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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: 7)
Aerospace and Electronic Systems, IEEE Transactions on     Hybrid Journal   (Followers: 53)
American Journal of Electrical and Electronic Engineering     Open Access   (Followers: 7)
Annals of Telecommunications     Hybrid Journal   (Followers: 4)
APL : Organic Electronics and Photonics     Hybrid Journal   (Followers: 1)
APSIPA Transactions on Signal and Information Processing     Open Access   (Followers: 2)
Archives of Electrical Engineering     Open Access   (Followers: 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: 14)
Biomedical Engineering, IEEE Transactions on     Hybrid Journal   (Followers: 11)
Biomedical Instrumentation & Technology     Full-text available via subscription   (Followers: 4)
Broadcasting, IEEE Transactions on     Hybrid Journal   (Followers: 5)
BULLETIN of National Technical University of Ukraine. Series RADIOTECHNIQUE. RADIOAPPARATUS BUILDING     Open Access   (Followers: 1)
Bulletin of the Polish Academy of Sciences : Technical Sciences     Open Access  
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 12)
China Communications     Full-text available via subscription   (Followers: 1)
Circuits and Systems     Open Access   (Followers: 7)
Consumer Electronics Times     Open Access   (Followers: 3)
Control Systems     Hybrid Journal   (Followers: 18)
Electronic Markets     Hybrid Journal   (Followers: 5)
Electronic Materials Letters     Hybrid Journal   (Followers: 2)
Electronics     Open Access   (Followers: 3)
Electronics and Communications in Japan     Hybrid Journal   (Followers: 4)
Electronics Letters     Hybrid Journal   (Followers: 15)
Embedded Systems Letters, IEEE     Hybrid Journal   (Followers: 14)
EPJ Quantum Technology     Open Access  
EURASIP Journal on Embedded Systems     Open Access   (Followers: 8)
Foundations and TrendsĀ® in Communications and Information Theory     Full-text available via subscription   (Followers: 5)
Foundations and TrendsĀ® in Signal Processing     Full-text available via subscription   (Followers: 4)
Frequenz     Full-text available via subscription   (Followers: 1)
Frontiers of Optoelectronics     Hybrid Journal   (Followers: 1)
Geoscience and Remote Sensing, IEEE Transactions on     Hybrid Journal   (Followers: 19)
Haptics, IEEE Transactions on     Hybrid Journal   (Followers: 4)
IEEE Consumer Electronics Magazine     Full-text available via subscription   (Followers: 7)
IEEE Journal of Emerging and Selected Topics in Power Electronics     Hybrid Journal   (Followers: 3)
IEEE Journal of the Electron Devices Society     Open Access   (Followers: 1)
IEEE Power Electronics Magazine     Full-text available via subscription  
IEEE Transactions on Audio, Speech, and Language Processing     Hybrid Journal   (Followers: 9)
IEEE Transactions on Automatic Control     Hybrid Journal   (Followers: 19)
IEEE Transactions on Consumer Electronics     Hybrid Journal   (Followers: 10)
IEEE Transactions on Electron Devices     Hybrid Journal   (Followers: 6)
IEEE Transactions on Information Theory     Hybrid Journal   (Followers: 13)
IEEE Transactions on Power Electronics     Hybrid Journal   (Followers: 11)
IEICE - Transactions on Electronics     Full-text available via subscription   (Followers: 7)
IEICE - Transactions on Information and Systems     Full-text available via subscription   (Followers: 7)
IET Power Electronics     Hybrid Journal   (Followers: 7)
IET Wireless Sensor Systems     Hybrid Journal   (Followers: 5)
IETE Journal of Education     Open Access   (Followers: 2)
IETE Journal of Research     Open Access   (Followers: 5)
IETE Technical Review     Open Access   (Followers: 1)
Industrial Electronics, IEEE Transactions on     Hybrid Journal   (Followers: 9)
Industry Applications, IEEE Transactions on     Hybrid Journal   (Followers: 5)
Informatik-Spektrum     Hybrid Journal  
Instabilities in Silicon Devices     Full-text available via subscription  
Intelligent Transportation Systems Magazine, IEEE     Full-text available via subscription   (Followers: 1)
International Journal of Advanced Electronics and Communication Systems     Open Access   (Followers: 4)
International Journal of Advanced Research in Computer Science and Electronics Engineering     Open Access   (Followers: 18)
International Journal of Advances in Telecommunications, Electrotechnics, Signals and Systems     Open Access   (Followers: 1)
International Journal of Aerospace Innovations     Full-text available via subscription   (Followers: 10)
International Journal of Applied Electronics in Physics & Robotics     Open Access  
International Journal of Biomedical Nanoscience and Nanotechnology     Hybrid Journal   (Followers: 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: 10)
International Journal of Electronics     Hybrid Journal   (Followers: 2)
International Journal of Electronics & Data Communication     Open Access   (Followers: 3)
International Journal of Electronics and Telecommunications     Open Access   (Followers: 3)
International Journal of Granular Computing, Rough Sets and Intelligent Systems     Hybrid Journal   (Followers: 1)
International Journal of High Speed Electronics and Systems     Hybrid Journal  
International Journal of Microwave and Wireless Technologies     Hybrid Journal   (Followers: 1)
International Journal of Nano Devices, Sensors and Systems     Open Access   (Followers: 1)
International Journal of Nanoscience     Hybrid Journal   (Followers: 1)
International Journal of Numerical Modelling:Electronic Networks, Devices and Fields     Hybrid Journal   (Followers: 2)
International Journal of Power Electronics     Hybrid Journal   (Followers: 3)
International Journal of Review in Electronics & Communication Engineering     Open Access   (Followers: 1)
International Journal of Sensors, Wireless Communications and Control     Hybrid Journal   (Followers: 2)
International Journal of Systems, Control and Communications     Hybrid Journal   (Followers: 2)
International Journal on Communication     Full-text available via subscription   (Followers: 7)
International Journal on Electrical and Power Engineering     Full-text available via subscription   (Followers: 10)
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: 1)
Journal of Electronics (China)     Hybrid Journal   (Followers: 2)
Journal of Field Robotics     Hybrid Journal   (Followers: 2)
Journal of Guidance, Control, and Dynamics     Full-text available via subscription   (Followers: 50)
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)

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IEEE Transactions on Power Electronics
   Journal TOC RSS feeds Export to Zotero [13 followers]  Follow    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
     ISSN (Print) 0885-8993
     Published by Institute of Electrical and Electronics Engineers (IEEE) Homepage  [172 journals]   [SJR: 3.308]   [H-I: 111]
  • IEEE Power Electronics Society Information
    • Pages: C3 - C3
      Abstract: Provides a listing of current committee members and society officers.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • Table of contents
    • Pages: C1 - C4
      Abstract: Presents the table of contents for this issue of the periodical.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • IEEE Transactions on Power Electronics publication information
    • Pages: C2 - C2
      Abstract: Provides a listing of current staff, committee members and society officers.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • Degraded Switching Characteristics of a High-Current, High-Action
           Reversely Switched Dynistor
    • Authors: Wang; H.;Zeng, Z.;He, X.;Chen, W.;Xie, L.;Guo, F.;Li, J.;Zhang, G.;
      Pages: 6245 - 6248
      Abstract: High-voltage, high-current, and high-coulomb transfer closing switches are required for many high-pulsed power systems. This letter presents the degraded switching characteristics of a high-power reversely switched dynistor (RSD). The degraded switching characteristics of the RSD were tested with a working voltage of 10 kV, the repetition rate of 0.2 Hz, and a peak current of about 107 kA. The action is about 1.45 MA2·s. The transferred charge and energy per shot are about 20 C and 100 kJ, respectively. Only minimal changes in the leakage current and voltage drop were witnessed after a serial test of 50 000 shots. The degraded switching characteristics of the RSD were investigated based on two different methods with the special parameters of static volt–ampere characteristics and dynamic voltage drop on RSD, respectively. The degraded switching model of RSD under high-current conditions for long-pulse application was established using the method of numerical fitting. The results show that these two methods agree well with each other.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • Voltage Regulator Buck Converter with a Tapped Inductor for Fast Transient
           Response Application
    • Authors: Gu; Y.;Zhang, D.;
      Pages: 6249 - 6254
      Abstract: In this letter, a novel voltage regulator buck converter with a tapped inductor for fast transient response applications is proposed. The output inductor of the conventional buck converter is replaced by a tapped inductor and an auxiliary switch to achieve fast transient response. Usually, the proposed converter works as a conventional buck converter with very large output inductance during the steady state to reduce the output current ripple. Once the transient load change appears, the auxiliary switch is turned ON in order to speed up the dynamic process by reducing the equivalent output inductance. A 10-V output voltage buck converter with maximum 30-A output current has been built and tested. The experimental results demonstrated the effectiveness of the proposed converter, which also means that the proposed method shows great potential for fast transient response voltage regulator applications.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • A Three-Phase Frequency-Adaptive Phase-Locked Loop for Independent
           Single-Phase Operation
    • Authors: Mirhosseini; M.;Pou, J.;Agelidis, V.G.;Robles, E.;Ceballos, S.;
      Pages: 6255 - 6259
      Abstract: This letter proposes a phase-locked loop (PLL) able to operate as an independent single-phase PLL in the context of three-phase systems. Its key advantage is that the extracted information allows the independent control of both the active and reactive powers for each phase. The proposed PLL utilizes moving average filters and, hence, remains robust under unbalanced and highly distorted voltages. A frequency estimator is also presented and incorporated in the PLL angle detector path to make it frequency adaptive. The performance of the proposed PLL is verified experimentally and results for frequency change, phase-angle jump, and unbalanced voltage sag are reported as a confirmation of its potential.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • Passivity-Based Stabilization of Resonant Current Controllers With
           Consideration of Time Delay
    • Authors: Harnefors; L.;Yepes, A.G.;Vidal, A.;Doval-Gandoy, J.;
      Pages: 6260 - 6263
      Abstract: Resonant parts can be used in current controllers to suppress harmonics. However, they may cause destabilization of poorly damped grid and/or input-filter resonances, particularly for a nonnegligible converter time delay. This letter presents a design method whereby destabilization is prevented by making the converter’s input admittance passive.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • A Quasi-Type-1 Phase-Locked Loop Structure
    • Authors: Golestan; S.;Freijedo, F.D.;Vidal, A.;Guerrero, J.M.;Doval-Gandoy, J.;
      Pages: 6264 - 6270
      Abstract: The grid voltage phase and frequency are crucial information in control of most grid-connected power electronic-based equipment. Most often, a phase-locked loop (PLL) is employed for this purpose. A PLL is a closed-loop feedback control system that the phase of its output signal is related to the phase of its input signal. Arguably, the simplest PLL is a type-1 PLL. The type-1 PLLs are characterized by having only one integrator in their control loop and, therefore, having a high stability margin. However, they suffer from a serious drawback: They cannot achieve zero average steady-state phase error in the presence of frequency drifts. To overcome this drawback of type-1 PLLs, and at the same time, to achieve a fast dynamic response and high filtering capability, a modified PLL structure is proposed in this letter. The proposed PLL has a similar structure to a type-1 PLL, but from the control point of view is a type-2 control system. For this reason, it is called the quasi-type-1 PLL. The effectiveness of the proposed PLL is confirmed through simulation and experimental results and comparison with standard PLLs.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • A Hybrid Power Control Concept for PV Inverters With Reduced Thermal
    • Authors: Yang; Y.;Wang, H.;Blaabjerg, F.;Kerekes, T.;
      Pages: 6271 - 6275
      Abstract: This letter proposes a hybrid power control concept for grid-connected photovoltaic (PV) inverters. The control strategy is based on either a maximum power point tracking control or a constant power generation (CPG) control depending on the instantaneous available power from the PV panels. The essence of the proposed concept lies in the selection of an appropriate power limit for the CPG control to achieve an improved thermal performance and an increased utilization factor of PV inverters, and thus, to cater for a higher penetration level of PV systems with intermittent nature. A case study on a single-phase PV inverter under yearly operation is presented with analyses of the thermal loading, lifetime, and annual energy yield. It has revealed the trade-off factors to select the power limit and also verified the feasibility and the effectiveness of the proposed control concept.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • Effects of Stray Inductance on Hard-Switched Switched Capacitor Converters
    • Authors: Muller; L.;Kimball, J.W.;
      Pages: 6276 - 6280
      Abstract: Switched capacitor (SC) converters are becoming quite popular for use in dc–dc power conversion. The concept of equivalent resistance in SC converters is frequently used to determine conduction losses that occur as a result of the load current. A variety of methodologies have been presented to predict the equivalent resistance in hard-switched SC converters. These works, however, did not consider the effect of stray inductance on equivalent resistance. Current power converter design practices favor higher switching frequencies, moving hard-switched SC converters into operating areas in which stray inductance affects converter performance. This paper presents an analytic equation that can be used to evaluate the effects of stray inductance on the equivalent resistance of SC converters. The concepts proposed here were verified by both digital simulation and a prototype converter. The equations presented can be used to evaluate the effects of stray inductance on SC converter performance, thereby helping designers set a maximum operating frequency to limit those effects.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • Analysis of the DC-Link Capacitor Current of Power Cells in Cascaded
           H-Bridge Inverters for High-Voltage Drives
    • Authors: Sun; L.;Zhenxing, W.;Weiming, M.;Xiao, F.;Cai, X.;Zhou, L.;
      Pages: 6281 - 6292
      Abstract: Cascaded H-bridge (CHB) inverters used in high-voltage variable frequency drives are usually composed of several power cells. Each power cell consists of a three-phase uncontrolled rectifier as its input stage and a single-phase inverter as its output stage. It is difficult to obtain the analytical expression of the dc-link capacitor current because of both the nonlinear characteristics of the uncontrolled rectifier and the low-frequency harmonics caused by the single-phase inverter. On the other hand, exact analysis of the capacitor current is important for dc-link capacitor selection. This paper proposes an analytical method for calculating the capacitor current. Considering both the input current of the inverter and the output current of the rectifier, an approximately linear equivalent circuit model is established. According to the proposed equivalent circuit model, the analytical expressions of the harmonic spectrum and the root mean square value of the capacitor current are derived. The capacitor ripple voltage is further estimated. Applicable conditions of the proposed method are also presented. This method may be useful when designing dc-link capacitors of power cells in CHB inverters. Simulation and experimental results show that the proposed method can achieve good accuracy in the continuous conduction mode.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • Modular Transformer Converter-Based Convertible Static Transmission
           Controller for Transmission Grid Management
    • Authors: Yousefpoor; N.;Parkhideh, B.;Azidehak, A.;Bhattacharya, S.;Fardanesh, B.;
      Pages: 6293 - 6306
      Abstract: This paper investigates the concept of convertible static transmission controller (CSTC) using modular transformer converter (MTC) as the building block. The MTC is a bidirectional back-to-back ac/ac power conversion unit and the CSTC is a versatile transmission controller asset for dynamic power flow control and contingency management of the transmission grid. The proposed CSTC with new functions has several advantages compared to existing flexible ac transmission system controllers. System modularity for manufacturers and utilities/system operators using standard high power electronic systems is one of the advantages of this structure. In this paper, algebraic models of the CSTC are derived in two different operation modes (series–shunt and shunt–shunt connecting configurations). The proposed algebraic models are used to define the reference values for the CSTC converters based on the desired operating points for the meshed power system, the power transformers in particular. The dynamic performance of the CSTC with the proposed control structures and algebraic models will be investigated based on the PSCAD simulation. To prove the CSTC as a transmission asset and to verify the control structure and algorithm, ultrahigh fidelity controller hardware-in-the-loop testing has been conducted and comparative results will be presented. Finally, lab-scale experimental results are reported on the dynamic performance of the MTC-based CSTC.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • Modified Three-Phase Three-Level DC/DC Converter With
           Zero-Voltage-Switching Characteristic-Adopting Asymmetrical Duty Cycle
    • Authors: Liu; F.;Chen, Y.;Hu, G.;Ruan, X.;
      Pages: 6307 - 6318
      Abstract: In the applications for high-power dc/dc conversion, the power devices usually suffer high voltage and current stress in traditional single-phase dc/dc topologies such as forward, half-bridge, and full-bridge converters, which limits the power level of converter to reach higher. As a superior alternative solution, a three-phase three-level (TPTL) dc/dc converter was investigated in this paper, which has the advantages of lower voltage and current stress on switches, as well as fewer power devices. Adopting a symmetrical control strategy, the input current and output current frequency can be increased by a factor of six compared to the switching frequency, resulting in a reduced filter requirement. However, all the switches are hard-switching, leading to a considerable switching loss. In this paper, an asymmetrical duty cycle control strategy was proposed to the TPTL dc/dc converter. The modified converter remains all the advantages of original control strategy; meanwhile, soft-switching can be achieved using the energy stored in output filter inductance and leakage inductances of transformers (or resonant inductances). The theoretical analysis was presented in details, along with the characteristics and soft-switching condition of the converter. Experimental results from 540 to 600 V input and 48 V/20 A output were presented to verify the theoretical analysis and the performance of the modified converter.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • Survey on Fault-Tolerant Techniques for Power Electronic Converters
    • Authors: Zhang; W.;Xu, D.;Enjeti, P.N.;Li, H.;Hawke, J.T.;Krishnamoorthy, H.S.;
      Pages: 6319 - 6331
      Abstract: With wide-spread application of power electronic converters in high power systems, there has been a growing interest in system reliability analysis and fault-tolerant capabilities. This paper presents a comprehensive review of conventional fault-tolerant techniques regarding power electronic converters in case of power semiconductor device failures. These techniques can be classified into four categories based on the type of hardware redundancy unit: switch-level, leg-level, module-level, and system-level. Also, various fault-tolerant methods are assessed according to cost, complexity, performance, etc. The intent of this review is to provide a detailed picture regarding the current landscape of research in power electronic fault-handling mechanisms.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • Passive Snubber for Reducing Switching-Power Losses of an IGBT in a
           DC–DC Boost Converter
    • Authors: Choe; H.;Chung, Y.;Sung, C.;Yun, J.;Kang, B.;
      Pages: 6332 - 6341
      Abstract: A passive snubber for an IGBT in a dc–dc boost converter is proposed. The snubber consists of one inductor, two capacitors, and two diodes. It improves the power-conversion efficiency significantly by providing zero-current turn-on and zero-voltage turn-off conditions for an IGBT, without increasing the voltage stress of an IGBT. When the snubber was adapted to the conventional dc–dc boost converter and tested at an output power of 300 W and a switching frequency of 180 kHz, the current noise level of the input current decreased by ∼30 dB at a frequency range of 2.5–48 MHz, and the power-conversion efficiency increased by ∼7.5% for both the MOSFET and IGBT switches. Also, the temperature of switch was stabilized at ∼60 °C, while the IGBT failed in the conventional boost converter. These experimental results show that the proposed snubber is useful for solving the reliability problem of boost converters.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • Arc Stability Control of a High-Power Thyristor Rectifier System in a DC
           Arc Furnace
    • Authors: Jung; K.;Suh, Y.;Kim, T.;Park, T.;Lee, Y.;
      Pages: 6342 - 6351
      Abstract: Fundamental features of the arc stability in a dc arc furnace of 720 V/100 kA/72 MW have been investigated. The Cassie–Mayr arc model has been employed and applied for the target dc arc furnace. In order to characterize the parameters of the Cassie–Mayr arc model and the behavior of unstable arc dynamics, the advanced arc simulations of magneto-hydrodynamics (MHD) have been performed. From the results of MHD simulation, the dc arc dynamic resistance is proposed to be an effective arc stability function reflecting the instability of dynamic arc behavior. A control strategy of the 12-pulse thyristor rectifier system to regulate the arc stability function is also proposed in this paper. The simulation and experimental results confirm the usefulness of the proposed dynamic arc resistance as the arc stability function along with the active control strategy. The proposed arc stability function can be regarded as an effective criterion for the overall power conversion system to maintain highly stable arcing operation leading to better productivity and reliability in a dc arc furnace.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • Topology and Modulation for a New Multilevel Diode-Clamped Matrix
    • Authors: Sun; Y.;Xiong, W.;Su, M.;Li, X.;Dan, H.;Yang, J.;
      Pages: 6352 - 6360
      Abstract: To expand the matrix converter application in high power area, a new three-level diode-clamped matrix converter topology as well as a related multicarrier-based modulation scheme is proposed. The topology inherits the features from the conventional multilevel inverter and the indirect matrix converter, which is composed of a cascaded-rectifier and a three-level diode-clamped inverter. The proposed topology can overcome the voltage rating limits of the power semiconductors for high-voltage applications to some extent. Meanwhile, except the general advantages, such as bidirectional power flow, sinusoidal input and output currents, simple switch commutation, and a compact structure, it also avoids the voltage balance issue that exists in most conventional multilevel inverters. Finally, the functionality and effectiveness of the proposed topology and modulation scheme are verified by simulation and experimental results.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • Improved AC Pickups for IPT Systems
    • Authors: James; J.E.;Robertson, D.;Covic, G.A.;
      Pages: 6361 - 6374
      Abstract: This paper presents two inductive power transfer (IPT) pickups capable of individually delivering 1.2 kW. The first circuit is a parallel-tuned ac–ac pickup and the second a series-tuned ac–ac pickup. Both circuits regulate the output power by creating a high-frequency ac source in a form suited to various applications requiring a controlled ac output but particularly stage lighting. These circuit topologies build on previous work by significantly improving the loading capability, reducing output noise and harmonic generation, and lowering the required switch ratings. This is achieved through the addition of a second resonant section within each pickup and the relocation of the soft-controlled ac switch. The addition moves the harmonics away from the load path and pickup while still providing full control of the output power. It enables a sinusoidal output waveform with low total harmonic distortion to be created, while placing less stress on the ac switch, which is no longer required to carry the load current. The steady-state operation of both circuits is analyzed herein and circuit waveforms have been verified by experimental results. Both the parallel and series circuits are used to drive a 1.2-kW load with a maximum pickup efficiency of 95% and 94%, respectively.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • A New Nested Neutral Point-Clamped (NNPC) Converter for Medium-Voltage
           (MV) Power Conversion
    • Authors: Narimani; M.;Wu, B.;Cheng, Z.;Zargari, N.;
      Pages: 6375 - 6382
      Abstract: In this paper, a new voltage source converter for medium voltage applications is presented which can operate over a wide range of voltages (2.4–7.2 kV) without the need for connecting the power semiconductor in series. The operation of the proposed converter is studied and analyzed. In order to control the proposed converter, a space-vector modulation (SVM) strategy with redundant switching states has been proposed. SVM usually has redundant switching state anyways. What is the main point we are trying to get to? These redundant switching states help to control the output voltage and balance voltages of the flying capacitors in the proposed converter. The performance of the converter under different operating conditions is investigated in MATLAB/Simulink environment. The feasibility of the proposed converter is evaluated experimentally on a 5-kVA prototype.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • Optimal Current Harmonic Extractor Based on Unified ADALINEs for Shunt
           Active Power Filters
    • Authors: Qasim; M.;Kanjiya, P.;Khadkikar, V.;
      Pages: 6383 - 6393
      Abstract: Adaptive linear neuron (ADALINE) is widely used in parameter estimation due to its algorithmic simplicity and parallel computing nature. One of the most popular training schemes for ADALINE is the least-mean-squared (LMS) rule, which can be implemented online to reduce the computation and storage requirements greatly. In this paper, an optimal current harmonic extractor based on unified ADALINEs for the shunt active power filter (APF) is proposed to achieve a better dynamic performance and reduced computation burden. The proposed control algorithm consists of three ADALINEs. Two ADALINEs are used for frequency estimation and supply voltage synchronization, while the third ADALINE is used to extract the fundamental active component of the load current. The main factor that affects the estimation speed and accuracy is the learning rate involved in LMS weight-update rule. Generally, this learning rate is selected by trial and error. In this paper, the learning rate of each ADALINE is tuned using particle swarm optimization to achieve the best dynamic performance. Furthermore, an adaptive learning rate for the frequency-ADALINE is proposed to enhance the estimation speed. The proposed ADALINE-based control structure is validated with a detailed experimental study.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • Grid-Side AC Line Filter Design of a Current Source Rectifier With
           Analytical Estimation of Input Current Ripple
    • Authors: Basu; K.;Sahoo, A.K.;Chandrasekaran, V.;Mohan, N.;
      Pages: 6394 - 6405
      Abstract: This paper presents a systematic step-by-step design procedure for the input filter of a current source rectifier (CSR). The design is based on the specifications of allowable ripple in the input voltage of the CSR and high-frequency harmonic components in the grid current. Analytical techniques have been developed to estimate the ripple present in the input current and to model the converter for fundamental or grid frequency. The analysis is done for carrier-based and space-vector modulation of the current source rectifier and the model at grid frequency is used to evaluate the design of the filter for grid power factor, voltage drop across filter, etc. A damping resistance is designed ensuring a minimum power loss. The analysis and design of the input filter have been verified by simulations in MATLAB/Simulink and experimental tests on a laboratory prototype.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • Asymmetric Coil Sets for Wireless Stationary EV Chargers With Large
           Lateral Tolerance by Dominant Field Analysis
    • Authors: Choi; S.Y.;Huh, J.;Lee, W.Y.;Rim, C.T.;
      Pages: 6406 - 6420
      Abstract: Asymmetric coil sets for wireless stationary electric vehicle (EV) chargers, which has significantly larger lateral tolerance than previous ones, is proposed. The pick-up coil set is much smaller than the power supply coil set, thereby allowing large lateral and longitudinal displacements as well as robustness to air-gap displacement. Electromagnetic field (EMF) is reasonably reduced by arranging magnetic poles along the EV's moving direction so that alternating magnetic flux through adjacent poles cancels each other. A dominant field analysis useful for complex vector magnetic flux simulation is newly proposed, which is applicable to any resonating coils of an inductive power transfer system (IPTS). Furthermore, a hysteresis loss model is suggested, which appropriately reflects the partial core saturation on a system analysis. A prototype IPTS including the proposed coil sets were designed and successfully verified by experiments. In the quick charging mode, maximum output power of 15 kW, large lateral displacement of 40 cm, longitudinal displacement of 20 cm, air gap of 15 cm were achieved, and low EMF of 6.1 μT at 20 kHz was achieved in the normal charging mode of 5 kW.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • Modeling and Analysis of Harmonic Stability in an AC
           Power-Electronics-Based Power System
    • Authors: Wang; X.;Blaabjerg, F.;Wu, W.;
      Pages: 6421 - 6432
      Abstract: This paper addresses the harmonic stability caused by the interactions among the wideband control of power converters and passive components in an ac power-electronics-based power system. The impedance-based analytical approach is employed and expanded to a meshed and balanced three-phase network which is dominated by multiple current- and voltage-controlled inverters with LCL- and LC-filters. A method of deriving the impedance ratios for the different inverters is proposed by means of the nodal admittance matrix. Thus, the contribution of each inverter to the harmonic stability of the power system can be readily predicted through Nyquist diagrams. Time-domain simulations and experimental tests on a three-inverter-based power system are presented. The results validate the effectiveness of the theoretical approach.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • SHE–PWM Cascaded Multilevel Inverter With Adjustable DC Voltage
           Levels Control for STATCOM Applications
    • Authors: Haw; L.;Dahidah, M.S.A.;Almurib, H.A.F.;
      Pages: 6433 - 6444
      Abstract: This paper presents a new multilevel selective harmonic elimination pulse-width modulation (MSHE–PWM) technique for transformerless static synchronous compensator (STATCOM) system employing cascaded H-bridge inverter (CHI) configuration. The proposed MSHE–PWM method optimizes both the dc-voltage levels and the switching angles, enabling more harmonics to be eliminated without affecting the structure of the inverter circuit. The method provides constant switching angles and linear pattern of dc-voltage levels over the modulation index range. This in turns eliminates the tedious steps required for manipulating the offline calculated switching angles and therefore, easing the implementation of the MSHE–PWM for dynamic systems. Although the method relies on the availability of the variable dc-voltage levels which can be obtained by various topologies, however, the rapid growth and development in the field of power semiconductor devices led to produce high-efficiency dc–dc converters with a relatively high-voltage capacity and for simplicity, a buck dc–dc converter is considered in this paper. Current and voltage closed loop controllers are implemented for both the STATCOM and the buck converter to meet the reactive power demand at different loading conditions. The technique is further compared with an equivalent conventional carrier-based pulse-width modulation to illustrate its enhanced characteristics. The effectiveness and the theoretical analysis of the proposed approach are verified through both simulation and experimental studies.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • Impedances Identification of DC/DC Converters for Network EMC Analysis
    • Authors: Ales; A.;Schanen, J.;Moussaoui, D.;Roudet, J.;
      Pages: 6445 - 6457
      Abstract: The design of optimal electromagnetic compatibility filters for converters used in electrical networks requires the precise knowledge of input and output terminal impedances. For this reason, the knowledge of the network impedance, including all connected converters, is determined. This paper proposes a study of both the common mode (CM) and the differential mode (DM) impedances of modern embedded networks including cables and several converters. Using a dc network for illustration, we determine the impedance taking into account all operating states of a converter (online or offline operations). Without any restrictions, a theoretical model is developed to express the CM and DM impedances using a switching function and a Fourier series decomposition. An experimental validation has been carried out in a frequency range from a few Hertz up to 80 MHz. Our model has then been used in a simple network, so as to compute the network impedance. Measurements have confirmed the proposed model accuracy.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • A Simple Energy Recovery Scheme to Harvest the Energy from Shaded
           Photovoltaic Modules During Partial Shading
    • Authors: Ramli; M.Z.;Salam, Z.;
      Pages: 6458 - 6471
      Abstract: This paper proposes a simple circuit to recover the energy that otherwise would be lost due to the partial shadings on photovoltaic (PV) modules. Since the circuit can be readily retrofitted to an existing PV system, no modification on the central inverter is required. The main idea of the scheme is that, during partial shading, parts of the current from the nonshaded modules are harvested by an energy recovery circuit using power electronic switches and storage components. In doing so, the current of the PV string is maintained at the level generated by the shaded module. There is no need for the shaded module to be short-circuited; as a result, it can still actively produce output power (despite being partially shaded). To investigate the idea, the proposed circuit is retrofitted to a prototype PV system using eight modules. The partial shading conditions are emulated using a solar simulator with a controllable irradiance capability. The results are validated by a good agreement between the experimental and simulation works.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • A Boost-Inverter-Based, Battery-Supported, Fuel-Cell Sourced Three-Phase
           Stand-Alone Power Supply
    • Authors: Jang; M.;Agelidis, V.G.;
      Pages: 6472 - 6480
      Abstract: In this paper, a three-phase boost-inverter topology is used to condition a typical low output voltage fuel cell (FC) as a stand-alone power supply. The key benefits of the proposed power supply include ability to deliver both the boosting and inversion functions in a single stage, compactness, and low cost. Additionally, the power supply incorporates a battery storage unit through a bidirectional converter to support the slow dynamics of the FC and simultaneously protect the FC as it acts as a filter for the low-frequency harmonics. The three-phase output voltage of the boost-inverter is voltage-mode controlled and the battery unit is current-mode controlled. Analysis, simulation, and experimental results taken from a 1-kW laboratory prototype three-phase boost-inverter operating at 20 kHz and bidirectional converter with two 12 V–24 Ah lead acid batteries are presented to confirm the operational performance of the proposed power supply.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • Weighted-Efficiency Enhancement Control for a Photovoltaic AC Module
           Interleaved Flyback Inverter Using a Synchronous Rectifier
    • Authors: Kim; Y.;Jang, J.;Shin, S.;Won, C.;
      Pages: 6481 - 6493
      Abstract: In this paper, a weighted-efficiency enhancement control method for an interleaved flyback inverter using a synchronous rectifier is proposed based on photovoltaic ac modules. In this control method, the operation of the synchronous rectifier is classified according to the voltage spike across the main switch. When the voltage spike across main switch is lower than the rating voltage of main switch, the operation of the active clamp circuit is interrupted to reduce the switching loss of the auxiliary switch. At this time, the synchronous rectifier is operated for the zero-voltage switching of main switch. When the voltage spike across main switch is higher than the rating voltage of main switch, the active circuit is activated to reduce the voltage spike. The synchronous rectifier is operated to reduce the conduction loss of the secondary output diode. Thus, the switching loss of the main switch can be reduced in the low power region, and the weighted efficiency can be improved. A theoretical analysis and the design principles of the proposed method are provided. The method is validated through simulation and experimental results.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • A Dual-Channel Current Source Driver for Complementary Switches
    • Authors: Tschirhart; D.;Jain, P.K.;
      Pages: 6494 - 6505
      Abstract: In this paper, a dual-channel current source driver is presented as an efficient means of driving complementary switches. The driver transfers charge between the gates of the power devices through a single magnetic core with a discontinuous current. This promotes lower conduction loss than continuous current resonant gate drivers (RGDs), and lower component count or conduction loss than existing discontinuous current RGD applied to complementary switches. In addition, controlled switching speed is achieved through nonzero inductor current resulting in lower current stress, and faster switching compared to some pulse RGD circuits. There is good correlation between the analysis and experimental results of a 1.8-MHz prototype.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • Improved Synchronous Rectifier Driving Strategy for Primary-Side Regulated
           (PSR) Flyback Converter in Light-Load Mode
    • Authors: Zhao; C.;Xie, X.;Dong, H.;Liu, S.;
      Pages: 6506 - 6517
      Abstract: Based on the concept derivation, this paper proposes an improved synchronous rectifier (SR) driving strategy focusing on the quasi-resonant primary-side regulation (QR-PSR) Flyback converter, for the applications of dc–dc front-end converter and ac–dc PFC converter both, to prevent reverse energy flowing in light-load/standby mode. Three different implementation candidates are exhibited and analyzed. This proposed driving strategy is programmable for the practical design with input voltage feedforward effect and helpful for achieving the rigorous target of low power loss under light output load condition presented by the U.S. Department of Energy (DoE). Two 60 W (12 V/5 A) lab-made prototypes of synchronous rectified QR-PSR Flyback ac–dc PFC converter and dc–dc front-end converter are built up, respectively, to verify the feasibility of this proposed driving strategy. In the lab-made prototype of ac–dc PFC converter, it improves the overall conversion efficiency more than 3% in light-load mode; in the lab-made prototype of dc–dc front-end converter, it saves the light load power loss up to 0.5 W, especially with 110  $V_{rm ac}$ input. Reliable operation is achieved when the proposed SR driving strategy is practically designed with enough margin; however, too large design margin could decrease the average conversion efficiency.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • Miniaturized Bridgeless High-Frequency Resonant AC–DC
           Step-Up/Step-Down Converters
    • Authors: Tang; Y.;Khaligh, A.;
      Pages: 6518 - 6533
      Abstract: This paper introduces two bridgeless resonant ac-to-dc converters to efficiently convert arbitrary input voltages into a regulated dc output voltage. The proposed topologies provide direct ac–dc power conversion with less number of components, in comparison to other resonant topologies. The converters utilize soft-switched LC networks and diodes to convert low-frequency and low-amplitude alternating input voltage into a dc output voltage. Zero-voltage switching (ZVS) and zero-current switching (ZCS) are achieved in switching both power transistors and diodes. High-frequency soft-switching operation due to LC resonance allows smaller footprint for passive components, thereby increasing the circuit power density without suffering from switching losses. A resonant gate drive circuit is designed and utilized to further reduce gating losses under high-frequency switching and light-load condition. The converters operate at a fixed switching frequency, while they regulate the output voltage by using module pulsewidth-modulated (PWM) on-off control with fast transient response. A 5-mm × 6-mm, 100-mg prototype is fabricated, which is operating at 2-MHz switching frequency. The maximum output power of the prototype reaches 650 mW, with a 3- $V_{rm rms}$ ac input voltage and a 7.6-V dc output voltage. The converter achieves higher than 70% closed-loop efficiency across wide range of input voltages and output powers.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • L-Z-Source Inverter
    • Authors: Pan; L.;
      Pages: 6534 - 6543
      Abstract: On the basis of the classical Z-source inverter (ZSI), this paper presents a novel ZSI which only contains inductors and diodes in Z-source network. The inverter uses a unique inductor and diode network for boosting its output voltage, provides a common ground for the dc source and inverter, and avoids the disadvantage causing by capacitor in the classical ZSI and SL-ZSI, especially in prohibiting the inrush current at startup and the resonance of Z-source capacitors and inductors. The inverter can increase the boost factor through adjusting shoot-through duty ratio and increasing the number of inductor. The working principle of the proposed ZSI and comparison with the classical ZSI and SL-ZSI are analyzed in detail. Simulation and experimental results are given to demonstrate the operation features of the inverter.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • A 13.56-MHz Low-Voltage and Low-Control-Loss RF-DC Rectifier Utilizing a
           Reducing Reverse Loss Technique
    • Authors: Hwang; Y.;Lei, C.;Yang, Y.;Chen, J.;Yu, C.;
      Pages: 6544 - 6554
      Abstract: A low-voltage and low-control-loss RF-dc rectifier with high power conversion efficiency (PCE) at 13.56 MHz band is presented in this paper. This is achieved by utilizing novel reducing reverse loss (RRL) techniques to reduce the reverse leakage current loss. Higher output voltage can also be generated by the multistage stacking method with RRL technology. A boost-type front-end converter composed of an RF-dc rectifier with the RRL technique and a boost converter operating in a discontinuous-conduction mode are also proposed. The single-stage, three-stage pump-type RF-dc rectifier and the boost-type front-end rectifier have been implemented in TSMC 0.18 μm 1P6M technology. Experimental results show that the maximum PCE of the single-stage and three-stage pump-type RF-dc active rectifiers are 68.6% and 67.9% with input powers of 4.9 and 12.8 dB·m, respectively. The maximum PCE of the boost-type front-end converter is 41.3% with 1.2 dB·m input power.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • Peak-Efficiency Detection and Peak-Efficiency Tracking Algorithm for
           Switched-Mode DC–DC Power Converters
    • Authors: Michal; V.;
      Pages: 6555 - 6568
      Abstract: In this paper, the system allowing to detect the peak-efficiency point of the periodically switching MOS power transistor is presented. The use of this system concerns namely the integrated dc–dc converters, charge pumps, class-E amplifiers, or isolated MOSFET power switches. Information about the peak-efficiency point position can be used to modify the power-switch operating conditions, which allows us to obtain the maximal available power-efficiency for a given operating point. The algorithm of the peak-efficiency tracking is developed here on the example of integrated 3.2 MHz step-down (buck) 5-A dc–dc converter. In this example, sizes of NMOS and PMOS power transistors are adjusted “on the fly,” in order to obtain the highest possible efficiency. In particular, power efficiency is optimized for the output current $I_{rm OUT}$ , battery and output voltages $V_{rm BAT}$ and $V_{rm OUT}$ , switching frequency $f_{rm SW}$ , temperature, and process variations. The principle of the method relies on the balancing of the Joule heat energy dissipated on the resistive elements, and energy dissipated during the charging process of the transistors’ driving capacitances. As the result of the peak-efficiency tracking algorithm, the flat efficiency curve is obtained in a wide current range.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • Low Power Very High Frequency Switch-Mode Power Supply With 50 V Input and
           5 V Output
    • Authors: Madsen; M.;Knott, A.;Andersen, M.A.E.;
      Pages: 6569 - 6580
      Abstract: This paper presents the design of a resonant converter with a switching frequency in the very high frequency range (30–300 MHz), a large step down ratio (ten times), and low output power (1 W). Several different inverters and rectifiers are analyzed and compared. The class E inverter and rectifier are selected based on complexity and efficiency estimates. Three different power stages are implemented; one with a large input inductor, one with a switch with small capacitances, and one with a switch with low on-resistance. The power stages are designed with the same specifications and efficiencies from 60.7–82.9% are achieved.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • Boost Three-Effective-Vector Current Control Scheme for a Brushless DC
           Motor With Novel Five-Switch Three-Phase Topology
    • Authors: Xia; C.;Xiao, Y.;Shi, T.;Chen, W.;
      Pages: 6581 - 6592
      Abstract: This paper presents a boost five-switch three-phase (BFSTP) topology in brushless dc motor (BLDCM) drives by combining a four-switch three-phase (FSTP) inverter and a boost circuit together. In BLDCM drives, load and speed ranges are greatly restricted when the conventional FSTP inverter is employed, especially in the cases of solar power and battery, where power supply voltage is lower than the rated voltage of motor. Based on the novel topology, a boost three-effective-vector (BTEV) scheme is also presented. With the proposed BTEV scheme, two functions are realized. First, the voltage across the capacitors on the side of dc link is boosted by inserting shoot-through vectors in Modes V and VI, thus widening the speed and load ranges under low power supply voltage. Second, by taking the advantages of two adjusting vectors, possible distortion of currents caused by phase C back-EMF is restrained by employing a three-effective-vector scheme in Modes I and IV. The proposed BFSTP topology has a compact structure and a small size. Moreover, the BTEV current control scheme is easy to implement and needs no complex calculation involved in conventional vector control. The effectiveness of the proposed BFSTP topology and the BTEV scheme is validated through experiment.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • Model Predictive Torque Control of Induction Motor Drives With Optimal
           Duty Cycle Control
    • Authors: Zhang; Y.;Yang, H.;
      Pages: 6593 - 6603
      Abstract: Model predictive torque control (MPTC) is emerging as a powerful control scheme for high performance control of induction motor (IM) drives. Compared to direct torque control, MPTC is more effective and accurate in voltage vector selection by incorporating the system model directly with the finite switching states. However, for two-level inverter-fed IM drives, the sampling frequency of MPTC has to be high to achieve good performance due to the limited number of voltage vectors. Recently, the concept of duty cycle control was introduced in MPTC by inserting a null vector along with the selected active voltage vector to achieve torque ripple reduction. The active vector is first selected from conventional MPTC and then its duration is determined based on a certain principle. The cascaded processing of active vector and its duration leads to poor low-speed performance and the sampling frequency still has to be high. This paper proposes an improved MPTC with duty cycle control by optimizing the vector selection and its duration simultaneously when minimizing both torque and flux errors. As a result, better steady-state performance at both low and high speeds is achieved, even if the sampling frequency is reduced by half. The effectiveness of the proposed MPTC is verified by both simulation and experimental results.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • Intermodulation Distortions of Bang–Bang Control Class D Amplifiers
    • Authors: Guo; L.;Ge, T.;Chang, J.;
      Pages: 6604 - 6614
      Abstract: Audio Class D amplifiers (CDAs) based on bang–bang architecture are arguably the most power efficient architecture of all CDAs reported to-date due to their sheer hardware simplicity. At this juncture, the intermodulation distortion (IMD), an imperative measure that defines fidelity, remains unreported for bang–bang CDAs. In this paper, we investigate the mechanisms of and circuit parameters affecting the IMD of bang–bang CDAs. An interesting phenomenon is that the even-order IMD which is usually negligible/unreported in other CDAs and linear amplifiers may be higher than odd-order IMD therein. We derive analytical expressions for the IMD of the ideal and practical bang–bang CDAs, and the derived expressions are verified against HSPICE simulations and on the basis of measurements on a physical bang–bang CDA. These derived analytical expressions are useful as they provide valuable insights to the design of bang–bang CDAs and how parameters can be tradedoff to improve the IMD.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • Self-Commissioning of Permanent Magnet Synchronous Machine Drives at
           Standstill Considering Inverter Nonlinearities
    • Authors: WANG; G.;Qu, L.;Zhan, H.;Xu, J.;Ding, L.;Zhang, G.;Xu, D.;
      Pages: 6615 - 6627
      Abstract: Offline parameter identification of permanent magnet synchronous machines (PMSMs) is essential for proper tuning of the controller and position observer for general-purpose drives with sensorless control. This paper proposes a self-commissioning method of electrical machine parameters at standstill only using a voltage source inverter fed drive. The influence of inverter nonlinearities including the effect of parasitic capacitance, which may cause estimation error, is analyzed. And an error model of inductance identification considering different rotor positions is established. Along with high-frequency sinusoidal signal, a supplementary direct current signal is injected into the estimated direct-axis to attenuate the inductance identification error. In addition, a compensation strategy based on the error model is adopted to enhance the accuracy of inductance identification. For stator resistance identification, the linear regression method is adopted to overcome the influence of inverter nonlinearities by injecting the linearly increasing current signal. The proposed method is promising and robust to extract the resistance information from the gradient coefficient of the voltage variation. The effectiveness of the proposed self-commissioning scheme is validated on a 22-kW PMSM drive.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • Core Loss Estimation of Various Materials Magnetized With the
           Symmetrical/Asymmetrical Rectangular Voltage
    • Authors: Hatakeyama; T.;Onda, K.;
      Pages: 6628 - 6635
      Abstract: Core losses were estimated for various magnetic core materials magnetized with a duty-cycle-changed symmetrical and asymmetrical rectangular voltage. Each voltage waveform is applied to a transformer and a dc reactor in a dc/dc converter, respectively. Core losses were measured for the four typical magnetic core materials often used in power electronics: 3% grain-oriented silicon steel sheet, 6.5% silicon steel sheet, amorphous material, and nanocrystalline material. Measurement results were evaluated by the loss separation model. An approximation method was proposed for the core loss magnetized with asymmetrical rectangular voltage that divides the total core loss into the core loss of the magnetization from $-B_{m}$ to $B_{m}$ and that of the magnetization from $B_{m}$ to $-B_{m}$ . This method was confirmed to approximate the core loss accurately except for silicon steel sheet in an extreme duty cycle condition. However, it was demonstrated experimentally that dc component of the magnetic field strength caused this error.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • Chromatic, Photometric and Thermal Modeling of LED Systems With
           Nonidentical LED Devices
    • Authors: Chen; H.;Lin, D.;Tan, S.;Hui, S.S.Y.;
      Pages: 6636 - 6647
      Abstract: With the emergence of new color-mixing LED systems based on LED devices of different color temperatures, the need for a new modeling technique for LED systems with nonidentical LED devices becomes imminent. This paper presents a modeling technique for LED systems with LED arrays comprising nonidentical LED devices that have nonidentical optical–thermal–electrical properties. Based on a general 3-D photo-electro-thermal LED node model, LED devices of different kinds can be arranged in various array forms according to their system construction and design. By linking the system matrix to the correlated-color-temperature prediction, the proposed modeling technique provides an accurate prediction of the temperature distribution, luminous flux, and correlated color temperature of the LED systems. The temperature distribution and light output of the LED systems have been measured using an infrared imaging system and a spectrophotocolorimeter with an integrating sphere. The modeling technique has been successfully demonstrated and experimentally verified on several LED systems comprising nonidentical LED devices. It is particularly useful as a modeling tool to study new color-mixing LED systems based on different types of LED devices.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • A High-Frequency Digitally Controlled LED Driver for Automotive
           Applications With Fast Dimming Capabilities
    • Authors: Corradini; L.;Spiazzi, G.;
      Pages: 6648 - 6659
      Abstract: This paper presents a high-frequency, digitally controlled high-brightness LED driver for automotive applications with fast dimming capabilities. The power converter is based on the magnetically coupled Ćuk topology and employs a single, off-the-shelf SMT mutual inductor. The proposed digital control technique exploits the inherent stabilizing effect of magnetic coupling, and combines it with a dedicated duty cycle feedforward technique for step-reference response enhancement during the dimming operation. No direct sensing of the LED string current is performed, bypassing the disadvantage of the Ćuk topology of having an inverted output polarity. Furthermore, the magnetically coupled Ćuk topology is a single-switch solution and it provides inherent filtering of the input and output currents without introducing the additional magnetic elements, strongly reducing the total required capacitance and maintaining the small form-factor required in the automotive environment. This paper discusses the theoretical and practical development of the proposed controller. Experimental tests on a 40-W, 1-A, 500-kHz prototype indicate a 0- to 1-A current rise time in the tens of microseconds time frame with excellent damping characteristics and regulation accuracy.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • Design and Implementation of a Transformerless Single-Stage Single-Switch
           Double-Buck Converter With Low DC-link Voltage, High Step-Down, and
           Constant Input Power Factor Features
    • Authors: Chen; Y.;Zhong, Z.;Kang, Y.;
      Pages: 6660 - 6671
      Abstract: This paper presents a new transformerless single-stage single-switch (S4) converter which integrates a buck-type power factor correction cell with a buck-type dc–dc output cell in a special way. The proposed converter preserves the advantages of existing transformerless S4 converters, such as the low voltage stress across the dc-link capacitor, low current stress of the switch, and high step-down input-to-output voltage. Moreover, the proposed converter provides a new attractive feature, i.e., its input power factor always keeps constant even when the line- and load-conditions vary. These characteristics make the proposed converter cost-efficient, easy-to-design, and suitable for the low-power and nonisolated applications. The principle and analysis of the proposed converter are presented in this paper, and a design example is also given to show the validity of analysis.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • Impact of Parasitic Elements on the Spurious Triggering Pulse in
           Synchronous Buck Converter
    • Authors: Wang; J.;Shu-Hung Chung, H.;
      Pages: 6672 - 6685
      Abstract: This paper derives a circuit-level analytical model for describing the mechanism of the spurious triggering pulse in the gate-source voltage of the synchronous MOSFET (SyncFET) in the synchronous buck converter. The model takes into account not only the parasitic capacitances and inductances of the control MOSFET (CtrlFET) and the SyncFET, but also the reverse recovery characteristics of the body diode of the SyncFET. An exhaustive investigation into the impact of all these factors on the spurious triggering pulse is conducted. The spurious triggering pulse can be attributed to two factors. The first one is the positive gate voltage caused by the displacement current through the gate-drain capacitance of the SyncFET, due to the increase in the drain-source voltage. The second one is the negative source voltage caused by the voltage drop across the source inductance of the SyncFET, due to the decrease in the drain current. It is discovered that the gate impedance of the SyncFET would exert different influence on the magnitude of the spurious triggering pulse, depending on the contributions of these two factors. Experimental results affirm that variation in the magnitude of the spurious triggering pulse with each parasitic element can be correctly inferred by the proposed model. Design guidelines for enhancing spurious turn-on immunity are advanced.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • Voltage and Current-Mode Control for a Buck-Converter based on Measured
           Integral Values of Voltage and Current Implemented in FPGA
    • Authors: Truntic; M.;Milanovic, M.;
      Pages: 6686 - 6699
      Abstract: This paper describes a complete digitally controlled dc–dc buck converter performed by field-programmable gate array (FPGA) circuitry. The voltage and current-mode control is based on a voltage control oscillator (VCO) performed measurements regarding output-voltage and inductor current, respectively. This measurement principle also uses digital-counters (digital-integrators) in order to obtain integral values for the output-voltage and inductor current. In analog current-mode control, the instantaneous inductor current-value-measurement is used for the switching action. When the VCO is used for the inductor current measurement, the integral is measured during the switching-on time set as an observation interval and the switching action occurs based on this measurement. Such a principle enables full digitalization of the voltage- and current-control loop and also the used measurement principle is capable of rejecting the switching disturbances during current and voltage measurements. All the tasks for current and voltage control were implemented within the FPGA. The algorithm was verified by simulation and experimentation at a switching-frequency of $hbox{25 }$ kHz.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • A Novel Adaptive Frequency Injection Method for Power Electronic System
           Impedance Measurement
    • Authors: Yue; X.;Fang, Z.;Wang, F.;Zhang, Z.;Shi, H.;
      Pages: 6700 - 6711
      Abstract: Power electronic systems are prone to negative impedance instability due to the constant-power nature of the individual components. The impedance measurement, therefore, is very important during the system designing because of the close relationship between impedance and stability. However, traditional frequency sweep methods, by injecting a series of sinusoidal perturbation signals equidistantly, always select the frequency interval on experience accumulating without guiding theory, which result in low accuracy, low reliability, and low efficiency. In this paper, the relationship between measured results and the frequency interval is built first, then the frequency interval selection criteria of injection signals are derived accordingly. Afterward, based on the above analysis, a novel adaptive frequency injection method of impedance measurement is proposed to figure out the practical issues in power electronic system impedance measurement process. With this method, variable frequency interval can be selected according to characteristics of the measured network automatically. Compared to the traditional frequency sweep method, the proposed one can measure impedance more accurately and efficiently. The simulation and experimental results validate the effectiveness of the proposed method.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • Symmetric and Asymmetric Design and Implementation of New Cascaded
           Multilevel Inverter Topology
    • Authors: Mokhberdoran; A.;Ajami, A.;
      Pages: 6712 - 6724
      Abstract: Nowadays, use of multilevel inverters in high-power applications clearly can be seen. High quality and lower distortion of the output voltage and low blocking voltage of semiconductor switches are being presented as the major privileges of the multilevel inverter compared to the traditional voltage source inverter. In this paper, a new topology of multilevel inverter is proposed as fundamental block. The proposed topology is generalized using series connection of the fundamental blocks. The proposed multilevel inverter has been analyzed in both symmetric and asymmetric operation modes. A great perfection in voltage levels number with minimum switching devices has been obtained in both symmetric and asymmetric modes. Thereafter, a detailed study of losses and peak inverse voltage (PIV) of the proposed multilevel inverter is given. Also, in continuation, a comparison between the proposed topology and the traditional one and a recently developed topology is carried out. Finally, a computer simulation using MATLAB/Simulink is presented and a laboratory prototype implementation verifies the results.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • Modular DC–DC Converters on Graphs: Cooperative Control
    • Authors: Behjati; H.;Davoudi, A.;Lewis, F.;
      Pages: 6725 - 6741
      Abstract: Modular dc–dc converters are popular in dc-power systems due to their advantageous characteristics such as fault tolerance, ease of thermal management, reducing voltage/current stress of the components, and modularity. In this paper, the concept of cooperative control in multiagent systems is introduced for modular dc–dc converters. Each constituent converter is represented by a node in a directed communication graph that models the information flow among converters. The proposed cooperative control scheme enjoys structural modularity, plug-and-play capability, fault tolerance against random failures in the converters and/or communication links, and satisfactory dynamic performance. This paper provides a general analytical framework to study modular dc–dc converters with an arbitrary communication graph. Hence, the designer has the freedom to choose among the various types of graphs based on the available communication resources and the desired level of reliability and fault tolerance. The dynamic model of the cooperative multiconverter system is developed and analyzed. Hardware measurements are presented to verify the plug-and-play capability, fault tolerance in both cyber and physical domains, and dynamic performance of the proposed cooperative control scheme.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • Transient Response Improvement at Startup of a Three-Phase AC/DC Converter
           for a DC Distribution System in Commercial Facilities
    • Authors: Shin; S.;Lee, H.;Kim, Y.;Lee, J.;Won, C.;
      Pages: 6742 - 6753
      Abstract: In this paper, a soft-start method for improvement of the transient response during the initial startup of power converters in building applications is proposed. Most dc loads have sensitive electrical characteristics regarding the input voltage. In such systems, the power converter is operated after connecting with dc loads to minimize the overshoot of the control voltage that may occur during connection to the loads. But whenever the power converter is started, the parameters in the circuit can differ, since the power converter is connected with various load types at each startup. This is disadvantageous for PI controller design for power converters. In order to solve this problem, a novel voltage control method using sliding-mode control theory is proposed. The advantage of the proposed voltage controller is that it is able to minimize an overshoot of the control voltage at the startup of the converter in terms of the types of loads or the magnitude variation of loads because a sliding mode controller has the robust characteristic of a variation in the parameters and load. The characteristics of three types of voltage controllers were compared through simulations and experiments. Despite the variations of the system parameters, the proposed voltage controller has fast response in the steady-state and robustness characteristics in the transient state. In addition, the proposed controller fundamentally minimizes the overshoot of the control voltage. The proposed controller was applied to a three-phase ac/dc converter, and the controller performance was verified.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • A Self-commissioning Notch Filter for Active Damping in a Three-Phase LCL
           -Filter-Based Grid-Tie Converter
    • Authors: Pena-Alzola; R.;Liserre, M.;Blaabjerg, F.;Ordonez, M.;Kerekes, T.;
      Pages: 6754 - 6761
      Abstract: LCL-filters are a cost-effective solution to mitigate harmonic current content in grid-tie converters. In order to avoid stability problems, the resonance frequency of LCL-filters can be damped with active techniques that remove dissipative elements but increase control complexity. A notch filter provides an effective solution, however tuning the filter requires considerable design effort and the variations in the grid impedance limit the LCL-filter robustness. This paper proposes a straightforward tuning procedure for a notch filter self-commissioning. In order to account for the grid inductance variations, the resonance frequency is estimated and later used for tuning the notch filter. An estimation for the maximum value of the proportional gain to excite the resonance is provided. The resonance frequency is calculated using the Goertzel algorithm, which requires little extra computational resources in the existing control processor. The discrete Fourier transform coefficients are therefore obtained, with less calculations than the running sum implementation and less memory requirements than with the fast Fourier transform (FFT). Thus, the self-commissioning technique is robust to grid impedance variations due to its ability to tune the grid-tie inverter on-site. Finally, the analysis is validated with both simulation and experiments.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • One-Dimensional Spectral Analysis of Complex PWM Waveforms Using
    • Authors: Mouton; H.D.T.;McGrath, B.;Holmes, D.G.;Wilkinson, R.H.;
      Pages: 6762 - 6778
      Abstract: This paper takes a new look at the mechanisms underlying the double-edge pulse-width modulation (PWM) process. It presents a novel way of deriving equations for the spectrum of double-edge PWM using basic mathematical techniques. In the process the underlying nonlinearities that generate the PWM sidebands are identified. Unlike the classical double Fourier series approach, the proposed method of deriving the PWM spectrum does not require the construction of the so-called unit cell. The interaction between this new model of the pulse-width modulator and the regular sampling process is studied, and generalized equations for the Fourier transforms of regularly sampled PWM waveforms are derived. A general solution to the important question of what happens to the PWM spectrum when the PWM reference consists of a summation of signals is presented. It is shown that the addition of reference signals in the time domain results in a double convolution of the PWM sidebands in the frequency domain. As an application of this result, it is shown how new analytic equations for the harmonics of third-harmonic injection PWM and space vector modulation can easily be derived. Finally, the new theoretical results are benchmarked against results from the well-established double Fourier series method.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • Power Measurement for Resonant Power Converters Applied to Induction
           Heating Applications
    • Authors: Jimenez; O.;Lucia, O.;Urriza, I.;Barragan, L.A.;Navarro, D.;
      Pages: 6779 - 6788
      Abstract: Nowadays, induction heating (IH) technology is dominating the domestic cooking market due to its advantages such as safety, cleanness, and high efficiency. Such high efficiency and high power density implementations are achieved by means of resonant power converters and, consequently, these need to be accurately controlled. This paper proposes a field-programmable gate array-based online power measurement system which allows the control system to perform the proper power control. The proposed power measurement system measures the output power from the digitized output voltage and current through two low-cost 1-bit second-order ΣΔ analog-to-digital converters. The bitstreams have been analyzed and, taking into account the results, several measurement approaches have been proposed and analyzed. Then, a noise sensitivity analysis has been performed in order to verify the proposed measurements methods. The analytical and simulation results have been tested through a resonant power converter applied to domestic IH whose switching frequency varies from 30 to 80 kHz. A statistical analysis of the implemented measurement approaches has been carried out in order to evaluate the system accuracy. Finally, the selected measurement method has been verified for several vessels. As a conclusion, an accurate and cost-effective output power measurement system is obtained, which can be applied to any resonant converter in the frequency operation range.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • Error Amplifier Design of Peak Current Controlled (PCC) Buck LED Driver
    • Authors: Kim; M.;
      Pages: 6789 - 6795
      Abstract: A discrete time-domain modeling and analysis for the peak current controlled (PCC) buck light-emitting diode (LED) driver is presented in this paper. The discrete time-domain equation representing the buck LED driver is derived and linearized about the equilibrium state. Also the switching control law, the proportional-integral compensator is used here as an example of the error amplifier, is linearized about the equilibrium state. The linearized buck LED driver and the control law are then combined to arrive at a linearized PCC buck LED driver. The root-locus method is employed to analyze the closed-loop system. The design guidelines and experimental results for the PCC buck LED driver are presented.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • Elimination of Coupling Transformer Core Saturation in Cascaded Multilevel
           Converter-Based T-STATCOM Systems
    • Authors: Gercek; C.;Ermis, M.;
      Pages: 6796 - 6809
      Abstract: This paper deals with coupling transformer core saturation problem in cascaded multilevel converter (CMC) based transmission-type static synchronous compensator (T-STATCOM) systems. The effects of nonlinear characteristics of the coupling transformer and CMCs on the core saturation phenomenon are investigated, and the associated mechanisms are described. In order to prevent the transformer core from being saturated, dc current components in the coupling transformer secondary lines are eliminated by modulating one or more than one voltage steps of staircase CMC voltage waveforms via the electronic gating circuitry. The proposed dc current elimination method is implemented on a 154-kV, ±50-MVAr CMC-based T-STATCOM system, which is operating either in interarea oscillation damping or terminal voltage regulation modes at any time in a 400/154-kV transformer substation since March 2010. The effectiveness of recommended dc current elimination method is verified in the field.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • Comparison of Two Three-Phase PLL Systems for More Electric Aircraft
    • Authors: Bifaretti; S.;Zanchetta, P.;Lavopa, E.;
      Pages: 6810 - 6820
      Abstract: The more electric aircraft power system is characterized by variable supply frequency, in general between 360 and 900 Hz. All equipment on board the aircraft have to operate delivering high performance under this variable frequency condition. In particular, power electronic converters need accurate control algorithms able to track the fundamental phase and frequency in real time, both in normal and unusual conditions. Phase-locked loop (PLL)-based algorithms are commonly used in traditional single- and three-phase power systems to provide phase and frequency estimations of the supply. Despite the simplicity of those algorithms, large estimation errors can arise when power supply voltage has variable frequency or amplitude, presents unbalances or is polluted with harmonics. To improve the quality of the phase and frequency real-time estimations, a robust PLL algorithm, based on a prediction-correction filter, is presented in this paper and compared with a discrete Fourier transform based procedure. The performances of the two algorithms, implemented in a floating-point DSP, have been compared through an experimental validation obtained on a laboratory power converter prototype.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • A Complementarity Model for Closed-Loop Power Converters
    • Authors: Sessa; V.;Iannelli, L.;Vasca, F.;
      Pages: 6821 - 6835
      Abstract: At a certain level of abstraction, power converters can be represented as linear circuits connected to diodes and controlled electronic switches. The evolutions of the electrical variables are determined by the state-dependent switchings, which complicate the mathematical modeling of controlled power converters. Differently from the complementarity models previously presented in the literature, the model proposed in this paper allows to represent as a linear complementarity system also closed-loop power converters, without requiring the a priori knowledge of the converter modes. A model construction procedure, not dependent on the specific converter topology, is presented. The discretization of the continuous-time model allows to formulate mixed linear complementarity problems for the computation of the control-to-output frequency response and the evolutions of both transient and steady-state currents and voltages. As illustrative examples, Z-source, boost, and buck dc–dc power converters under voltage-mode control and current-mode control operating both in continuous and discontinuous conduction modes are considered.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • Multistep Finite Control Set Model Predictive Control for Power
    • Authors: Geyer; T.;Quevedo, D.E.;
      Pages: 6836 - 6846
      Abstract: For direct model predictive control with reference tracking of the converter current, we derive an efficient optimization algorithm that allows us to solve the control problem for very long prediction horizons. This is achieved by adapting sphere decoding principles to the underlying optimization problem. The proposed algorithm requires only few computations and directly provides the optimal switch positions. Since the computational burden of our algorithm is effectively independent of the number of converter output levels, the concept is particularly suitable for multilevel topologies with a large number of voltage levels. Our method is illustrated for the case of a variable speed drive system with a three-level voltage source converter.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
  • Bandwidth Expansion Method for Circulating Current Control in Parallel
           Three-phase PWM Converter Connection System
    • Authors: Xueguang; Z.;Jiaming, C.;Yan, M.;Yijie, W.;Dianguo, X.;
      Pages: 6847 - 6856
      Abstract: The use of common dc-link parallel three-phase PWM converters without isolating transformers will cause zero-sequence circulating current problem. Previous works have proven that the circulating current is mainly affected by zero vectors employed in each PWM cycle. This paper proposes a novel method to suppress the circulating current. Detailed analysis is presented on the causes of zero-sequence circulating current based on a derived average model. A zero vectors feed-forward control strategy in combination with traditional PI control method is proposed to reject disturbances in zero-axis current system. In addition, a dual current sampling and dual PWM duty ratio update (DSDU) scheme is used to expand the bandwidth of zero-axis current loop. As a result, better circulating current suppression performance can be achieved in different filter inductance and converter output currents condition. Compared with the PI control method, the converters operated in parallel can be switched on and switched off separately with small current impact. Experimental results confirm the performance and effectiveness of the proposed method.
      PubDate: Dec. 2014
      Issue No: Vol. 29, No. 12 (2014)
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