• Journal of Advanced Marine Engineering and Technology
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• 제22권5호
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• pp.617-625
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• 1998

A passive energy recovery snubber for high-power-factor boost rectifier, in which the main switch is implemented with a MOSFET, is described in terms of the equivalent circuits that are operational during turn-on and turn-off sequences. These equivalent circuits are analyzed so that the overshoot voltage across the main switch, the snubber current, and the turn-off transition time can be predicted analytically. From these results, the normalized overshoot voltage is reduced to 1 as $_W2T_on$ varies from zero to $\pi$/2, and then it is fIxed at 1 for $_W2T_on$> $\pi$/2. The peak snubber inductor current is directly proportional to the input current. The turn-offtransition time wltoffvaries from 0 to 2.57, depending on $_W2T_on$. The main switch combined with proposed snubber can be turned on with zero current and turned off at limited voltage stress. The high-power-factor boost rectifier with proposed snubber is implemented, and the experimental results are presented to confirm the validity of proposed snubber.

• 전력전자학회논문지
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• 제27권3호
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• pp.247-255
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• 2022

This paper proposes a multiphase interleaved zero-voltage-transition boost converter with a single soft-switching cell for high-voltage DC-DC converter (HDC) of fuel cell systems. The proposed single soft-switching cell structure can reduce the system volume by minimizing the passive and active elements added even in the multiphase-interleaved structure. To analyze the feasibility of the proposed structure, this paper mathematically analyzes the operation modes of the converter with the proposed single soft-switching cell structure and presents guidelines for design and considerations. In addition, the feasibility of the 210[kW] HDC was confirmed through PSIM simulation, and the system volume reduction of up to 10.48% was confirmed as a result of the 5[kW] HDC test-bed experiment considering the fuel cell system. Through this, the validity of the proposed structure was verified.

• Journal of Power Electronics
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• 제17권6호
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• pp.1422-1432
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• 2017

This paper presents a buck-boost converter-based bipolar pulse generator, which is able to generate bipolar exponential pulses across a resistive load. The concept of the proposed approach depends on operating the involved buck-boost converters in discontinuous current conduction mode with high-voltage gain and enhanced efficiency. A full design of the pulse generator and its passive components is presented to ensure generating the pulses with the desired specifications (rise time, pulse width, and pulse magnitude) for a given load resistance and input dc voltage. In case of moderate pulsed output voltages (i.e. few of kV), one module of the presented bipolar generator can be employed. While in case of high-voltage pulsed output, multi-module version can be employed, where each module is fed from an isolated dc source and their outputs are connected in series. Simulation models for the proposed approach are built to elucidate their performance in case of one-module as well as multi-module based generator. Finally, a scaled-down prototype for one-module of buck-boost converter-based bipolar pulse generator is implemented to validate the proposed concept.

• 전력전자학회논문지
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• 제14권3호
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• pp.211-219
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• 2009

이 논문에서는 단일 스위치를 사용하여 영전류 또는 영전압 스위칭 하는 부스트 컨버터를 기술하였다. 제안된 토폴로지는 소프트스위칭 함으로써 IGBT소자의 스위칭 손실을 감소시킬 수 있다. 이에 따라 수동소자의 크기와 무게를 줄일 수 있다. 모드 해석을 근거로 하여 실제적인 고려되어야할 설계를 제시하였다. 컨버터 토폴로지 동작원리를 설명하고 PSIM 소프트웨어 설계를 통하여 시뮬레이션 결과를 확인하였다. 제안된 컨버터의 성능은 30kHz에서 동작하는 1kW(400V, 2.5A) 실험실수준 레벨에서 증명하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2008년도 하계학술대회 논문집
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• pp.28-30
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• 2008

This paper proposes soft switching boost converter operating in zero current switching(ZCS) mode for photovoltaic and fuel cell power generation. The proposed topology is capable of reducing the size, and capability of passive element by using soft switching, and it allows for reduction of IGBT switching losses, for the increased of switching frequency. A detail mode analysis of operating in presented. We present the converter topology, principle of operation and simulation results obtained from the PSIM simulator. The performance of the proposed technique in evaluation on 1kW(380V,2.6A) experimental prototype circuit operating at 30kHz.

• 한국산업정보학회논문지
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• 제22권2호
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• pp.71-78
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• 2017

본 논문에서는 휴대기기용 DC-DC 부스트 컨버터를 설계하였다. 제안하는 DC-DC 부스트 컨버터는 1MHz의 스위칭 주파수로 구동되며, 인덕터, 출력 커패시터, MOS 트랜지스터 등으로 이루어지는 파워단 부분과 보호회로단, 컨트롤블럭단으로 구성하였다. CMOS magnachip $0.18{\mu}m$ 공정을 이용하여 SPICE 모의실험을 통하여 동작을 확인하였고, 칩을 제작하여 모의실험결과와 비교 분석하였다. 설계된 컨버터는 3.3 V 입력 전압 조건에서 출력전압 4.8 V 가 나타났고, 출력전류 95 mA 로 기존의 25~50 mA보다 큰 출력을 얻었다.

• 전력전자학회논문지
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• 제14권4호
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• pp.315-322
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• 2009

기존의 부스트 컨버터는 출력 전압이 커질수록 스위치와 다이오드의 전압, 전류 스트레스가 커지고 다이오드 역 방향회복에 의한 서지로 인해 실제 사용 가능한 승압비가 제한된다. 본 논문에서는 고승압 응용에 적합한 새로운 비절연 부스트 컨버터를 제안한다. 제안한 컨버터는 듀티비 0.5로 약 6배의 승압비를 가지며 CCM에서도 ZVS 스위칭이 가능하므로 넓은 ZVS 영역을 갖는다. 또한 스위치와 다이오드 전압정격이 출력전압의 1/3로 작고 인터리빙이 가능하여 입출력 수동소자의 정격도 작다. 다이오드도 ZCS 턴오프 동작으로 인해 역방향 회복에 의한 서지가 거의 없다. 제안하는 컨버터의 동작원리를 설명하였고 이론적 해석과 시뮬레이션 및 실험을 통해 타당성을 검증하였다.

• 전력전자학회논문지
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• 제6권3호
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• pp.243-249
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• 2001

본 논문에서는 전파형 ZVT-PWM 승압형 컨버터를 제안한다. 보조 스위치를 전파형 모드에서 동작을 시킴으로써, 기존의 컨버터에서 보조 스위치가 턴-오프 순간에 하드 스위칭(hard switching)을 하는 반면에 제안된 컨버터는 수동 및 능동 소자를 추가하지 않고 보조 스위치의 턴-오프 손실과 스위칭 잡음(noise)을 줄였고 그리고 고전력 밀도 시스템을 구현할 수 있다.

• 공학기술논문지
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• 제5권4호
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• pp.349-353
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• 2012

Recently, Mobile multimedia equipments as smart phone and tablet pc requirement is increasing and this market is also being expanded. These mobile equipments require large multi-media function, so more power consumption is required. For these reasons, the needs of power management IC as switching type dc-dc converter and linear regulator have increased. DC-DC buck converter become more important in power management IC because the operating voltage of VLSI system is very low comparing to lithium-ion battery voltage. There are many people to be concerned about digital DC-DC converter without using external passive device recently. Digital controlled DC-DC converter is essential in mobile application to various external circumstance. This paper proposes the DC-DC Buck Converter using the AVR RISC 8-bit micro-processor control. The designed converter receives the input DC 18-30 [V] and the output voltage of DC-DC Converter changes by the feedback circuit using the A/D conversion function. Duty ratio is adjusted to maintain a constant output voltage 12 [V]. Proposed converter using the micro-processor control was compared to a typical boost converter. As a result, the current loss in the proposed converter was reduced about 10.7%. Input voltage and output voltage can be displayed on the LCD display to see the status of the operation.

• Journal of Power Electronics
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• 제16권1호
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• pp.153-162
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• 2016

Given their structural arrangement, photovoltaic (PV) modules exhibit parasitic capacitance, which creates a path for high-frequency current during zero-state switching of the converter in transformerless systems. This current has to be limited to ensure safety and electromagnetic compatibility. Many solutions that can minimize or completely avoid this phenomenon, are available. However, most of these solutions are patented because they rely on specific and often complex converter topologies. This study aims to solve this problem by introducing a solution based on a classic converter topology with an appropriate modulation technique and passive filtering. A 5.5 kW single-phase residential PV system that consists of DC-DC boost stage and DC-AC H-bridge converter is considered. Control schemes for both converter stages are presented. An overview of existing modulation techniques for H-bridge converter is provided, and a modification of hybrid modulation is proposed. A system prototype is built for the experimental verification. As shown in the study, with simple filtering and proper selection of switching states, achieving low leakage current level is possible while maintaining high converter efficiency and required energy quality.