• Journal of Power Electronics
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• v.5 no.2
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• pp.99-103
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• 2005

In this paper, a novel circuit topology of a three-winding coupling inductor-assisting a high-frequency PWM boost chopper type DC-DC power converter with a high boost voltage conversion ratio and low switch voltage stress is proposed for the new energy interfaced DC power conditioner in solar photovoltaic and fuel cell generation systems. The operating principle in a steady state is described by using its equivalent circuits under the practical condition of energy processing of a lossless capacitive snubber. The newly-proposed power MOSFET boost chopper type DC-DC power converter with the three-winding coupled inductor type transformer and a single lossless capacitor snubber is built and tested for an output power of 500W. Utilizing the lower voltage and internal resistance power MOSFET switch in the proposed PWM boost chopper type DC-DC power converter can reduce the conduction losses of the active power switch compared to the conventional model. Therefore, the total actual power conversion efficiency under a condition of the nominal rated output power is estimated to be 81.1 ％, which is 3.7％ higher than the conventional PWM boost chopper DC power conversion circuit topology.

• Proceedings of the KIPE Conference
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• 2017.11a
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• pp.21-22
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• 2017

본 논문에서는 새로운 액티브 스너버 셀을 적용한 부스트 컨버터를 제안한다. 제안하는 컨버터의 메인 스위치는 ZVS 턴 온 및 오프, 보조회로 스위치는 ZCS 턴 온 및 ZVS 턴 오프하며 모든 다이오드는 ZCS 턴 오프를 성취한다. 또한, 제안하는 컨버터는 고전력 응용을 위한 인터리빙 기법으로 구현이 용이하다. 따라서 PWM 컨버터의 전력밀도와 효율을 높이고 EMI 노이즈를 줄일 수 있다. 제안하는 컨버터의 타당성을 검증하기 위해 600W/100kHz의 프로토 타입을 제작하여 실험을 진행하였다.

• Journal of Power Electronics
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• v.6 no.1
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• pp.1-7
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• 2006

This paper is a record of the study on a high efficiency and high power chopper based on the new soft switching method QRAS (Quasi~resonant Regenerating Active Snubber) designed for a Fuel Cell Electric Vehicle (FCEV). This power chopper is basically proposed for 25kHz soft switching. To confirm the practicality and effectiveness of the converter, the fabrication of a prototype-model using IGBTs was completed. Additionally, a 8kW rating test, a light load test, a current discontinuous mode test and a stable operation resonance test was completed. The circuit geometry, the basic operation, and the 8kW one-tenth-prototype test results are reported with a $97.5\%$ efficiency measurement.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.237-239
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• 2017

The isolated boost DC-DC converter based on three switches in fuel cell applications is presented in this paper. The major advantages of the proposed converter are as follows: continuous input current; decrease one active switch and no use snubber circuit. The operating principles and analysis of the proposed converter have been discussed. A 400 W prototype has been tested in the laboratory to verify the performance of the proposed converter and a PID controller was used to clarify the DC output voltage at 400 V. The simulation and experimental results are shown to validate the theoretical analysis.

• Journal of Electrical Engineering and Technology
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• v.1 no.2
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• pp.216-225
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• 2006

This paper presents a new circuit topology of DC busline switch and snubbing capacitor-assisted full-bridge soft-switching PWM inverter type DC-DC power converter with a high frequency link for low voltage large current applications as DC feeding systems, telecommunication power plants, automotive DC bus converters, plasma generator, electro plating plants, fuel cell interfaced power conditioner and arc welding power supplies. The proposed power converter circuit is based upon a voltage source-fed H type full-bridge high frequency PWM inverter with a high frequency transformer link. The conventional type high frequency inverter circuit is modified by adding a single power semiconductor switching device in series with DC rail and snubbing lossless capacitor in parallel with the inverter bridge legs. All the active power switches in the full-bridge inverter arms and DC busline can achieve ZVS/ZVT turn-off and ZCS turn-on commutation operation. Therefore, the total switching losses at turn-off and turn-on switching transitions of these power semiconductor devices can be reduced even in the high switching frequency bands ranging from 20 kHz to 100 kHz. The switching frequency of this DC-DC power converter using IGBT power modules is selected to be 60 kHz. It is proved experimentally by the power loss analysis that the more the switching frequency increases, the more the proposed DC-DC converter can achieve high performance, lighter in weight, lower power losses and miniaturization in size as compared to the conventional hard switching one. The principle of operation, operation modes, practical and inherent effectiveness of this novel DC-DC power converter topology is proved for a low voltage and large current DC-DC power supplies of arc welder applications in industry.