• 전기학회논문지
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• 제62권8호
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• pp.1101-1107
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• 2013

A light emitting diodes(LED) lighting has been increasingly used due to its low power consumption, long life time, high efficiency, and environment friendly characteristics. Also various power converters has been applied to drive these LED lighting. Among many power converters, a LLC resonant converter could be applied for LED lighting because of its high efficiency and high power density. Furthermore, the function of power factor correction(PFC) might be added. In this paper, 1-stage asymmetrical LLC resonant converter is proposed. The proposed converter performs both input-current harmonics reduction and PFC using the discontinuous conduction mode(DCM). The proposed 1-stage LLC resonant converter approach has the lower voltage stress across switching devices and achieve the zero voltage switching(ZVS) in switching devices. To verify the performance of the proposed converter, simulation and experimental results from a 300[W] prototype are provided.

• 조명전기설비학회논문지
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• 제22권7호
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• pp.7-15
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• 2008

A single active capacitor snubber-assisted soft-switching sinewave pulse modulation utility-interactive power conditioner with a three-winding flyback high frequency transformer link and a bidirectional active power switch in its secondary side has been proposed. With the aid of the switched-capacitor quasi-resonant snubber cell, the high frequency switching devices in the primary side of the proposed DC-to-AC sinewave power inverter can be turned-off with ZVS commutation. In addition to this, the proposed power conditioner in the DCM can effectively take the advantages of ZCS turn-on commutation. Its output port is connected directly to the utility AC power source grid. At the end, the prototype of the proposed HF-UPC is built and tested in experiment. Its power conversion conditioning and processing circuit with a high frequency flyback transformer link is verified and the output sinewave current is qualified in accordance with the power quality guidelines of the utility AC interactive power systems.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제53권10호
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• pp.610-617
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• 2004

This paper presents a novel high frequency generating circuit integrated chopper-inverter using ZVS with high power-factor. The proposed topology is integrated half-bridge boost rectifier as power factor corrector(PFC) and half-bridge high frequency resonant inverter into a single-stage. The input stage of the half-bridge boost rectifier works in discontinuous conduction mode(DCM) with constant duty cycle and variable switching frequency. So that a boost converter makes the line current follow naturally the sinusoidal line voltage waveform. Simulation results have demonstrated the feasibility of the proposed high frequency resonant inverter. Characteristics values based on characteristics analysis through circuit analysis is given as basis data in design procedure. Also, experimental results are presented to verify theoretical discussion. This proposed inverter will be able to be practically used as a power supply in various fields as induction heating applications. fluorescent lamp and DC-DC converter etc.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2018년도 전력전자학술대회
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• pp.24-26
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• 2018

본 논문은 Solid-state Marx modulator(SSMM)용 10kV, 1kW급 고전압 커패시터 충전기의 설계에 대해 기술한다. 직렬 공진형 인버터를 기반으로 Marx modulator용 충전기 구현을 위해 다수의 커패시터를 동시에 충전할 수 있도록 다단 변압기와 정류기를 사용하는 구조를 제안한다. 변압기 1차 권선으로 단일 턴의 고전압 케이블을 사용하여 설계하고, 작은 누설 인덕턴스만으로 공진 인덕터를 구현하기 위해 DCM(Discontinuous Conduction Mode)를 기반으로 공진 파라메터를 설계한다. 6개의 환형 코어에 각각 2개의 2차 권선을 권취하고 각 2차 권선은 배전압 정류회로와 연결되어 총 24개의 커패시터를 각각 417V로 동시에 충전할 수 있도록 설계한다. 본 논문에서는 DCM영역에서 동작하는 직렬공진형 컨버터의 공진 파라메터 상세 설계에 대하여 기술하고, 24개의 커패시터 직렬 결선을 통한 10kV, 1kW 정격운전 시뮬레이션 및 실험결과를 통해 제안된 회로를 검증한다.

• 한국조명전기설비학회지:조명전기설비
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• 제7권1호
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• pp.30-36
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• 1993

본 연구는 정류기의 입력전류에 포함되어 있는 고조파성분을 제거하고 입력역률을 개선하기 위해 무손실 저항(Loss Free Resistor) 개념에 기본을 둔, PC, 가전기기 및 형광등용 전자안정기등과 같은 저전력 전원설비에 적합한 불연속 도통모드(DCM) 플라이백 방식의 능동역률 보정기의 등가회로모델 및 설계법을 제시하였다. 이 개념에 의하여 능동역률 보정기의 등가입력저항, 출력전력원 특성을 정확하게 나타낼 수 있었으며 또 설계방정식을 유도하여 능동역률 보정기를 설계 시험한 결과, 적은 부품으로 정류기의 입력교류 전류에 포함되어 있는 고주파를 제거하였고 따라서 0.98의 고입력역률의 정류를 할 수 있었다.

• Journal of Power Electronics
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• 제12권6호
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• pp.960-973
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• 2012

The winding loss analysis of a flyback transformer is difficult and ambiguous because the primary side current and the secondary side current differs both in shape and phase, especially for DCM (Discontinuous Conduction Mode) operation. Meanwhile, the fringing field caused by the air gaps further makes the traditional 1-D loss analysis model not directly applicable. The paper gives a thorough investigation into the phase shift of winding currents, which indicates that the phase shift of the high order harmonics is still close to $180^{\circ}$ out-of-phase. Based on the analysis, a simplified 2-D winding loss analytical model for flyback transformers considering the effects of low order harmonics is proposed. By neglecting the y components of the fringing field, the proposed model has an acceptable accuracy and a simple form that is similar to the conventional 1-D model. The power loss calculated with the proposed analysis model is verified by FEA (Finite Element Analysis) simulations and experimental results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.29-31
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• 2011

본 논문은 압전 폴리머를 이용한 마이크로 에너지 포집 시스템을 설계하여 신발에 접목하고, 보행자의 운동에너지로부터 발생한 전기에너지를 포집하여 원하는 부하를 구동하는 시스템을 제시한다. 또한, 시스템으로부터 발생된 전기에너지를 축전지에 저장하고, 최대 에너지 전력점을 보증하기 위하여 전류 불연속 모드(DCM; discontinuous conduction mode)로 동작하는 벅-부스트 컨버터를 이용한다. 즉, 본 논문은 압전 폴리머와 전류 불연속 모드로 동작하는 벅-부스트 컨버터를 이용한 마이크로 에너지 포집 시스템을 설계하여 실험을 통해 본 논문에서 제시한 시스템의 타당성 및 본 논문에서 제안한 자가발전 신발을 위한 적용가능성을 확인한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.318-320
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• 2003

This paper presents a novel single-stage high frequency resonant 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 a high power factor is achieved naturally. Simulation results through the Pspice 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.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2002년도 학술대회논문집
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• pp.287-291
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• 2002

This paper presents active-clamp class-E high frequency resonant inverter with single-stage. The proposed circuit is integrated active-clamp class-E circuit to boost converter with the function of power factor correction. Boost converter is operated in positive and negative half cycle respectively at line frequency(60Hz), Such a operating in discontinuous conduction mode(DCM) of boost converter performs high power factor. By adding active-clamp circuit in class-E inverter, main switch of inverter part is operated not only ZVS(Zero Voltage Switch) but also reduced the switching voltage stress of main switch. This paper shows that simulation result using Psim 4.1 prove the validity of theoretical analysis. This proposed inverter 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 2004년도 전력전자학술대회 논문집(2)
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• pp.547-550
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• 2004

An interleaved single-stage power-factor-correction (PFC) AC/DC converter is presented in this paper. The proposed converter is combined by two single-stage AC/DC converters based on flyback converter Each PFC stage operates in discontinuous conduction mode (DCM). By exploiting the interleaving technique, the input ripple current and output ripple voltage are reduced. The proposed converter complied with EN/1EC61000-3-2 harmonic regulations achieves high efficiency and low cost. The performance of the proposed converter was evaluated on a 180W $(90W\times2,\;24V,\;7.5A)$ experimental prototype.