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  Subjects -> ELECTRONICS (Total: 152 journals)
Advances in Biosensors and Bioelectronics     Open Access   (Followers: 2)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 5)
Advances in Microelectronic Engineering     Open Access   (Followers: 1)
Advances in Power Electronics     Open Access   (Followers: 8)
Aerospace and Electronic Systems, IEEE Transactions on     Hybrid Journal   (Followers: 59)
American Journal of Electrical and Electronic Engineering     Open Access   (Followers: 10)
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: 8)
Biomedical Engineering, IEEE Reviews in     Full-text available via subscription   (Followers: 15)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 12)
Biomedical Instrumentation & Technology     Full-text available via subscription   (Followers: 4)
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 5)
BULLETIN of National Technical University of Ukraine. Series RADIOTECHNIQUE. RADIOAPPARATUS BUILDING     Open Access   (Followers: 1)
Bulletin of the Polish Academy of Sciences : Technical Sciences     Open Access  
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 13)
China Communications     Full-text available via subscription   (Followers: 2)
Circuits and Systems     Open Access   (Followers: 9)
Consumer Electronics Times     Open Access   (Followers: 4)
Control Systems     Hybrid Journal   (Followers: 20)
Electronic Markets     Hybrid Journal   (Followers: 5)
Electronic Materials Letters     Hybrid Journal   (Followers: 3)
Electronics     Open Access   (Followers: 7)
Electronics and Communications in Japan     Hybrid Journal   (Followers: 5)
Electronics Letters     Hybrid Journal   (Followers: 17)
Embedded Systems Letters, IEEE     Hybrid Journal   (Followers: 18)
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: 8)
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     Full-text available via subscription   (Followers: 2)
Frontiers of Optoelectronics     Hybrid Journal   (Followers: 2)
Geoscience and Remote Sensing, IEEE Transactions on     Hybrid Journal   (Followers: 20)
Haptics, IEEE Transactions on     Hybrid Journal   (Followers: 4)
IEEE Antennas and Propagation Magazine     Hybrid Journal   (Followers: 14)
IEEE Antennas and Wireless Propagation Letters     Hybrid Journal   (Followers: 12)
IEEE Consumer Electronics Magazine     Full-text available via subscription   (Followers: 11)
IEEE Journal of Emerging and Selected Topics in Power Electronics     Hybrid Journal   (Followers: 8)
IEEE Journal of the Electron Devices Society     Open Access   (Followers: 2)
IEEE Power Electronics Magazine     Full-text available via subscription   (Followers: 5)
IEEE Transactions on Antennas and Propagation     Full-text available via subscription   (Followers: 9)
IEEE Transactions on Audio, Speech, and Language Processing     Hybrid Journal   (Followers: 11)
IEEE Transactions on Automatic Control     Hybrid Journal   (Followers: 21)
IEEE Transactions on Consumer Electronics     Hybrid Journal   (Followers: 13)
IEEE Transactions on Electron Devices     Hybrid Journal   (Followers: 6)
IEEE Transactions on Information Theory     Hybrid Journal   (Followers: 14)
IEEE Transactions on Power Electronics     Hybrid Journal   (Followers: 15)
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: 6)
IET Power Electronics     Hybrid Journal   (Followers: 7)
IET Wireless Sensor Systems     Hybrid Journal   (Followers: 6)
IETE Journal of Education     Open Access   (Followers: 2)
IETE Journal of Research     Open Access   (Followers: 5)
IETE Technical Review     Open Access   (Followers: 1)
Industrial Electronics, IEEE Transactions on     Hybrid Journal   (Followers: 11)
Industry Applications, IEEE Transactions on     Hybrid Journal   (Followers: 5)
Informatik-Spektrum     Hybrid Journal  
Instabilities in Silicon Devices     Full-text available via subscription  
Intelligent Transportation Systems Magazine, IEEE     Full-text available via subscription   (Followers: 1)
International Journal of Advanced Electronics and Communication Systems     Open Access   (Followers: 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: 6)
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: 12)
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: 4)
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: 4)
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 Systems, Control and Communications     Hybrid Journal   (Followers: 2)
International Journal on Communication     Full-text available via subscription   (Followers: 8)
International Journal on Electrical and Power Engineering     Full-text available via subscription   (Followers: 11)
International Transaction of Electrical and Computer Engineers System     Open Access  
ISRN Electronics     Open Access   (Followers: 1)
ISRN Signal Processing     Open Access  
Journal of Advanced Dielectrics     Open Access   (Followers: 1)
Journal of Artificial Intelligence     Open Access   (Followers: 5)
Journal of Circuits, Systems, and Computers     Hybrid Journal   (Followers: 1)
Journal of Electrical and Electronics Engineering Research     Open Access   (Followers: 2)
Journal of Electrical Bioimpedance     Full-text available via subscription   (Followers: 2)
Journal of Electrical Engineering & Electronic Technology     Full-text available via subscription   (Followers: 1)
Journal of Electromagnetic Analysis and Applications     Open Access   (Followers: 3)

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IEEE Transactions on Power Electronics
   [17 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  [175 journals]   [SJR: 3.308]   [H-I: 111]
  • Table of contents
    • Pages: C1 - C4
      Abstract: Presents the table of contents for this issue of the periodical.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • IEEE Transactions on Power Electronics publication information
    • Pages: C2 - C2
      Abstract: Provides a listing of current staff, committee members and society officers.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • IEEE Power Electronics Society Information
    • Pages: C3 - C3
      Abstract: Provides a listing of current committee members and society officers.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • Flexible Control Strategy for Grid-Connected Inverter Under Unbalanced
           Grid Faults Without PLL
    • Authors: Xiaoqiang Guo;Wenzhao Liu;Xue Zhang;Xiaofeng Sun;Zhigang Lu;Guerrero; J.M.;
      Pages: 1773 - 1778
      Abstract: Power oscillation and current quality are the important performance targets for the grid-connected inverter under unbalanced grid faults. First, the inherent reason for the current harmonic and power oscillation of the inverter is discussed with a quantitative analysis. Second, a new control strategy is proposed to achieve the coordinate control of power and current quality without the need for a phase-locked loop (PLL) or voltage/current positive/negative sequence extraction calculation. Finally, the experimental tests are conducted under unbalanced grid faults, and the results verify the effectiveness of the propose method.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • Hybrid Multicarrier Modulation to Reduce Leakage Current in a
           Transformerless Cascaded Multilevel Inverter for Photovoltaic Systems
    • Authors: Selvamuthukumaran; R.;Garg, A.;Gupta, R.;
      Pages: 1779 - 1783
      Abstract: This letter proposes a hybrid multicarrier pulse width modulation (H-MCPWM) technique to reduce leakage current in a transformerless cascaded multilevel inverter for photovoltaic (PV) systems. The transformerless PV inverter topology has the advantages of simple structure, low weight and provides higher efficiency. However, the topology makes a path for leakage current to flow through parasitic capacitance formed between the PV module and the ground. A modulation technique has significant impact to reduce the leakage current without adding any extra component. The proposed H-MCPWM technique ensures low leakage current in the transformerless PV inverter system with simplicity in implementation of the modulation technique using lesser number of carriers. Experimental prototype developed in the laboratory demonstrates the performance of the proposed modulation technique in reducing the leakage current.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • A Bidirectional Wireless Power Transfer EV Charger Using Self-Resonant PWM
    • Authors: Jun-Young Lee;Byung-Moon Han;
      Pages: 1784 - 1787
      Abstract: This letter suggests a large air-gap bidirectional wireless power transfer charger for electric vehicle. It is controlled by pulse width modulation with a self-resonant frequency formed by self-inductance and resonant capacitor so that constant frequency operation can be accomplished under large air-gap without additional current chopper. The feasibility of the proposed method has been verified with a 6.6-kW prototype with air-gap of 12-20 cm.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • An Enhanced SVM Method to Drive Matrix Converters for Zero Common-Mode
    • Authors: Huu-Nhan Nguyen;Hong-Hee Lee;
      Pages: 1788 - 1792
      Abstract: This paper presents an enhanced space vector modulation (SVM) method to drive matrix converters (MCs) with zero common-mode voltage by using the rotating vectors, which are not used in the traditional SVM for MCs. The reference output voltage vector is generated by a combination of the closer rotating vectors in order to minimize the output distortion. Explicit equations are used to develop the switching patterns so that the proposed SVM method can achieve full control of the output voltage vector and input current phase angle with good performance of the input/output current waveforms. Together with the theoretical analysis, the experimental results are provided to validate the feasibility of the proposed method.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • A High Step-Down Multiple Output Converter With Wide Input Voltage Range
           Based on Quasi Two-Stage Architecture and Dual-Output LLC
           Resonant Converter
    • Authors: Hongfei Wu;Chengan Wan;Kai Sun;Yan Xing;
      Pages: 1793 - 1796
      Abstract: In this letter, a quasi two-stage architecture is proposed for wide input voltage range (voltage ranges ≈ 1:2) and high step-down multiple output conversion. A dc-DCX, which operates as a dc-dc converter with regulated output when the input voltage is low and as a dc-dc transformer with unregulated output when the input voltage is high, is adopted in the first stage to provide optimized intermediate dc-bus voltages for the second-stage point-of-load converters. The input and output of the dc-DCX are in series and connected to the total input voltage. Hence, part of the input power is directly transferred to the intermediate bus without conversion. The devices' voltage stresses and the transformer turns ratio of the dc-DCX are reduced by using the proposed quasi two-stage architecture. Thus, the conversion efficiency is improved significantly. Furthermore, a dual-output LLC resonant converter with hybrid center-tapped and full-bridge rectifier is proposed for the dc-DCX to achieve high efficiency and high power density. A 100-W prototype with three outputs is built and tested to verify the analysis.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • A Novel Accurate Primary-Side Control (PSC) Method for Half-Bridge (HB)
           LLC Converter
    • Authors: Jae-Bum Lee;Chong-Eun Kim;Jae-Kuk Kim;Jae-Hyun Kim;Sang-Cheol Moon;Gun-Woo Moon;
      Pages: 1797 - 1803
      Abstract: Recently, several researches have been progressed on the primary-side control (PSC) methods which decrease the size and cost of the control stage. However, most of the researches have been applied to the flyback converter, and they have some challenges in applying them to the half-bridge (HB) LLC converter due to the large voltage across the secondary leakage inductor of the transformer. In this letter, a new PSC method for the HB LLC converter is proposed to obtain accurate output voltage. In the proposed method, the output voltage is regulated by obtaining the voltage across the primary side of the transformer when the external resonant inductor voltage becomes 0 V. At this time, since the voltage across the transformer secondary leakage inductor is small, the proposed method can accurately regulate the output voltage. A 400 V input and 20 V/85 W output laboratory prototype is built and tested to verify the effectiveness of the proposed PSC method.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • Optimal Switching Transition-Based Voltage Balancing Method for Flying
           Capacitor Multilevel Converters
    • Authors: Ghias; A.M.Y.M.;Pou, J.;Agelidis, V.G.;Ciobotaru, M.;
      Pages: 1804 - 1817
      Abstract: This paper proposes a voltage balancing method for flying capacitor multilevel converters based on phase-disposition pulse width modulation (PD-PWM) using optimal transitions between converter switching states. The optimal transitions between converter switching states are possible due to the converter states' redundancy and are decided with the continuous evaluation and minimization of a cost function. Simulation and experimental results verify the robustness of the proposed voltage balancing method against different load conditions. A significant reduction of the average switching frequency is achieved, when compared to the use of the optimal state voltage balancing method, where the optimal states are decided independently for each voltage level ignoring how transitions impact on the converter switching frequency. Moreover, the line-to-line output voltages are compared with the ones obtained with other modulation techniques in terms of total harmonic distortion values, and PD-PWM with the proposed voltage balancing method produces the best results.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • A Nonisolated Multiinput Multioutput DC–DC Boost Converter for
           Electric Vehicle Applications
    • Authors: Nahavandi; A.;Hagh, M.T.;Sharifian, M.B.B.;Danyali, S.;
      Pages: 1818 - 1835
      Abstract: A new nonisolated multiinput multioutput dc-dc boost converter is proposed in this paper. This converter is applicable in hybridizing alternative energy sources in electric vehicles. In fact, by hybridization of energy sources, advantages of different sources are achievable. In this converter, the loads power can be flexibly distributed between input sources. Also, charging or discharging of energy storages by other input sources can be controlled properly. The proposed converter has several outputs with different voltage levels which makes it suitable for interfacing to multilevel inverters. Using of a multilevel inverter leads to reduction of voltage harmonics which, consequently, reduces torque ripple of electric motor in electric vehicles. Also, electric vehicles which using dc motor have at least two different dc voltage levels, one for ventilation system and cabin lightening and other for supplying electric motor. The proposed converter has just one inductor. Depending on charging and discharging states of the energy storage system (ESS), two different power operation modes are defined for the converter. In order to design the converter control system, small-signal model for each operation mode is extracted. The validity of the proposed converter and its control performance are verified by simulation and experimental results for different operation conditions.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • A Level-Increased Nearest Level Modulation Method for Modular Multilevel
    • Authors: Pengfei Hu;Daozhuo Jiang;
      Pages: 1836 - 1842
      Abstract: The modular multilevel converter (MMC) is emerging to be a promising approach for medium- and high-voltage applications. This paper proposes a modified nearest level modulation (NLM) method for the MMC, with which the level number of ac output voltage increases to 2N + 1 (where N is the submodule numbers per arm) as great as that of the carrier-phase-shifted PWM and the improved submodule unified PWM methods. The level number is almost doubled and the height of the step in the step wave is halved. Therefore, the ac output voltage waveform quality using the proposed method is better than that using the conventional NLM method. Besides, the proposed method keeps the conventional NLM method's characteristics such as low switching frequency and simple implementation. The performance of the proposed method is verified by simulations and experiments using a laboratory-scale prototype.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • Three-Phase Multilevel PFC Rectifier Based on Multistate Switching Cells
    • Authors: Silveira Ortmann; M.;Mussa, S.A.;Lobo Heldwein, M.;
      Pages: 1843 - 1854
      Abstract: This paper presents a three-phase multilevel power factor correction (PFC) rectifier employing multistate switching cells. A generalized converter structure is presented based on the connection of switching networks of Vienna-type rectifier topologies through multiinterphase transformers (MIPTs). The resulting rectifier presents the intrinsic benefits to the employed building blocks and the ones added by a modular construction that enables the reduction of passive components and overall losses. The operation of the PFC rectifier is described, including appropriate modulation and control strategies. Design guidelines for the magnetic components are derived for the MIPTs, boost inductors, and power semiconductor devices. Finally, a lab prototype is used to present experimental results. This prototype is rated at 7.5 kW and uses a modular structure to assemble a four legs per phase rectifier. Efficiency above 98% from 40% load and IEC61000-3-2 requirements are observed.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • Decoupling of Fluctuating Power in Single-Phase Systems Through a
           Symmetrical Half-Bridge Circuit
    • Authors: Yi Tang;Blaabjerg; F.;Poh Chiang Loh;Chi Jin;Peng Wang;
      Pages: 1855 - 1865
      Abstract: Single-phase ac/dc or dc/ac systems are inherently subject to the harmonic disturbance that is caused by the well-known double-line frequency ripple power. This issue can be eased through the installation of bulky electrolytic capacitors in the dc link. Unfortunately, such passive filtering approach may inevitably lead to low power density and limited system lifetime. An alternative approach is to use active power decoupling so that the ripple power can be diverted into other energy storage devices to gain an improved system performance. Nevertheless, all existing active methods have to introduce extra energy storage elements, either inductors or film capacitors in the system to store the ripple power, and this again leads to increased component costs. In view of this, this paper presents a symmetrical half-bridge circuit which utilizes the dc-link capacitors to absorb the ripple power, and the only additional components are a pair of switches and a small filtering inductor. A design example is presented and the proposed circuit concept is also verified with simulation and experimental results. It shows that at least ten times capacitance reduction can be achieved with the proposed active power decoupling method, and both the input current and output voltage of the converter can be well regulated even when very small dc-link capacitors are employed.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • A Transformerless Back-To-Back (BTB) System Using Modular Multilevel
           Cascade Converters For Power Distribution Systems
    • Authors: Khamphakdi; P.;Sekiguchi, K.;Hagiwara, M.;Akagi, H.;
      Pages: 1866 - 1875
      Abstract: This paper presents an intensive discussion on a transformerless back-to-back (BTB) system using modular multilevel cascade converters based on double-star chopper cells (MMCC-DSCC). It is expected to be applied to a power distribution system with many distributed power generators. This paper designs, constructs, and tests a three-phase 200-V, 10-kW DSCC-based BTB system installed on a 200-V, 40-kW power distribution simulator consisting of two radial feeders. Experimental results show that the BTB system can mitigate power-flow imbalance between the two feeders. Moreover, the zero-sequence current circulating between the two feeders can be suppressed to be as small as 10 mA (0.02%) in rms by connecting a common-mode choke to the common dc link of the BTB system.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • Double-Phase High-Efficiency, Wide Load Range High- Voltage/Low-Voltage
           LLC DC/DC Converter for Electric/Hybrid Vehicles
    • Authors: Gang Yang;Dubus; P.;Sadarnac, D.;
      Pages: 1876 - 1886
      Abstract: In this paper, a 2.5-kW 330-410-V/14-V, 250-kHz dc/dc converter prototype is developed targeted for electric vehicle/hybrid vehicle applications. Benefiting from numerous advantages brought by the LLC resonant topology, this converter is able to perform high efficiency, high power density, and low EMI. To arrange high-output current, this paper proposes a parallel-connected LLC structure with developed novel double-loop control to realize an equal current distribution and an overall efficiency improvement. Considering the LLC cell's dimensioning, this paper establishes a more precise model by taking the secondary leakage inductance into consideration. System amelioration and design considerations of the developed LLC are also presented in this paper. A special transformer is presented, and various types of power losses are quantified to improve its efficiency. This converter also implements synchronous rectification, power semiconductor module, and an air-cooling system. The power conversion performance of this prototype is measured and the developed prototype attains a peak efficiency of 95% and efficiency is higher than 94% from 500 W to 2 kW, with a power density of 1 W/cm3. Finally, the EMC results of this prototype are also measured and presented.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • Impedance-Source Networks for Electric Power Conversion Part II: Review of
           Control and Modulation Techniques
    • Authors: Siwakoti; Y.P.;Fang Zheng Peng;Blaabjerg, F.;Poh Chiang Loh;Town, G.E.;Shuitao Yang;
      Pages: 1887 - 1906
      Abstract: Impedance-source networks cover the entire spectrum of electric power conversion applications (dc-dc, dc-ac, ac-dc, ac-ac) controlled and modulated by different modulation strategies to generate the desired dc or ac voltage and current at the output. A comprehensive review of various impedance-source-network-based power converters has been covered in a previous paper and main topologies were discussed from an application point of view. Now Part II provides a comprehensive review of the most popular control and modulation strategies for impedance-source network-based power converters/inverters. These methods are compared in terms of theoretical complexity and performance, when applied to the respective switching topologies. Further, this paper provides as a guide and quick reference for researchers and practicing engineers in deciding which control and modulation method to consider for an application in a given topology at a certain power level, switching frequency and demanded dynamic response.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • Double Modulation Technique for a ZVS Self-Oscillating Half-Bridge
    • Authors: Belloumi; H.;Kourda, F.;
      Pages: 1907 - 1913
      Abstract: This paper proposes a simple power control scheme in order to convert the conventional nonadjustable self-oscillating half-bridge series-resonant inverter into an adjustable one. The proposed topology, based on a self-oscillating structure, can automatically ensure the turning on and the turning off of the switches without any external control. A simple modification in one of the gate drivers side circuit allows one to adjust the output power without compromising the simplicity, reliability, and low cost, which characterize the self-oscillating half-bridge inverter. Moreover, this topology achieves a stable and efficient zero-voltage switching over the entire operating range with a constant switching frequency; as a consequence, the inverter overall efficiency is significantly improved. Experimental results are proposed to validate the analysis and to demonstrate the performance of the proposed control scheme.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • Exponential ADE Solution Based Compact Model of Planar Injection Enhanced
           IGBT Dedicated to Robust Power Converter Design
    • Authors: Igic; P.;
      Pages: 1914 - 1924
      Abstract: The compact model of an injection enhanced insulated gate bipolar transistors based on the exponential solution of the ambipolar diffusion equation is presented in this paper. To model plasma carrier distribution, an exponential shape function is used, and in steady-state forward bias operation, the plasma carrier concentration has a distribution of catenary form with just two exponential basis functions, while in transient operation, more complex profiles can be approximated using a number of exponential basis functions with a range of decay length parameters, shorter than the steady state ones. The device model developed has been implemented in Saber circuit simulator and successfully tested against complete set of high current, high voltage experimental results.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • Analysis of a Switched Impedance Transformer-Type Nonsuperconducting Fault
           Current Limiter
    • Authors: Song Chen;Peng Li;Ball; R.;de Palma, J.-F.;Lehman, B.;
      Pages: 1925 - 1936
      Abstract: This paper proposes a nonsuperconducting fault current limiter (NSFCL) topology and control strategy. The switched impedance transformer-type NSFCL topology is optimized to protect against short transients and to work in conjunction with other fuses or circuit breakers, hence has the merits of being simple, low cost, and compact. A prototype has been designed and built for a three-phase 600-VRMS,L-L system. It has been tested in a UL-certified high-power test lab with 5-A normal current and 100-kA potential fault current.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • Investigation of Multiple Decoupled Coil Primary Pad Topologies in Lumped
           IPT Systems for Interoperable Electric Vehicle Charging
    • Authors: Zaheer; A.;Hao Hao;Covic, G.A.;Kacprzak, D.;
      Pages: 1937 - 1955
      Abstract: Today many vehicle manufacturers are interested in an inductive power transfer system design with a secondary side that is simple and low in cost, weight, and size. To achieve this, a more sophisticated primary side design is required to ensure interoperability with various magnetic topologies. Simple secondary pads such as the circular pad and double-D pad (DDP) (similar to the flat solenoid) can only couple either the perpendicular or parallel component of flux entering the surface of the pad respectively. This paper investigates using various known multiple coil pad designs as the primary that can be switched between various excitation modes during operation, without making tuning or other expensive adjustments. The primary pads considered here include; the DDP, the double-D quadrature pad (DDQP) and the bipolar pad (BPP). Results show that the mutually coupled structure of the DDP primary makes it a poor choice for interoperability, whereas the DDQP and BPP are able to achieve good results because of the decoupled coil structures inherent in their design. The DDQP has improved leakage characteristics while the BPP shows better interoperability characteristics with improved material usage efficiency and is easy to drive because of its identical coil structures.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • Adaptive Peak-Inductor-Current-Controlled PFM Boost Converter With a
           Near-Threshold Startup Voltage and High Efficiency
    • Authors: Wu; H.-H.;Wei, C.-L.;Hsu, Y.-C.;Darling, R.B.;
      Pages: 1956 - 1965
      Abstract: A high-efficiency boost dc-dc converter with adaptive peak-inductor-current (APIC) control method is proposed. Besides, a novel two-step startup procedure is also proposed and applied on the boost converter. The proposed integrated boost converter was fabricated by using a 0.18-μm 1P6M mixed-signal process with a die area of 0.96 mm × 0.75 mm, and it is meant to be used with low-power, low-voltage green energy sources and batteries, such as fuel cells, solar cells, and nickel-metal hydride batteries. Hence, the power efficiency, minimal startup voltage, and minimal input voltage are the most important design considerations. The output voltage of the proposed converter is set to 1.8V, and the measured power efficiency is up to 90.6%, occurring when the input voltage is 1.3 V, the output voltage is 1.8 V, and the load current is 50 mA. According to the measured results, the proposed converter can start up successfully with a 0.43-V input voltage. Then, the input voltage can be further lowered to 0.22 V after startup. Moreover, both the efficiency and the output voltage ripple are improved with the proposed APIC method. Furthermore, a two-step startup procedure, which does not require any extra startup assist circuit, is proposed.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • Frequency-Adaptive Filtering of Low-Frequency Harmonic Current in Fuel
           Cell Power Conditioning Systems
    • Authors: Cao; L.;Loo, K.H.;Lai, Y.M.;
      Pages: 1966 - 1978
      Abstract: Based on one of the most researched multiinput dc-dc converter topologies for renewable energy systems, the multi-input dual-active bridge (DAB) dc-dc converter, the effectiveness of harmonic current absorption by the energy storage branch in fuel cell power conditioning systems is critically evaluated. The closed-loop output impedances of the converter under single-voltage-loop and dual-loop controls are derived and compared. It is shown that both control strategies can effectively reduce the converter's closed-loop output impedance, thus favoring the flow of harmonic current and prevent it from being drawn from either the fuel cell branch or the dc-link capacitor. However, as shown by experimental results, the use of conventional PI control alone still produces noticeable voltage ripple on the dc voltage bus due to harmonic current being drawn from the dc-link capacitor. Proportional-resonant control is proposed to effectively compensate for the dc-bus voltage variation by generating an extremely low impedance path for harmonic current flow at specific frequency. An analog-based frequency tracking circuit is further proposed to adjust the resonant frequency for compensating the effect of harmonic frequency variation.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • Control and Monitoring for Grid-Friendly Wind Turbines: Research Overview
           and Suggested Approach
    • Authors: Peng Li;Yong-Duan Song;Dan-Yong Li;Wen-Chuan Cai;Kai Zhang;
      Pages: 1979 - 1986
      Abstract: Recent years have witnessed a continuing increase in the wind turbine (WT) size and penetration level into the grid, revealing critical challenges to sustainable market development and urgent demands of low voltage ride-through, load reduction, and optimal operation. This paper presents an overview on grid-friendly WTs and relevant technologies for control and monitoring. The development trends are discussed as well to explore potential approaches for optimizing WT systems. The main body contains three parts: the “grid-friendly” criterion and a prototype, the overview and suggestions for WT controller design concerning load reduction and power optimization, and suggested solutions for wind power monitoring systems. This paper is expected to be a reference for extending the knowledge of grid-friendly WTs and optimizing the performance of future large-scale wind power systems.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • Converter Rating Analysis for Photovoltaic Differential Power Processing
    • Authors: Kim; K.A.;Shenoy, P.S.;Krein, P.T.;
      Pages: 1987 - 1997
      Abstract: When photovoltaic (PV) cells are connected in series, they experience internal and external mismatch that reduces output power. Differential power processing (DPP) architectures achieve high system efficiency by processing a fraction of the total power while maintaining distributed local maximum power point operation. This paper details the computational methods and analysis used to determine the operation of PV-to-bus and PV-to-PV DPP architectures with rating-limited converters. Simulations for both DPP architectures are used to evaluate system performance over 25 years of operation. Based on data from field studies, a PV power coefficient of variation can be estimated as 0.086 after 25 years. An improvement figure of merit reflecting the ratio of energy produced to that delivered in a conventional system is introduced to evaluate comparative performance. Converter ratings of 15-17% for PV-to-bus and 23-33% for PV-to-PV architectures are identified as appropriate ratings for a 15-submodule system (five PV panels in series). Both DPP architectures with these ratings are shown to deliver up to 2.8% more power compared to a conventional series-string architecture based on the expected panel variation over 25 years of operation. DPP converters also outperform dc optimizers in terms of lifetime performance.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • Switching State Vector Selection Strategies for Paralleled Multilevel
           Current-Fed Inverter Under Unequal DC-Link Currents Condition
    • Authors: Vekhande; V.;Kothari, N.;Fernandes, B.G.;
      Pages: 1998 - 2009
      Abstract: A paralleled multilevel inverter topology consists of n three-phase three-level current-fed inverters (CFIs) connected in parallel on ac side. AC currents with (2n+1) levels can be generated utilizing redundant switching states when all three-level inverters have equal dc-link currents. However, the multilevel space vector diagram gets modified, redundancy in the switching states is lost and the multilevel current pattern changes when the dc-link current of all inverters is not the same. This introduces low-frequency harmonics in output current, thereby deteriorating total harmonic distortion (THD). The presence of low-frequency components in the output current could be avoided by selecting suitable switching state vectors and ensuring proper time sharing among these vectors. Two methods to select such switching state vectors are proposed in this paper. In the first method, a reference current space vector is realized using the nearest switching state vectors. However, this method results in low-frequency pulsation in dc-link voltage of each inverter. In the second method, the switching state vectors are chosen to eliminate this low-frequency pulsation. Effectiveness of these methods is experimentally validated for a five-level CFI. Further, performance of these methods is compared based on efficiency, THD, and dc-link voltage ripple for various inequality ratios in dc-link currents.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • Modeling and Triple-Loop Control of ZVS Grid-Connected DC/AC Converters
           for Three-Phase Balanced Microinverter Application
    • Authors: Lin Chen;Changsheng Hu;Qian Zhang;Kun Zhang;Batarseh; I.;
      Pages: 2010 - 2023
      Abstract: This paper presents modeling and triple-loop control for a high-efficiency three-phase balanced inverter for using in grid-connected two-stage microinverter applications. An average signal model based on a synchronous rotation frame for a three-phase four-wire inverter has been developed. The inner current loop consists of a variable frequency bidirectional current mode (VFBCM) controller which regulates output filter inductor current thereby achieving ZVS, improved system response, and reduced grid current THD. Active damping of the LCL output filter using filter inductor current feedback is discussed along with small signal modeling of the proposed control method. Since the dc-link capacitor plays a critical role in two-stage microinverter applications, a dc-link controller is implemented outside of the two current control loops to keep the bus voltage constant. Finally, based on a two-stage 400-W prototype, simulation and experimental results are presented to verify the validity of the theoretical analysis, the effectiveness and feasibility of the proposed VFBCM control strategy.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • A Distributed Approach to Maximum Power Point Tracking for Photovoltaic
           Submodule Differential Power Processing
    • Authors: Shibin Qin;Cady; S.T.;Dominguez-Garcia, A.D.;Pilawa-Podgurski, R.C.N.;
      Pages: 2024 - 2040
      Abstract: This paper presents the theory and implementation of a distributed algorithm for controlling differential power processing converters in photovoltaic (PV) applications. This distributed algorithm achieves true maximum power point tracking of series-connected PV submodules by relying only on local voltage measurements and neighbor-to-neighbor communication between the differential power converters. Compared to previous solutions, the proposed algorithm achieves reduced number of perturbations at each step and potentially faster tracking without adding extra hardware; all these features make this algorithm well-suited for long submodule strings. The formulation of the algorithm, discussion of its properties, as well as three case studies are presented. The performance of the distributed tracking algorithm has been verified via experiments, which yielded quantifiable improvements over other techniques that have been implemented in practice. Both simulations and hardware experiments have confirmed the effectiveness of the proposed distributed algorithm.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • A High-Efficiency DC–DC Boost Converter for a Miniaturized
           Microbial Fuel Cell
    • Authors: Xu Zhang;Hao Ren;Soonjae Pyo;Jae-Ik Lee;Jongbaeg Kim;Junseok Chae;
      Pages: 2041 - 2049
      Abstract: This paper presents a high-efficiency dc-dc boost converter to interface a miniaturized 50 μL microbial fuel cell (MFC) having 1 cm2 vertically aligned carbon nanotube anode and 1 cm2 Cr/Au cathode. Geobacteraceae-enriched mixed bacterial culture in growth medium and 100 mM buffered ferricyanide solutions are used as the anolyte and catholyte, respectively. The miniaturized MFC produces up to approximately 10 μW with an output voltage of 0.4-0.7 V. Such low voltage, which is also load dependent, prevents the MFC to directly drive low power electronics. A pulse-frequency modulation type dc-dc converter in discontinuous conduction mode is designed and implemented to address the challenges and provides a load independent output voltage with high conversion efficiency. The fabricated dc-dc converter in UMC 0.18 μm has been tested with the MFC. At 0.9 V output, the converter has a peak efficiency of 85% with 9 μW load.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • A Fully Integrated Three-Level Isolated Single-Stage PFC Converter
    • Authors: Dusmez; S.;Xiong Li;Akin, B.;
      Pages: 2050 - 2062
      Abstract: For low-cost isolated ac/dc power converters adopting high-voltage dc-link, research efforts focus on single-stage multilevel topologies. This paper proposes a new single-stage three-level isolated ac/dc PFC converter for high dc-link voltage low-power applications, achieved through an effective integration of ac/dc and dc/dc stages, where all of the switches are shared between two operations. With the proposed converter and switching scheme, input current shaping and output voltage regulation can be achieved simultaneously without introducing additional switches or switching actions. In addition, the middle two switches are turned on under zero current in discontinuous conduction mode operation, and the upper and bottom switches are turned on under zero voltage. Due to the flexible dc-link voltage structure, high power factor can be achieved at high line voltage. A 500 W/48 V prototype is designed to serve as the proof of concept, which exhibits 90.8% peak efficiency at low input line voltage.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • Multicell Switched-Inductor/Switched-Capacitor Combined Active-Network
    • Authors: Yu Tang;Ting Wang;Dongjin Fu;
      Pages: 2063 - 2072
      Abstract: High step-up voltage gain dc/dc converters are widely used in renewable energy power generation, uninterruptible power system, etc. In order to avoid the influence of leakage inductor in coupled inductors based converters, switched-inductor boost converter (SL-boost), switched-capacitor boost converter (SC-boost) and active-network converter (ANC) have been developed. With the transition in series and parallel connection of the inductors and capacitors, high step-up voltage conversion ratio can be achieved. This paper discusses the characteristics of the switched inductor and switched-capacitor cell; makes some comparisons between the ANC and boost converter. Based on the aforementioned analysis, this paper proposed the multicell switched-inductor/ switched-capacitor combined active network converters (MSL/SC-ANC). The proposed converters combine the advantages of SL/SC unit and active-network structure. Compared with previous high step-up converters, the novel converter provides a higher voltage conversion ratio with a lower voltage/current stress on the power devices, moreover, the structure of proposed SL/SC-ANC is very flexible, which means the quantity of SL and SC cells can be adjusted according to required voltage gain. A 20 times gain prototype is designed as an example to show the design procedure. Theoretical analysis and experimental results are presented to demonstrate the feature of the proposed converter.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • Multiple Conversion Ratio Resonant Switched-Capacitor Converter With
           Active Zero Current Detection
    • Authors: Hamo; E.;Cervera, A.;Peretz, M.M.;
      Pages: 2073 - 2083
      Abstract: This paper introduces an active method for zero current switching for resonant switched capacitor converters (SCC) with wide dynamic range. The method is demonstrated on a binary SCC that features wide range of conversion ratios. Due to the resultant high efficiency of the converter operating under soft-switching conditions, it is applicable for higher power levels up to the medium power range (100 W). The resonant operation is achieved with a single air core inductor and precise commutation at zero current. The sensing signals of the resonant currents are obtained from the flying capacitors rather than form element in which the current includes a dc component. The zero detection method developed is capable of compensating for both the processing delays (from detection to switching action) and for the large variations of the resonant characteristics (due to transition between subcircuits), and for any other component variations. A 100 W prototype with maximum input voltage of 100 V and up to 19 conversion ratios has been built and tested experimentally. The current sensing has been implemented with a simple, cost-efficient, passive sensor. For proper construction of a higher power experimental prototype with desired target efficiency, a set of design considerations for the selection of the power stage components, based on an expanded equivalent resistance concept for multiple subcircuits converter, has been delineated. In addition, a simple and efficient isolated gate driver circuitry is presented.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • Buck-Derived Converters Based on Gallium Nitride Devices for Envelope
           Tracking Applications
    • Authors: Miaja; P.F.;Rodriguez, A.;Sebastian, J.;
      Pages: 2084 - 2095
      Abstract: Envelope tracking (ET) is a technique designed to enhance the efficiency of radio frequency power amplifiers (RF PA). It is based on providing the voltage to the RF PA with variations that mimic the shape of the envelope of the communication signal that the RF PA is processing. As the bandwidth of these signals can be around several megahertz, the switching frequency of the switching mode power supply designed for ET applications has to be very high. The good switching characteristics of Gallium Nitride devices makes them suitable for this application. This paper presents two multiphase converters to be used as envelope modulators in envelope tracking applications.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • On-Chip Compensated Wide Output Range Boost Converter with Fixed-Frequency
           Adaptive Off-Time Control for LED Driver Applications
    • Authors: Lin Cheng;Jinhua Ni;Yao Qian;Minchao Zhou;Wing-Hung Ki;Bill Yang Liu;Li; G.;Zhiliang Hong;
      Pages: 2096 - 2107
      Abstract: An on-chip compensated wide output range boost converter with fixed-frequency adaptive off-time current-mode control is presented. The small signal characteristic of the boost converter with current-mode control is reviewed, and an adaptive current sensing technique is proposed to reduce the variation of phase margin at different output voltages. On-chip compensation is achieved with a Type II compensator. Adaptive off-time control is adopted for its fast response and no need for slope compensation, while its disadvantage of varying switching frequency is eliminated by the proposed off-time generator. The IC controller was fabricated in a 0.5 μm 2P3M BCD 40 V process. Measurement results confirm that an output range of 5.5 V ~ 36 V with an input voltage of 5 V is achieved. The switching frequency is fixed at 1 MHz with a variation of ±1%. The measured peak efficiency and maximum output power are 92.9% and 8.6 W, respectively. For a load step of 200 mA using a 3.3-μH inductor and a 20-μF output capacitor, overshoot and undershoot of the load transient responses are smaller than 1% of the output voltage.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • A Novel Load Adaptive ZVS Auxiliary Circuit for PWM Three-Level
           DC–DC Converters
    • Authors: Das; P.;Pahlevaninezhad, M.;Kumar Singh, A.;
      Pages: 2108 - 2126
      Abstract: Three-level PWM dc-dc converters convert high dc voltage (>500 V) generally at the output of a three-phase ac-dc PWM rectifier in ac-dc converters to an isolated dc output voltage which can be used to power data center loads. Strict efficiency requirements at loads from 20% to 50% of full load of ac-dc converters for telecom applications have been introduced by energy star enforcing industries to improve efficiency of the dc-dc converter in an ac-dc converter powering data-center loads at those loads. High-efficiency requirements at low and mid loads in high switching frequency PWM dc-dc three-level converters implemented with MOSFETs can be achieved by reducing switching losses through optimized load adaptive ZVS for the entire load range. In this paper, a simple yet novel load adaptive ZVS auxiliary circuit for three-level converter is proposed for so that the resulting three-phase ac-dc converter can meet energy star platinum efficiency standard. The operation of the proposed dc-dc converter is described, analyzed, and validated by experimental results from an industrial prototype of a three-phase ac-dc converter comprising of a front-end three-phase boost PWM rectifier followed by the proposed converter.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • Hybrid Transformer ZVS/ZCS DC–DC Converter With Optimized Magnetics
           and Improved Power Devices Utilization for Photovoltaic Module
    • Authors: Bin Gu;Dominic; J.;Baifeng Chen;Lanhua Zhang;Jih-Sheng Lai;
      Pages: 2127 - 2136
      Abstract: This paper presents a nonisolated, high boost ratio dc-dc converter with the application for photovoltaic (PV) modules. The proposed converter utilizes a hybrid transformer to incorporate the resonant operation mode into a traditional high boost ratio active-clamp coupled-inductor pulse-width-modulation dc-dc converter, achieving zero-voltage-switching (ZVS) turn-on of active switches and zero-current-switching turn-off of diodes. As a result of the inductive and capacitive energy being transferred simultaneously within the whole switching period, power device utilization (PDU) is improved and magnetic utilization (MU) is optimized. The improved PDU allows reduction of the silicon area required to realize the power devices of the converter. The optimized MU reduces the dc-bias of magnetizing current in the magnetic core, leading to smaller sized magnetics. Since the magnetizing current has low dc-bias, the ripple magnetizing current can be utilized to assist ZVS of main switch, while maintaining low root-mean-square (RMS) conduction loss. The voltage stresses on the active switches and diodes are maintained at a low level and are independent of the wide changing PV voltages as a result of the resonant capacitor in series in the energy transfer loop. The experimental results based on 250 W prototype circuit show 97.7% peak efficiency and system CEC efficiencies greater than 96.7% over 20 to 45 V input voltages. Due to the high efficiency over wide power range, the ability to operate with a wide variable input voltage and compact size, the proposed converter is an attractive design for PV module applications.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • Novel Single-Phase PWM AC–AC Converters Solving Commutation Problem
           Using Switching Cell Structure and Coupled Inductor
    • Authors: Shin; H.-H.;Cha, H.;Kim, H.-G.;Yoo, D.-W.;
      Pages: 2137 - 2147
      Abstract: This paper presents novel single-phase pulse width modulation (PWM) ac-ac converters that can solve the commutation problem in single-phase direct PWM ac-ac converters without sensing the input voltage polarity. By using a basic switching cell structure and coupled inductors, the proposed ac-ac converters can be short- and open-circuited without damaging the switching devices. Neither lossy RC snubber nor dedicated soft commutation strategy is required in the proposed converter. By replacing the conventional phase-leg of the PWM ac-ac converters with the switching cell structure and the coupled inductor, three novel buck, boost, and buck-boost type PWM ac-ac converters are developed. Although two coupled inductors are required for the proposed converter, the input inductor of the proposed converter can be much smaller than that of the conventional PWM ac-ac converters. The volume of the magnetic components can be further reduced by increasing switching frequency of the converter because very fast recovery diodes can be selected externally. In order to verify performance and robustness of the proposed converter, a 200-W boost type prototype converter was built and tested with both mismatched gate signals and highly distorted input voltage.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • High-Frequency-Fed Unity Power-Factor AC–DC Power Converter With
           One Switching Per Cycle
    • Authors: Chi-Kwan Lee;Kiratipongvoot; S.;Siew-Chong Tan;
      Pages: 2148 - 2156
      Abstract: This paper presents a power converter and its control circuit for high-frequency-fed ac to dc conversion. Based on the resonant technique, the input current is shaped to be sinusoidal and is forced to follow the high-frequency sinusoidal input voltage so as to achieve unity power factor. With the proper selection of the characteristic impedance of the resonant tank, the converter is able to perform the function of a buck, boost, or buck-boost converter. The initial condition of the resonant tank is used to control the output voltage gain of the converter. Since all the switches are operated at the fundamental frequency of the input ac source, the switching loss of the converter is small. A control scheme is also proposed for the converter. A proof-of-concept prototype operating at 400 kHz is constructed and its performance is experimentally measured. Results show that the proposed converter operates as theoretically anticipated.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • Online MTPA Control Approach for Synchronous Reluctance Motor Drives Based
           on Emotional Controller
    • Authors: Daryabeigi; E.;Abootorabi Zarchi, H.;Arab Markadeh, G.R.;Soltani, J.;Blaabjerg, F.;
      Pages: 2157 - 2166
      Abstract: In this paper, speed and torque control modes (SCM and TCM) of synchronous reluctance motor (SynRM) drives are proposed based on emotional controllers and space vector modulation under an automatic search of the maximum-torque-per-ampere (MTPA) strategy. Furthermore, in order to achieve an MTPA strategy at any operating condition, after recognition of transient state by two new indicators, a search algorithm changes the stator flux magnitude automatically. The indicators operate based on slip effect generated at transient conditions in a SynRM with cage. The performance of the proposed controller is compared with an optimized conventional PI controller under different operating conditions. Simulation and experimental results demonstrate the benefits of the proposed approach. This structure shows superiority of the proposed method, such as fast dynamic, simple implementation and robustness to parameter variations and external disturbances in both TCM and SCM. In addition, the proposed MTPA strategy shows a reliable and fast response to operating point change.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • A Low-Loss “RL-Plus-C” Filter for Overvoltage Suppression in
           Inverter-Fed Drive System With Long Motor Cable
    • Authors: Yuen; K.K.-F.;Chung, H.S.-H.;
      Pages: 2167 - 2181
      Abstract: Inverter-fed drive systems have been widely used in residential, commercial, and industrial applications. Special emphasis is placed on avoiding overvoltage spikes traveling along the cable and inside the motor, when a long motor cable is used. Such phenomenon would cause premature failure of the motor and cable insulation. Many passive and active overvoltage suppression techniques have been proposed to tackle this issue. Among them, passive overvoltage filters are dominant solutions, as their implementation is simple, cost effective, and robust. However, they have the main drawback of high power dissipation. This paper gives a new perspective on this subject. A generalized model for characterizing the inverter-cable-motor system with the filter included will be formulated to describe the interactions between the filter and the drive system. Then, the characteristics of an ideal overvoltage filter will be derived. Furthermore, a low-loss filter, named as “RL-plus-C” filter that exhibits near ideal characteristics will be proposed. Its performance will be compared with that of the commonly adopted RC and RLC filters, theoretically and experimentally on a 1-hp motor drive system. Results reveal that the proposed filter has the lowest power dissipation.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • Torque-Ripple Minimization and Fast Dynamic Scheme for Torque Predictive
           Control of Permanent-Magnet Synchronous Motors
    • Authors: Cho; Y.;Lee, K.-B.;Song, J.-H.;Lee, Y.I.;
      Pages: 2182 - 2190
      Abstract: This paper proposes a simple and effective method to reduce torque ripples for the torque predictive control (TPC) of permanent-magnet synchronous motors (PMSMs). The conventional TPC analyzes the relationship among the electrical torque, stator flux, and stator voltage using the magnitude of the stator voltage vector of PMSMs to obtain the angle of the reference voltage vector and accurately control the torque. In addition, the stator-flux control uses the hysteresis method. However, the voltage vector that can be chosen in an inverter is limited because the conventional TPC fixes the magnitude of the reference voltage vector, and thus, a large torque ripple is generated in the low-speed region. The proposed TPC does not fix but varies the magnitude of the reference voltage vector using both the torque and flux error information. Therefore, it not only has the fast dynamic of a direct torque control but also can reduce effectively the torque ripple. The proposed method is proven by the simulation and experimental results, and the proposed algorithm provides an excellent steady-state response and fast dynamics.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • Discontinuous SVPWM Techniques of Three-Leg VSI-Fed Balanced Two-Phase
           Loads for Reduced Switching Losses and Current Ripple
    • Authors: Charumit; C.;Kinnares, V.;
      Pages: 2191 - 2204
      Abstract: In this paper, various types of discontinuous space vector pulse-width modulation techniques for a three-leg voltage source inverter supplying balanced two-phase loads are proposed. The main objectives of the paper are to analyze switching loss characteristics associated with semiconductor devices and to reduce output current ripple by dealing with various types of zero space vector time in each switching sequence. Capabilities of reductions in switching losses and current ripple for both balanced and unbalanced output phase voltages at high modulation index and load power factor angle of 30° lagging are focused. The validity of the proposed techniques is verified by simulation and experimental results in terms of voltage spectrum, current waveforms, reductions in switching losses, and output current ripple at high modulation index when compared to a continuous space vector pulse-width modulation technique.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • Effect of Number of Layers on Performance of Fractional-Slot
           Concentrated-Windings Interior Permanent Magnet Machines
    • Authors: Reddy; P.B.;El-Refaie, A.M.;Kum-Kang Huh;
      Pages: 2205 - 2218
      Abstract: Interior PM machines equipped with fractional-slot concentrated-windings are good candidates for high-speed traction applications. This is mainly due to the higher power density and efficiency that can be achieved. The main challenge with this type of machines is the high rotor losses at high speeds/frequencies. This paper will thoroughly investigate the effect of number of winding layers on the performance of this type of machines. It will be shown that by going to higher number of layers, there can be significant improvement in efficiency especially at high speeds mainly due to the reduction of the winding factor/magnitude of the most dominant stator mmf subharmonic component. It will also be shown that there is significant improvement in torque density. Even though there is reduction in the winding factor of the stator synchronous torque-producing mmf component, this is more than offset by increase in machine saliency and reluctance torque. The paper will provide general guidelines regarding the optimum slot/pole/phase combinations based on torque density and efficiency. Sample designs of various slot/pole combinations are used to quantify the benefit of going to higher number of layers in terms of torque density, efficiency, and torque ripple.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • A Mathematical Expression to Determine Copper Losses in Switching-Mode
           Power Supplies Transformers Including Geometry and Frequency Effects
    • Authors: Lopera; J.M.;Prieto, M.J.;Diaz, J.;Garcia, J.;
      Pages: 2219 - 2231
      Abstract: High-frequency copper losses, or copper losses produced during switching in switching-mode power supplies, are very much related to variations of the magnetic field distribution within the core window. When operating at high frequency, the current flowing through the windings of a magnetic component experiences redistribution across the section of the conductor due to skin and proximity effects. Current redistribution depends not only on actual frequency, but also on conductor size and layer distribution. While previous works aim to optimize windings size by considering just the current flowing through that winding, this paper shows that, in most of the cases, current redistribution is strongly affected by the currents at the other transformer windings, which should also be taken into account. This paper derives a mathematical expression to calculate the evolution, in the time domain, of the magnetic field during the switching, which will be later used to obtain the current density distribution and copper losses in the component. An easy-to-calculate expression will be derived that allows magnetic windings to be analyzed and/or optimized, because losses are expressed as a function of the winding geometry and position. An application example is also included. All the equations derived are verified by comparing them with the results obtained from a differential equations solver, and with previous works when applicable. Experimental results are also provided.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • Power Loss Prediction and Precise Modeling of Magnetic Powder Components
           in DC–DC Power Converter Application
    • Authors: Hilal; A.;Raulet, M.-A.;Martin, C.;Sixdenier, F.;
      Pages: 2232 - 2238
      Abstract: In power electronics applications, magnetic components are often subjected to nonsinusoidal waveforms, variable frequencies, and dc bias conditions. These operating conditions generate different losses in the core compared to sinusoidal losses provided by manufacturers. In the conception and design stage, lack of precise losses diagnosis has unacceptable effects on system's efficiency, reliability, and power consumption. Since virtual prototyping is used to predict and improve system's behavior before realization, losses and behavior prediction of components is possible. Circuit simulators and their compatible components models are required. This paper is summarized by proposing nonlinear dynamic model of powdered material magnetic core for use in circuit simulators. It includes the material's nonlinear hysteresis behavior with accurate winding and core modeling. The magnetic component model is implemented in circuit simulation software “Simplorer” using VHDL-AMS modeling language. Waveforms and losses of a powder core inductor in a buck converter application are simulated and compared to measured ones. The model is validated for different ripple currents, different loads, and a wide frequency range. DC bias is taken into account in both continuous and discontinuous conduction modes.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • A Comparative Performance Investigation of Single-Stage Dimmable
           Electronic Ballasts for Electrodeless Fluorescent Lamp Applications
    • Authors: Fraytag; J.;Schlittler, M.E.;Dalla Costa, M.A.;Seidel, A.R.;Alonso, J.M.;do Prado, R.N.;da Silva, M.F.;
      Pages: 2239 - 2252
      Abstract: This paper presents a comparative investigation, design and development issues about six different single-stage topologies, applied as electronic ballasts, for electrodeless fluorescent lamps. The ballast is intended to feed a 100 W lamp at 250 kHz, with dimming feature. The proposed topologies use different converters for the power factor correction (PFC) stage: Buck-Boost, SEPIC, Zeta, Cúk, Flyback, and Boost. All of them operate in discontinuous conduction mode. A resonant half-bridge inverter is used as lamp power control (PC) stage. The integration of both stages (PFC and PC) is proposed in this paper. In this way, it is possible to reduce the number of active switches, as well as simplify the required driving and control circuitry. Experimental results demonstrate the feasibility of the proposed dimming technique that achieved around 56% lamp power dimming, from 100 W down to 44 W. The implemented topologies attained high average power factor (>0.98), and low line current average total harmonic distortion (
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • A Dimming Method for Hot Cathode Fluorescent Lamp Using a Resonant
           Inverter Operating at Fixed Switching Frequency
    • Authors: Kadota; M.;Shoji, H.;Furuya, S.;
      Pages: 2253 - 2261
      Abstract: This paper describes a dimming method for hot cathode fluorescent lamp (HCFL) using a resonant inverter operating at fixed switching frequency. The proposed method is based on burst dimming and decreases the inverter output voltage during the burst-off period by changing the switching pattern of the inverter. Consequently, the lamp can be turned OFF, while the filaments of lamp are kept preheated without adding an inverter for preheating. Once the lamp is turned OFF, N-times resonant mode (where N means a natural number) occurs because the characteristic of the resonant circuit (which depends on lamp impedance) changes drastically. This mode keeps the root mean square of filament currents large enough to ensure long lamp life. Moreover, the inverter operates in zero-voltage-switching resonant mode during both the burst-on and burst-off periods. Experimental results showed that stable burst dimming and preheating characteristics were attained. The proposed method thus contributes to achieving long lifetime, small size, and low cost of lighting system for HCFLs.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • 120% Harvesting Energy Improvement by Maximum Power Extracting
           Control for High Sustainability Magnetic Power Monitoring and Harvesting
    • Authors: Tzu-Chi Huang;Ming-Jhe Du;Yu-Chai Kang;Ruei-Hong Peng;Ke-Horng Chen;Ying-Hsi Lin;Tsung-Yen Tsai;Chao-Cheng Lee;Long-Der Chen;Jui-Lung Chen;
      Pages: 2262 - 2274
      Abstract: The magnetic energy harvesting (MEH) circuit and the power monitoring system are proposed in this paper to enlarge the system sustainability on wireless sensing or the monitoring system. The proposed MEH circuit harvests magnetic power on power wires through a power sensing current transformer (CT) and charges power monitoring system. The MEH circuit includes the direct ac-dc rectifier and the maximum power extracting (MPE) control circuit. The direct ac-dc rectifier can directly rectify ac input to the dc output current. The proposed MPE control fits the characteristic of magnetic energy source compared to the conventional resistor emulation maximum power point tracking method. Owing to continuous tracking the maximum power of the CT, 120% harvesting power improvement can be achieved under the same CT's sensing current. Peak efficiency of 82% can be achieved under the sensing current of 8 A. The test chip is fabricated in 0.25 μm CMOS process with an active area of 0.98 mm2.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • A Simple Current Control Strategy for a Four-Leg Indirect Matrix Converter
    • Authors: Garcia; C.;Rivera, M.;Lopez, M.;Rodriguez, J.;Pena, R.;Wheeler, P.W.;Espinoza, J.R.;
      Pages: 2275 - 2287
      Abstract: In this paper, the experimental validation of a predictive current control strategy for a four-leg indirect matrix converter is presented. The four-leg indirect matrix converter can supply energy to an unbalanced three-phase load while providing a path for the zero sequence load. The predictive current control technique is based on the optimal selection among the valid switching states of the converter by evaluating a cost function, resulting in a simple approach without the necessity for modulators. Furthermore, zero dc-link current commutation is achieved by synchronizing the state changes in the input stage with the application of a zero-voltage space vector in the inverter stage. Simulation results are presented and the strategy is experimentally validated using a laboratory prototype.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • Distributed Cooperative Control of DC Microgrids
    • Authors: Nasirian; V.;Moayedi, S.;Davoudi, A.;Lewis, F.L.;
      Pages: 2288 - 2303
      Abstract: A cooperative control paradigm is used to establish a distributed secondary/primary control framework for dc microgrids. The conventional secondary control, that adjusts the voltage set point for the local droop mechanism, is replaced by a voltage regulator and a current regulator. A noise-resilient voltage observer is introduced that uses neighbors' data to estimate the average voltage across the microgrid. The voltage regulator processes this estimation and generates a voltage correction term to adjust the local voltage set point. This adjustment maintains the microgrid voltage level as desired by the tertiary control. The current regulator compares the local per-unit current of each converter with the neighbors' and, accordingly, provides a second voltage correction term to synchronize per-unit currents and, thus, provide proportional load sharing. The proposed controller precisely handles the transmission line impedances. The controller on each converter communicates with only its neighbor converters on a communication graph. The graph is a sparse network of communication links spanned across the microgrid to facilitate data exchange. The global dynamic model of the microgrid is derived, and design guidelines are provided to tune the system's dynamic response. A low-voltage dc microgrid prototype is set up, where the controller performance, noise resiliency, link-failure resiliency, and the plug-and-play capability features are successfully verified.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • A High-Frequency Model for a PCM Buck Converter
    • Authors: Shen Xu;Fei Li;Yunpeng Yao;Shengli Lu;Weifeng Sun;
      Pages: 2304 - 2312
      Abstract: In order to analyze the high-frequency behaviors of the peak current mode (PCM) Buck converter, a small-signal multifrequency model is proposed. The multifrequency model explains the influences from the sideband frequency components generated by the nonlinear PWM comparator. It can effectively reflect some features which cannot be shown by the conventional average model, such as the phase delay. In addition, based on the proposed model, the sample-hold effect is also introduced and analyzed in this paper. Through the derivation and validation of the new model, frequency characteristics of the PCM Buck converter can be well understood, especially in the high-frequency region.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • Robust Sliding-Mode Control Design for a Voltage Regulated Quadratic Boost
    • Authors: Lopez-Santos; O.;Martinez-Salamero, L.;Garcia, G.;Valderrama-Blavi, H.;Sierra-Polanco, T.;
      Pages: 2313 - 2327
      Abstract: A robust controller design to obtain output voltage regulation in a quadratic boost converter with high dc gain is discussed in this paper. The proposed controller has an inner loop based on sliding-mode control whose sliding surface is defined for the input inductor current. The current reference value of the sliding surface is modified by a proportional-integral compensator in an outer loop that operates over the output voltage error. The stability of the two-loop controller is proved by using the Routh-Hurwitz criterion, which determines a region in the Kp-Ki plane, where the closed-loop system is always stable. The analysis of the sliding-mode-based control loop is performed by means of the equivalent control method, while the outer loop compensator is derived by means of the Nyquist-based Robust Loop Shaping approach with the M-constrained Integral Gain Maximization technique. Robustness is analyzed in depth taking into account the parameter variation related with the operation of the converter in different equilibrium points. Simulations and experimental results are presented to validate the approach for a 20-100-W quadratic boost converter stepping-up a low dc voltage (15-25-V dc) to a 400-V dc level.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • Frequency-Coordinating Virtual Impedance for Autonomous Power Management
           of DC Microgrid
    • Authors: Yunjie Gu;Wuhua Li;Xiangning He;
      Pages: 2328 - 2337
      Abstract: In this paper, the concept of frequency-coordinating virtual impedance is proposed for the autonomous control of a dc microgrid. This concept introduces another degree of freedom in the conventional droop control scheme, to enable both time-scale and power-scale coordination in a distributed microgrid system. As an example, the proposed technique is applied to the coordinating regulation of a hybrid energy storage system composed of batteries and supercapacitors. With an effective frequency-domain shaping of the virtual output impedances, the battery and supercapacitor converters are designed to absorb low-frequency and high-frequency power fluctuations, respectively. In this way, their complementary advantages in energy and power density can be effectively exploited. Furthermore, the proposed concept can be integrated into a mode-adaptive power management framework with autonomous mode transitions. The entire solution features highly versatile functions based on fully decentralized control. Therefore, both flexibility and reliability can be enhanced. The effectiveness of the presented solution is verified by experimental results.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • Optically Switched-Drive-Based Unified Independent dv/dt
           and di/dt Control for Turn-Off Transition of Power
    • Authors: Riazmontazer; H.;Mazumder, S.K.;
      Pages: 2338 - 2349
      Abstract: To control the switching dynamics of an optically triggered hybrid device, a photonic-control mechanism is outlined. The optically triggered hybrid device comprises a power MOSFET, as the main power semiconductor device (PSD), and a pair of GaAs-based optically triggered power transistors (OTPTs), serving as the driver for the power MOSFET . The switching-transition controller modulates the turn-off transition of the power MOSFET by modulating the optical intensity of the OTPTs. The independent and unified $dv/dt$ and $di/dt$ control of the PSD is achieved using a single control circuit which also predicts the onset of transition between the $di/dt$ and the $dv/dt$ regions of control. Experimental control results validating the OTPT-based dynamical modulation of the turn-off characteristic of the power MOSFET are provided. In this study, the power MOSFET is chosen to be a SiC mosfet . However, the proposed photonic-control mechanism can be extended to Si power MOSFETS as well.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • Wavelet Fuzzy Neural Network With Asymmetric Membership Function
           Controller for Electric Power Steering System via Improved Differential
    • Authors: Ying-Chih Hung;Faa-Jeng Lin;Jonq-Chin Hwang;Jin-Kuan Chang;Kai-Chun Ruan;
      Pages: 2350 - 2362
      Abstract: A wavelet fuzzy neural network using asymmetric membership function (WFNN-AMF) with improved differential evolution (IDE) algorithm is proposed in this study to control a six-phase permanent magnet synchronous motor (PMSM) for an electric power steering (EPS) system. First, the dynamics of a steer-by-wire EPS system and a six-phase PMSM drive system are described in detail. Moreover, the WFNN-AMF controller, which combines the advantages of wavelet decomposition, fuzzy logic system, and asymmetric membership function (AMF), is developed to achieve the required control performance of the EPS system for the improvement of stability of the vehicle and the comfort of the driver. Furthermore, the online learning algorithm of WFNN-AMF is derived using back-propagation method. However, degenerated or diverged responses will be resulted due to the inappropriate selection of small or large learning rates of the WFNN-AMF. Therefore, an IDE algorithm is proposed to online adapt the learning rates of WFNN-AMF. In addition, a 32-bit floating-point digital signal processor, TMS320F28335, is adopted for the implementation of the proposed intelligent controlled EPS system. Finally, the feasibility of the proposed WFNN-AMF controller with IDE for the EPS system is verified through experimental results.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • Improved Stator Flux Estimator for Speed Sensorless Induction Motor Drives
    • Authors: Stojic; D.;Milinkovic, M.;Veinovic, S.;Klasnic, I.;
      Pages: 2363 - 2371
      Abstract: In this paper, an improved induction motor (IM) stator flux estimation method is proposed, based on a novel integrator scheme with a closed-loop dc offset compensation algorithm. When compared with the existing stator flux estimators, the proposed solution represents an improved programmable low-pass filter. Namely, by introducing a novel closed-loop dc offset compensation structure, two major drawbacks of existing stator flux estimators are overcome; their stability and accuracy at low frequencies, and the estimator response time over the whole frequency range, introducing an estimation algorithm much simpler than existing solutions. The performance of the novel stator flux estimator is tested by means of simulation runs and experimental tests, with the proposed algorithm used for the estimation of the stator flux, rotor flux, and rotor speed in a direct field-oriented controlled IM control algorithm. The simulations and experimental results show that the proposed estimator enables accurate and stable operation under all operating conditions, including the critical low stator frequency range.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
  • Comments on “An Efficient Partial Power Processing DC/DC Converter
           for Distributed PV Architectures”
    • Authors: Suntio; T.;Kuperman, A.;
      Pages: 2372 - 2372
      Abstract: In this paper, “An Efficient Partial Power Processing DC/DC Converter for Distributed PV Architectures” by Agamy et al. (IEEE Trans. Power Electron., vol. 29, no. 2, Feb. 2014), a dc-dc converter for distributed photovoltaic plant architectures, capable of performing series-type partial power processing under maximum power point control was proposed and tested for various performance parameters. The purpose of this note is correcting (IEEE Trans. Power Electron., vol. 29, no. 2, Feb. 2014) by proving that while the overall operation and results are technically correct, the proposed converter is actually a boost stage performing full rather than partial power processing.
      PubDate: April 2015
      Issue No: Vol. 30, No. 4 (2015)
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