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  Subjects -> ELECTRONICS (Total: 138 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: 57)
American Journal of Electrical and Electronic Engineering     Open Access   (Followers: 8)
Annals of Telecommunications     Hybrid Journal   (Followers: 4)
APL : Organic Electronics and Photonics     Hybrid Journal   (Followers: 1)
APSIPA Transactions on Signal and Information Processing     Open Access   (Followers: 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: 1)
Circuits and Systems     Open Access   (Followers: 7)
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)
EPJ Quantum Technology     Open Access  
EURASIP Journal on Embedded Systems     Open Access   (Followers: 8)
Foundations and TrendsĀ® in Communications and Information Theory     Full-text available via subscription   (Followers: 6)
Foundations and TrendsĀ® in Signal Processing     Full-text available via subscription   (Followers: 4)
Frequenz     Full-text available via subscription   (Followers: 1)
Frontiers of Optoelectronics     Hybrid Journal   (Followers: 2)
Geoscience and Remote Sensing, IEEE Transactions on     Hybrid Journal   (Followers: 20)
Haptics, IEEE Transactions on     Hybrid Journal   (Followers: 4)
IEEE Consumer Electronics Magazine     Full-text available via subscription   (Followers: 11)
IEEE Journal of Emerging and Selected Topics in Power Electronics     Hybrid Journal   (Followers: 7)
IEEE Journal of the Electron Devices Society     Open Access   (Followers: 1)
IEEE Power Electronics Magazine     Full-text available via subscription   (Followers: 5)
IEEE Transactions on Audio, Speech, and Language Processing     Hybrid Journal   (Followers: 10)
IEEE Transactions on Automatic Control     Hybrid Journal   (Followers: 20)
IEEE Transactions on Consumer Electronics     Hybrid Journal   (Followers: 12)
IEEE Transactions on Electron Devices     Hybrid Journal   (Followers: 6)
IEEE Transactions on Information Theory     Hybrid Journal   (Followers: 13)
IEEE Transactions on Power Electronics     Hybrid Journal   (Followers: 16)
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 Power Electronics     Hybrid Journal   (Followers: 9)
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 Applied Electronics in Physics & Robotics     Open Access   (Followers: 1)
International Journal of Biomedical Nanoscience and Nanotechnology     Hybrid Journal   (Followers: 5)
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: 11)
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: 2)
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: 7)
International Journal on Electrical and Power Engineering     Full-text available via subscription   (Followers: 11)
ISRN Electronics     Open Access   (Followers: 1)
ISRN Signal Processing     Open Access  
Journal of Advanced Dielectrics     Open Access   (Followers: 1)
Journal of Artificial Intelligence     Open Access   (Followers: 5)
Journal of Circuits, Systems, and Computers     Hybrid Journal   (Followers: 1)
Journal of Electrical and Electronics Engineering Research     Open Access   (Followers: 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)
Journal of Electromagnetic Waves and Applications     Hybrid Journal   (Followers: 2)
Journal of Electronic Design Technology     Full-text available via subscription   (Followers: 2)
Journal of Electronics (China)     Hybrid Journal   (Followers: 2)
Journal of Field Robotics     Hybrid Journal   (Followers: 2)
Journal of Guidance, Control, and Dynamics     Full-text available via subscription   (Followers: 55)
Journal of Intelligent Procedures in Electrical Technology     Open Access  
Journal of Low Power Electronics     Full-text available via subscription   (Followers: 4)
Journal of Low Power Electronics and Applications     Open Access   (Followers: 1)

        1 2 | Last

IEEE Transactions on Power Electronics
   Journal TOC RSS feeds Export to Zotero [18 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  [174 journals]   [SJR: 3.308]   [H-I: 111]
  • IEEE Power Electronics Society Information
    • Pages: C3 - C3
      Abstract: Provides a listing of current committee members and society officers.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • IEEE Transactions on Power Electronics publication information
    • Pages: C2 - C2
      Abstract: Provides a listing of current staff, committee members and society officers.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • Table of contents
    • Pages: C1 - C4
      Abstract: Presents the table of contents for this issue of this periodical.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • Enhanced Phase-Shifted PWM Carrier Disposition for Interleaved
           Voltage-Source Inverters
    • Authors: Capella; G.J.;Pou, J.;Ceballos, S.;Konstantinou, G.;Zaragoza, J.;Agelidis, V.G.;
      Pages: 1121 - 1125
      Abstract: This letter presents a novel implementation of pulse width modulation that improves the quality of the line-to-line output voltages in interleaved multiphase voltage-source inverters (VSIs). In multiphase VSIs with n interleaved parallel-connected legs, the best single-phase output voltage is achieved when the carriers are evenly phase shifted. However, switching among nonadjacent levels can be observed at regular intervals in the line-to-line voltages, causing bad harmonic performance. With the proposed method, switching in the line-to-line voltages happens exclusively between adjacent levels. The modulator utilizes two sets of n evenly phase-shifted carriers that are dynamically allocated. Because of its generality, the proposed implementation is valid for any number of phases and any number of legs in parallel. A MATLAB/Simulink model has been set up for simulation purposes. Selected experimental results obtained from a three-phase VSI made up with two and three legs in parallel per phase are reported, confirming the enhancement attained with the proposed implementation.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • Deterioration Monitoring of DC-Link Capacitors in AC Machine Drives by
           Current Injection
    • Authors: Nguyen; T.H.;Lee, D.;
      Pages: 1126 - 1130
      Abstract: This letter proposes a novel condition monitoring scheme of dc-link capacitors in PWM inverter-fed induction machine drives with front-end diode rectifiers, which is based on the online capacitance estimation scheme. While the motor is operating in the regenerative mode for the estimation process, a regulated ac component is injected into the stator winding, which causes a dc-link voltage ripple at the same frequency. From the ac components of the dc-link voltage and current, the capacitance is estimated with a recursive least squares algorithm. With this method, experimental results have shown that the estimation error of the capacitance is less than 1%, from which the deterioration condition of the capacitors can be diagnosed reliably.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • EMI Generation Characteristics of SiC and Si Diodes: Influence of
           Reverse-Recovery Characteristics
    • Authors: Yuan; X.;Walder, S.;Oswald, N.;
      Pages: 1131 - 1136
      Abstract: Silicon carbide (SiC) Schottky diodes with zero reverse-recovery current (RRC) are perceived as superior due to their reduced switching losses. The absence of reverse-recovery behavior in these devices is also expected to result in reduced electromagnetic interference (EMI), compared with the conventional silicon (Si) PIN diodes. In this letter, the influence of SiC Schottky diodes on EMI generation in hard-switched power converters is investigated. A simplified analytical model enabling the spectral envelope of the diode current waveform to be predicted is presented. Numerical simulations and experimental tests are employed to validate this model. It is found that although the reverse-recovery characteristics are very different between Si diodes and SiC Schottky diodes, the actual improvement with SiC diodes on the spectral content of the diode current waveforms is relatively small except at frequencies around 5 MHz. Factors affecting the EMI performance such as the peak amplitude and the “snappiness” of the RRC are also analyzed. Experimental measurements of the switching current waveforms for both Si diodes and SiC diodes are presented and their frequency spectra are compared.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • Design and Operation of a Hybrid Modular Multilevel Converter
    • Authors: Zeng; R.;Xu, L.;Yao, L.;Williams, B.W.;
      Pages: 1137 - 1146
      Abstract: This paper presents a hybrid modular multilevel converter (MMC), which combines full-bridge submodules (FBSM) and half-bridge submodules (HBSM). Compared with the FBSM-based MMC, the proposed topology has the same dc fault blocking capability but uses fewer power devices hence has lower power losses. To increase power transmission capability of the proposed hybrid MMC, negative voltage states of the FBSMs are adopted to extend the output voltage range. The optimal ratio of FBSMs and HBSMs, and the number of FBSMs generating a negative voltage state are calculated to ensure successful dc fault blocking and capacitor voltage balancing. Equivalent circuits of each arm consisting of two individual voltage sources are proposed and two-stage selecting and sorting algorithms for ensuring capacitor voltage balancing are developed. Comparative studies for different circuit configurations show excellent performance balance for the proposed hybrid MMC, when considering dc fault blocking capability, power losses, and device utilization. Experimental results during normal operation and dc fault conditions demonstrate feasibility and validity the proposed hybrid MMC.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • Capacitor Voltage Balancing of a Five-Level ANPC Converter Using
           Phase-Shifted PWM
    • Authors: Wang; K.;Xu, L.;Zheng, Z.;Li, Y.;
      Pages: 1147 - 1156
      Abstract: Five-level active neutral-point clamped (5L-ANPC) converter is an attractive topology for high-power medium-voltage motor drives. This paper presents a capacitor voltage-balancing method for the 5L-ANPC converter, including the voltage balancing of dc-link capacitors and flying capacitors. In order to ensure that the series-connected or high-voltage switches of the 5L-ANPC converter are operated at fundamental frequency and the other switches are operated at a constant switching frequency, phase-shifted pulse width modulation is used to control this converter. The relationship between the average neutral-point current and zero-sequence voltage is investigated, and an optimum zero-sequence voltage is calculated to regulate the neutral-point potential. The voltage across the flying capacitor is also regulated by adjusting the switching duty cycles of two PWM signals, which varies the operation time of redundant switching states in each switching period. Simulation and experimental results are presented to verify the validity of this method.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • Implementation of Kernel Incremental Metalearning Algorithm in
           Distribution Static Compensator
    • Authors: Arya; S.R.;Singh, B.;
      Pages: 1157 - 1169
      Abstract: This paper presents implementation of distribution static compensator (DSTATCOM) using kernel incremental metalearning algorithm (KIMEL) control algorithm. It demonstrates the functions of DSTATCOM such as reactive power compensation, harmonics elimination, and load balancing under linear and nonlinear loads with its self-supporting dc-bus voltage. The proposed control algorithm based on KIMEL is applied for extraction of fundamental active and reactive power components of load currents that are required for estimation of reference supply currents. These reference supply currents are used for gating pulses generation using indirect current control principle. A DSTATCOM with features of self-supporting dc bus (capacitor) is developed using DSP (dSPACE-1104), and the response of proposed control algorithm is studied under various operating conditions and found satisfactory.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • A Stepping On-Time Adjustment Method for Interleaved Multichannel PFC
           Converters
    • Authors: Chen; Y.;Chen, H.;Chen, Y.;Liu, K.H.;
      Pages: 1170 - 1176
      Abstract: A simple and effective stepping on-time adjustment (SOTA) method with status judgment for interleaved multichannel critical mode (CRM) boost-type power factor correction (PFC) converters is proposed. The boost-type PFC converter with CRM operation is commonly used for ac–dc conversion because of its circuit simplicity and high efficiency. The interleaved multichannel PFC converter becomes the trend for high-power applications. However, conventional interleaved methods are complicated and difficult to implement when more than two channels are required. Also, noise disturbances or on-time mismatching can easily lead to continuous conduction mode operation which will increase current distortion, reduce power conversion efficiency, or even damage the converter. The proposed SOTA method with status judgment can greatly simplify the control complexity of the interleaved multichannel operation. A prototype 600-W three-channel interleaved CRM boost PFC converter is built to verify the performance of the proposed SOTA method.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • A Novel SPLL and Voltage Sag Detection Based on LES Filters and Improved
           Instantaneous Symmetrical Components Method
    • Authors: Chen; G.;Zhang, L.;Wang, R.;Zhang, L.;Cai, X.;
      Pages: 1177 - 1188
      Abstract: The software phase-locked loop and the voltage sag detection algorithm are the two key factors to evaluate the performance of a dynamic voltage restorer, whose dynamic response is usually impacted by phase jump, voltage unbalance, and harmonics of the grid voltage. This paper proposes a novel algorithm based on the combination of least error squares filters and an improved instantaneous symmetrical components method. Hence, a detailed theoretical procedure is first presented. Then, the simulation model is built in MATLAB/SINMULINK. To verify its effectiveness, a series of comparison and analysis have been carried out. Also, a 10-kV/2-MVA prototype is developed with a voltage sag generator platform. Finally, experiments have been done and the results show that the novel algorithm has an improved dynamic response compared with the traditional methods.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • A Novel Control Method for Transformerless H-Bridge Cascaded STATCOM With
           Star Configuration
    • Authors: Xu; R.;Yu, Y.;Yang, R.;Wang, G.;Xu, D.;Li, B.;Sui, S.;
      Pages: 1189 - 1202
      Abstract: This paper presents a transformerless static synchronous compensator (STATCOM) system based on multilevel H-bridge converter with star configuration. This proposed control methods devote themselves not only to the current loop control but also to the dc capacitor voltage control. With regards to the current loop control, a nonlinear controller based on the passivity-based control (PBC) theory is used in this cascaded structure STATCOM for the first time. As to the dc capacitor voltage control, overall voltage control is realized by adopting a proportional resonant controller. Clustered balancing control is obtained by using an active disturbances rejection controller. Individual balancing control is achieved by shifting the modulation wave vertically which can be easily implemented in a field-programmable gate array. Two actual H-bridge cascaded STATCOMs rated at 10 kV 2 MVA are constructed and a series of verification tests are executed. The experimental results prove that H-bridge cascaded STATCOM with the proposed control methods has excellent dynamic performance and strong robustness. The dc capacitor voltage can be maintained at the given value effectively.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • A Multilevel Energy Buffer and Voltage Modulator for Grid-Interfaced
           Microinverters
    • Authors: Chen; M.;Afridi, K.K.;Perreault, D.J.;
      Pages: 1203 - 1219
      Abstract: Microinverters operating into the single-phase grid from solar photovoltaic (PV) panels or other low-voltage sources must buffer the twice-line-frequency variations between the energy sourced by the PV panel and that required for the grid. Moreover, in addition to operating over wide average power ranges, they inherently operate over a wide range of voltage conversion ratios as the line voltage traverses a cycle. These factors make the design of microinverters challenging. This paper presents a multilevel energy buffer and voltage modulator (MEB) that significantly reduces the range of voltage conversion ratios that the dc–ac converter portion of the microinverter must operate over by stepping its effective input voltage in pace with the line voltage. The MEB partially replaces the original bulk input capacitor, and functions as an active energy buffer to reduce the total size of the twice-line-frequency energy buffering capacitance. The small additional loss of the MEB can be compensated by the improved efficiency of the dc–ac converter stage, leading to a higher overall system efficiency. The MEB architecture can be implemented in a variety of manners, allowing different design tradeoffs to be made. A prototype microinverter incorporating an MEB, designed for 27 to 38 V dc input voltage, 230-V rms ac output voltage, and rated for a line cycle average power of 70 W, has been built and tested in a grid-connected mode. It is shown that the MEB can successfully enhance the performance of a single-phase grid-interfaced microinverter by increasing its efficiency and reducing the total size of the twice-line-frequency energy buffering capacitance.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • Wireless Power Transmission Through Concrete Using Circuits Resonating at
           Utility Frequency of 60 Hz
    • Authors: Ishida; H.;Furukawa, H.;
      Pages: 1220 - 1229
      Abstract: A first attempt was made to perform wireless power transmission using circuits resonating at the utility frequency of 60 Hz. The purpose of this research is to develop a method for transmitting electrical power through concrete walls. An equation for the theoretical transmission efficiency that considers the copper and core losses was derived through equivalent circuit analysis. There is good agreement between the experimental and calculated values. The transmission efficiency was found to be strongly dependent on the shape of the magnet pole pieces. For a single flared shape, 165 W of power was transmitted over a distance of 100 mm through a concrete plate, representing a transmission efficiency of 78%. The efficiency dropped to approximately 67% for a concrete plate containing a steel frame.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • The Worst Conducted EMI Spectrum of Critical Conduction Mode Boost PFC
           Converter
    • Authors: Ji; Q.;Ruan, X.;Ye, Z.;
      Pages: 1230 - 1241
      Abstract: The switching frequency of the boost power factor correction (PFC) converter operating in critical conduction mode (CRM) varies in a line cycle, making the conducted electromagnetic interference (EMI) spectra of the converter appear great differences under different input voltage and load conditions. The EMI filter should be designed according to the worst conducted EMI spectrum of the converter, so as to suppress the conducted EMI of the converter to be lower than the standard limits under all working conditions. This paper analyzes the characteristics of the common-mode (CM) and differential-mode (DM) noise spectra of the CRM boost PFC converter, and discusses the effects of the varied switching frequency on the peak, quasi-peak (PK), and average (AV) conducted EMI spectra. It is revealed that, for the conducted EMI limits defined in EN55022 class B, which are specified within 150 kHz to 30 MHz, the EMI filters required for suppressing the QP spectra of the conducted EMI of the CRM boost PFC converter are larger than that for suppressing the AV spectra, and the QP values of the conducted EMI under all working conditions are lower than a certain maximum boundary. The input voltage and load conditions for the worst CM and DM noise spectra of the converter are derived in this paper, thus the repetitive measurements and numerical calculations are avoided. A CRM boost PFC converter prototype is fabricated, and the evaluation of the measured conducted EMI spectra and the EMI filter design example verified the theoretical analysis.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • Discontinuous Modulation Scheme for a Differential-Mode Ćuk
           Inverter
    • Authors: Mehrnami; S.;Mazumder, S.K.;
      Pages: 1242 - 1254
      Abstract: The differential-mode Ćuk inverter (DMCI) is a single-stage inverter with low device count. It offers advantages over other topologies because of compactness, higher power density, and reduced cost. It is a promising topological configuration for renewable-/alternative-energy applications with isolated as well as nonisolated structures. The continuous modulation scheme (CMS), which was introduced originally for this inverter, activates all the modules of the DMCI. The new discontinuous modulation scheme (DMS) deactivates one module in each half line-cycle leading to discontinuous operation of modules. This paper outlines the DMS and a mechanism to realize it. The experimental open-loop and closed-loop results of the DMCI using CMS and DMS are provided along with a comparison of their performances. It is shown that, the DMS reduces the circulating power and hence mitigates the losses. The voltage ratings of the devices also are reduced with the DMS. In contrast, the CMS has wider linearity in its normalized dc-voltage gain and yields reduced harmonic distortion of the output voltage. For DMS, to achieve comparable linearity in normalized dc-voltage gain and distortion, harmonic compensation under closed-loop control is a pathway that has been demonstrated.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • Objective-Oriented Power Quality Compensation of Multifunctional Grid-Tied
           Inverters and Its Application in Microgrids
    • Authors: Zeng; Z.;Yang, H.;Tang, S.;Zhao, R.;
      Pages: 1255 - 1265
      Abstract: Multifunctional grid-tied inverters (MFGTIs) have been paid much attention to handle the commonly concerned power quality issues of the microgrids. An MFGTI can not only interface the renewable energy resource into the utility grid, but also can compensate the harmonic and reactive current in the microgrid as an auxiliary service. However, the apparent capacity of an MFGTI for power quality compensation is limited. Therefore, how to enhance the power quality of the microgrid by optimal utilization of the limited and valuable capacity becomes a technical challenge. In this paper, two optimal control objectives of MFGTIs are presented based on a comprehensive power quality evaluation algorithm by means of analytic hierarchy process theory. One objective aims to obtain the expected power quality using minimal apparent capacity of the MFGTI. Another objective focuses on enhancing the power quality as well as possible in the given available apparent capacity condition. The two proposed strategies are compared in performance, and the paper also discusses how to use them in practice for the best performance. Experimental results performed on a microgrid in the laboratory confirm the validation and feasibility of the proposed optimal control strategies.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • A Novel Control Strategy of Suppressing DC Current Injection to the Grid
           for Single-Phase PV Inverter
    • Authors: He; G.;Xu, D.;Chen, M.;
      Pages: 1266 - 1274
      Abstract: Photovoltaic (PV) inverters without the isolation transformer become more attractive due to higher efficiency and lower weight. However, it may have dc offset current problem and is critical to the power system. In this paper, a novel control strategy of suppressing dc current injection to the grid for PV inverters is investigated. It is based on the idea of accurately sensing the dc offset voltage of PV inverter output. Since dc component of the inverter output can be eliminated, dc injection to the grid can be effectively suppressed. Finally, the control scheme is verified by the experiment.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • Advanced Fabrication, Modeling, and Testing of a Microphotosynthetic
           Electrochemical Cell for Energy Harvesting Applications
    • Authors: Ramanan; A.V.;Pakirisamy, M.;Williamson, S.S.;
      Pages: 1275 - 1285
      Abstract: Unconventional renewable energy sources are scarce and have not been explored thoroughly or exploited. The photosynthetic power cell (PSC) is one among them. Though there are few prototypes fabricated earlier, there has not been a comprehensive electrical equivalent model developed. This paper proposes an electrical equivalent model for a microphotosynthetic power cell (μPSC), which is tested and authenticated with experimental verification on a fabricated prototype. The developed model is further used for testing emulation behavior, to efficiently and accurately design an energy harvesting power electronic converter. The principle of the operation of the device is based on “photosynthesis.” Photosynthesis and respiration both involve an electron transfer chain. The electrons are extracted with the help of electrodes and a redox agent, and a power electronic converter is designed to harvest the energy. The fabricated cell is capable of producing an open-circuit voltage of 0.9 V and about 200 μW of peak power. The μPSC has an active area of $4.84, {rm cm}^{2}$ , which approximately translates to a power density of $400, {rm mW/m}^{2}$ . This makes it as one of the best-performing μPSC. The other top-performing μPSC devices report power densities of between 100 and $250, {rm mW/m}^{2}$ . The PSC produces energy under both dark and light conditions.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • A Scheme for the Power Control in a DFIG Connected to a DC Bus via a Diode
           Rectifier
    • Authors: Iacchetti; M.F.;Marques, G.D.;Perini, R.;
      Pages: 1286 - 1296
      Abstract: This paper deals with a new conversion topology for doubly-fed induction generators (DFIGs) suitable for wind energy conversion systems integrated in microgrids. It consists of a DFIG which is fed by a pulse width modulation converter on the rotor and with the stator connected to a dc grid through a diode rectifier. In this configuration, the stator diode rectifier and the rotor-side inverter share the same dc bus, so that the conventional grid-side inverter is avoided. Since only a diode rectifier designed for the full power and a reduced power inverter are required, this layout allows a cheap and effective integration of the DFIG with other generating and storage systems connected to the same dc bus. A simple control technique suitable to regulate the power delivered to the dc grid is proposed. The scheme is based on the regulation of the amplitude of a suited fraction of the rotor flux linkage: the optimal value of this fraction is theoretically deduced in order to minimize the DFIG derating due to the current harmonics. The effectiveness of the proposed control is proven by simulations and experimental tests.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • A Photovoltaic Array Transformer-Less Inverter With Film Capacitors and
           Silicon Carbide Transistors
    • Authors: Breazeale; L.C.;Ayyanar, R.;
      Pages: 1297 - 1305
      Abstract: A new photovoltaic (PV) array power converter circuit is presented. This inverter is a transformer-less topology with grounded PV array and only film capacitors. The motivations are to reduce circuit complexity, eliminate leakage ground currents, and improve reliability. The use of silicon carbide (SiC) transistors is the key enabling technology for this particular circuit to attain reasonable (>97%) efficiency. Some background about the challenges of ground currents and power decoupling to be addressed is first discussed. The proposed solution of a bidirectional buck boost converter, dynamically varying dc link, and half-bridge inverters is then presented along with details on the basic functionality. Some aspects of selecting passive components for the circuit are discussed. The average dynamic model and control system are then presented. Finally, simulation and experiment results are shown demonstrating that the proposed topology is a viable solution.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • A High Gain Input-Parallel Output-Series DC/DC Converter With Dual Coupled
           Inductors
    • Authors: Hu; X.;Gong, C.;
      Pages: 1306 - 1317
      Abstract: High voltage gain dc–dc converters are required in many industrial applications such as photovoltaic and fuel cell energy systems, high-intensity discharge lamp (HID), dc back-up energy systems, and electric vehicles. This paper presents a novel input-parallel output-series boost converter with dual coupled inductors and a voltage multiplier module. On the one hand, the primary windings of two coupled inductors are connected in parallel to share the input current and reduce the current ripple at the input. On the other hand, the proposed converter inherits the merits of interleaved series-connected output capacitors for high voltage gain, low output voltage ripple, and low switch voltage stress. Moreover, the secondary sides of two coupled inductors are connected in series to a regenerative capacitor by a diode for extending the voltage gain and balancing the primary-parallel currents. In addition, the active switches are turned on at zero current and the reverse recovery problem of diodes is alleviated by reasonable leakage inductances of the coupled inductors. Besides, the energy of leakage inductances can be recycled. A prototype circuit rated 500-W output power is implemented in the laboratory, and the experimental results shows satisfactory agreement with the theoretical analysis.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • Naturally Clamped Zero-Current Commutated Soft-Switching Current-Fed
           Push–Pull DC/DC Converter: Analysis, Design, and Experimental
           Results
    • Authors: Xuewei; P.;Rathore, A.K.;
      Pages: 1318 - 1327
      Abstract: The proposed converter has the following features: 1) zero-current commutation (ZCC) and natural voltage clamping (NVC) eliminate the need for active-clamp circuits or passive snubbers required to absorb surge voltage in conventional current-fed topologies. 2) Switching losses are reduced significantly owing to zero-current switching of primary-side devices and zero-voltage switching of secondary-side devices. Turn-on switching transition loss of primary devices is also negligible. 3) Soft switching and NVC are inherent and load independent. 4) The voltage across primary-side device is independent of duty cycle with varying input voltage and output power and clamped at rather low reflected output voltage enabling the use of low-voltage semiconductor devices. These merits make the converter good candidate for interfacing low-voltage dc bus with high-voltage dc bus for higher current applications. Steady state, analysis, design, simulation, and experimental results are presented.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • High-Input-Voltage High-Frequency Class E Rectifiers for Resonant
           Inductive Links
    • Authors: Aldhaher; S.;Luk, P.C.;Drissi, K.E.K.;Whidborne, J.F.;
      Pages: 1328 - 1335
      Abstract: The operation of traditional rectifiers such as half-wave and bridge rectifiers in wireless power transfer applications may be inefficient and can reduce the amount of power that is delivered to a load. An alternative is to use Class E resonant rectifiers that are known to operate efficiently at high resonant frequencies and at large input voltages. Class E rectifiers have a near sinusoidal input current which leads to an improved overall system performance and increased efficiency, especially that of the transmitting coil driver. This paper is the first to investigate the use of Class E resonant rectifiers in wireless power transfer systems based on resonant inductive coupling. A piecewise linear state-space representation is used to model the Class E rectifier including the rectifying diode’s forward voltage drop, its ON resistance, and the equivalent series resistance of the resonant inductor. Power quality parameters, such as power factor and total harmonic distortion, are calculated for different loading conditions. Extensive experimental results based on a 10-W prototype are presented to confirm the performed analysis and the efficient operation of the rectifier. An impressive operating efficiency of 94.43 $%$ has been achieved at a resonant frequency of 800 kHz.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • Derivation, Analysis, and Comparison of Nonisolated Single-Switch High
           Step-up Converters With Low Voltage Stress
    • Authors: Kim; J.;Moon, G.;
      Pages: 1336 - 1344
      Abstract: This paper presents nonisolated single-switch high step-up converters with low voltage stress. Based on the conventional flyback converter, one single-switch high step-up converter is derived. The voltage stresses on the switch and diodes are limited by using a clamping diode and voltage doubler structure. Also, to further reduce the voltage stresses of them, another single-switch high step-up converter is proposed simply by using one additional capacitor and rearranging the components. Thus, lower voltage-rated switch and diodes can be used, which results in higher efficiency. The operational principle, analysis and design considerations of each converter are presented in this paper. The validity of this study is confirmed by the experimental results from 24 V input and 250 V/125 W output prototype.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • Analysis and Design of LLC Resonant Converters With
           Capacitor–Diode Clamp Current Limiting
    • Authors: Tsang; C.W.;Foster, M.P.;Stone, D.A.;Gladwin, D.T.;
      Pages: 1345 - 1355
      Abstract: This paper presents a design methodology for LLC resonant converters with capacitor–diode clamp for current limiting in overload conditions. A new fundamental harmonic approximation-based equivalent circuit model is obtained through the application of describing function techniques, by examining the fundamental behavior of the capacitor–diode clamp. An iterative procedure to determine the conduction point of the diode clamp is also given. The behavior of this type of converter is analyzed and guidelines for designing the current limiting characteristics are discussed. The characterization of a 90 W converter design using the proposed methodology is presented. The converter voltage gain and the voltage–current characteristics under different overload conditions and operating frequencies are predicted using the proposed model, which accuracies are validated against the prototype with good correlation.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • Low-Volume PFC Rectifier Based on Nonsymmetric Multilevel Boost Converter
    • Authors: Mahdavikhah; B.;Prodic, A.;
      Pages: 1356 - 1372
      Abstract: This paper introduces a digitally controlled single-phase rectifier with power factor correction (PFC) based on a modified three-level boost converter topology. In comparison with the conventional boost-based systems, the new PFC rectifier has about three times smaller inductor and significantly lower switching losses. The improvements are achieved by replacing the output capacitor of the boost converter with a nonsymmetric active capacitive divider, with a 3:1 division ratio, and by utilizing the downstream converter stage for the capacitive divider's center-tap voltage regulation. The nonsymmetric voltage divider and applied switching sequence effectively provide four-level converter behavior using the same number of components as three-level converters. As a result, a 66% reduction of the inductor compared to the conventional boost-based PFC and a 33% compared to the standard three-level solutions operating at the same effective switching frequencies are also achieved. Experimental results obtained with a 400 W, 200 kHz, universal input voltage $(85 {rm V_{rm rms}}hbox{-}265 {rm V_{rm rms}})$ PFC prototype demonstrate three times smaller inductor current ripple than that of the conventional boost converter allowing for the same inductor reduction. Efficiency improvements of up to a 6% are also demonstrated.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • A High-Efficiency Resonant Switched Capacitor Converter With Continuous
           Conversion Ratio
    • Authors: Cervera; A.;Evzelman, M.;Peretz, M.M.;Ben-Yaakov, S.S.;
      Pages: 1373 - 1382
      Abstract: A resonant switched capacitor converter with high efficiency over a wide and continuous conversion ratio range is introduced. The efficiency of the topology depends primarily on the conduction losses and is decoupled, to a large extent, from the voltage conversion ratio. This is an advantage over classical switched capacitor converters, for which the efficiency is strongly related to the conversion ratio. The operation principle applies three zero current switching states to charge, discharge, and balance the remaining charge of the flying capacitor. This results in a gyrator, i.e., a voltage-dependent current source, with a wide range of voltage conversion ratios (smaller as well as greater than unity) as well as bidirectional power flow capabilities. The analytical expressions for the conversion ratio and expected efficiency are provided and validated through simulations and experiments. The experimental verifications of the converter demonstrate peak efficiency of 96% and above 90% efficiency over a wide range of voltage gains and loading conditions. In addition, the system was found to be highly efficient at the extreme cases of both light and heavy loads.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • Resonance Analysis and Soft-Switching Design of Isolated Boost Converter
           With Coupled Inductors for Vehicle Inverter Application
    • Authors: Wang; Y.;Liu, W.;Ma, H.;Chen, L.;
      Pages: 1383 - 1392
      Abstract: The comprehensive resonance analysis and soft-switching design of the isolated boost converter with coupled inductors are investigated in this paper. Due to the resonance participated by the voltage doubler capacitor, clamping capacitor, and leakage inductance of coupled inductors, the reverse-recovery problem of the secondary diodes is restrained within the whole operation range. By choosing appropriate magnetic inductance of the coupled inductors, zero-voltage switching on of the main mosfets is obtained collectively at the same working conditions without any additional devices. Moreover, the range of duty ratio is enlarged to achieve soft switching and an optimal operation point is obtained with minimal input current ripple, when duty ratio approaches 0.5. Additionally, two kinds of resonances are analyzed and an optimized resonance is utilized to achieve better power density. The prototype is implemented for the vehicle inverter requiring a 150 W output power, input voltage range varying from 10.8 to 16 V, and 360 V output voltage. Experiment results verify the design and show that the minimum efficiency is about 93.55% and 90.53% at low load and full load, respectively.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • A Step-Up Bidirectional Series Resonant DC/DC Converter Using a Continuous
           Current Mode
    • Authors: Ibanez; F.M.;Echeverria, J.M.;Vadillo, J.;Fontan, L.;
      Pages: 1393 - 1402
      Abstract: This paper presents the analysis and design of a novel technique that allows the conventional series resonant dc/dc converter (SRC) to work as a step-up and step-down converter. This is useful in bidirectional dc/dc converters where one port is attached to a fixed voltage dc line, e.g., a 360-V dc line, and the other port is attached to an energy storage device such as a bank of supercapacitors or batteries. Every converter that works in this scenario requires step-up and step-down modes to transfer energy from one port to the other. The paper presents the SRC as an alternative to the well-known dual active bridge (DAB). The dc analysis is detailed to demonstrate the step-up capability. In addition, the ac analysis is presented. Experimental results from a 6-kW prototype validate the theoretical analysis. The results indicate that this technique achieves better efficiency compared to the phase-shift DAB in a wide power range, from heavy to light loads. The main reason for this is that the converter works with smaller currents than the DAB at light loads.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • Techniques of Dual-Path Error Amplifier and Capacitor Multiplier for
           On-Chip Compensation and Soft-Start Function
    • Authors: Liu; P.;Hsu, C.;Chang, Y.;
      Pages: 1403 - 1410
      Abstract: Techniques of a dual-path error amplifier and two capacitor multipliers for providing on-chip frequency compensation and soft-start function are proposed in this paper. The concept of the dual-path error amplifier is to use two currents to charge and discharge a compensation capacitor simultaneously. As a result, the equivalent capacitance is enlarged significantly with little additional power and silicon area. The dc–dc converter with the dual-path architecture also has great performance in transient response because the compensation capacitor is reduced significantly. For the soft-start function, the subtractive-type and time-average capacitor multipliers are used to relax the restriction of the capacitance and the charging current. Consequently, it is easy to integrate the soft-start capacitance into a chip and the output overshoot voltage can be suppressed. A prototype converter fabricated with TSMC 0.35-μm 2P4M CMOS process verifies the effectiveness of the techniques of a dual-path error amplifier and two capacitor multipliers. Experimental results demonstrate the converter stability, transient response, and soft-start function. The transient recovery time and transient ripple are less than 20 μs and 25 mV, respectively, for the load current swing from 50 to 500 mA. Moreover, the soft-start time is up to 8 ms. With the proposed techniques, the external pins of the dc–dc converters are minimized and their performance is improved significantly.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • An Interface Circuit for Low-Voltage Low-Current Energy Harvesting Systems
    • Authors: Dallago; E.;Barnabei, A.L.;Liberale, A.;Malcovati, P.;Venchi, G.;
      Pages: 1411 - 1420
      Abstract: In this paper, we present an interface circuit designed to match low-power and low-voltage harvesters to generic electronic loads. The interface circuit consists of a power management unit, a supply regulation unit, and an energy storage module. The electric power delivered by the harvester is stored in a low leakage capacitor, converted to match the load electrical characteristics, and used cyclically to supply the load during fixed time-windows. The interface circuit is compatible with dc harvesters with a current of at least 2 $mu$ A at 0.5 V and exhibits an efficiency of 65% in the 1 $mu$ W $-$ 1 mW range. The supply regulation unit is a two-stage, self-starting boost circuit that steps-up the 0.5-V input voltage to 3 V. To test the interface circuit, an autonomous wireless sensor node has been realized; it exploits the little electric power delivered by a 385 $mu$ m $times$ 245 $mu$ m photovoltaic harvester to sense and transmit information about the environment wirelessly. The harvester is implemented with a custom 0.35- $mu$ m BCD SOI chip. The system has been designed to be low cost, fully autonomous and smaller of 9 cm $^{3}$ .
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • High-Density Integration of High-Frequency High-Current Point-of-Load
           (POL) Modules With Planar Inductors
    • Authors: Zhang; W.;Su, Y.;Mu, M.;Gilham, D.J.;Li, Q.;Lee, F.C.;
      Pages: 1421 - 1431
      Abstract: Planar inductors made by mixed laminates of low-temperature sintered Ni-Cu-Zn ferrite tapes and metal-flake composite materials are used for high-density integration of point-of-load (POL) modules. Incremental permeability and core loss density were characterized on toroidal samples under high dc bias to demonstrate that both materials are suitable for application in high-frequency high-current POL converters. In order to realize a high power density POL module, a multilayer ferrite inductor laminated with alternating layers of ESL 40010 and ESL 40012 in a 1:1 ratio has been fabricated and integrated with the active layer. Meanwhile, standard printed circuit board (PCB) processing has been adopted for the POL integration with a PCB-embedded inductor using NEC-TOKIN's metal-flake composite materials. These developed 3-D integration approaches can be used to reduce the footprint and increase the power density for POL converters. It has been demonstrated that the power efficiency of both POL modules with integrated planar inductors can achieve above 87% at an operating frequency of 2 MHz and an output current of 15 A. Additionally, no obvious efficiency degradation was observed on the integrated POL modules after a certain number of thermal cycling from −40 °C to +150 °C.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • A High Temperature Silicon Carbide mosfet Power Module With Integrated
           Silicon-On-Insulator-Based Gate Drive
    • Authors: Wang; Z.;Shi, X.;Tolbert, L.M.;Wang, F.F.;Liang, Z.;Costinett, D.;Blalock, B.J.;
      Pages: 1432 - 1445
      Abstract: This paper presents a board-level integrated silicon carbide (SiC) mosfet power module for high temperature and high power density application. Specifically, a silicon-on-insulator (SOI)-based gate driver capable of operating at 200 °C ambient temperature is designed and fabricated. The sourcing and sinking current capability of the gate driver are tested under various ambient temperatures. Also, a 1200 V/100 A SiC mosfet phase-leg power module is developed utilizing high temperature packaging technologies. The static characteristics, switching performance, and short-circuit behavior of the fabricated power module are fully evaluated at different temperatures. Moreover, a buck converter prototype composed of the SOI gate driver and SiC power module is built for high temperature continuous operation. The converter is operated at different switching frequencies up to 100 kHz, with its junction temperature monitored by a thermosensitive electrical parameter and compared with thermal simulation results. The experimental results from the continuous operation demonstrate the high temperature capability of the power module at a junction temperature greater than 225 °C.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • A Seamless Transition Control of Sensorless PMSM Compressor Drives for
           Improving Efficiency Based on a Dual-Mode Operation
    • Authors: Lee; K.;Park, S.;Jeong, S.;
      Pages: 1446 - 1456
      Abstract: The sinusoidal-wave and square-wave driving modes have been commonly used in permanent-magnet synchronous motor (PMSM) drives for household refrigerator compressors. In general, the sinusoidal-wave drive performs better in some aspects such as torque ripples, a starting performance, and a flux-weakening capability than the square-wave drive. The square-wave drive, however, has the advantage of higher efficiency at low-output-power conditions because of its relatively lower switching loss than the sinusoidal-wave drive. To selectively utilize the benefits of both driving modes, a seamless transition control between the two driving modes is proposed in this paper. Considering that the overall control structure of the sensorless PMSM drive is quite different according to the driving mode, initialization strategies, necessary for a smooth transition, for the pulse-width modulator of the inverter, speed and current controller, and sensorless position/speed estimator are presented. With the proposed method, a dual-mode operation of the sensorless PMSM drive can be achieved without stopping the compressor. The dynamic performance of the proposed transition scheme is tested using simulations and verified by experiments. Experimental result shows that the efficiency of a refrigerator increases up to 2 [%] using the dual-mode operation in comparison with the sinusoidal-wave only drive.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • An Extended-Speed Low-Ripple Torque Control of Switched Reluctance Motor
           Drives
    • Authors: Ye; J.;Bilgin, B.;Emadi, A.;
      Pages: 1457 - 1470
      Abstract: In this paper, an extended-speed low-ripple torque control of switched reluctance motor (SRM) drives using torque sharing function (TSF) is proposed. Two operational modes are defined for the online TSF during commutation: In Mode I, absolute value of rate of change of flux linkage (ARCFL) of incoming phase is higher than outgoing phase; in Mode II, ARCFL of outgoing phase is higher than incoming phase. In order to compensate the torque error produced by imperfect tracking of phase current, a proportional and integral compensator with torque error is added to the torque reference of outgoing phase in Mode I and incoming phase in Mode II. Therefore, the total torque is determined by the phase with lower ARCFL rather than the phase with higher ARCFL as in conventional TSFs. The maximum torque-ripple-free speed of the proposed TSF is increased to more than ten times as the best case in conventional TSFs. Finally, the proposed TSF is verified by both simulations and experiments with a 2.3 kW, 6000 rpm, three-phase 12/8 SRM operating in both linear magnetic and saturated magnetic regions. Results show that the proposed TSF has higher average torque, and much lower torque ripples compared to conventional TSFs.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • Carrier-Based Implementation of SVPWM for Dual Two-Level VSI and Dual
           Matrix Converter With Zero Common-Mode Voltage
    • Authors: Baranwal; R.;Basu, K.;Mohan, N.;
      Pages: 1471 - 1487
      Abstract: Pulse width modulation (PWM) converters generate switching common-mode voltages (CMVs) across the load terminals. These voltages cause common-mode currents, leading to bearing failure in motor loads and electromagnetic interference problems. This paper presents a generalized carrier-based PWM technique for open-end winding motor drives that completely eliminates switching CMV. The proposed method is applicable to both dual two-level voltage source inverter and dual matrix converter-based open-end winding drives. Detailed analysis shows that the carrier-based method requires significantly less computation compared to the corresponding space vector implementation. This paper also outlines the relationship between the two implementations. The carrier-based method is shown to achieve superior performance in terms of resource requirements and execution time when implemented on a field-programmable gate array-based real-time control platform. Simulation and experimental results have been presented to validate the proposed method.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • Z-Source Inverter-Based Approach to the Zero-Crossing Point Detection of
           Back EMF for Sensorless Brushless DC Motor
    • Authors: Xia; C.;Li, X.;
      Pages: 1488 - 1498
      Abstract: Based on the Z-source inverter, this paper proposed a novel approach to zero-crossing point (ZCP) detections during the shoot-through vectors for sensorless brushless dc motor (BLDCM). The proposed approach separates the ZCP detections from speed adjustment, and makes the shoot-through vector not influence the motor speed-adjustment directly, while the zero-vectors and active-vectors are used exclusively to adjust the speed of BLDCM. With the proposed approach, the sensorless BLDCM can operate in a wide speed range without switching the detection points and the reference levels, and it is unnecessary to change the reference levels according to the PWM technique. The terminal voltages limited by diode can be directly compared with the reference zero level during the shoot-through vectors, so as to reduce the detection error caused by attenuation. Moreover, Z-source inverter not only provides boost voltage for sensorless BLDCM drive system, but also improves the utilization rate of dc source voltage and the safety of the drive system. In addition, this paper analyzed the terminal voltages of the floating phase during each vector. The experimental results verified the correctness of above theories and proved the effectiveness of the proposed approach.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • Elimination of Mutual Flux Effect on Rotor Position Estimation of Switched
           Reluctance Motor Drives
    • Authors: Ye; J.;Bilgin, B.;Emadi, A.;
      Pages: 1499 - 1512
      Abstract: An approach to eliminate mutual flux effect on rotor position estimation of switched reluctance motor drives at rotating shaft conditions without a prior knowledge of mutual flux is proposed in this paper. Neglecting the magnetic saturation, the operation of conventional self-inductance estimation using phase current slope difference method can be classified into three modes: Mode I, II, and III. At positive-current-slope and negative-current-slope sampling point of one phase, the sign of current slope of the other phase changes in Mode I and II, but does not change in Mode III. Theoretically, based on characteristics of a 2.3 kW, 6000 rpm, three-phase 12/8 SRM, mutual flux introduces a maximum ±7% self-inductance estimation error in Mode I and II, while, in Mode III, mutual flux effect does not exist. Therefore, in order to ensure that self-inductance estimation is working in Mode III exclusively, two methods are proposed: variable-hysteresis-band current control for the incoming phase and variable-sampling self-inductance estimation for the outgoing phase. Compared with the conventional method which neglects mutual flux effect, the proposed position estimation method demonstrates an improvement in position estimation accuracy by 2°. The simulations and experiments with the studied motor validate the effectiveness of the proposed method.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • A Fast Method for Generating Time-Varying Magnetic Field Patterns of
           Mid-Range Wireless Power Transfer Systems
    • Authors: Zhang; C.;Zhong, W.;Liu, X.;Hui, S.Y.R.;
      Pages: 1513 - 1520
      Abstract: Visualizing the magnetic flux paths for wireless power transfer systems enables researchers and engineers to understand the operations and design the geometrical dimensions of the practical systems. However, time-domain transient simulations of 3-D electromagnetic fields of complex wireless power transfer systems with multiple coil-resonators are extremely time-consuming. This paper describes a fast hybrid approach that combines the time-domain coupled circuit modeling and the magnetostatic analysis to form a fast time-domain analytical tool for studying complex wireless power transfer systems. The proposed methodology has been successfully applied to several wireless domino-resonator systems. For the first time, the time-varying magnetic flux variations of wireless power domino-resonator systems can be visualized in computer simulations.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • Time-Shift Current Balance Technique in Four-Phase Voltage Regulator
           Module with 90% Efficiency for Cloud Computing
    • Authors: Su; Y.;Chen, W.;Huang, Y.;Chen, C.;Ni, C.;Chen, K.;
      Pages: 1521 - 1534
      Abstract: Four power stages for voltage regulator module (VRM) are adopted to provide high current driving capability and low output ripple in cloud computing. Thus, the time-shift current balance (TSCB) technique is proposed to achieve high performance power supply for servers. In addition, the power request, which includes the number of active phases and voltage identification, is acknowledged by servers for high driving capability during high throughput and high efficiency during standby mode. Furthermore, to equally distribute the current in each phase, the proposed TSCB technique in either voltage-mode or peak current-mode control improves the current balance performance and solves the stability problem. In the scale-down clouding computing prototype, the efficiency can be kept higher than 90% over a wide load current range of 2 A. In addition, the performance and operating frequency of the servers in stable operation are not limited by the VRM with the TSCB technique.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • In Situ Diagnostics and Prognostics of Solder Fatigue in
           IGBT Modules for Electric Vehicle Drives
    • Authors: Ji; B.;Song, X.;Cao, W.;Pickert, V.;Hu, Y.;Mackersie, J.W.;Pierce, G.;
      Pages: 1535 - 1543
      Abstract: This paper proposes an in situ diagnostic and prognostic (D&P) technology to monitor the health condition of insulated gate bipolar transistors (IGBTs) used in EVs with a focus on the IGBTs’ solder layer fatigue. IGBTs’ thermal impedance and the junction temperature can be used as health indicators for through-life condition monitoring (CM) where the terminal characteristics are measured and the devices’ internal temperature-sensitive parameters are employed as temperature sensors to estimate the junction temperature. An auxiliary power supply unit, which can be converted from the battery's 12-V dc supply, provides power to the in situ test circuits and CM data can be stored in the on-board data-logger for further offline analysis. The proposed method is experimentally validated on the developed test circuitry and also compared with finite-element thermoelectrical simulation. The test results from thermal cycling are also compared with acoustic microscope and thermal images. The developed circuitry is proved to be effective to detect solder fatigue while each IGBT in the converter can be examined sequentially during red-light stopping or services. The D&P circuitry can utilize existing on-board hardware and be embedded in the IGBT's gate drive unit.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • Universal Integrated Synchronization and Control for Single-Phase DC/AC
           Converters
    • Authors: Karimi-Ghartemani; M.;
      Pages: 1544 - 1557
      Abstract: The universal integrated synchronization and control (UISC) is proposed to operate a single-phase dc/ac converter in both grid-connected (GC) and stand-alone (SA) modes and offer seamless transition between these modes without any reconfiguration of control structure. As a matter of fact, the UISC does not need to use an islanding detection algorithm in the conventional sense. In GC mode, the UISC controls the real and reactive powers independently. In SA mode, it provides voltage and frequency support. The UISC is not based on direct current control or direct output voltage control. It adjusts the internal converter voltage through a nonlinear mechanism that amounts to the control of the current in GC mode and the voltage in SA mode. The UISC does not require a separate synchronization unit such as a phase-locked loop (PLL). In principle, the UISC is analogous to the combined governor and automatic voltage regulator controls in a synchronous machine (SM). In this sense, it may be considered among the converters that mimic the SMs such as the synchronverter. The proposed UISC is arguably the most unified method that can address different modes of operation of a converter within a microgrid environment without control switching actions. This paper presents the derivations, stability analysis, and numerical results to illustrate the performance of the proposed controller in a single phase situation. A mathematical analysis on the analogies and differences between the UISC and some similar methods is also presented.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • Predictive Control Method With Future Zero-Sequence Voltage to Reduce
           Switching Losses in Three-Phase Voltage Source Inverters
    • Authors: Kwak; S.;Park, J.-C.;
      Pages: 1558 - 1566
      Abstract: This paper proposes a predictive control method with zero-sequence voltage injection to efficiently reduce the switching losses of three-phase voltage source inverters (VSIs). In the proposed predictive control method, three-phase future voltage references modified by a zero-sequence voltage injection are generated to clamp one of the three legs with the largest load current. Furthermore, the future zero-sequence voltage, which is produced online with the future voltage and current references in every sampling period, optimally adjusts the clamping duration on each leg, depending on the load angle. In addition, the proposed method selects the zero vector on the basis of the polarity of the future zero-sequence voltage to reduce the switching losses. Using a predefined cost function, the proposed predictive control scheme chooses one optimal voltage state closest to the future voltage references modified by the zero-sequence voltage injection. Therefore, the proposed predictive control method can perform load current control and minimize the switching losses of the VSI under any load condition regardless of the load angle.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • An Enhanced Model for Small-Signal Analysis of the Phase-Shifted
           Full-Bridge Converter
    • Authors: Di Capua; G.;Shirsavar, S.A.;Hallworth, M.A.;Femia, N.;
      Pages: 1567 - 1576
      Abstract: This paper presents an in-depth critical discussion and derivation of a detailed small-signal analysis of the phase-shifted full-bridge (PSFB) converter. Circuit parasitics, resonant inductance, and transformer turns ratio have all been taken into account in the evaluation of this topology's open-loop control-to-output, line-to-output, and load-to-output transfer functions. Accordingly, the significant impact of losses and resonant inductance on the converter's transfer functions is highlighted. The enhanced dynamic model proposed in this paper enables the correct design of the converter compensator, including the effect of parasitics on the dynamic behavior of the PSFB converter. Detailed experimental results for a real-life 36 V-to-14 V/10 A PSFB industrial application show excellent agreement with the predictions from the model proposed herein.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • Improved Transient Response of Controllers by Synchronizing the Modulator
           With the Load Step: Application to $V^2I_{rm
           c}$
    • Authors: Cortes; J.;Svikovic, V.;Alou, P.;Oliver, J.A.;Cobos, J.A.;
      Pages: 1577 - 1590
      Abstract: $V^2I_{rm c}$ is a ripple-based control with an excellent performance for load transients and reference voltage tracking because it exhibits a feedforward of the load current and the error of the output voltage. However, if $V^2I_{rm c}$ is modulated with constant frequency, constant on-time or constant off-time, its dynamic response is hindered by delays in the response. This paper proposes a technique that synchronizes the clock of the converter to initialize the duty cycle when a worst-case load transient occurs using the current through the output capacitor to detect load transients. It is exemplified on a $V^2I_{rm c}$ control but it is applicable to most of controllers as it only acts on the modulator.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • Power Controllability of a Three-Phase Converter With an Unbalanced AC
           Source
    • Authors: Ma; K.;Chen, W.;Liserre, M.;Blaabjerg, F.;
      Pages: 1591 - 1604
      Abstract: Three-phase dc–ac power converters suffer from power oscillation and overcurrent problems in case of the unbalanced ac source voltage that can be caused by grid/generator faults. Existing solutions to handle these problems are properly selecting and controlling the positive- and negative-sequence currents. In this paper, a new series of control strategies which utilize the zero-sequence components are proposed to enhance the power control ability under this adverse condition. It is concluded that by introducing proper zero-sequence current controls and corresponding circuit configurations, the power converter can enable more flexible control targets, achieving better performances in the delivered power and the load current when suffering from the unbalanced ac voltage.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • Accurate Reactive Power Sharing in an Islanded Microgrid Using Adaptive
           Virtual Impedances
    • Authors: Mahmood; H.;Michaelson, D.;Jiang, J.;
      Pages: 1605 - 1617
      Abstract: In this paper, a reactive power sharing strategy that employs communication and the virtual impedance concept is proposed to enhance the accuracy of reactive power sharing in an islanded microgrid. Communication is utilized to facilitate the tuning of adaptive virtual impedances in order to compensate for the mismatch in voltage drops across feeders. Once the virtual impedances are tuned for a given load operating point, the strategy will result in accurate reactive power sharing even if communication is disrupted. If the load changes while communication is unavailable, the sharing accuracy is reduced, but the proposed strategy will still outperform the conventional droop control method. In addition, the reactive power sharing accuracy based on the proposed strategy is immune to the time delay in the communication channel. The sensitivity of the tuned controller parameters to changes in the system operating point is also explored. The control strategy is straightforward to implement and does not require knowledge of the feeder impedances. The feasibility and effectiveness of the proposed strategy are validated using simulation and experimental results from a 2-kVA microgrid.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • dq-Frame Cascaded Delayed Signal Cancellation- Based PLL:
           Analysis, Design, and Comparison With Moving Average Filter-Based PLL
    • Authors: Golestan; S.;Ramezani, M.;Guerrero, J.M.;Monfared, M.;
      Pages: 1618 - 1632
      Abstract: To improve the performance of phase-locked loops (PLLs) under adverse grid conditions, incorporating different filtering techniques into their structures have been proposed in the literature. These filtering techniques can be broadly classified into in-loop and preloop filtering techniques depending on their position in the PLL structure. Inspired from the concept of delayed signal cancellation (DSC), the idea of cascaded DSC (CDSC) has recently been introduced as an effective solution to improve the performance of the PLL under adverse grid conditions. However, the focus has been on the application of CDSC operator as the prefiltering stage of PLL, and little work has been conducted on its application as the in-loop filtering stage of PLL. This paper provides a detailed analysis and design of dqCDSC-PLL (PLL with in-loop dq-frame CDSC operator). The study is started with an overview of this PLL. A systematic design method to fine tune its control parameters is then proposed. The performance of the dqCDSC-PLL under different grid scenarios is then evaluated in detail. It is then shown that how using the proportional-integral-derivative controller as the loop filter can improve the response time of dqCDSC-PLL. A detailed comparison between the dqCDSC-PLL and moving average filter (MAF) based PLL (MAF-PLL) is then carried out. Through a detailed mathematical analysis, it is also shown that these PLLs are equivalent under certain conditions. The suggested guidelines in this paper make designing the dqCDSC-PLL a simple and straightforward procedure. Besides, the analysis performed in this paper provides a useful insight for designers about the advantages/disadvantages of dqCDSC-PLL for their specific applications.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • Performance of Multistep Finite Control Set Model Predictive Control for
           Power Electronics
    • Authors: Geyer; T.;Quevedo, D.E.;
      Pages: 1633 - 1644
      Abstract: The performance of direct model predictive control (MPC) with reference tracking and long prediction horizons is evaluated through simulations, using the current control problem of a variable speed drive system with a voltage source inverter as an illustrative example. A modified sphere decoding algorithm is used to efficiently solve the optimization problem underlying MPC for long horizons. For a horizon of five and a three-level inverter, for example, the computational burden is reduced by four orders of magnitude, compared to the standard exhaustive search approach. This paper illustrates the performance gains that are achievable by using prediction horizons larger than one. Specifically, for long prediction horizons and a low switching frequency, the total harmonic distortion of the current is significantly lower than for space vector modulation, making direct MPC with long horizons an attractive and computationally viable control scheme.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • Analytical Formulas for Phase Voltage RMS Squared and THD in PWM
           Multiphase Systems
    • Authors: Dordevic; O.;Jones, M.;Levi, E.;
      Pages: 1645 - 1656
      Abstract: The analysis and assessment of the pulsewidth modulation (PWM) techniques is commonly based on the comparison of the total harmonic distortion (THD) results. THD is usually calculated by application of the Fourier transformation and by taking a limited number of harmonics into the consideration. In this paper, derivation of analytical formulas for the phase voltage THD is presented. The considered system is a symmetrical multiphase star-connected load, supplied from a multilevel pulsewidth-modulated voltage-source inverter (VSI, three-phase case is also covered). The solution is based on the Parseval's theorem, which links frequency spectrum and time domain through the average power (i.e., root-mean-square (rms) squared value) of the signal. The assumption throughout the derivations is that the ratio of the switching to fundamental frequency is high. Derivations are based on the integration of the power of the PWM signal in a single switching period over the fundamental period of the signal. Only ideal sinusoidal reference voltages are analyzed, and no injection of any type is considered. Formulas for phase voltage THD for any number of phases are derived for two- and three-level cases, for the most commonly used carrier-based methods. Comparison of the analytically obtained curves with simulation and experimental results shows a high level of agreement and validates the analysis and derivations.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • A Systematic Approach for Load Monitoring and Power Control in Wireless
           Power Transfer Systems Without Any Direct Output Measurement
    • Authors: Yin; J.;Lin, D.;Lee, C.;Hui, S.Y.R.;
      Pages: 1657 - 1667
      Abstract: A systematic method is presented in this paper to show that, based only on the measurements of the input voltage and current, the load impedance of a wireless power transfer system can be instantaneously monitored and load power controlled without using any direct measurement from the load. A new mathematic procedure for deriving the output load information based on input voltage and current is explained. This systematic method, which can be applied to wireless power systems with two or more coils, eliminates the need for sensors and communication devices on the load side, thereby greatly simplifying the power control circuitry. The principle of the load estimation method, the power loss optimization and control scheme are described and favorably verified with measurements obtained from an eight-coil wireless power transfer system.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • Automatic Mode-Shifting Control Strategy With Input Voltage Feed-Forward
           for Full-Bridge-Boost DC–DC Converter Suitable for Wide Input
           Voltage Range
    • Authors: Yao; C.;Ruan, X.;Wang, X.;
      Pages: 1668 - 1682
      Abstract: Full-bridge (FB)-boost converter is suitable for applications with wide input voltage range and galvanic isolation requirement, and a two-mode phase-shift (PS)-two-edge modulation (TEM) control scheme based on two modulation signals and one carrier can be used to achieve automatic mode shifting and high efficiency. In order to reduce the influence of the input voltage disturbance on the output voltage, the small-signal model of FB-boost converter is built and the input voltage feed-forward (IVFF) functions under different operating modes are derived in this paper. In view of the small-signal and large-signal control laws of the derived IVFF functions, the two-mode PS-TEM control schemes with small-signal and large-signal IVFF compensations are proposed, respectively. Both of them can realize automatic selection of operating modes and the corresponding IVFF compensations, and thus high efficiency and improved input transient response can be guaranteed. Besides, the IVFF function in boost mode is simplified for easy implementation, and the comparisons among the two-mode PS-TEM control schemes with small-signal, large-signal, and without IVFF compensations are presented in this paper. Finally, a 250–500-V input, 360-V output, and 6-kW-rated power prototype demonstrates the effectiveness of the proposed control schemes.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • A Simple Average Current Control With On-Time Doubler for Multiphase CCM
           PFC Converter
    • Authors: Kim; H.;Seo, G.;Cho, B.;Choi, H.;
      Pages: 1683 - 1693
      Abstract: This paper proposes a new modulated carrier control method for an interleaved continuous conduction mode (CCM) power factor correction (PFC) boost converter. The proposed method allows precise sinusoidal line current shaping for a PFC boost converter operating in CCM. This is accomplished by simply comparing modulated carrier signal with switch current, such that inner current loop compensation design and rectified line voltage sensing are not required. The proposed control method greatly simplifies current sensing and control circuitry of multiphase converters since average current control is available by just sensing the switch current for each module. This also enables simple current balancing between parallel converters by employing modulated carrier signals with same amplitude. The principle of the control method is presented. The performance of the proposed control method is experimentally verified on a 600-W PFC converter. The measured power factor remains above 94.9% down to 20% of a full load for $110hbox{-}V_{rm rms}$ and $220hbox{-}V_{rm rms}$ line voltages. The line current harmonics also meet the IEC61000-3-2 Class D standard.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • A High Step-Up DC to DC Converter Under Alternating Phase Shift Control
           for Fuel Cell Power System
    • Authors: Zhang; L.;Xu, D.;Shen, G.;Chen, M.;Ioinovici, A.;Wu, X.;
      Pages: 1694 - 1703
      Abstract: This paper investigates a novel pulse width modulation (PWM) scheme for two-phase interleaved boost converter with voltage multiplier for fuel cell power system by combining alternating phase shift (APS) control and traditional interleaving PWM control. The APS control is used to reduce the voltage stress on switches in light load while the traditional interleaving control is used to keep better performance in heavy load. The boundary condition for swapping between APS and traditional interleaving PWM control is derived. Based on the aforementioned analysis, a full power range control combining APS and traditional interleaving control is proposed. Loss breakdown analysis is also given to explore the efficiency of the converter. Finally, it is verified by experimental results.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • Asymmetrical Fault Ride Through as Ancillary Service by Constant Power
           Loads in Grid-Connected Wind Farm
    • Authors: Jelani; N.;Molinas, M.;
      Pages: 1704 - 1713
      Abstract: The introduction of distributed generation (DG) into low voltage (LV) systems demands that the generation system remain grid connected during voltage sags to ensure the operational stability. The DG consisting of fixed speed squirrel cage induction generator (SCIG)-based wind turbines is unable to provide reactive power control and needs a dedicated compensating device. Under asymmetrical grid faults the negative sequence flux circulation in the airgap introduces the torque oscillations that lead to the reduction of lifetime of the generation system. This paper proposes the use of distributed constant power loads (CPLs) for asymmetrical fault ride through (FRT) instead of using a centralized STATCOM. It has also been observed that the compensation of negative sequence voltage improves the performance of SCIG by eliminating the torque ripples. The compensation of positive sequence voltage avoids a possible voltage collapse at the LV distribution level and improves the reliability and stability of the wind farm. Centralized compensation of the asymmetrical grid fault by a STATCOM is compared with the distributed compensation by CPLs. The results suggest that each individual CPL injects lower current for maximum FRT enhancement compared to a dedicated STATCOM.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • Hybrid Control of DC–DC Series Resonant Converters: The Direct
           Piecewise Affine Approach
    • Authors: Molla-Ahmadian; H.;Tahami, F.;Karimpour, A.;Pariz, N.;
      Pages: 1714 - 1723
      Abstract: The control and stabilization of resonant converters are essential problems in power electronics. The conventional controller design and stability analysis for these converters are based on the linearized averaged model. Nevertheless, the state variables in resonant converters have large ac variations and the validity of the linearized average model is violated. Hence, using large signal and nonaveraged models are necessary for controller design and stability analysis. In this paper, a new hybrid controller is presented that is applicable to dc–dc series resonant converters and use neither averaging nor small signal approximation. The dc–dc resonant converters are inherently switched affine systems with constrained switching law. The proposed controller is based on the switched behavior of the converter and the concept of piecewise affine methodology. Moreover, it has switched inner and proportional-integral (PI) outer control loops and does not require a modulator. The large signal and closed loop stability analysis of the resonant converters is presented by a theorem. The minimum phase attribute of the control system is investigated by zero dynamic stability analysis. The proposed controller has less complexity in comparison to other suggested controllers and can be implemented using simple analog circuits. The simulation and experimental results show the effectiveness of the proposed method.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • Small-Signal Analysis and Optimal Design of Constant Frequency
            $V^{2}$ Control
    • Authors: Tian; S.;Lee, F.C.;Mattavelli, P.;Yan, Y.;
      Pages: 1724 - 1733
      Abstract: Recently, $V^{2}$ control and its variety named ripple-based control has been gaining more and more popularity in academia research and commercial products. However, for constant frequency $V^{2}$ control, design methodology is not clear due to insufficient knowledge about the small-signal model. This paper investigates the small-signal model and optimal design strategy for constant frequency $V^{2}$ control. The factorized small-signal control-to-output voltage transfer function and output impedance are investigated. The stability criterion is obtained and design considerations are analyzed. Moreover, the small-signal model with ramp compensations is presented and optimal design guidelines from dynamic performance point of view are provided. For the first time, it is found the external ramp is good enough to get a well-damped performance when current feedback strength is strong (for example, when employing OSCON capacitors). However, the current ramp is necessary to achieve a good dynamic performance when the current feedback strength is weak (for example, when employing ceramic capacitors). As a result, a new control strategy with the hybrid ramp is proposed for ceramic capacitor applications. The small-signal model and proposed design guidelines are verified with Simplis simulation and experimental results.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • A Single-Stage Solid-State Transformer for PWM AC Drive With Source-Based
           Commutation of Leakage Energy
    • Authors: Basu; K.;Shahani, A.;Sahoo, A.K.;Mohan, N.;
      Pages: 1734 - 1746
      Abstract: A solid-state transformer is a three-phase ac/ac converter with a high-frequency transformer. Due to advanced features like high power density, on demand var support and frequency regulation, solid-state transformer is an enabling technology for the modern power distribution system. It can also find application in high-power-density motor drives. The single-stage solid-state transformer considered in this paper is capable of bidirectional power flow and open loop power factor correction. This topology uses a minimum amount of copper and has relatively few semiconductor switches. One major problem in this converter is the commutation of leakage energy which results in power loss, reduction in switching frequency, loss of output voltage, and additional common-mode voltage switching. This paper presents a source-based commutation strategy along with a novel modulation technique resulting in 1) elimination of additional snubber circuits, 2) minimization of the frequency of leakage inductance commutation, 3) recovery of the leakage energy, and 4) soft switching of the output converter. The topology and its proposed control have been analyzed. Simulation and experimental results confirm the operation.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • A Technique to Estimate the Equivalent Loss Resistance of Grid-Tied
           Converters for Current Control Analysis and Design
    • Authors: Vidal; A.;Yepes, A.G.;Freijedo, F.D.;Malvar, J.;Lopez, O.;Doval-Gandoy, J.;
      Pages: 1747 - 1761
      Abstract: Rigorous analysis and design of the current control loop in voltage source converters (VSCs) requires an accurate modeling. The loop behavior can be significantly influenced by the VSC working conditions. To consider such effect, converter losses should be included in the model, which can be done by means of an equivalent series resistance. This paper proposes a method to identify the VSC equivalent loss resistance for the proper tuning of the current control loop. It is based on analysis of the closed-loop transient response provided by a synchronous proportional-integral current controller, according to the internal model principle. The method gives a set of loss resistance values linked to working conditions, which can be used to improve the tuning of the current controllers, either by online adaptation of the controller gains or by open-loop adaptive adjustment of them according to prestored data. The developed identification procedure is tested in the laboratory at different specifications of power level and switching frequency.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
  • Rotating Switching Surface Control of Series-Resonant Converter Based on a
           Piecewise Affine Model
    • Authors: Momeni; M.;Kelk, H.M.;Talebi, H.;
      Pages: 1762 - 1772
      Abstract: In this paper, the control signal of the series-resonant converter is considered as a slope of a switching surface. The output characteristic of the converter, for an ideal case and above the resonant frequency, is achieved based on the slope of the switching surface. This output characteristic leads us to find the related slope for a specific converter gain. Nonlinear state equations of the series-resonant converter with new control input are represented in widely used class of hybrid systems that have been called piecewise affine systems. Considering the effects of the slope variations in the switching surface, a simple and efficient control law is achieved. The main advantage of the proposed method is the absence of microcontroller and frequency modulator integrated circuits in hardware implementation. This property makes the proposed method more beneficial in high-frequency applications. Experimental results confirm our theoretical investigations.
      PubDate: March 2015
      Issue No: Vol. 30, No. 3 (2015)
       
 
 
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