• 전력전자학회:학술대회논문집
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• 전력전자학회 2005년도 전력전자학술대회 논문집
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• pp.289-291
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• 2005

In this paper results of the experiment which used LLC resonant half bridge DC-DC converter to a portable electrical equipment. LLC resonance Half Bridge DC-DC converter which was used in this experiment improved an efficiency because it reduced switching, conduction losses and with synchronous rectifier. As a result of the experiment, this proposed converter could verified an increase of 2% to the efficiency more than diode rectifier.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2007년도 하계학술대회 논문집
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• pp.147-149
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• 2007

A new half bridge converter without DC offset of magnetizing current is proposed. The proposed half bridge converter can realize no DC offset of magnetizing current as well as no circulating current, and guarantee ZVS operation. Therefore it has high efficiency and high power density, especially in wide input range. The operational principle, DC conversion ratio and ZVS analysis are presented. Experimental results demonstrate that the proposed converter can achieve a significant improvement in the efficiency.

• Journal of Electrical Engineering and Technology
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• 제10권1호
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• pp.271-279
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• 2015

Induction cooking application with multiple loads need high power inverters and appropriate control techniques. This paper proposes an inverter configuration with buck-boost converter for multiple load induction cooking application with independent control of each load. It uses one half-bridge for each load. For a given dc supply of $V_{DC}$, one more $V_{DC}$ is derived using buck-boost converter giving $2V_{DC}$ as the input to each half-bridge inverter. Series resonant loads are connected between the centre point of $2V_{DC}$ and each half-bridge. The output voltage across each load is like that of a full-bridge inverter. In the proposed configuration, half of the output power is supplied to each load directly from the source and remaining half of the output power is supplied to each load through buck-boost converter. With buck-boost converter, each half-bridge inverter output power is increased to a full-bridge inverter output power level. Each half-bridge is operated with constant and same switching frequency with asymmetrical duty cycle (ADC) control technique. By ADC, output power of each load is independently controlled. This configuration also offers reduced component count. The proposed inverter configuration is simulated and experimentally verified with two loads. Simulation and experimental results are in good agreement. This configuration can be extended to multiple loads.

• 전력전자학회논문지
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• 제10권1호
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• pp.78-86
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• 2005

최근 들어, 저전압·대전류 출력 특성을 갖는 연료전지를 위한 새로운 발전시스템이 주목받고 있다. 연료전지 발전시스템에서는 dc-dc 승압용 컨버터와 dc-ac 인버터가 필요하다. 그러므로 본 논문에서는 연료전지 발전시스템을 위한 ZVS 동작을 가진 dc-dc 능동 클램프 전류형 하프 브리지 컨버터를 제안하였다. 제안된 컨버터는 일반적인 dc-dc 컨버터에 비해 높은 효율과 높은 소자 이용율을 가진다. 연료전지 발전시스템은 연료전지(PEMFC)의 낮은 전압(28∼43[Vdc])을 380[Vdc]로 승압하기 위한 능동 클램프 전류형 하프 브리지 컨버터로 구성하였다. 단상 풀 브리지 인버터는 220[Vac], 60[Hz] 교류 출력을 얻기 위해 적용하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 B
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• pp.1190-1192
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• 2003

This paper presents a novel single-stage high frequency resonant inverter link type DC-DC converter using zero voltage switching with high input power factor. The proposed high frequency resonant converter integrates half-bridge boost rectifier as power factor corrector (PFC) and half-bridge resonant converter into a single stage. The input stage of the half-bridge boost rectifier is working in discontinuous conduction mode(DCM) with constant duty cycle and variable switching frequency. So that boost converter make the line current follow naturally the sinusoidal line voltage waveform. Experimental results have demonstrated the feasibility of the proposed DC-DC converter. This proposed converter will be able to be practically used as a power supply in various fields as induction heating applications, DC-DC converter etc.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2006년도 전력전자학술대회 논문집
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• pp.251-253
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• 2006

This paper presents a start-up in-rush current reduction technique of asymmetry half-bridge DC/DC converter for PC power supply. The proposed converter is composed center-tapped half-bridge converter with blocking capacitor. The proposed converter can reduce the severe in-rush current when the proposed converter is power up. The validity of this study is confirmed from the experimental results.

• Journal of Electrical Engineering and Technology
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• 제2권1호
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• pp.89-97
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• 2007

This paper presents a new circuit topology of active edge resonant snubbers assisted half-bridge soft switching PWM inverter type DC-DC high power converter for DC bus feeding power plants. The proposed DC-DC power converter is composed of a typical voltage source-fed half-bridge high frequency PWM inverter with a high frequency planar transformer link in addition to input DC busline side power semiconductor switching devices for PWM control scheme and parallel capacitive lossless snubbers. The operating principle of the new DC-DC converter treated here is described by using switching mode equivalent circuits, together with its unique features. All the active power switches in the half-bridge arms and input DC buslines can achieve ZCS turn-on and ZVS turn-off commutation transitions. The total turn-off switching losses of the power switches can be significantly reduced. As a result, a high switching frequency IGBTs can be actually selected in the frequency range of 60 kHz under the principle of soft switching. The performance evaluations of the experimental setup are illustrated practically. The effectiveness of this new converter topology is proved for such low voltage and large current DC-DC power supplies as DC bus feeding from a practical point of view.

• 전력전자학회논문지
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• 제16권3호
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• pp.293-301
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• 2011

본 논문에서는 정류용 브릿지 다이오드가 없는 고효율 하프 브릿지 AC-DC 컨버터를 제안한다. 제안하는 컨버터는 비대칭 펄스 폭 변조 방식의 하프 브릿지 DC-DC 컨버터와 정류용 브릿지 다이오드가 없는 역률 개선 회로가 통합된 회로 구조를 지닌다. 제안하는 컨버터는 정류용 브릿지 다이오드를 사용하지 않고 교류 입력 전압으로부터 절연된 직류 출력 전압을 공급한다. 간단한 회로 구조와 함께 도통 손실을 줄일 수 있다. 또한 스위칭 소자들의 영전압 스위칭을 통하여 스위칭 손실을 줄일 수 있다. 두 개의 직렬 연결된 트랜스포머를 구비함으로서 프로파일을 낮추고 전력밀도를 높일 수 있다. 250 W (48 V / 5.2 A) 회로 설계 및 실험을 통하여 제안된 컨버터의 성능을 $90 \;V_{rms}$ 교류 입력 전압에 대하여 입증하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 하계학술대회 논문집 A
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• pp.516-518
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• 1994

A new class of zero-voltage switching (ZVS) pulse width modulated (PWM) half-bridge converter is investigated. The new converter is capable of switching zero voltage and keeping advantages of quasi-resonant half-bridge converter while maintaining constant frequency operation. The theoretical analysis of a ZVS PWM half bridge converter is presented and is verified by PSPICE simulation results.

• 전기학회논문지P
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• 제63권4호
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• pp.345-350
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• 2014

DC electrolytic capacitor is widely used in the power converter including PWM inverter, switching power supply and PFC Boost converter system because of its large capacitance, small size and low cost. In this paper, basic characteristics of DC electrolytic capacitor vs. frequency is presented and the real-time estimation scheme of ESR and capacitance based on the bandpass filtering is adopted to the single phase boost converter of uninterruptible power supply to diagnose its split dc-link capacitors. The feasibility of this real-time failure prediction monitoring system is verified by the computer simulation of the 5[kW] singe phase PFC half-bridge boost converter.