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Power Electronics, IET

Issue 2 • Date March 2010

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Displaying Results 1 - 12 of 12
  • Single-phase power factor controller topologies for permanent magnet brushless DC motor drives

    Page(s): 147 - 175
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1458 KB)  

    This study presents various configurations, control schemes and design of single-phase power factor controller (PFC) topologies for permanent magnet brushless DC motor (PMBLDCM) drives and provides a basis for selection of a suitable PFC topology for a specific application. Several AC-DC converter (buck, boost, buck-boost, C-uk, SEPIC, Zeta, push-pull, half bridge, full bridge) based PFC topologies are designed, modelled and applied to a 1.5-kW PMBLDCM drive for comparison of performance. Some of bidirectional bridge converter and unipolar inverter topologies are also evaluated to provide a comprehensive comparison of the PFC topologies for PMBLDCM drives. The proposed PFC converter topologies show conformity to international power quality standards with improved performance of PMBLDCM drive, such as reduction of AC mains current harmonics, near unity power factor and reduction of speed and torque ripples. A classified list of more than 200 research publications on the state of art of various PFC topologies and PMBLDCM drives is also given for a quick reference. View full abstract»

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  • Single-phase two-stage boost rectifiers with sinusoidal input current

    Page(s): 176 - 186
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (996 KB)  

    Single-phase two-state boost rectifiers with sinusoidal input current are presented and a novel topology with two active power devices is proposed. These contain a capacitor for pumping action in DC circuit. This gives two-stage boost operation to obtain higher DC output voltage. The rectifier can be operated in the switch mode for pumping action and for forcing the input current to follow its sinusoidal reference independent of the working conditions. The results of the proposed rectifier are compared with those of the rectifier with a single active power device. The prototype tested is implemented to investigate the steady-state operation in the output voltage regulation. The experimental and the simulated results prove that the proposed rectifier has the expected performance. View full abstract»

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  • Zero voltage switching double-ended converter

    Page(s): 187 - 196
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (938 KB)  

    A new zero voltage switching (ZVS) converter with a double-ended rectifier is presented to reduce switching losses on power semiconductors, decrease voltage stresses on rectifier diodes and achieve bidirectional power delivery to output load. A buck-boost type of active snubber is connected in parallel with the primary side of a transformer to recycle the energy stored in transformer leakage and magnetising inductors and to limit voltage stress on the main switch. During the transition interval, the transformer leakage inductor and the output capacitor of power MOSFET are resonant to realise the ZVS turn-on of the switch. Finally, the experimental results were given to demonstrate the circuit performance and to verify the feasibility of the proposed converter. View full abstract»

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  • Multi-output DC-DC converters based on diode-clamped converters configuration: topology and control strategy

    Page(s): 197 - 208
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1260 KB)  

    This study presents a new DC-DC multi-output boost (MOB) converter which can share its total output between different series of output voltages for low- and high-power applications. This configuration can be utilised instead of several single output power supplies. This is a compatible topology for a diode-clamed inverter in the grid connection systems, where boosting low rectified output-voltage and series DC link capacitors is required. To verify the proposed topology, steady-state and dynamic analyses of a MOB converter are examined. A simple control strategy has been proposed to demonstrate the performance of the proposed topology for a double-output boost converter. The topology and its control strategy can easily be extended to offer multiple outputs. Simulation and experimental results are presented to show the validity of the control strategy for the proposed converter. View full abstract»

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  • Common mode modelling and filter design for a three-phase buck-type pulse width modulated rectifier system

    Page(s): 209 - 218
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (845 KB)  

    The EMC input filter design for a three-phase pulse width modulated (PWM) rectifier is usually separated into the design of the differential mode (DM) and common mode (CM) stages. While for the DM filter design rules and procedures are well known and easier to predict, the CM filter design is often based on trial-and-error methods and/or on the experience of the designer. In the present study, a comprehensive design procedure for a CM EMC input filter is performed for a three-phase three-switch buck-type PWM rectifier. A model of the CM noise propagation is developed and the relevant parasitic impedances are identified. A capacitive connection from the star-point of the DM input filter to the capacitive centre point of the rectifier output voltage is proposed and the effect of this measure-concerning CM is verified. Finally, a two-stage CM filter is designed and compliance to the conducted emission (CE) requirements of CISPR 22 Class B is verified through measurements on a 5 kW prototype. View full abstract»

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  • Improved switching frequency variation control of hysteresis controlled voltage source inverter-fed IM drives using current error space vector

    Page(s): 219 - 231
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1729 KB)  

    A constant switching frequency current error space vector-based hysteresis controller for two-level voltage source inverter-fed induction motor (IM) drives is proposed in this study. The proposed controller is capable of driving the IM in the entire speed range extending to the six-step mode. The proposed controller uses the parabolic boundary, reported earlier, for vector selection in a sector, but uses simple, fast and self-adaptive sector identification logic for sector change detection in the entire modulation range. This new scheme detects the sector change using the change in direction of current error along the axes jA, jB and jC. Most of the previous schemes use an outer boundary for sector change detection. So the current error goes outside the boundary six times during sector change, in one cycle, introducing additional fifth and seventh harmonic components in phase current. This may cause sixth harmonic torque pulsations in the motor and spread in the harmonic spectrum of phase voltage. The proposed new scheme detects the sector change fast and accurately eliminating the chance of introducing additional fifth and seventh harmonic components in phase current and provides harmonic spectrum of phase voltage, which exactly matches with that of constant switching frequency voltage-controlled space vector pulse width modulation (VC-SVPWM)-based two-level inverter-fed drives. View full abstract»

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  • Single-phase Z-source cycloconverter with safe-commutation strategy

    Page(s): 232 - 242
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1417 KB)  

    A new single-phase to single-phase Z-source cycloconverter (SPZC) based on single-phase matrix converter (SPMC) topology is proposed. The proposed SPZC can boost to a desired voltage with various frequencies, in which output frequency is an integer fraction of input frequency. Thus, it is also called a frequency step-down and amplitude voltage step-up converter. A safe-commutation strategy is employed to eliminate voltage spikes on switches, and the operating principle and analysis of the SPZC are presented. To verify the successful operation of the proposed topology, a DSP TMS320F2812 based prototype is implemented, and the results of PSIM simulations and experiments are also presented. View full abstract»

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  • Medium-voltage pulse width modulated current source rectifiers using different semiconductors: loss and size comparison

    Page(s): 243 - 258
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (2120 KB)  

    In this study, a comparison of losses and physical size is presented for three semiconductor devices suitable for medium-voltage high-power applications. The comparison is made for medium-voltage pulse width modulated (PWM) current source rectifiers (CSRs) using a selective harmonic elimination technique. The devices are high-voltage insulated gate bipolar transistors and two types of hard-driven thyristors, namely the symmetrical gate commutated thyristor and the asymmetrical gate commutated thyristor. The study is based on practical devices using data sheets from semiconductor device vendors, taking into account accurate discrimination between turn-off and recovery states. The constant-voltage switching energy data sheet curves for voltage source converters are adapted to suit varying voltage applications like the PWM-CSR, with emphasis on how voltage is shared between series devices during each commutation instant. View full abstract»

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  • Analysis and implementation of an interleaved ZVS bi-flyback converter

    Page(s): 259 - 268
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1594 KB)  

    The system analysis, circuit implementation and design consideration of interleaved bi-flyback converter with zero voltage switching (ZVS) are presented. To reduce the ripple current on the input and output capacitors and decrease the current stress on the transformer secondary windings, two modules with interleaved pulse-width modulation (PWM) are connected in parallel at the input and output sides. Thus, the transformer copper losses and the conduction losses on the output diodes are reduced. Active snubber is connected in parallel with the main switch to limit the voltage spike because of the transformer leakage inductance when main switch is turned off. All power switches are turned on at ZVS during the commutation stage. Thus, the switching losses and thermal stresses of the semiconductors are reduced. Finally, experiments based on a 720 W (24 V 30 A) prototype are provided to verify the theoretical analysis and the effectiveness of the proposed converter. View full abstract»

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  • Switched-capacitor bi-directional converter performance comparison with and without quasi-resonant zero-current switching

    Page(s): 269 - 278
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1135 KB)  

    The proposed quasi-resonant (QR) zero-current switching (ZCS) switched-capacitor (SC) converter is a new type of bi-directional power flow control conversion scheme. This device provides voltage conversion ratios from 2 against 1/2 (double-mode/half-mode) to n against 1/n (n-mode/1/n-mode) by adding a different number of SCs and power multi-oxide-semiconductor field-effect-transistor (MOSFET) switches with a small series-connected resonant inductor for forward and reverse schemes. The proposed QR SC converter presents low current stress and balanced resonant current advantages. The operating principle and theoretical analysis of the proposed bi-directional power conversion scheme are described in detail with circuit model analysis. The proposed device is compared with the conventional SC converter. Simulations and experimental verification are carried out to verify and compare the proposed QR ZCS SC bi-directional converter performance with the conventional device. At maximum efficiency, the proposed device can achieve 96% and 93% for the forward and reverse power flow control schemes, respectively. View full abstract»

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  • Intelligent diagnosis of open and short circuit faults in electric drive inverters for real-time applications

    Page(s): 279 - 291
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (714 KB)  

    This study presents a machine learning technique for fault diagnostics in induction motor drives. A normal model and an extensive range of faulted models for the inverter-motor combination were developed and implemented using a generic commercial simulation tool to generate voltages and current signals at a broad range of operating points selected by a machine learning algorithm. A structured neural network system has been designed, developed and trained to detect and isolate the most common types of faults: single switch open circuit faults, post short-circuits, short circuits and the unknown faults. Extensive simulation experiments were conducted to test the system with added noise, and the results show that the structured neural network system which was trained by using the proposed machine learning approach gives high accuracy in detecting whether a faulty condition has occurred, thus isolating and pin-pointing to the type of faulty conditions occurring in power electronics inverter-based electrical drives. Finally, the authors show that the proposed structured neural network system has the capability of real-time detection of any of the faulty conditions mentioned above within 20-ms or less. View full abstract»

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  • Capacitor voltage balancing using redundant states of space vector modulation for five-level diode clamped inverters

    Page(s): 292 - 313
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (2822 KB)  

    A redundancy balancing technique for the five-level diode-clamped inverter is presented, which balances the four dc-link capacitor voltages at high modulation index and high power factor. The technique is based on dividing the vector space of the five-level inverter into six two-level vector spaces. Dwell times are calculated as for conventional two-level space vector modulation, and the switching sequence is determined depending on the four capacitor voltages, using a redundant state method. The double Fourier series is used to theoretically determine the resultant spectral components. The proposed technique maintains link capacitor balance for high modulation indices, including over modulation, irrespective of the power factor. The proposed algorithm is validated by simulation and practically. View full abstract»

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Aims & Scope

IET Power Electronics brings together five principal power electronics themes including: applications of power semiconductor technology; circuits; devices; techniques; and performance management.

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