been experimentally validated. The results are compared with existing SOC estimation methods such as Coulomb counting, portable fuel gauge, and EKF. The proposed method has an absolute root mean square error (RMSE) of 1.42% and an absolute maximum error of 4.96%. These errors are lower than the other three methods. When compared with EKF, it represents 37% and 44% improvement in RMSE and maximum error respectively. Furthermore, the Sqrt-UKFST is less sensitive to parameter variation than EKF and it requires 32% less computational requirement than the regular UKF.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • Aalborg Inverter - A New Type of “Buck in Buck, Boost in
           Boost” Grid-Tied Inverter
    • Authors: Weimin Wu;Junhao Ji;Blaabjerg; F.;
      Pages: 4784 - 4793
      Abstract: This paper presents a new family of high efficiency dc/ac grid-tied inverter with a wide variation of input dc voltage. It is a “boost in boost, buck in buck” inverter, meaning that only one power stage works at high frequency in order to achieve minimum switching loss. The minimum voltage drop of the filtering inductor in the power loop is achieved to reduce the conduction power loss in both “boost” and “buck” mode. The principle of operation is demonstrated through the analysis on the equivalent circuits of a “half-bridge” single-phase inverter. The theoretical analysis shows that when input dc voltage is larger than the magnitude of the ac voltage, it is a voltage-source inverter, and on the contrary it is current-source inverter in the other mode. A 220 V/50 Hz/ 2000 W prototype has been constructed. Simulations and experiments show that it has a good control and system performance.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • Frequency-Based Energy-Management Strategy for Stand-Alone Systems With
           Distributed Battery Storage
    • Authors: Urtasun; A.;Sanchis, E.L.;Sanchis, P.;Marroyo, L.;
      Pages: 4794 - 4808
      Abstract: Distributed generation is an attractive solution for stand-alone ac supply systems. In such systems, the installation of two or more energy-storage units is recommended for system redundancy and may also be required when there is a consumption increase following installation. However, energy management with multiple energy-storage units has been, but vaguely analyzed in the literature and the few studies made are based on communication cables with a central supervisor. This paper proposes an energy-management strategy for a multiple-battery system which makes it possible to avoid the use of communication cables, rendering the system more cost effective and reliable. The strategy modifies the conventional droop method so that the power becomes unbalanced, allowing for the regulation of one or more battery voltages or currents, as required. Furthermore, whenever the frequency is high, the PV inverters reduce their power in order to prevent the battery from overcharge or high charging currents. On the other hand, whenever the frequency is low, then either the noncritical loads are regulated or the system stops in order to prevent the battery from overdischarge or high discharging currents. Simulation and experimental validation are performed for a system with two-battery inverters, two-PV inverters, and a number of loads.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • A Single-Stage Photovoltaic System for a Dual-Inverter-Fed Open-End
           Winding Induction Motor Drive for Pumping Applications
    • Authors: Jain; S.;Thopukara, A.K.;Karampuri, R.;Somasekhar, V.T.;
      Pages: 4809 - 4818
      Abstract: This paper presents an integrated solution for a photovoltaic (PV)-fed water-pump drive system, which uses an open-end winding induction motor (OEWIM). The dual-inverter-fed OEWIM drive achieves the functionality of a three-level inverter and requires low value dc-bus voltage. This helps in an optimal arrangement of PV modules, which could avoid large strings and helps in improving the PV performance with wide bandwidth of operating voltage. It also reduces the voltage rating of the dc-link capacitors and switching devices used in the system. The proposed control strategy achieves an integration of both maximum power point tracking and V/f control for the efficient utilization of the PV panels and the motor. The proposed control scheme requires the sensing of PV voltage and current only. Thus, the system requires less number of sensors. All the analytical, simulation, and experimental results of this work under different environmental conditions are presented in this paper.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • Grid-Connected Forward Microinverter With Primary-Parallel
           Secondary-Series Transformer
    • Authors: Meneses; D.;Garcia, O.;Alou, P.;Oliver, J.A.;Cobos, J.A.;
      Pages: 4819 - 4830
      Abstract: This paper presents a primary-parallel secondary-series multicore forward microinverter for photovoltaic ac-module application. The presented microinverter operates with a constant off-time boundary mode control, providing MPPT capability and unity power factor. The proposed multitransformer solution allows using low-profile unitary turns ratio transformers. Therefore, the transformers are better coupled and the overall performance of the microinverter is improved. Due to the multiphase solution, the number of devices increases but the current stress and losses per device are reduced contributing to an easier thermal management. Furthermore, the decoupling capacitor is split among the phases, contributing to a low-profile solution without electrolytic capacitors suitable to be mounted in the frame of a PV module. The proposed solution is compared to the classical parallel-interleaved approach, showing better efficiency in a wide power range and improving the weighted efficiency.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • Modularized Control Strategy and Performance Analysis of DFIG System Under
           Unbalanced and Harmonic Grid Voltage
    • Authors: Yipeng Song;Heng Nian;
      Pages: 4831 - 4842
      Abstract: The paper presents a modularized control strategy of doubly fed induction generator (DFIG) system, including the grid-side converter (GSC) and rotor-side converter (RSC), under unbalanced and harmonic grid voltage. The sequence decomposition process and complicated control reference calculation can be avoided in the proposed control strategy. From the perspective of power grid friendly operation, the control targets of DFIG system in this paper are chosen as: 1) smooth active and reactive power injected into the power grid; 2) balanced and sinusoidal current injected into the power grid. The RSC and GSC can work as two independent modules and the communication between RSC and GSC can be removed. Furthermore, the third harmonic current component, dc-link voltage fluctuation, and electromagnetic torque pulsation under the different control targets are theoretically analyzed. Finally, the availability of the proposed modularized control strategy of DFIG system under unbalanced and distorted grid voltage is verified by experiment results.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • Modeling and Controller Design of a Semiisolated Multiinput Converter for
           a Hybrid PV/Wind Power Charger System
    • Authors: Cheng-Wei Chen;Chien-Yao Liao;Kun-Hung Chen;Yaow-Ming Chen;
      Pages: 4843 - 4853
      Abstract: The objective of this paper is to propose the development of a multiinput dc-dc converter (MIC) family, which is composed of isolated and/or nonisolated dc-dc converters. By analyzing five basic isolated dc-dc converters, four isolated pulsating voltage source cells and three isolated pulsating current source cells are generated. Moreover, a semiisolated multiinput converter (S-MIC) for hybrid PV/wind power charger system which can simplify the power system, reduce the cost, deliver continuous power, and overcome high-voltage-transfer-ratio problems is proposed. In this paper, the operational principle of the proposed S-MIC is explained, the small-signal ac model is derived, and the controller design is developed. Computer simulations and experimental results are presented to verify the accuracy of the proposed small-signal ac model and the performance of the proposed S-MIC.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • A Voltage-Feed High-Frequency Resonant Inverter With Controlled Current
           Output as a High-Frequency AC Power Source
    • Authors: Jun Zeng;Junfeng Liu;Jinming Yang;Fei Luo;
      Pages: 4854 - 4863
      Abstract: A current-based power distribution is presented for the applications of high-frequency ac power distribution system (PDS). Comparing with the traditional voltage-based counterpart, the current-based system can be applied into some specific applications, such as high-voltage gate-driving system, contactless power transmission, etc. A modified resonant topology based on LCL-T tank is proposed to implement high-frequency current source. The effective magnitude control and high conversion efficiency are both achieved. First, the proposed topology is examined with circuit principle, operational cycle analysis, and soft-switching description. Second, the phase-shifted control scheme is explored to calculate the equivalent resonant capacitor of LCL-T resonant tank, as well as the relations between current gain ratio and phase-shifted angle control are discussed in depth. Finally, the simulation model and experiment prototype are implemented with rated peak current of 2 A, rated output frequency of 30 kHz, and rated output power of 50 W. The experimental results in accordance with simulation prove that the constant current characteristics are maintained with high conversion efficiency. Hence, the proposed circuit topology and control scheme are a feasible realization of current source that is used to feed high-frequency PDS.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • Interleaved Phase-Shift Full-Bridge Converter With Transformer Winding
           Series–Parallel Autoregulated (SPAR) Current Doubler Rectifier
    • Authors: Xinke Wu;Hui Chen;Junming Zhang;Fangzheng Peng;Zhaoming Qian;
      Pages: 4864 - 4873
      Abstract: The analysis and design guidelines for a two-phase interleaved phase-shift full-bridge converter with transformer winding series-parallel autoregulated current doubler rectifier are presented in this paper. The secondary windings of two transformers work in parallel when the equivalent duty cycle is smaller than 0.25 but in series when the duty cycle is larger than 0.25 owing to the series-parallel autoregulated rectifier. With the proposed rectifying structure, the voltage stress of the rectifier is reduced. Also, the interleaving operation reduces the output current ripple. A 1-kW prototype with 200-400-V input and 50-V/20-A output is built up to verify the theoretical analysis.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • Analysis of Active-Network Converter With Coupled Inductors
    • Authors: Yu Tang;Dongjin Fu;Ting Wang;Zhiwei Xu;
      Pages: 4874 - 4882
      Abstract: High step-up voltage gain dc-dc converters are widely applied in fuel cell stacks, photovoltaic arrays, battery sources, and high intensity discharge lamps power systems. Active-network converters with coupled inductors (CL-ANC) are derived from switched inductor active-network converters (SL-ANC). The proposed converter contains two coupled inductors which can be integrated into one magnetic core and two power switches. The converter can provide a relatively high voltage conversion ratio with a small duty cycle; the voltage and current stress of power switches are low which is helpful to reduce the losses. This paper shows the key waveforms of the CL-ANC and detailed derivation of the steady-state operation principle. The voltage conversion ratio and the effect of the leakage inductance on voltage gain are discussed. The voltage stress and current stress on the power devices are illustrated and the comparison between the proposed converter and SL-ANC are given. Finally, the prototype has been established in the lab with 200 V and 400 V output under different turn ratios. Experimental results are given to verify the correctness of the analysis.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • A Fully Soft-Switched Single Switch Isolated DC–DC Converter
    • Authors: Minjae Kim;Sewan Choi;
      Pages: 4883 - 4890
      Abstract: This paper proposes a soft-switched single switch isolated converter. The proposed converter is able to offer low cost and high power density in step-up application due to the following features: zero-current switching (ZCS) turn-on and zero-voltage switching (ZVS) turn-off of switch and ZCS turn-off of diodes regardless of voltage and load variation; low rated lossless snubber; reduced transformer volume compared to flyback-based converters due to low magnetizing current. Experimental results on a 100 kHz, 250 W prototype are provided to validate the proposed concept.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • A Four-Switch Three-Phase SEPIC-Based Inverter
    • Authors: Diab; M.S.;Elserougi, A.;Massoud, A.M.;Abdel-Khalik, A.S.;Ahmed, S.;
      Pages: 4891 - 4905
      Abstract: The four-switch three-phase (FSTP) inverter has been proposed as an innovative inverter design to reduce the cost, complexity, size, and switching losses of the dc-ac conversion system. Traditional FSTP inverter usually operates at half the dc input voltage; hence, the output line voltage cannot exceed this value. This paper proposes a novel design for the FSTP inverter based on the topology of the single-ended primary-inductance converter (SEPIC). The proposed topology provides pure sinusoidal output voltages with no need for output filter. Compared to traditional FSTP inverter, the proposed FSTP SEPIC inverter improves the voltage utilization factor of the input dc supply, where the proposed topology provides higher output line voltage which can be extended up to the full value of the dc input voltage. The integral sliding-mode control is used with the proposed topology to optimize its dynamics and to ensure robustness of the system during different operating conditions. Derivation of the equations describing the parameters design, components ratings, and the operation of the proposed SEPIC inverter is presented in this paper. Simulation model and experimental setup are used to validate the proposed concept. Simulations and experimental results show the effectiveness of the proposed inverter.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • Parallel Architecture for Battery Charge Equalization
    • Authors: Bo Dong;Ye Li;Yehui Han;
      Pages: 4906 - 4913
      Abstract: One limitation of many battery charge equalizers is their slow equalization speed, especially when there are a large number of batteries in the series-string in high-voltage and high-power applications. This paper presents a new architecture for battery charge equalization. In this architecture, independent equalizers are placed in different layers and all the layers can equalize the corresponding batteries simultaneously, thus reducing equalization time by 50%. We explore the operation, performance characteristics, and the design of the architecture. Both simulation and experimental results are presented to validate the analysis in this paper.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • High-Efficiency-Isolated Single-Input Multiple-Output Bidirectional
           Converter
    • Authors: Rong-Jong Wai;Jun-Jie Liaw;
      Pages: 4914 - 4930
      Abstract: This study presents a high-efficiency-isolated single-input multiple-output bidirectional (HISMB) converter for a power storage system. According to the power management, the proposed HISMB converter can operate at a step-up state (energy release) and a step-down state (energy storage). At the step-up state, it can boost the voltage of a low-voltage input power source to a high-voltage-side dc bus and middle-voltage terminals. When the high-voltage-side dc bus has excess energy, one can reversely transmit the energy. The high-voltage dc bus can take as the main power, and middle-voltage output terminals can supply powers for individual middle-voltage dc loads or to charge auxiliary power sources (e.g., battery modules). In this study, a coupled-inductor-based HISMB converter accomplishes the bidirectional power control with the properties of voltage clamping and soft switching, and the corresponding device specifications are adequately designed. As a result, the energy of the leakage inductor of the coupled inductor can be recycled and released to the high-voltage-side dc bus and auxiliary power sources, and the voltage stresses on power switches can be greatly reduced. Moreover, the switching losses can be significantly decreased because of all power switches with zero-voltage-switching features. Therefore, the objectives of high-efficiency power conversion, electric isolation, bidirectional energy transmission, and various output voltage with different levels can be obtained. The effectiveness of the proposed HISMB converter is verified by experimental results of a kW-level prototype in practical applications.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • A High-Efficiency PFM Half-Bridge Converter Utilizing a Half-Bridge
           LLC Converter Under Light Load Conditions
    • Authors: Jae-Bum Lee;Jae-Kuk Kim;Jae-Hyun Kim;Jae-Il Baek;Gun-Woo Moon;
      Pages: 4931 - 4942
      Abstract: Recently, the various types of the half-bridge (HB) converters with the output inductor have been developed, and they exhibit a good performance in medium power applications such as the server power supplies and personal computer power supplies requiring high output current. However, they have common problems such as the primary and secondary switch turn-off losses and snubber loss in the secondary side caused by the output inductor, which degrades light load efficiency. To relieve these limitations of the conventional HB converters, a new HB converter, which employs one additional switch and capacitor in the secondary side, is proposed for a high efficiency under light load conditions in this paper. Since the proposed converter operates like the HB LLC converter with below operation by turning on additional switch under light load conditions, the switch turn-off losses and snubber loss can be minimized, and the zero-voltage switching (ZVS) capability can be improved. Consequently, the proposed converter can achieve a high efficiency under light load conditions. To confirm the operation, features, and validity of the proposed converter, a 330-400 V input and 12 V/300 W output laboratory prototype is built and tested.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • Resonant Switched-Capacitor Voltage Regulator With Ideal Transient
           Response
    • Authors: Cervera; A.;Mordechai Peretz, M.;
      Pages: 4943 - 4951
      Abstract: A new, small and efficient voltage regulator, realized using a resonant switched-capacitor converter technology, is introduced. Voltage regulation is implemented by means of simple digital pulse density modulation. It displays an ideal transient response with a zero-order nature to all disturbance types. The newly developed topology acts as a gyrator with a wide range of voltage conversion ratios (below as well as above unity) with constant efficiency characteristics for the entire operation range. The operation of the voltage regulator is verified on a 20 W experimental prototype, demonstrating ideal transient recovery without over/undershoots in response to load and line transients. Simple design guidelines for the voltage regulation system are provided and verified by experiments.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • Modeling and Analysis of Resonant Switched-Capacitor Converters With
           Free-Wheeling ZCS
    • Authors: Hamo; E.;Evzelman, M.;Peretz, M.M.;
      Pages: 4952 - 4959
      Abstract: This paper introduces a unified modeling methodology to describe and explore the loss mechanism of resonant switched-capacitor converter (SCC) operating in a self-commutation zero current switching (ZCS) mode. The conventional equivalent resistance concept, which assumes a single conduction path of the resonant current, is generalized and extended to model the losses in cases where the resonant current is divided across several conduction loops. The new modeling concept is compatible to describe the losses resulting from resistive elements as well as P-N junction devices, offering a solution for the equivalent resistance. Verification of the concept has been carried out by simulations and experiments on 3-30 W unity, double gain and multiphase Fibonacci resonant SCC with free-wheeling ZCS. A very good agreement is obtained between the theoretical calculations, simulations, and experimental results, well demonstrating model capability to identify the loss contributors in each conduction path.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • Design of Class E Resonant Rectifiers and Diode Evaluation for VHF Power
           Conversion
    • Authors: Santiago-Gonzalez; J.A.;Elbaggari, K.M.;Afridi, K.K.;Perreault, D.J.;
      Pages: 4960 - 4972
      Abstract: Resonant rectifiers have important applications in very-high-frequency (VHF) power conversion systems, including dc-dc converters, wireless power transfer systems, and energy recovery circuits for radio-frequency systems. In many of these applications, it is desirable for the rectifier to appear as a resistor at its ac input port. However, for a given dc output voltage, the input impedance of a resonant rectifier varies in magnitude and phase as output power changes. This paper presents a design methodology for class E rectifiers that maintain near-resistive input impedance along with the experimental demonstration of this approach. Resonant rectifiers operating at 30 MHz over 10:1 and 2:1 power ranges are used to validate the design methodology and identify its limits. Furthermore, a number of Si Schottky diodes are experimentally evaluated for VHF rectification and categorized based on performance.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • Development of a Wind Interior Permanent-Magnet Synchronous
           Generator-Based Microgrid and Its Operation Control
    • Authors: Kai-Wei Hu;Chang-Ming Liaw;
      Pages: 4973 - 4985
      Abstract: This paper presents the development of a wind interior permanent-magnet synchronous generator (IPMSG)-based dc microgrid and its operation control. First, the derated characteristics of PMSG systems with various ac/dc converters and operation controls are comparatively analyzed. Then, the IPMSG followed by a three-phase Vienna switch-mode rectifier is developed to establish the common dc bus of dc microgrid. Good developed power and voltage regulation characteristics are achieved via the proposed commutation tuning, robust current, and voltage controls. Second, a single-phase three-wire inverter is constructed to serve as the test load. Good ac 220 V/110 V output voltage waveforms under unknown and nonlinear loads are preserved by the developed robust waveform tracking control scheme. Third, a battery energy storage system is established, and the fast energy storage support response is obtained via the proposed droop control approach with adaptive predictive current control method. In addition, a chopped dump load is equipped to enhance the energy balance control flexibility.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • On the Performance of Multiobjective Evolutionary Algorithms in Automatic
           Parameter Extraction of Power Diodes
    • Authors: Prada; D.;Bellini, M.;Stevanovic, I.;Lemaitre, L.;Victory, J.;Vobecky, J.;Sacco, R.;Lauritzen, P.O.;
      Pages: 4986 - 4997
      Abstract: In this paper, a general, robust, and automatic parameter extraction of nonlinear compact models is presented. The parameter extraction is based on multiobjective optimization using evolutionary algorithms, which allow fitting of several highly nonlinear and highly conflicting characteristics simultaneously. Two multiobjective evolutionary algorithms which have been proved to be robust for a wide range of multiobjective problems [1]-[3], the nondominated sorting genetic algorithm II and the multiobjective covariance matrix adaptation evolution strategy, are used in the parameter extraction of a novel power diode compact model based on the lumped charge technique. The performance of the algorithms is assessed using a systematic statistical approach. Good agreement between the simulated and measured characteristics of the power diode shows the accuracy of the used compact model and the efficiency and effectiveness of the proposed multiobjective optimization scheme.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • A Novel Drive Method for High-Speed Brushless DC Motor Operating in a Wide
           Range
    • Authors: Chenjun Cui;Gang Liu;Kun Wang;
      Pages: 4998 - 5008
      Abstract: In this paper, a novel drive method, which is different from the traditional motor drive techniques, for high-speed brushless DC (BLDC) motor is proposed and verified by a series of experiments. It is well known that the BLDC motor can be driven by either pulse-width modulation (PWM) techniques with a constant dc-link voltage or pulse-amplitude modulation (PAM) techniques with an adjustable dc-link voltage. However, to our best knowledge, there is rare study providing a proper drive method for a high-speed BLDC motor with a large power over a wide speed range. Therefore, the detailed theoretical analysis comparison of the PWM control and the PAM control for high-speed BLDC motor is first given. Then, a conclusion that the PAM control is superior to the PWM control at high speed is obtained because of decreasing the commutation delay and high-frequency harmonic wave. Meanwhile, a new high-speed BLDC motor drive method based on the hybrid approach combining PWM and PAM is proposed. Finally, the feasibility and effectiveness of the performance analysis comparison and the new drive method are verified by several experiments.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • Criteria-Based Modulation for Multilevel Inverters
    • Authors: Dagan; K.J.;Rabinovici, R.;
      Pages: 5009 - 5018
      Abstract: Pulse width modulation schemes are aimed at adjusting the fundamental component while reducing the harmonic content of an inverter output voltage or current. This paper addresses the topic of optimal inverter operation in reference to a given objective function. The objective function could embody either a single performance criterion, such as voltage or current total harmonic distortion (THD), or a weighted sum of multiple criteria. The proposed method ensures primacy of the chosen solution while imposing no restriction over its modulation index. In particular, operating the inverter by the chosen solution would result in performances superior to any other modulation scheme commutating in an equal number of switching angles per fundamental cycle. The proposed method allows for the consideration of practical inverter constraints and prevents the possibility of impractical switching sequence. A detailed investigation of the method is given, accompanied by two practical cases minimizing, respectively, phase-voltage THD and line-current THD of a three-level inverter. Selected simulation and experimental results are presented to validate the theoretical part.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • Model Predictive Control Methods to Reduce Common-Mode Voltage for
           Three-Phase Voltage Source Inverters
    • Authors: Sangshin Kwak;Sung-ki Mun;
      Pages: 5019 - 5035
      Abstract: In this paper, we propose model predictive control methods to reduce the common-mode voltage of three-phase voltage source inverters (VSIs). In the reduced common-mode voltage-model predictive control (RCMV-MPC) methods proposed in this paper, only nonzero voltage vectors are utilized to reduce the common-mode voltage as well as to control the load currents. In addition, two nonzero voltage vectors are selected from the cost function at every sampling period, instead of using only one optimal vector during one sampling period. The two selected nonzero vectors are distributed in one sampling period in such a way as to minimize the error between the measured load current and the reference. Without utilizing the zero vectors, the common-mode voltage controlled by the proposed RCMV-MPC algorithms can be restricted within ±Vdc/6. Furthermore, application of the two nonzero vectors with optimal time sharing between them can yield satisfactory load current ripple performance without using the zero vectors. Thus, the proposed RCMV-MPC methods can reduce the common-mode voltage as well as control the load currents with fast transient response and satisfactory load current ripple performance compared with the conventional model predictive control method. Simulation and experimental results are included to verify the effectiveness of the proposed RCMV-MPC methods.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • Maximum Torque Per Ampere (MTPA) Control for Interior Permanent Magnet
           Synchronous Machine Drives Based on Virtual Signal Injection
    • Authors: Tianfu Sun;Jiabin Wang;Xiao Chen;
      Pages: 5036 - 5045
      Abstract: This paper introduces a novel virtual signal injection-based control method for maximum torque per ampere (MTPA) operation of interior permanent magnet synchronous machine (IPMSM) drives. The proposed method injects a small virtual current angle signal mathematically for tracking the MTPA operating point and generating d-axis current command by utilizing the inherent characteristic of the MTPA operation. This method is parameter independent in tracking the MTPA points, and it does not inject any real signal to current or voltage command. Consequently, the problems associated with real high-frequency signal injection, such as increases in copper and iron loss can be avoided. Moreover, it is robust to current/voltage harmonics and motor torque disturbances. The proposed method is verified by simulations and experiments under various operating conditions on a prototype IPMSM drive system.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • The Dynamic Control of Reactive Power for the Brushless Doubly Fed
           Induction Machine With Indirect Stator-Quantities Control Scheme
    • Authors: Rongli Zhao;Ailing Zhang;Yun Ma;Xin Wang;Jun Yan;Zhizhong Ma;
      Pages: 5046 - 5057
      Abstract: Compared to the doubly fed induction machine (DFIM), the brushless doubly fed induction machine (BDFIM) has higher reliability by virtue of the absence of a brush gear. Recent research on structure optimization design and control strategy of BDFIM has made remarkable progress. BDFIM indirect stator-quantities control (ISC) is a new control strategy, which, in comparison to vector control strategy, requires fewer parameters and does not need rotating coordinate transformation. This paper further develops the dynamic control of reactive power for the BDFIM with ISC scheme. Detailed theoretical analysis is done to show the controller structure of the reactive power. The experimental results of the prototype show the feasibility of the proposed scheme. As a result, the proposed ISC controllers have been able to control not only speed and torque, but also the reactive power.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • Investigating a MOSFET Driver (Buffer) Circuit Transition
           Ringings Using an Analytical Model
    • Authors: Azizoglu; B.T.;Karaca, H.;
      Pages: 5058 - 5066
      Abstract: In this paper, a new analytical model introduced extracting from datasheet of a MOSFET and developed a MATLAB code for simulating a MOSFET driver circuit is proposed in the literature to observe the ringings of its output for capacitively loaded case. The output waveform is studied only for high-to-low transition. Gate drive resistance, wiring parasitics of the printed circuit board layout, and the characteristic properties of the MOSFET affect both the delay time of the MOSFET to become ON and performance of the driver circuit. Also, voltage stress of the MOSFET and therefore safe operating range for the circuit all depend on these effects. These effects are all considered in the design stage. The simulation results obtained from CST Design Studio software are compared with the results of experimental work. The analytical modeling results solved in the MATLAB are found congruent with the simulation results and experimental results as well. The simulation work showed that developed MATLAB code along with extracted models from datasheets has less convergence problems and also requires less simulation time.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • An LCL-LC Filter for Grid-Connected
           Converter: Topology, Parameter, and Analysis
    • Authors: Fei Li;Xing Zhang;Hong Zhu;Haoyuan Li;Changzhou Yu;
      Pages: 5067 - 5077
      Abstract: In order to further cut down the cost of filter for grid-connected pulsewidth modulation (PWM) converter under the more and more stringent grid code, a new kind of high-order filter, named LCL-LC filter, is presented in this paper. The resonant frequency characteristics of the filter are analyzed, and a parameter design method on the base of the characteristics is also proposed in the paper. The proposed parameter design method can easily make full use of the existing research results about the traditional LCL filter parameter design. And then a parameter robustness analysis method based on four-dimensional graphics is proposed to analyze parameter robustness of the presented filter. Compared with the traditional one, the proposed analysis method can analyze the filter performance under variations of several parameters at a time without any iteration. The comparative analysis and discussion considering the LCL filter, the trap filter, and the LCL- LC filter, are presented and verified through the experiments on a 5 kW grid-connected converter prototype. Experiment results demonstrate the accuracy of theoretical analysis and prove that the presented filter has a better performance than two others.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • Electrodeposited Nanolaminated CoNiFe Cores for Ultracompact DC–DC
           Power Conversion
    • Authors: Jooncheol Kim;Minsoo Kim;Herrault; F.;Park, J.Y.;Allen, M.G.;
      Pages: 5078 - 5087
      Abstract: Laminated metallic alloy cores (i.e., alternating layers of thin film metallic alloy and insulating material) of appropriate lamination thickness enable suppression of eddy current losses at high frequencies. Magnetic cores comprised of many such laminations yield substantial overall magnetic volume, thereby enabling high-power operation. Previously, we reported nanolaminated permalloy (Ni80Fe20) cores based on a sequential electrodeposition technique, demonstrating negligible eddy current losses at peak flux densities up to 0.5 T and operating at megahertz frequencies. This paper demonstrates improved performance of nanolaminated cores comprising tens to hundreds of layers of 300-500-nm-thick CoNiFe films that exhibit superior magnetic properties (e.g., higher saturation flux density and lower coercivity) than permalloy. Nanolaminated CoNiFe cores can be operated up to a peak flux density of 0.9 T, demonstrating improved power handling capacity and exhibiting 30% reduced volumetric core loss, attributed to lowered hysteresis losses compared to the nanolaminated permalloy core of the same geometry. Operating these cores in a buck dc-dc power converter at a switching frequency of 1 MHz, the nanolaminated CoNiFe cores achieved a conversion efficiency exceeding 90% at output power levels up to 7 W, compared to an achieved permalloy core conversion efficiency below 86% at 6 W.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • 3-D Microtransformers for DC–DC On-Chip Power Conversion
    • Authors: Moazenzadeh; A.;Suarez Sandoval, F.;Spengler, N.;Badilita, V.;Wallrabe, U.;
      Pages: 5088 - 5102
      Abstract: We address the miniaturization of power converters by introducing novel 3-D microtransformers with magnetic core for low-megahertz frequency applications. The core is fabricated by lamination and microstructuring of Metglas 2714A magnetic alloy. The solenoids of the microtransformers are wound around the core using a ball-wedge wirebonder. The wirebonding process is fast, allowing the fabrication of solenoids with up to 40 turns in 10 s. The fabricated devices yield the high inductance per unit volume of 2.95 μH/mm3 and energy per unit volume of 133 nJ/mm3 at the frequency of 1 MHz. The power efficiency of 64-76% is measured for different turns ratio with coupling factors as high as 98%. To demonstrate the applicability of our passive components, two PWM controllers were selected to implement an isolated and a nonisolated switch-mode power supply. The isolated converter operates with overall efficiency of 55% and maximum output power of 136 mW; then, we experimentally demonstrate how we increased this efficiency to 71% and output power to 408 mW. The nonisolated converter can deliver an overall efficiency of 81% with a maximum output power of 515 mW. Finally, we benchmarked the results to underline the potential of the technology for power on-chip applications.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • A Novel Line Frequency Multistage Conduction LED Driver With High Power
           Factor
    • Authors: Tsorng-Juu Liang;Wei-Jing Tseng;Jiann-Fuh Chen;Jyun-Peng Wu;
      Pages: 5103 - 5115
      Abstract: This paper proposes a novel line frequency multistage conduction LED driver with current-limiting mechanism. By operating the LED driver in multistage conduction, the number of LEDs can be automatically adjusted to be driven with low ac voltage, which increases the LED utilization rate. The current-limiting mechanism offers overcurrent protection to the LEDs. With the aim of shaping the input current into a sinusoidal waveform, the number of LEDs and the current-limit values are determined by the proposed analysis methods; these steps improve the power factor (PF) and the total harmonic distortion of input current (THDi). Finally, two prototype circuits--two-stage conduction and three-stage conduction LED drivers- are built to verify the performances, such as LED utilization rate, THDi, PF, and system efficiency.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • Conceptual Study of Sub-600 V IGBTs
    • Authors: Bauer; F.D.;
      Pages: 5116 - 5124
      Abstract: Very low voltage, 60-600 V insulated-gate bipolar transistors (IGBTs) were compared to power mosfet s with conventional and superjunction drift layers of identical voltage classes using mixed-mode numerical device simulation. This study was done in the light of forthcoming 400 V class IGBTs for use in electric vehicle/hybrid electric vehicle: the 600 V borderline, which previously separated the bulk of power mosfet from IGBT applications, has become fragile recently. We find that the 400 V class must not represent a lower limit for IGBTs based on silicon: in fact, LV IGBTs could offer lower losses down to the 60-100 V level. Most importantly, low-voltage IGBTs may outperform power mosfets not only with respect to on-state voltage drop but also regarding switching offering up to 30% lower turn-off losses. This paper presents physics-based arguments focusing on the device transconductance to augment these projections. LV IGBTs or hybrid devices (monolithic integration of mosfet plus IGBT) could become lower cost, high performance alternatives to SJ power mosfets thanks to short development cycles common in mature silicon technologies.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • A High-Efficiency Self-Oscillating Class-D Amplifier for Piezoelectric
           Speakers
    • Authors: Colli-Menchi; A.I.;Sanchez-Sinencio, E.;
      Pages: 5125 - 5135
      Abstract: The design tradeoffs of the class-D amplifier (CDA) for driving piezoelectric (PZ) speakers are presented, including efficiency, linearity, and electromagnetic interference. An implementation is proposed to achieve high efficiency in the CDA architecture for PZ speakers to extend battery life in mobile devices. A self-oscillating closed-loop architecture is used to obviate the need for a carrier signal generator to achieve low power consumption. The use of stacked-cascode CMOS transistors at the H-bridge output stage provides low-input capacitance to allow high-switching frequency to improve linearity with high efficiency. Moreover, the CDA monolithic implementation achieves 18 VPP output voltage swing in a low-voltage CMOS technology without requiring expensive high-voltage semiconductor devices. The prototype experimental results achieved a minimum THD + N of 0.025%, and a maximum efficiency of 96%. Compared to available CDA for PZ speakers, the proposed CDA achieved higher linearity, lower power consumption, and higher efficiency.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • Proposed Switching Losses Model for Integrated Point-of-Load Synchronous
           Buck Converters
    • Authors: Orabi; M.;Shawky, A.;
      Pages: 5136 - 5150
      Abstract: Nowadays, point-of-load (POL) converters' investments are counted as a main part in power management markets; especially the synchronous buck converters. Today's products forces designers to highly integrate POL converters by increasing the switching frequency; so the latest technology has used megahertz range to obtain this target. On the other hand, increasing switching frequency means increasing the switching losses. Therefore, it is very important to optimize the operating switching frequency tradeoff, which requires an accurate model taking in consideration the converter operating conditions. This paper presents an accurate mathematical loss model taking in consideration the physical behavior of the MOSFET switch in addition to the converter operating conditions. This model introduces accurate equations for every switching intervals and so accurate loss calculations. An integrated POL synchronous buck converter of 5 MHz, 5-1.8 V/3 A prototype is fabricated. The results of the proposed model are compared with simulation and experimental results under variable operating conditions. Good matching between the mathematical, experimental, and simulation results are obtained.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • Evaluation of Gallium Nitride Transistors in High Frequency Resonant and
           Soft-Switching DC–DC Converters
    • Authors: Reusch; D.;Strydom, J.;
      Pages: 5151 - 5158
      Abstract: The emergence of gallium nitride (GaN)-based power devices offers the potential to achieve higher efficiencies and higher switching frequencies than possible with mature silicon (Si) power MOSFETs. In this paper, we will evaluate the ability of gallium nitride transistors to improve efficiency and output power density in high frequency resonant and soft-switching applications. To experimentally verify the benefits of replacing Si MOSFETs with enhancement mode GaN transistors (eGaNFETs) in a high frequency resonant converter, 48-12 V unregulated isolated bus converter prototypes operating at a switching frequency of 1.2 MHz and an output power of up to 400 W are compared using Si and GaN power devices.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • A Multiphase Synchronous Buck Converter With a Fully Integrated Current
           Balancing Scheme
    • Authors: Yong-Seong Roh;Young-Jin Moon;Jeongpyo Park;Min-Gyu Jeong;Changsik Yoo;
      Pages: 5159 - 5169
      Abstract: A multiphase synchronous buck converter has been developed, in which the number of switching phases is determined by the sensed average load current. The maximum number of switching phases is four. The dc resistance (DCR) of switching inductor is used to detect the average current, which is also utilized to balance the load current among the multiple switching phases. The instantaneous inductor current is sensed as well to generate the pulsewidth modulation (PWM) signal to switch the inductors. The multiphase synchronous buck converter implemented in a 0.13-μm BCDMOS process shows 91.1% maximum power efficiency when the input voltage is 2.8 V, output voltage is 1.0 V, and output current is 2.0 A.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • Digital Slew Rate and S-Shape Control for Smart Power Switches to Reduce
           EMI Generation
    • Authors: Blank; M.;Gluck, T.;Kugi, A.;Kreuter, H.-P.;
      Pages: 5170 - 5180
      Abstract: Smart power switches are power switches with integrated control and protection functions for the switching of middle- and high-current loads. In particular in automotive applications, smart power switches have to be operated without additional stabilization networks, EMI filters, and heat sinks to keep the weight, required space and costs of the circuit boards as low as possible. Therefore, the generated electromagnetic emissions must be reduced by another measure without significantly increasing the switching losses. This can be achieved by the active control of the first and/or second derivative of the output voltage. This paper presents a digital slew rate control and its extension to an S-shape control strategy, which in addition to the slew rate, also controls the second derivative of the output voltage. Both strategies are based on feedforward gate current profiles, which are iteratively adapted by an iterative learning control strategy to compensate for load variations and temperature dependences. A rapid prototyping test bench is presented, and the performance and robustness of the control strategies are demonstrated by a series of measurement results. An EMC compliance test according to the CSIPR 25 standard shows that the generation of conducted electromagnetic emissions can be reduced in a power efficient way by the proposed approach.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • A Generalized Model of Nonisolated Multiphase DC–DC Converter Based
           on Novel Switching Period Averaging Method
    • Authors: Difu Zhan;Li Wei;Yicheng Zhang;Yongtao Yao;
      Pages: 5181 - 5191
      Abstract: The continuously innovated topologies of the nonisolated multiphase dc-dc converter (NMDC) demand generalized and flexible models for the controller design. However, the increased phase number, coupling of inductors, stray circuit parameters, and asymmetric problems make the modeling work difficult. In this paper, a novel switching period averaging method aiming to simplify the modeling process is proposed. The method takes full advantage of the linear characteristic of the circuit differential equations to find out the relationship between averaged state variables and switch duty cycles. Then, the generalized model applicable to several different topologies of the NMDC is derived. The analytical solutions of steady-state model, dynamic model in both time and frequency domain are all approached. In order to verify the results, a MATLAB/Simulink model and the corresponding experimental prototype of a four-phase boost converter with two groups of two-phase coupled inductors are built. Both results coincide with the theoretical derivation, which indicates the effectiveness of the proposed method. Finally, a design process of the H∞ controller for the NMDC is presented to show the application of this model.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • A Parallel Approach to Real-Time Simulation of Power Electronics Systems
    • Authors: Benigni; A.;Monti, A.;
      Pages: 5192 - 5206
      Abstract: We define here a new parallel simulation method designed for real-time execution. This method is highly parallelizable and scalable, and the simulation execution time is fully predictable, which is very important for real-time execution. The stability conditions for the method are defined. Furthermore, we show how to define appropriate flow variable injections so that this method can be extended to multiphysic applications and how to implement multirate time step in the defined method. Finally, we present simulation tests that validate the presented method.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • Multiphase Current-Controlled Buck Converter With Energy Recycling Output
           Impedance Correction Circuit (OICC)
    • Authors: Svikovic; V.;Cortes, J.J.;Alou, P.;Oliver, J.A.;Garcia, O.;Cobos, J.A.;
      Pages: 5207 - 5222
      Abstract: This study is related to the improvement of the output impedance of a multiphase buck converter with peak current mode control (PCMC) by means of introducing an additional power path, which virtually increases the output capacitance during transients. Various solutions that can be employed to improve the dynamic behavior of the converter system exist, but nearly all solutions are developed for a single-phase buck converter with voltage mode control, while in the voltage regulation module applications, due to the high currents and dynamic specifications, the system is usually implemented as a multiphase buck converter with current mode control to ensure current sharing. The proposed circuit, output impedance correction circuit (OICC), is used to inject or extract a current n - 1 times larger than the output capacitor current, thus virtually increasing n times the value of the output capacitance during the transients. Furthermore, the OICC concept is extended to a multiphase buck converter system and the proposed solution is compared with the system that has n times bigger output capacitor in terms of dynamic behavior and static and dynamic efficiency. The OICC is implemented as a synchronous buck converter with PCMC, thus reducing its penalty on the system efficiency.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • Nonlinear Dynamic Power Tracking of Low-Power Wind Energy Conversion
           System
    • Authors: Yun Yang;Kwan-Tat Mok;Siew-Chong Tan;Hui; S.Y.R.;
      Pages: 5223 - 5236
      Abstract: This paper addresses the use of variable structure control (i.e., sliding mode (SM) control) for improving the dynamic performance of a low-power wind energy conversion system (WECS) that is connected to a dc grid. The SM control is applied to simultaneously match 1) the maximum power generation of the wind turbine system from the wind with 2) the maximum power injection of the grid-connected power converter into the grid. The amount of energy extractable from a dynamically changing wind using the WECS with SM control is compared with that of classic PI control. Both the simulation and experimental results show that more energy can be harvested with the SM control as compared to the PI control for any dynamically changing or random wind conditions.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • Energy Encryption for Wireless Power Transfer
    • Authors: Zhen Zhang;Chau; K.T.;Chun Qiu;Chunhua Liu;
      Pages: 5237 - 5246
      Abstract: This paper presents a novel energy encryption strategy for wireless power transfer (WPT) systems, which can effectively improve the security performance of wirelessly transferred energy. In a WPT system, energy is expected to transfer to specific receptors as well as to switch off other unauthorized energy transmission channels, so the security of energy transmission is an important issue. In the proposed secure WPT system, the energy is encrypted by chaotically regulating the frequency of the power source. Then, the authorized receptor can receive the energy by simultaneously adjusting the circuit to decrypt the encrypted energy based on the security key obtained from the power supply, while the unauthorized receptor cannot receive the energy without knowledge of the security key. Hence, a secure energy transmission channel is established to effectively prevent unauthorized receptors from stealing the energy. In this paper, both simulation and experimental results are provided to verify the validity of the proposed encrypted WPT system.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • Wide Damping Region for LCL-Type Grid-Connected Inverter
           With an Improved Capacitor-Current-Feedback Method
    • Authors: Xiaoqiang Li;Xiaojie Wu;Yiwen Geng;Xibo Yuan;Chenyang Xia;Xue Zhang;
      Pages: 5247 - 5259
      Abstract: This paper has presented a stability analysis of a LCL-type grid-connected inverter in the discrete-time domain. It has been found that even though the system is stable when the resonance frequency f,. is higher than one-sixth of the sampling frequency (f8/6), an effective damping scheme is still required due to the potential influence of the grid impedance. With a conventional proportional capacitor-current-feedback active damping (AD), the valid damping region is only up to f8/6. This however is not sufficient in the design process for obtaining a high quality output current and the system can easily become unstable due to the resonance frequency shifting. Considering the resonance frequency design rules of the LCL filter, this paper proposes an improved capacitor-current-feedback AD method. With a detailed analysis and proper parameter design, the upper limit of the damping region is extended to f8/4, which can cover all the possible resonance frequencies. Then, the damping performance of the proposed AD method is studied. It shows that the optimal damping is obtained when the actual resonance frequency is (fr + f8/4)/2. Moreover, an approximate calculation for the optimal damping coefficient R is given. Finally, the experimental results have validated the effectiveness of the proposed AD method.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • Active damping control strategy of matrix converter via modifying input
           reference currents
    • Authors: Jiaxing Lei;Bo Zhou;Xianhui Qin;Jiadan Wei;Jinliang Bian;
      Pages: 5260 - 5271
      Abstract: The matrix converter (MC) with an LC filter at source side suffers from system instability, thereby requiring damping control. To improve system stability, this paper proposes a novel active damping control strategy. First, the method of generating space vector modulation signals is improved, in order to make the amplitude and phase angle of input currents directly controllable without affecting the priority of output voltage control. Then, the proposed strategy, which is realized by injecting damping signals into input reference currents, is presented. In this way, the proposed strategy can suppress the oscillations in source currents directly. Besides, it is effective with source voltages or capacitor voltages sampled for modulation, regardless of the operation mode of MC. Furthermore, it is applicable to most of existing modulation algorithms. Finally, experimental results of four-quadrant operation on a 2.4-kW prototype illustrate that, under the condition of the same parameters, the proposed active damping control strategy performs better than passive damping control in filtering and the same in damping at source side, without sacrificing the driving performance at output side.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • A Three-Phase PLL Algorithm Based on Signal Reforming Under Distorted Grid
           Conditions
    • Authors: Baoquan Liu;Fang Zhuo;Yixin Zhu;Hao Yi;Feng Wang;
      Pages: 5272 - 5283
      Abstract: This paper proposes a novel three-phase phase-locked loop (PLL) algorithm, which focuses on the reforming of the primary signals before grid synchronization rather than improving the phase estimation methodologies. The unbalanced signals are reformed to balanced ones without damage to the phase angle, through which the negative sequence of the grid voltages is removed. This eliminates the estimation errors of conventional synchronous reference frame PLL and enhances its response speed with a higher bandwidth. The reforming process is supposed to be carried out at every zero-crossing point of the three-phase voltages and choose one phase as reference to balance the other two. Coefficients for the signal reforming are calculated at one zero-crossing point and updated until the next comes. In implementation, a certain phase is chosen as the reference all along and the reforming process will be suspended when it just crosses the zero line. This PLL algorithm has a fast and precise character to reform the three-phase grid voltages and is flexible for application. Under heavily distorted grid conditions, it can still perform effectively even with multiple zero-crossings. Comprehensive experimental results from a digital signal processor-based laboratory prototype are provided to validate the performance of this PLL algorithm.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • Three-Phase AC-Side Voltage-Doubling High Power Density Voltage Source
           Converter With Intrinsic Buck–Boost Cell and Common-Mode Voltage
           Suppression
    • Authors: Peng Li;Adam; G.P.;Yihua Hu;Holliday, D.;Williams, B.W.;
      Pages: 5284 - 5298
      Abstract: The three-phase two-level voltage source converter (VSC) is widely employed in power conversions between ac and dc for its four-quadrant operation and control flexibility. However, it suffers from the low output voltage range with a peak value of half dc-link per phase, which necessitates the use of either high dc-link voltage or bulky step-up transformer to enable the medium voltage operation. Additionally, the high common-mode (CM) voltage between ac loads neutral points and ground may reduce the service life and reliability of electric machinery. In this paper, a three-phase ac-side voltage-doubling VSC topology with intrinsic buck-boost cell is analyzed. By this configuration, the ac-side voltage is doubled with the phase peak value equal to dc link. That is, only half of the dc-side capacitor bank is needed to generate the same output voltage. The proposed converter uses its buck-boost cell as a virtual voltage source to synthesize negative half of the output voltage by modulating its output ac phase voltage around the negative bus (which is the real zero when grounded). This permits the average CM voltage to be suppressed to zero, and loads connected to converter ac side not to withstand any dc voltage stress (reducing the insulation requirement). Modeling and control design for both rectifier and inverter modes of this converter in synchronous reference frame have been investigated to ensure a four-quadrant three-phase back-to-back system. Experimental results have verified the feasibility and the effectiveness of the proposed configuration and the designed control strategies.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • Analysis and Comparison of Audible Noise Caused by Magnetic Components in
           Switch-Mode Power Supplies Operating in Burst Mode and Frequency-Foldback
           Mode
    • Authors: Huber; L.;Jovanovic, M.M.;
      Pages: 5299 - 5308
      Abstract: In this paper, it is theoretically shown and experimentally verified that operation of switch-mode power supplies in burst mode (BM) results in lower audible noise than operation in frequency-foldback mode (FFM). However, the selection of the switching frequency in a burst package can have a significant impact on the audible noise. In both BM and FFM, the audible noise can be reduced by decreasing the peak value of current pulses and proportionally increasing the burst frequency in BM and the switching frequency in FFM. In BM, the audible noise can be further reduced if instead of increasing the burst frequency, the number of burst pulses is increased without changing the burst frequency. The presented BM and FFM audible noise analyses are experimentally verified on a dc-dc boost test circuit.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • An Improved Modeling and Analysis Technique for Peak Current-Mode
           Control-Based Boost Converters
    • Authors: Amir; S.;van der Zee, R.;Nauta, B.;
      Pages: 5309 - 5317
      Abstract: A modeling approach is presented that calculates an accurate open-loop transfer characteristic for a boost converter that employ peak current-mode control (PCMC). Many techniques exist for modeling a PCMC-based boost converter; however, all these techniques focus on purely resistive loads and are not always accurate for a purely capacitive load. In this paper, a new modeling technique is presented, which is simple and gives accurate results for both capacitive and resistive loads. Furthermore, the useful expressions for dc gain and pole locations of a boost converter operating in continuous-conduction mode with PCMC are derived and compare well to simulations and measurements.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • Analysis of Low-Frequency Oscillation in Electric Railways Based on
           
    • Authors: Hui Wang;Wu Mingli;Juanjuan Sun;
      Pages: 5318 - 5330
      Abstract: The line-side converter, which can represent an ac-dc-ac drive electric vehicle when analyzing the low-frequency oscillation in electric railways, is modeled in dq frame with the proposed single-phase dq-decomposition method. With this model, an underdamped mechanism of the vehicle-grid interaction is confirmed. Besides, a low-frequency stability prediction approach is presented, based on the dominant-pole analysis and verified by the simulation and the testing result. The proposed modeling method and prediction approach benefit in three aspects: It is more convenient to rebuild the model with a change of either the line-side converter controller or the system condition, much quicker to predict the low-frequency instability and more explicit to guide the modification of the controller software to damp the low-frequency oscillations.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
  • A New PWM Strategy for Grid-Connected Half-Bridge Active NPC Converters
           With Losses Distribution Balancing Mechanism
    • Authors: Lin Ma;Kerekes; T.;Rodriguez, P.;Xinmin Jin;Teodorescu, R.;Liserre, M.;
      Pages: 5331 - 5340
      Abstract: Photovoltaic systems technological development is driven by the request for higher efficiency and safety. These concerns influence also the choice of the power converter stage. Several topologies have been proposed and many of them are available commercially. Among them, the neutral point clamped (NPC) and derived topologies offers high efficiency, low leakage current, and low EMI. However, one main disadvantage of the NPC inverter is given by an unequal distribution of the losses in the semiconductor devices, which leads to an unequal distribution of temperature that can affect lifetime. By using the active NPC (ANPC) topology, where the clamping diodes are replaced by bidirectional switches, the power losses distribution problem is alleviated. The modulation strategy is a key issue for losses distribution in this topology. In this paper, two known strategies are discussed and a new PWM strategy, namely the adjustable losses distribution is proposed for better losses distribution in the ANPC topology. Simulations and experimental results help in evaluating the modulation strategies.
      PubDate: Sept. 2015
      Issue No: Vol. 30, No. 9 (2015)
       
 
 
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