• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부A
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• pp.117-120
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• 1998

This paper proposes a new high efficiency single-phase AC-DC boost converter for power factor correction. Lossless commutation circuit is interposed in the proposed converter for soft-switching. Due to this commutation circuit, the converter operates in 9 mode. In spite of changing input voltage and load, It attracts a constant DC output voltage because of the PWM control scheme using both the output voltage feedback and the input voltage feedforward. The converter is suitable for high power applications and operates in continuous conduction mode. In this paper, a 2.4[kW] converter is designed and simulated.

• 대한전자공학회논문지TE
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• 제37권3호
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• pp.66-71
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• 2000

다중 폴딩 스너버 망(folding snubber network)에 의하여 동작되는 새로운 형태의 영전압 영전류 스위칭 의사 공진형 컨버터를 제안한다. 이 새로운 컨버터는 기존의 의사 공진형 컨버터에 수동소자인 케패시턴스와 다이오드로 구성된 폴딩 스너버 망(folding snubber network)을 결합하여 구성된다. 컨버터의 주 정류 다이오드의 역 회복 손실(reverse recovery loss)은 다중공진 기법으로 억제된다. 이 제안된 컨버터는 매우 높은 효율을 구현하므로 고 출력에 매우 적합하다. 이 개념을 다른 컨버터에도 적용시켜 새로운 소프트 스위칭 의사 공진형 컨버터(soft switching quasi-resonance converter) 군을 할 수 있다.

• Journal of Power Electronics
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• 제19권2호
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• pp.431-442
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• 2019

This paper proposes a unified high-frequency bipolar buck-boost (UHFBB) control strategy for a dual-active-bridge (DAB), which is derived from the classical buck and boost DC/DC converter. It can achieve optimized current stress of the switches and soft switching in wider range. The UHFBB control strategy includes multi-control-variables, which can be achieved according to an algorithm derived from an accurate mathematical model. The design method for the parameters, such as the transformer turns ratio and the inductance, are shown. The current stress of the switches is analyzed for selecting an optimal inductor. The analysis is verified by the experimental results within a 500W prototype.

• Journal of Power Electronics
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• 제14권4호
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• pp.632-640
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• 2014

For low-power high-frequency LED driver applications in small form factor mobile products, a high-efficiency boundary conduction mode tapped-inductor boost converter is proposed. In the proposed converter, the switch and the diode achieve soft-switching, the diode reverse-recovery is alleviated, and the switching frequency is very insensitive to output voltage variations. The circuit is quantitatively characterized, and the design guidelines are presented. Experimental results from an LED backlight driver prototype for a 14 inch notebook computer are also presented.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제3B권3호
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• pp.147-154
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• 2003

This paper presents a high-frequency boost type ZVS-PWM chopper-fed DC-DC power converter with a single active auxiliary edge-resonant snubber at the load stage which can be designed for power conditioners such as solar photovoltaic generation, fuel cell generation, battery and super capacitor energy storages. Its principle operation in steady-state is described in addition to a prototype setup. The experimental results of boost type ZVS-PWM chopper proposed here, are evaluated and verified with a practical design model in terms of its switching voltage and current waveforms, the switching v-i trajectory and the temperature performance of IGBT module, the actual power conversion efficiency, and the EMI of radiated and conducted emissions, and then discussed and compared with the hard switching scheme from an experimental point of view. Finally, this paper proposes a practical method to suppress parasitic oscillation due to the active auxiliary resonant switch at ZCS turn-off mode transition with the aid of an additional lossless clamping diode loop, and can be reduced the EMI conducted emission.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2010년도 추계학술대회
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• pp.198-199
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• 2010

In this paper, bi-directional DC/DC converter using a LC series resonant converter is proposed. A proposed converter is consisted by adding LC series resonant tank into a conventional bi-directional DC/DC converter and performs soft-switching at both boost and buck mode. A LC series resonance occurs in whole operation mode and switching point is determined by specific condition. Through the theoretical analysis and simulation results, operation modes and characteristics of the proposed topology is verified.

• Journal of Electrical Engineering and Technology
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• 제12권6호
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• pp.2237-2246
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• 2017

A nonisolated two-phase bidirectional dc-dc converter (NTPBDC) is a very attractive solution for the battery energy storage system (BESS) applications due to the high voltage conversion ratio and the reduced conduction loss of the switching devices. However, a hard-switching based NTPBDC decreases the overall voltage conversion efficiency. To overcome this problem, this paper proposes a novel NTPBDC with zero-voltage-transition (NTPBDC -ZVT). The soft-switching for the boost and buck main switches is achieved by using a resonant cell, which consists of a single resonant inductor and four auxiliary switches. Furthermore, due to the single resonant inductor, the proposed NTPBDC-ZVT has the advantages of simple implementation, reduced size, and low cost. The validity of the proposed NTPBDC-ZVT is verified through experimental results.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2006년도 춘계학술대회 논문집
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• pp.387-390
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• 2006

This paper presents a novel soft-switching PWM utility frequency AC to high frequency AC power conversion circuit Incorporating boost-half-bridge inverter topology, which is more suitable and acceptable for cost effective consumer induction heating applications. The operating principle and the operation modes are presented using the switching mode and the operating voltage and current waveforms. The performances of this high-frequency inverter using the latest IGBTs are illustrated, which includes high frequency power regulation and actual efficiency characteristics based on zero voltage soft switching (ZVS) operation ranges and the power dissipation as compared with those of the previously developed high-frequency inverter. In addition, a dual mode control scheme of this high frequency inverter based on asymmetrical pulse width modulation (PWM) and pulse density modulation (PDM) control scheme is discussed in this paper in order to extend the soft switching operation ranges and to improve the power conversion efficiency at the low power settings. The power converter practical effectiveness is substantially proved based on experimental results from practical design example.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제52권12호
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• pp.632-640
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• 2003

In conventional Zero-Voltage-Transition(ZVT) PWM converters, zero-voltage turn-on and turn-off for main switch without increasing voltage/current stresses is achieved at a fixed frequency. The switching loss, stress, and noise, however, can't be minimized because they adopt auxiliary switches turned off under hard-switching condition. In this paper, new ZVS-PWM converters of which both active and passive switches are always operating with soft-switching condition are proposed. Therefore, the proposed ZVS-PWM converters are most suitable for avionics applications requiring high-power density. Breadboarded ZVS-PWM boost converters using power MOSFET are constructed to verify theoretical analysis.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.556-560
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• 2001

In this paper, a soft-switching discontinuous mode (DCM) power factor corrected (PFC) converter is analyzed by applying the double Fourier series expansion. It is found that the fundamental component and higher-order harmonics included in the input current waveform are obtained by the Fourier series expansion of the mean value of the inductor current. From the theoretical analysis, a new method removing the distortion of the input current waveform is proposed. In spite of an open loop system, the proposed method makes a great improvement of the total harmonic distortion even if the ratio of output voltage to input voltage is very low.