• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.438-439
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• 2011

In this paper, soft switching bidirectional DC-DC converter is proposed. The proposed topology is added two auxiliary switches, two resonant capacitors and one resonant inductor to convectional bidirectional DC-DC converter. Therefore, this proposed topology can reduce switching loss of each power switch by ZVS (Zero Voltage Switching) and ZCS (Zero Current Switching). We have performed mode analysis, simulation and experiment for the proposed topology.

• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.13-14
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• 2011

This paper deals with the ZVS characteristics of a bidirectional DC/DC converter in idling mode. Simulations are carried out with the supercapacitor which maximum voltage is 50 V. It is found that the ZVS can be achieved as far as the supercapacitor voltage is below 94% of the maximum voltage in idling mode. Therefore, the switching loss in the mode can be small by control the upper limit of the supercapacitor voltage.

• Proceedings of the KIPE Conference
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• 2004.07b
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• pp.479-483
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• 2004

Fuel Cell (FC) has slow response characteristic for load variation. During a load step, the inverter cannot pull more power from the fuel cell than is currently available so supplemental power must be provide by some sort of energy storage elements. In this paper, hi-directional do-dc converter for FC generation system is proposed to improve load response characteristic. The hi-directional converter interfaces the low voltage battery to the inverter dc link of FC generation system. The converter is based on a active full bridge in the primary side and on a half bridge in the secondary of a high frequency isolation transformer. The complete operating principles and simulation results in presented.

• Proceedings of the KIPE Conference
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• 2004.07a
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• pp.446-450
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• 2004

The amount of electric energy used in a vehicle will be increased continuously. The increment of electric power demand causes interest on new higher power system such as 42V Power Net. Furthermore, the necessity for development of energy storage device is highlighted recently. Bidirectional nm Converter is one of the important parts in 42V power system. Therefore, this paper proposes bidirectional Cascade Buck-Boost DC/DC Converter which can satisfies required specifications in 42V power system The operation principle is described along with simple control method, and experimental results on a 500W prototype are provided.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.1023-1025
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• 2001

This paper proposes a bi-directional current switch with snubber regeneration using Power MOSFETs and this paper proposes to use a loss-less snubber with switching device to perform soft-switching. It results in not only decreasing switching loss in the device drastically, but also improving input ac current waveform distortion. The computer simulation results show that the input current waveform and show the requirements necessary for the elimination of the 3rd harmonic component. We also show the procedure to design the parameters of the converter.

• Proceedings of the KIPE Conference
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• 2014.11a
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• pp.58-59
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• 2014

본 논문에서는 비례-적분(PI) 제어의 상태관측기를 구성하여 리튬폴리머 배터리의 충전량(SOC)을 추정하는 기법에 대해 설계한 뒤 실험을 통하여 검증하였다. 리튬폴리머 배터리는 1차 R-C 등가모델로 단순화하여 표현하였고, PI상태관측기를 Matlab/Simulink에서 설계하였다. 상온($25^{\circ}C$)에서 양방향 DC-DC 컨버터를 이용하여 리튬폴리머 배터리에 FTP-72 충 방전 사이클의 전류패턴을 인가한 뒤 SOC 추정기법을 검증하였다. PI상태관측기는 임의의 초기 SOC 상태에서도 오차율 2%이내로 SOC를 추정하여 모델링 에러나 외란에도 강인한 특성이 있는 것을 확인하였다.

• Proceedings of the KIPE Conference
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• 2014.11a
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• pp.46-47
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• 2014

본 논문은 태양광 발전 시스템 중 차동 전력 조절기가 다루는 전력을 최소화하기 위한 LPPT (Least Power Point Tracking) 에 관한 것이다. 두 개 이상의 태양광 모듈에서 그늘짐 등으로 인해 발생 하는 전력 차이를 양방향 차동 전력 조절기를 통해 다루게 되는데, 이 때 태양광 모듈을 입력으로 하는 부스트 컨버터의 스트링 전류를 조절하게 되면 차동 전력 조절기가 담당하는 전력이 최소가 되도록 할 수 있다. 차동 전력 조절기의 용량이 줄어듦에 따라 시스템 크기를 줄일 수 있고, 이와 함께 단가도 감소하는 효과를 낼 수 있다. 본 논문에서는 차동 전력 조절기의 전력이 최소가 되게 하는 LPPT 방법을 PSIM 시뮬레이션과 실험을 통해 입증 하고자 한다.

• Proceedings of the KIPE Conference
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• 2012.11a
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• pp.103-104
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• 2012

In the AC module system, mismatch problem between AC power and constant input power is occurred. To solve this problem, electrolytic capacitor is utilized for diminishing power pulsation in PV side. However, it has disadvantages of low life span and weak in temperature. Decoupling method has been studied to reduce the capacitance and replaces electrolytic capacitor to film capacitor. This paper proposes design method for decoupling circuit which bidirectional DC-DC converter using soft switching. Proposed system is verified by design optimization and simulation results.

• Proceedings of the KIPE Conference
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• 2012.11a
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• pp.50-51
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• 2012

The paper presents a non-isolated bidirectional DC-DC converter for use in renewable power generation, battery, electric vehicles (EV) and small scale DC-UPS systems. In the propose design, the conventional interleaved operation of two-inductor boost structure is modified to accommodate bidirectional operation, and zero-voltage-transition (ZVT) is applied, where both the switch and the rectifier diode achieve soft condition without increasing their voltage and current stresses. The proposed converter has the merits of simple circuitry, reduced size, low cost and high efficiency. The operation principle of the converter is analyzed and verified. Also, simulation results of the proposed bidirectional dc-dc converter is shown.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.9
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• pp.1306-1314
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• 2015

This paper deals with a switching method of a three-phase interleaved bidirectional DC-DC converter to obtain high efficiency in wide load range. The proposed soft-switching method provides ZVS and ZCS at turn-on, and ZVS at turn-off of the switch as well as considerably reduced conduction loss in light load. Simulation and experiment are carried out with a bidirectional DC-DC converter having the power rating of 3 [kW], and those results show the validity of the proposed switching method.