• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 A
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• pp.537-539
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• 1996

In this paper, a design method of the phase shift ZVS-PWM converter is proposed to minimize the volume and increase the efficiency. The trade-offs of switching frequency, efficiency vs volume and ZVS range vs efficiency is also presented. The simulation of the designed converter is performed using the P-SPICE in which a phase-shift controller is proposed. For minimization of the converter volume, switching frequency is selected 100kHz, a simple drive circuit and single auxiliary supply are applied. In consideration of efficiency and load condition, ZVS range is decided from 50% to full load. A 28V, 1Kwatt prototype converter, of which the switch is MOSFET is made, verified the performance.

• Journal of Advanced Marine Engineering and Technology
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• 제39권3호
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• pp.286-291
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• 2015

Nd:YAG 레이저의 출력조절을 위하여 LLC 공진 컨버터를 사용하였다. ZVS(Zero Voltage Switching) 방식을 LLC 공진형 컨버터에 적용함으로써 스위칭 손실을 최소화하였다. 금속박막의 점용접과 같은 레이저가공에 있어서 단일 펄스에 대한 출력에너지가 가공특성을 결정하므로, 적절한 목표출력으로 단일펄스 당 50 [J]로 결정하였다. 따라서 레이저 출력은 출력전류를 변화시켜가면서 측정하고 분석하였다. 이 때, 전류는 커패시터의 충전전압의 크기에 따라 변한다. 이러한 결과로부터 충전 커패시터의 용량 12,000 [${\mu}F$], 반복율이 1 [Hz]일 때, 방전전압 620 [V], 방전전류 861 [A]에서 58.2 [J]의 레이저빔 최대 출력을 얻음으로써 전기에너지 입력에 대한 레이저빔 출력에너지 변환효율은 2.52%를 달성하였다.

• 전기학회논문지
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• 제56권2호
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• pp.301-310
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• 2007

Bidirectional DC-DC converters allow transfer of power between two dc sources, in either direction. Due to their ability to reverse the direction of flow of power, Dey are being increasingly used in many applications such as battery charge/dischargers, do uninterruptible power supplies, electrical vehicle motor drives, aerospace power systems, telecom power supplies, etc. This Paper Proposes a new bidirectional Sepic/Zeta converter. It has low switching loss and low conduction loss due to auxiliary communicated circuit and synchronous rectifier operation, respectively Because of positive and buck/boost-like DC voltage transfer function(M=D/1-D), the proposed converter is very desirable for use in distributed power system. The proposed converter also has both transformer-less version and transformer one.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 A
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• pp.365-367
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• 1995

This paper is concerned on developing low-voltage high-current DC-DC converter using FB-ZVS PWM Converter. The converter output is 28V, 100A and regulated by phase-shift control method. IGBT is used by the main switching device and high frequency transformer is made for operating at 30kHz switching frequency. When the load vary widely, converter's ZVS characteristic is expressed by experiment result.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.320-323
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• 2001

A ZVZCS(Zero-Voltage and Zero-Current-Switching) Three Level DC/DC Converter is presented to secondary auxiliary circuit. The converter presented in this paper used a phase shift control with a flying capacitor in the primary side to achieve ZVS for the outer switch. A secondary auxiliary circuit, which consists of one small capacitor and two small diode, is added in the secondary to provides ZVZCS conditions to primary switches, and aids to clamp secondary rectifier voltage. The auxiliary circuit Includes neither lossy component nor addition active switch, which makes the proposed converter efficient and effective. The principle of operation, feature, and design considerations are illustrated and verified through the experiment with a 500W 50kHz prototype converter.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2008년도 하계학술대회 논문집
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• pp.523-525
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• 2008

Novel zero-voltage switching(ZVS) dual inductor-fed DC-DC converter integrating a conventional dual inductor-fed boost converter(DIFBC) and a parallel bidirectional boost converter has been proposed. Most of current-fed type boost topologies including dual inductor schemes have crucial defects such as a high voltage spike on the main switch when it comes to turning off, an unattainable soft start-up due to the limited range of duty ratio, above 50%, and considerable switching losses due to the hard switching. By adding two auxiliary switches and an output capacitor on the conventional DIFBC, the proposed circuit can solve mentioned problems and improve the efficiency with simple methods. The operational principle and theoretical analysis of the proposed converter have been included. Experimental results based on a 42V input, 400V/1A output and 50kHz prototype are shown to verify the proposed scheme.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술대회 논문집 전문대학교육위원
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• pp.158-161
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• 2003

A new soft switching technique that improves performance of the high power factor boost rectifier by reducing switching losses is introduced. The losses are reduced by air active snubber which consists of an inductor, a capacitor a rectifier, and an auxiliary switch. Since the boost switch turns off with zero current, this technique is well suited for implementations with insulated gate bipolar transistors. The reverse recovery related losses of the rectifier are also reduced by the snubber inductor which is connected in series with the boost switch and the boost rectifier. In addition, the auxiliary switch operates with zero voltage switching. A complete design procedure and extensive performance evaluation of the proposed active snubber using a 1.2[kW] high power factor boost rectifier operating from a $90[V_{rms}]$ input are also presented.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2010년도 하계학술대회 논문집
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• pp.572-573
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• 2010

본 논문은 30kW급 CCPS(Capacitor Charging Power Supply)용 FB(Full Bridge)-PS(Phase Shift)- Zero Voltage Switching(ZVS) DC/DC Converter의 스위칭 손실저감을 위한 스너버 커패시터의 설계에 대해 논하였다. FB-PS-ZVS DC-DC 컨버터의 하드스위칭 손실과 스너버 커패시터에 의한 스위칭 손실 저감 효과를 비교했다. 첨두 전류를 이용하여 스너버 커패시터를 설계하였으며, 부하 실험을 통해 설계의 타당성을 실험적으로 검증했다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.79-84
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• 1998

A novel zero voltage and zero current switching (ZVZCS) full bridge (FB) PWM converter with low output current ripple is presented. A simple auxiliary circuit added in the secondary provides ZVZCS conditions to primary switches, ZVS for leading-leg switches and ZCS for lagging-leg switches, as well as reduces the output current ripple (ideally zero ripple). The auxiliary circuit includes neither lossy components nor additional active switches which are demerits of the previously presented ZVZCS converters. Many advantages including simple circuit topology, high efficiency, low cost and low current ripple make the new converter attractive for high performance high power (＞1kW) applications. The principle of operation, features and design considerations are illustrated and verified on a 2.5kW, 100KHz IGBT based experimental circuit.

• Journal of Power Electronics
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• 제19권1호
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• pp.11-23
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• 2019

In this study, a novel zero voltage zero current transition (ZVZCT) bidirectional DC-DC converter is proposed by employing coupled inductors. This converter can turn the main switch on at ZVZCT and it can turn it off with zero voltage switching (ZVS) for both the boost and buck modes. These characteristics are obtained by using a simple auxiliary sub-circuit regardless of the power flow direction. In the boost mode, the auxiliary switch achieves zero current switching (ZCS) turn-on and ZVS turn off. Due to the coupling inductors, this converter can make further efficiency improvements because the resonant energy in the capacitor or inductor can be transferred to the load. The main diode operates with ZVT turn-on and ZCS turn-off in the boost mode. For the buck mode, there is a releasing circuit to conduct the currents generated by the magnetic flux leakage to the output. The auxiliary switch turns on with ZCS and it turns off with ZVT. The main diode also turns on with ZVT and turns off with ZCS. The design method and operation principles of the converter are discussed. A 500 W experimental prototype has been built and verified by experimental results.