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Applied Power Electronics Conference and Exposition, 1996. APEC '96. Conference Proceedings 1996., Eleventh Annual

Date 3-7 March 1996

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  • Energy efficient C-dump converters for switched reluctance motors

    Page(s): 968 - 973 vol.2
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    Two energy-efficient converter topologies, derived from the conventional C-dump converter, are proposed for switched reluctance motor (SRM) drives. The proposed topologies overcome the limitations of the conventional C-dump converter, and could reduce the overall cost of the SRM drive. The voltage ratings of the dump capacitor and the switching devices in the proposed converters are reduced to the supply voltage (V/sub dc/) level compared to being twice the supply voltage (2V/sub dc/) in the conventional C-dump converter. Also, the size of the dump inductor is considerably reduced. The converters have simple control that allows the motor phase current to freewheel during chopping mode. Simulation and experimental results of the converter are presented and discussed. View full abstract»

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  • Conference Author Index

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    Freely Available from IEEE
  • Design and experimental investigation of a three-phase high power density high efficiency unity power factor PWM (VIENNA) rectifier employing a novel integrated power semiconductor module

    Page(s): 514 - 523 vol.2
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    The development of guidelines for the practical application of a new power module (IXYS VUM25-E) realizing a bridge leg of a three-phase/switch/level PWM (VIENNA) rectifier system with low effects on the mains is discussed. The inner circuit structure of the power module is formed by a bidirectional bipolar switch and of two free-wheeling diodes. In a first step the switching losses of the power MOSFET and of the free-wheeling diodes are determined by measurement in dependency on the switched current for characteristic values of the junction temperature. The isolated driving stage of the MOSFET is designed for minimum switching losses considering the occurring switching overvoltages and the ringing between the parasitic circuit elements. The conduction losses of the semiconductor elements are calculated directly via simple analytical approximations of the mean and rms values of the device currents. Based on the knowledge of the dependency of the main loss contributions of the semiconductors of the power module on the operating parameters (mains voltage, output voltage, heat sink temperature and switching frequency) the thermally maximum allowable mains current amplitude is calculated. Furthermore, for different switching frequencies an overview over the power loss contributions of the semiconductor elements is given. Also, the reduction of the efficiency caused by the total semiconductor losses is determined. Finally, the overall efficiency of a PWM (VIENNA) rectifier system realised by using the IXYS VUM25-E module is estimated and further possible developments of this module are discussed View full abstract»

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  • Design and experimental results of a 6 kW single-switch three-phase high power factor rectifier using multi-resonant zero current switching

    Page(s): 524 - 530 vol.2
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    The design and breadboard implementation of a single-switch three-phase high power factor multi-resonant rectifier delivering 147 V (DC) at 6 kW from a 3φ 240 V (L-L, rms) AC input is described. This rectifier has continuous input and output currents. By the use of a multi-resonant scheme, the transistor operates with zero current switching and the diodes operate with zero voltage switching. This paper focuses on the design, implementation, and performance of the rectifier. High quality input current waveforms at nearly unity power factor, wide load range, and low stresses on the semiconductor devices are attained. The total harmonic distortion (THD) of the line current is less than 5% and the system efficiency is about 94% at full load View full abstract»

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  • The design and development of a high power factor current source controller for small appliance brushless DC motors

    Page(s): 778 - 781 vol.2
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    The harmonic content in electric utility supply current has increased recently due to the proliferation of devices using peak rectifiers. This paper presents a variable speed high power factor DC motor controller with application in small appliances. The circuit uses a single high-voltage high-frequency switching transistor in a buck power converter topology. Theoretical analysis shows a large pulse width range giving a broad RFI/EMI spectrum. Experimental results verify the design with a 50 watt prototype controller having a power factor of 0.99 View full abstract»

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  • Evaluation of double layer capacitors for power electronic applications

    Page(s): 725 - 730 vol.2
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    Advancement of double layer capacitor technology has made commercially available capacitors with capacitance values exceeding 470 Farads. This paper presents test results on double layer capacitors operating from DC to 50 kHz. Equivalent series resistance variation with frequency, duty cycle, polarity, load current, and charging voltage are examined, along with DC capacitance measurements and implementation in practical power electronic circuits View full abstract»

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  • An AC-AC converter made of two semi direct frequency changers has no limits on the voltage gain

    Page(s): 918 - 924 vol.2
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    Despite many attempts, the voltage gain of a direct frequency changer (DFC) remains limited to 0.87. However, the introduction of a new converter topology, inspired from the DFC and called semi direct frequency changer (SDFC), opens the way toward an AC-AC conversion without any limitation on the voltage gain. Two SDFCs, made of six unidirectional switches, can form a full 3 phase-3 phase converter; the SDFCs are operated under the scalar control algorithm. Functionality of the SDFC is analyzed in depth with the help of both HSPICE and EMTP programs. Laboratory test results from a 100 W prototype are also presented View full abstract»

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  • A compact, high-efficiency and high-power-factor rectifier for telecommunications systems

    Page(s): 509 - 513 vol.2
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    We have developed a rectifier which consists of a boost-chopper with zero-voltage switching and a full-bridge zero-voltage switching converter using bipolar-mode static induction transistors (B-SITs). A 5 kW-output experimental model achieved the following: high efficiency of 93%, high power density of 0.28 W/cm3, and its harmonic currents satisfy IEC standards View full abstract»

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  • A new simple topology for three-phase buck-mode PFC rectifier

    Page(s): 531 - 537 vol.2
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    The author proposes a new and simple topology for three-phase buck-mode PFC-rectifier which obtains a very high input-power-factor, high-quality input-line-currents and a regulated output-voltage in buck-mode-range. The proposed rectifier, obtained by modifying a conventional simple topology for three-phase boost-mode PFC, employs new principal of current-synthesis and a simple and unique modulation-technique to improve the input-characteristics. In this paper, the proposed topology, principal of the current-synthesis and the modulation-technique are introduced. Then, experimental results obtained a 2 kW prototype-converter are shown to confirm the validity of the theory View full abstract»

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  • An optimized single-phase AC power supply with DC bus synchronization

    Page(s): 905 - 910 vol.2
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    In this paper, a new control technique for a single-phase AC power supply system is presented. By synchronizing the AC output with the DC bus ripple, only a very small DC bus capacitor is required. This improves the power factor and the quality of the input current. In addition, a simple voltage integral control technique is introduced to control the PWM inverter. The performance of the system is analyzed and results are verified through experimental setup View full abstract»

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  • Design of a low input voltage converter for thermoelectric generator

    Page(s): 856 - 860 vol.2
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    Low-grade exhaust heat is used to provide a reliable and independent power source for instrumentation circuitry by means of a thermoelectric generator (TEG). A design of a self-starting DC-DC power converter is developed and optimized for very low input voltages (below 300 mV) in order to allow operation at temperature differences of 20°C and less. A prototype is built, and the results are experimentally verified View full abstract»

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  • Optimal-efficiency control for constant-power operation of phase-decoupling permanent-magnet brushless motor drives

    Page(s): 751 - 757 vol.2
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    In this paper, a control approach to optimize the system efficiency of phase-decoupling (PD) permanent magnet (PM) brushless motor drives during constant-power operation is presented. The approach is to adaptively adjust the advanced conduction angle to minimize the total system losses for a given operation point in the constant power region. The corresponding minimum total losses are determined by minimizing the input current for a fixed voltage source. Both computer simulation and experimental results are given for illustration View full abstract»

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  • A simplified discontinuous-switching-modulation for three-phase current-fed PFC-converters and experimental study for the effects

    Page(s): 552 - 558 vol.2
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    The authors propose a new modulation scheme to obtain discontinuous switching in instantaneous current-controlled three-phase buck and buck-boost power factor correction (PFC) power converters. Since the proposed discontinuous switching modulation eliminates the switching actions which produce the highest energy dissipation in modulation period, the average switching loss is reduced by half. The loss reduction effect is analyzed theoretically and experimentally. Further, a simple scheme to generate the discontinuous switching patterns in the instantaneous current controller is introduced. The validity of the theory and applicability of the discontinuous switching modulation in practice are confirmed through experimental results obtained from 2 kW prototype power converters View full abstract»

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  • Low temperature performance of a boost converter with MPP and HTS inductors

    Page(s): 883 - 888 vol.2
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    Low temperature performance of a 150 W, 50 kHz, 24/48 V boost PWM DC-to-DC power converter is reported. The efficiency of the power converter using a molypermalloy powder (MPP) core based inductor went up from 94% at room temperature (23°C) to 95.9% at liquid nitrogen temperature (-196°C). A BSCCO based high temperature superconducting (HTS) inductor with a transition temperature of approximately -158°C was compared to a MPP core based inductor in terms of the power converter performance at liquid nitrogen temperature. The use of the HTS inductor in the power converter tested yielded no significant performance improvement over the same power converter with the MPP inductor. The experimental results are discussed along with the HTS inductor characteristics View full abstract»

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  • Ion migration in a resistor network

    Page(s): 731 - 736 vol.2
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    After a short time in service, resistor networks (R-pacs) in high current regulator circuits experienced decreasing resistance causing some power supplies to latch off. The root cause of the resistance decrease was determined to be ion migration on the R-pac alumina substrate, under the passivation oxide layer. The main corrective action was the replacement of the relatively porous passivation oxide layer with an essentially nonporous and acid resistant passivation oxide layer View full abstract»

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  • Analysis and design of constant-frequency peak-current-controlled high-power-factor boost rectifier with slope compensation

    Page(s): 807 - 813 vol.2
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    This paper presents the analysis and the design of a peak-current-controlled high-power-factor boost rectifier, with slope compensation, operating at constant frequency. The input current shaping is achieved, with continuous inductor current mode, with no multiplier to generate a current reference. The resulting overall circuitry is very simple, in comparison with the average-current-controlled boost rectifier. Experimental results are presented, taken from a laboratory prototype rated at 370 W and operating at 67 kHz. The measured power factor was 0.99, with a input current THD equal to 5.6%, for an input voltage THD equal to 2.26% View full abstract»

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  • Fault tolerant distributed power

    Page(s): 671 - 677 vol.2
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    Redundant power systems are used where safety or power availability is critical. An alternate approach is proposed and compared to existing power system configurations. An example as applied to critical avionics on aircraft is presented, illustrating cost and weight savings in addition to improved power system performance. The reliability models, fault tolerant modular redundant systems and power distribution are discussed as is the proposed fault tolerant system View full abstract»

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  • High efficiency automotive power supply with hysteretic current mode controller

    Page(s): 861 - 868 vol.2
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    A switched mode power supply for an automotive power control module with a novel hysteretic current mode control (HCMC) controller is presented. The HCMC operation principle is described and a method of reducing switching frequency variation is analyzed. Experimental results and critical waveforms of the power switching regulator are shown. Several monitoring and indication functions are designed into the controller to interface with the rest of the system. The controller includes a linear regulator to provide power for memory registers while the system is in the “key-off” state View full abstract»

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  • Steady-state analysis of a voltage-fed inverter with second-order network and fluorescent lamp load

    Page(s): 609 - 615 vol.2
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    A new analysis method is presented for the steady-state response of electronic ballast circuits. The method gives closed-form expressions for dimming curves, inverter power factor, and circuit sensitivities. This paper applies the method to the voltage-fed inverter topology with second-order network View full abstract»

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  • An improved “charge pump” electronic ballast with low THD and low crest factor

    Page(s): 622 - 627 vol.2
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    The “charge pump” electronic ballast circuit, which employs a charging capacitor and a high frequency AC source to implement power factor correction (PFC), has become an attractive topology for ballasting fluorescent lamps because it eliminates the use of a bulky boost inductor. However, this circuit has the problems of high total harmonic distortion (THD) of the input current, and high crest factor (CF) of the lamp current. This paper analyzes the origin of the problems and proposes a novel solution. With the addition of two small clamping diodes, very good input current (PF>0.99, THD <5%) and lamp current (CF<1.6) can be obtained with open loop control. Experimental results are provided for verification View full abstract»

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  • Torque maximizing control of permanent magnet synchronous motor under voltage and current limitations of PWM inverter

    Page(s): 758 - 763 vol.2
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    A method to improve torque capability of surface mounted permanent magnet synchronous motors (SPMSM) in a higher speed region, where the back EMF of the motor is approaching to the voltage limit of a PWM inverter, is proposed. In this speed region, a voltage vector laid on the boundary of the hexagon limit of the voltage of a PWM inverter is selected to optimally use the capability of the inverter and motor. The voltage vector, which gives maximum torque under the limitation of voltage and current, is calculated at the given operating condition in real time. Experimental results show that the operation speed, by using the proposed method, can be extended to 45% compared to that of not using flux weakening scheme. Of flux weakening schemes, the speed by using this proposed method can be extended 5% to 13% View full abstract»

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  • Design considerations for an inverter output filter to mitigate the effects of long motor leads in ASD applications

    Page(s): 579 - 585 vol.2
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    In this paper, design considerations for an inverter output filter to mitigate the effects of long motor leads in ASD applications are presented. It is shown by analysis that for a given length of cable, reducing the dv/dt of the PWM inverter output voltage applied to the cable below a critical value will eliminate overvoltages due to voltage reflections. Design issues for a low pass filter at the inverter output terminals to reduce the dv/dt of the inverter output pulse are examined in detail. The filter operation is verified for the entire variable frequency range of the inverter. The performance of the filter is evaluated in simulation, and experimentally on a 208 V L-L system and on a 480 V commercially available AC motor drive (PWM IGBT). The proposed inverter output filter is then compared with a motor terminal shunt filter also designed to reduce overvoltages and ringing at the motor terminals View full abstract»

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  • Time quantity one-cycle control for power factor correctors

    Page(s): 821 - 827 vol.2
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    The time quantity one-cycle control method is proposed in this paper for unity power factor AC-DC converters. Converters controlled by this method operate at constant switching frequency, require no current sensing, have a simple control circuit, and exhibit purely resistive input impedance at the AC side. A feedback loop design method is provided to minimize the current distortion when the output voltage ripple is not negligible. Experimental results confirmed the theoretical prediction View full abstract»

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  • Hybrid solutions for improving passive filter performance in high power applications

    Page(s): 911 - 917 vol.2
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    This paper presents a new control scheme for a parallel hybrid active filter system intended for harmonic compensation of large nonlinear loads upto 20 MVA to meet IEEE 519 recommended harmonic standards. The control scheme is based on the concept of synthesizing a dynamically variable inductance and is used for an active filtering application. A synchronous reference frame based controller implements the dynamically varying, negative or positive inductance, by generating active filter inverter voltage commands. This controller based parallel hybrid active filter system can selectively synthesize multiple active inductances at dominant harmonic frequencies without affecting passive filter impedances at all other frequencies. The controller can be used to provide `current limiting' function to prevent passive filter overloading under ambient harmonic loads and/or supply voltage distortions. Three implementation variations of parallel hybrid active filter system are presented. This paper also proposes the use of power factor correction capacitors as passive filters for parallel hybrid active filter system, controlled to provide multiple tuned harmonic sinks and to increase cost-effectiveness for high power applications. Simulation results with both PWM and square-wave inverters validate the controller operation for mis-tuned passive filters, single and multiple frequency tuning, to achieve harmonic compensation of a 325 kVA harmonic load under supply voltage harmonics and ambient harmonic loads View full abstract»

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  • Self-commutated static flicker compensator for arc furnaces

    Page(s): 891 - 897 vol.2
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    To suppress a flicker that occurs in a power system with arc furnaces, the authors have developed a self-commutated static flicker compensator (SFC). To verify the SFC's compensation performance, the authors performed experiments with a mini-model and an analog simulator. As a result of these experiments, it was confirmed that the current deviation of the SFC output current was less than the desired value of 5%, and the response time of current control was about 1 ms. They also tested the flicker compensating effect with an actual SFC which was installed in a power system. The SFC achieved a flicker suppression factor of 36%, and has been operating trouble-free since April 1995 View full abstract»

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