• Journal of Power Electronics
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• 제2권4호
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• pp.278-287
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• 2002

A novel zero-voltage and zero-current switching PWM DC-DC converter with lowered conduction losses is presented in this paper. A new double two-switch forward high frequency transformer type soft-switching converter topology is developed to minimize circulating currents occurs during freewheeling period. This converter has advantages as less number of the components, simple control principle under constant operation frequency, free of transformer Imbalance effect. The principle of operation is illustrated with steady-state analysis. Moreover, the effectiveness of the proposed converter topology is verified by implementation of a 500w-100kHz breadboard using IGBTs.

• 전력전자학회논문지
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• 제16권2호
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• pp.114-121
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• 2011

본 논문에서는 고승압.대전력 응용에 적합한 소프트스위칭 인터리빙 부스트 컨버터를 제안한다. 제안하는 컨버터는 동일 듀티로 기존 부스트 컨버터보다 약 2배의 승압비를 얻을 수 있고 스위치와 다이오드의 전압정격은 약 1/2로 감소되어 $R_{DS(ON)}$과 전압 강하가 작은 소자 사용으로 도통손실을 감소시킬 수 있다. 또한 수동소자의 전압정격이 감소되어 전체 에너지량도 1/2로 감소된다. 더욱이 CCM에서도 스위치의 ZVS 턴온이 가능하고 다이오드의 ZCS 턴오프 동작으로 역방향 회복에 의한 서지가 거의 없어 스위칭 손실이 감소된다. 2kW의 시작품으로 제안하는 컨버터의 타당성을 검증하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.687-693
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• 1998

An improved zero voltage and zero current switching (ZVZCS) full bridge (FB) PWM converter is proposed to solve the problems of the previously presented ZVACS-FB-PWM converter with secondary active clamp such as narrow ZVS range of leading-leg switches [6]. By adding an auxiliary inductor in between the leading-leg and separated input source voltages, the ZVS of leading leg switches can be extended to the whole line and load ranges, which eliminates unwanted hard switching of clamp switch and simplifies its control. The principle of operation is explained and analyzed. The features and design considerations of the proposed converter are also illustrated and verified on a 3 kW, 100 KHz IGBT based experimental circuit.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제49권10호
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• pp.683-692
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• 2000

A new primary-side-assisted zero-voltage and zero-current switching full bridge DC-DC converter with transformer isolation is proposed. The auxiliary circuit adopted to assist ZCS for the leading leg is composed of only one small transformer and two diodes. It has a simple and robust structure, and load current control capability even in short circuit conditions. Possibility of magnetic saturation due to asymmetricity of circuits or transient phenomena is greatly reduced, which is a very attractive feature in DC/DC converters with transformer isolation. The power rating of the auxiliary transformer is about 10% of that of the main transformer. Operation of a 12.5KW prototype designed for welding application was verified by experiments.

• Journal of Power Electronics
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• 제19권5호
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• pp.1182-1192
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• 2019

In order to improve the conversion efficiency and mitigate the EMI problem of conventional hard-switching inverters, a new soft-switching DC-AC inverter with a compact structure and a low modulation complexity is proposed in this paper. In the proposed structure, resonant inductors are connected in series for the arm branches, and resonant capacitors are connected in parallel for the neutral point branches. With the help of resonant components, the proposed structure achieves zero-current switching on the arm branches and zero-voltage switching on the neutral point branches. When compared with state-of-art soft-switching topologies, the proposed topology does not need auxiliary switches. Moreover, the commutation algorithm to realize soft-switching can be easily implemented. In this paper, the principle of the resonant operation of the proposed soft-switching converter is presented and its performance is verified through simulation studies. The feasibility of the proposed inverter is evaluated experimentally with a 2.4-kW prototype.

• Journal of Power Electronics
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• 제19권6호
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• pp.1413-1428
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• 2019

In this paper, a novel zero-voltage and zero-current switching (ZVZCS) interleaved two switch forward converter is proposed. By using a coupled-inductor-type smoothing filter, a snubber capacitor, the parallel capacitance of the leading switches and the transformer parasitic inductance, the proposed converter can realize soft-switching for the main power switches. This converter can effectively reduce the primary circulating current loss by using the coupled inductor and the snubber capacitor. Furthermore, this converter can reduce the reverse recovery loss, parasitic ringing and transient voltage stress in the secondary rectifier diodes caused by the leakage inductors of the transformer and the coupled inductance. The operation principle and steady state characteristics of the converter are analyzed according to the equivalent circuits in different operation modes. The practical effectiveness of the proposed converter was is illustrated by simulation and experimental results via a 500W, 100 kHz prototype using the power MOSFET.