• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.233-234
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• 2014

본 논문에서는 비상 전원 공급 장치(emergency power supply 이하 EPS)를 위한 양방향 컨버터에 대하여 다룬다. 비상 전원 공급 장치용 양방향 컨버터는 대용량의 방전을 위한 Full Bridge(이하 PSFB)와 완속 충전을 위한Two-Transistor Forward converter로 구성된 비상전원 장치용 배터리 충방전 시스템을 제안한다.

• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.175-176
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• 2015

위상천이 풀브리지 컨버터는 소자의 기생성분과 PWM의 위상천이를 이용한 소프트 스위칭을 통해 고효율을 얻을 수 있기 때문에 산업현장에서 널리 사용되어 왔다. 그러나 ZVS(Zero Voltage Switching) 범위가 한정적이며, 누설인던턴스에 의해 듀티 손실이 발생하고, 특히 경부하시 순환전류에 의한 손실 증가로 인해 효율이 낮아지는 단점이 있다. 본 논문에서는 2차측에 프리휠링을 위한 스위치와 다이오드를 추가함으로써 기존의 위상천이 풀브리지(PSFB) 컨버터가 가지는 단점들을 극복한 새로운 소프트 스위칭 풀브리지 컨버터를 소개하고, 3kW급 프로토 타입을 통하여 그 유효성을 검증하였다.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.99-100
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• 2012

본 논문에서는 차량용 저전압 DC-DC 컨버터 (Low voltage DC-DC Converter, LDC)에 최적화된 자성소자를 개발하기 위한 Test Platform 구축 과정을 제시한다. 현재 연구, 개발된 LDC를 토대로 자성소자 개발에 범용성을 가지는 정격사양을 결정하고 그에 따른 시스템을 구성한다. 또한 시스템에 적용된 위상천이 풀-브리지 (Phase-Shift Full-Bridge, PSFB) 컨버터에서 자성소자가 미치는 영향을 분석한다. 분석 결과를 기반으로 구성한 시스템에서 안정적인 성능 검증을 위한 자성소자의 적정 설계범위를 제시하고, 범용성을 위해 입출력 변화에 따른 자성소자 설계 요소들의 변화 추이를 제시한다.

• Proceedings of the KIPE Conference
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• 2010.11a
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• pp.30-31
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• 2010

Filament power supply (FPS) for neutral beam injection (NBI) consists of an insulation type is a device that heats the interior of Tokamak. The input/output specifications of FPS are 3-phase AC 200[Vpeak] and DC16V/300A respectively. A conventional FPS is composed of a 3-phase diode rectifier with DC-link, a H-bridge DC/DC converter, a high frequency transformer, a secondary rectifier and a LC-filter. In this paper, to improve the efficiency of PSFB DC/DC converter it is substituted IGBT devices instead of diode rectifier in secondary side. The proposed method is verified by computer simulation and experiment result.

• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.17-19
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• 2019

본 논문에서는 전기자동차(EV) 충전기용 위상천이 풀브리지(PSFB) 컨버터의 정류기 다이오드 전압 스트레스를 저감하기 위한 새로운 형태의 클램핑 회로를 제안한다. 제안하는 회로는 하나의 커패시터로 구성된 매우 단순한 구조임에도 불구하고, 정류기 다이오드의 전압 스트레스를 큰 폭으로 감소시킨다. 뿐만 아니라, 해당 회로는 프리휠링 구간의 전류를 감소시키며, 출력 인덕터의 사이즈 또한 줄일 수 있다는 장점을 지닌다. 따라서 제안된 컨버터는 정류기 다이오드의 도통손실을 큰 폭으로 저감하여 고효율을 달성할 수 있으며, 간단한 구조의 클램핑 회로와 줄어든 출력 필터 사이즈에 의해서 고밀도화를 달성할 수 있다. 제안된 컨버터의 타당성은 3.3kW, $270-420V_{DC}$의 CC-CV 모드 충전 조건하에서 실험하여 검증되었다.

• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.346-347
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• 2019

본 논문에서는 3.3 [kW] on-board charger (OBC) 용 phasw-shifted full-bridge (PSFB) 컨버터의 고효율 및 고전력 밀도 달성을 위한 스위칭 주파수 설계 방안을 제안한다. 스위칭 주파수에 따라 달라지는 손실 양상 및 전력 밀도에 대해 분석하기 위해 각 스위칭 주파수 별 반도체 소자 손실과 수동 소자 손실을 계산하고, 수동 소자의 부피 변화에 따른 전력밀도 변화를 분석한다. 분석 결과를 바탕으로 고효율 및 고전력밀도 달성을 위한 시스템 설계 포인트를 선정하고 시뮬레이션을 통하여 설계 결과를 검증한다.

• The Transactions of the Korean Institute of Power Electronics
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• v.15 no.2
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• pp.103-110
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• 2010

In this paper, a new mode changeable asymmetric full bridge dc/dc converter is proposed to solve the freewheeling current problem of the conventional zero voltage switching(ZVS) phase shift full bridge(PSFB) dc/dc converter of low output voltage and high output current applications. The proposed converter is operated as an asymmetric full bridge converter when the duty cycle is less than 50% and active clamp full bridge converter when the duty cycle is greater than 50%. As a result, since its freewheeling current is eliminated, the conduction loss is lower than that of the conventional ZVS PSFB dc/dc converter. Moreover, ZVS of all power switches can be ensured along a wide load ranges and output current ripple is very small. Therefore, high efficiency of the proposed converter can be achieved. Especially since its operation mode is changed to the active clamp full bridge converter during hold up time and can be operated with 50~100% duty ratio, it can produce the stable output voltage along wide input voltage range. The operational principles, theoretical analysis and design considerations are presented. To confirm the operation, validity and features of the proposed converter, experimental results from a 1.2kW($400V_{dc}/12V_{dc}$) prototype are presented.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.10
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• pp.600-608
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• 2016

This paper proposes a new high-efficient interleaved phase-shift full-bridge (PSFB) converter for low-voltage and high-current power systems. The proposed converter is composed of three switch-bridges and two transformers in the primary side and two rectifiers in the secondary side. Each transformer handles half of the total power with an interleaved operation, so that the proposed converter has high system reliability, as much as the conventional interleaved PSFB converter. The soft-switching characteristics of the proposed converter are better than those of the conventional converter due to the modulated primary side configuration. The proposed converter represents a single lagging-leg bridge, which has a poor soft switching condition in its operation, while the conventional converter has two lagging-leg bridges in its operation. Therefore, the number of switches having hard-switching conditions is reduced by half in the proposed converter. In addition, the reduced switch counts in the primary side of the proposed converter helps decrease the complexity of the proposed converter compared to that of the conventional converter. The operational principle and analysis are presented in this paper and the characteristics are verified using a PSIM simulation with 3kW server power specification.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.11
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• pp.1860-1867
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• 2016

In this paper, first, a linearized modeling of a phase shift full-bridge converter used in chargers of electric vehicles is derived by using state-space approach and transfer functions from the duty ratio to output voltage and the inductor current are also verified. second, control systems for the output voltage and the inductor current are designed using the root locus technique. It is illustrated by experimental results that the control performance on the output variables is satisfied with the designed digital control system based on a automobile qualified 32-bit microcontroller.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.379-381
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• 2008

Generally additional leakage inductance and two clamp diodes are adopted into the conventional phase shift full bridge (PSFB) converter for reducing the voltage stress of secondary rectifier diodes and extending the range of zero voltage switching (ZVS) operation. However, since additional leakage inductance carries the ac current similar to the primary one, the core and copper loss oriented from additional leakage inductance can be high enough to decrease the whole efficiency of DC/DC converter. Therefore, in this paper, a new ZVS phase shift full bridge converter with separated primary winding (SPW) is proposed. Proposed converter makes the transformer and additional leakage inductor with one ferrite core. Using this method, leakage inductance is controlled by the winding ratio of separated primary winding. Moreover, by manufacturing the both magnetic components with one core, size and core loss can be reduced and it turns out the improvement of efficiency and power density of DC/DC converter. The operational principle of proposed converter is analyzed and verified by the 1.2kW prototype.