• 전기학회논문지
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• 제64권4호
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• pp.552-559
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• 2015

Hydrogen is commonly used in many industrial field. However, hydrogen should be filled in a high pressure container to use it. Therefore, many researches have been conducted about an electrolyzer. The operating principle of the electrolyzer is that the electrolyzer can separate water molecules into hydrogen and oxygen. To use the electrolyzer, a power conversion system is needed because the current of the electrolyzer increases exponentially depending on the voltage of the electrolyzer. Thus, this paper proposes the power conversion system for the electrolyzer using a full-bridge DC-DC converter topology.

• 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.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2012년도 전력전자학술대회 논문집
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• pp.35-36
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• 2012

본 논문은 EV용 탑재형 배터리 충전기(OBC)와 같은 중 대용량 충전시스템에 적용한 Phase Shift Full Bridge Converter (PSFB) 토폴로지를 사용하는 경우, 트랜스포머의 구조에 따른 특성을 분석한다. 일반적으로 PSFB는 다른 토폴로지에 비해 코어 사용 효율이 높기 때문에 상대적으로 소형 경량화 설계가 용이하다. 그러나 수 kW급의 시스템 응용에서는 기존 코어 형상이나 Ap-limit과 제약이 따른다. 또한 특화된 코어의 경우 높은 가격으로 설계 경쟁력이 낮아진다. 따라서 본 논문에서는 이러한 대용량 PSFB의 응용 시스템에 적합한 코어 설계를 위해 다양한 트랜스포머의 구조를 선정하여 그 특성을 비교분석한다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2016년도 추계학술대회 논문집
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• pp.149-150
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• 2016

본 논문은 500W급 GaN (Gallium Nitride) FET을 적용한 Full Bridge Converter 의 2차측 소자에 따른 손실을 분석한다. Diode를 적용하였을 경우의 도통손실과 Si MOSFET과 GaN FET의 스위칭 손실 및 도통손실을 분석하여 최종적인 효율 및 동기정류의 필요성을 검증하고 그에 따른 방열설계를 수식을 통해 도출하여 제안한다.

• Journal of international Conference on Electrical Machines and Systems
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• 제1권2호
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• pp.98-104
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• 2012

This paper presents a novel transformer isolated parallel connected full-bridge dc-dc converter using recently developed trans-Z-source network. Unlike the traditional voltage -fed or current-fed converters, the proposed converter can be open- and short-circuited without damaging switching devices. Therefore, the desired buck and boost function can be achieved and the converter reliability can be greatly improved. A 6 kW prototype dc-dc converter is built and tested to verify performances of the proposed converter.

• Journal of Power Electronics
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• 제19권5호
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• pp.1099-1107
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• 2019

A soft switching converter with wide voltage range operation is investigated in this paper. A series resonant converter is implemented to achieve a high circuit efficiency with soft switching characteristics on power switches and rectifier diodes. To improve the weakness of the narrow voltage range in LLC converters, an alternating current (ac) power switch is used on the primary side to select a half-bridge or full-bridge resonant circuit to implement 4:1 voltage range operation. On the secondary-side, another ac power switch is adopted to select a full-wave rectifier or voltage-doubler rectifier to achiever an additional 2:1 output voltage range. Therefore, the proposed resonant converter has the capacity for 8:1 (320V~40V) wide output voltage operation. A single-stage hybrid resonant converter is employed in the study circuit instead of a two-stage dc converter to achiever wide voltage range operation. As a result, the study converter has better converter efficiency. The theoretical analysis and circuit characteristics are verified by experiments with a prototype circuit.

• Journal of Power Electronics
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• 제16권3호
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• pp.872-882
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• 2016

A novel pseudo-continuous conduction mode (PCCM) voltage-fed single-stage power factor correction (PFC) full-bridge battery charger is proposed in this paper. By connecting a freewheeling transistor in parallel with an input inductor, the PFC cell can operate in the PCCM with a constant duty ratio. Thus, the dc/dc stage can be designed using this constant duty ratio and the restriction on the duty ratio of the PFC cell is eliminated. As a result, the input current distortion is less and the dc bus voltage becomes controllable over the wide output power range of the battery charger. Moreover, the operation principle of the dc/dc stage is designed to be similar to that of a conventional phase-shifted full-bridge converter. Therefore, it is easy to implement. In this paper, the operation of the new converter is explained, and the design considerations of the controller and key parameters are presented. Simulation and experimental results obtained from a 1 kW prototype are given to confirm the operation of the proposed converter.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 전력전자학술대회 논문집
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• pp.520-524
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• 2001

Recently, the demand of large capacity SMPS for industrial area is increasing. Full-bridge dc-dc converter with IGBT is most widely used for large capacity SMPS because IGBT has a low-conduction loss and large current capacity, But most large capacity Full-bridge do-dc converter using IGBT has low operating frequency because of switching loss at IGBT especially at turn-off by current tail and it's cause of relatively big converter size. MOSFET has low switching losses has been widely used for high frequency SMPS but it has a problem to apply to large capacity SMPS because it has large conduction resistance causing large on-time losses. In this paper, for reduction losses at switching device, MOSFET is applied at parallel with IGBT in full-bridge dc/dc converter.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.205-207
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• 2007

Isolated Current fed full-bridge converter with active clamp is analyzed in this paper. An active clamp branch is used for limiting the voltage overshoot in the bridge switches and rectifier diodes. Zero voltage switching(ZVS) is also realized by using the energy stored in the transformer leakage inductance. To analyze the converter, 6 modes of operation are introduced and investigated. For each of the modes, voltage and current equations are derived together with corresponding equivalent circuits. 200W prototype dc-dc converter is assembled and verifies the effectiveness of the analysis and simulation.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2005년도 전력전자학술대회 논문집
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• pp.286-288
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• 2005

Conventional phase shift full bridge (PSFB) converter has serious voltage oscillation problem across the secondary rectifier diodes, which would require the dissipate snubber circuit, thus degrades the overall efficiency. To overcome this problem, a new voltage oscillation reduction technique (VORT) which effectively reduce the voltage oscillation of the secondary rectifier diodes for phase shift 1011 bridge converter is proposed. Therefore, no dissipate snubber for rectifier diodes is needed. In addition, since it has wide zero voltage switching (ZVS) range, high efficiency can be achieved. Operational principle, analysis of voltage oscillation, and design consideration are presented compare with that of the conventional PSFB converter. To confirm the validity of the proposed VORT, experimental results from a 420W, 385Vdc/210Vdc prototype are presented.