• Proceedings of the KIPE Conference
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• 2007.11a
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• pp.21-23
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• 2007

In this paper a high efficiency bi-directional DC-DC converter for hybrid vehicles is proposed. The proposed converter a three-phase half-bridge interleaved ZVS converter, is designed to have high efficiency in the main operation range. The component ratings are calculated, the actual devices are selected, and the efficiency analysis has been performed to determine optimal ZVS range. The input and output current ripples are significantly reduced due to the interleaved operation. The dual loop control for the interleaved three-phase converter is also presented. To confirm the proposed convert ter, The simulation and experimental results are presented.

• The Transactions of the Korean Institute of Power Electronics
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• v.18 no.2
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• pp.192-198
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• 2013

The rapidly growing demand for electric power systems in electric vehicles (EVs) and hybrid electric vehicles (HEVs) require simpler, cost-effective, and higher performance components. In this paper, a novel power conversion system for hybrid electric vehicles is proposed for these needs. The proposed power conversion system reduces the conversion system cost while preserving same functionality. The proposed power conversion system can boost multi-sources to drive a traction motor and to store energy at the same time reducing number of switching components. In this paper, all operational modes of the proposed converter are explained in detail and verified by a computer simulation first. Then, the topology and operational modes are experimentally verified. Based on the results, the feasibility of the proposed multi-mode single leg power conversion system for EV and HEV applications is discussed.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.11a
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• pp.251-255
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• 2005

This paper proposes a new soft switching technique for a phase-shift controlled bi-directional DC-DC converter. The described converter employs a low profile high frequency transformer and two active full-bridge converters for bidirectional power flow capability. A new soft switching technique is proposed, which guarantees soft switching over wide range (no load to full load) without any additional circuit components. In the proposed switching scheme, the switch pairs in the diagonal position of the converter each are turned on/off simultaneously by the switching signals with a variable duty ratio depending on the phase shift amount, and the converter is operated without freewheeling interval.

• The Transactions of the Korean Institute of Power Electronics
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• v.26 no.2
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• pp.82-89
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• 2021

This study proposes a DAB two-stage series structure with insulated bidirectional DC-DC converter for two-way power transfer between the renewable energy of high voltages (1 kV and above). The proposed circuit transforms the existing DAB converter into a two-stage series structure to reduce the pressure in the switch. The problem of power imbalance occurring in the design of the DAB converter second-stage series is improved by applying the cell balancing method circuit and the common mode coupled inductor using an external flying capacitor instead of reflecting the existing improvement measures, voltage balance control, and inductor current control. In addition, a no-load supercharging sequence is proposed in high voltages and high-speed switching by using the fixed duty output method. This study presents the analysis results through the structure of the proposed circuit, the principle of improving the power imbalance problem, and simulations. Prototypes were manufactured to meet the specifications of input/output voltage of 1700 V, maximum load of 65 kW, and switching frequency of 51kHz, and the validity of the topology was verified using the experimental results and efficiency data.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.25-26
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• 2010

본 논문은 전기자동차용 인버터의 DC-Link 전압 가변을 위한 2상 양방향 DC-DC 컨버터의 제어 기법을 제안한다. 제안된 DC-DC 컨버터는 2-스위치 Buck-Boost 컨버터를 병렬구성 하여 전기자동차의 높은 출력에 대응하였으며 출력단 다이오드를 스위치로 교체하여 회생동작을 가능하게 하였다. 이를 시뮬레이션을 통하여 제어알고리즘의 가능성을 확인하였다.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1043_1044
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• 2009

본 논문에서는 하루 24시간동안의 전원의 특성과 사용시간, 사용량을 고려한 부하를 전기적으로 모델링 하고 그를 통해 양방향 DC-DC 컨버터가 최적으로 동작할 수 있는 알고리즘을 제안하였다. 양방향 DC-DC 컨버터의 최적 알고리즘 제안을 위해 전체 시스템의 에너지 밸런싱에 초점을 맞춰 분석하였으며 하루 중 잉여 및 부족 전력에 따라 양방향 DC-DC 컨버터를 제어하도록 시뮬레이션을 구성하였고 그 결과를 통해 타당성을 검증하였다.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.18-19
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• 2013

본 논문에서는 Energy storage system을 위한 양방향 DC-to-DC 컨버터를 제안한다. 제안된 양방향 DC-to-DC 컨버터는 플라이백 컨버터와 벅 컨버터를 결합한 구조로, 벅 컨버터의 인덕터는 플라이백 컨버터의 변압기 1차측으로 대체된다. 벅 컨버터의 인덕터를 변압기 1차측으로 대체함으로써 소자의 수를 줄이고, 변압기를 이용함으로써 턴수비에 따른 높은 출력값을 얻을 수 있다. 전력 수요가 적을 시 강압 모드로 동작하여 전력을 저장해 두었다가 전력이 필요한 시점에 승압모드로 동작하여 필요 에너지를 제공한다. 제안된 컨버터의 동작 모드에 따른 이론적 분석을 시행하고 PSIM을 이용한 시뮬레이션을 통해 타당성을 검증한다.

• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.6
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• pp.551-560
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• 2003

This paper summarizes development of a 10KW stand-alone power processing unit for 5KW SOFC-low voltage battery hybrid fuel cell power generation system. The power processing unit Includes three parts a high frequency DC-DC converter boosts low fuel cell voltage, a DC-AC inverter converts a dc voltage into a regulated ac voltage and a bidirectional DC-DC converter charges or discharges the battery. The converter topology, design, control method, and experimental result arc presented to meet the specifications such as efficiency of 90% and cost of $40/KW laid down for the "2003 Future Energy Challenge Competition" organized by the U.S. Department of Energy and IEEE. and IEEE.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.200-201
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• 2013

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.454-455
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• 2012