• The Transactions of the Korean Institute of Power Electronics
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• v.13 no.4
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• pp.311-318
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• 2008

This paper proposes synchronous bidirectional DC-DC converter applying soft-switching technique. The proposed converter integrates two advantages which are conduction loss minimization and switching loss elimination by applying interleaved synchronous buck and ZVT-cell with a single resonant inductor. ZVS is guaranteed for wide load range in CCM(Continuous Conduction Mode) as well as wide output voltage range by current injection method. Also, reverse recovery effects of body diode can be minimized. In addition, it is possible to significantly reduce diode drop voltage occurred during dead time of conventional synchronous buck converter. The validity of the proposed converter is verified through experimental results.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.2
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• pp.82-90
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• 2015

This paper proposes an efficient bi-directional DC/DC converter topology using multi-phase interleaved method for power storage system. The proposed converter topology is used for a power storage system using a vanadium redox flow battery(VRFB) and is configured to enable bidirectional power flow for charging and discharging of VRFB. Proposed DC/DC converter of the 4 leg method is reduced to 1/4 times the rating of the reactor and the power semiconductor device so can be reduce the system size. Also, proposed topology is obtained the effect of four times the switching frequency as compared to the conventional converter in each leg with a 90 degree phase shift 4 leg method. This can suppress the reduction of the life of the secondary battery because it is possible to reduce the current ripple in accordance with the charging and discharging of VRFB and may increase the efficiency of the entire system. In this paper, it proposed bidirectional high-efficiency DC/DC converter topology Using multi-phase interleaved method and proved the validity through simulations and experiments.

• Journal of Advanced Marine Engineering and Technology
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• v.41 no.1
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• pp.76-82
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• 2017

Since the introduction of electronically controlled engines and electric propulsion ships, the need for an uninterruptible power supply for emergency power supply devices that use batteries has gained importance. The bidirectional converter in such emergency power supply devices is a crucial component. This paper proposes, a topology for an improved DC-DC bidirectional converter that is characterized by a high voltage conversion ratio and low voltage stress of switches. To confirm the performance of the converter, a computer simulation was executed with PSIM software. The conversion ratio of the proposed converter was found to be four times higher than the conventional boost converter in step-up mode and one-fourth that of the conventional buck converter in step-down mode, and the voltage stress of the switches was one-fourth of the high-side voltage. Moreover, the proposed converter was confirmed to be able to distribute equal currents between two interleaved modules without using any extra current-sharing control method because of the charge balance of its blocking capacitors.

• Journal of Power Electronics
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• v.17 no.2
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• pp.323-333
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• 2017

This paper proposes a model-based optimal control algorithm for the clamp switch of a zero-voltage switching (ZVS) bidirectional DC-DC converter. The bidirectional DC-DC converter (BDC) can accomplish the ZVS operation using the clamp switch. The minimum current for the ZVS operation is maintained, and the inductor current is separated from the input and output voltages by the clamp switch in this topology. The clamp switch can decrease the inductor current ripple, switching loss, and conduction loss of the system. Therefore, the optimal control of the clamp switch is significant to improve the efficiency of the system. This paper proposes a model-based optimal control algorithm using phase shift in a micro-controller unit. The proposed control algorithm is demonstrated by the results of PSIM simulations and an experiment conducted in a 1-kW ZVS BDC system.

• The Transactions of the Korean Institute of Power Electronics
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• v.22 no.4
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• pp.312-323
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• 2017

This paper introduces the bidirectional dc-dc converter design case study, which employs silicon-carbide (SiC) MOSFETs for battery energy storage system (BESS). This converter topology is selected as bidirectional synchronous buck converter, which is composed of a half bridge converter, an inductor, and a capacitor, where the converter has less conduction loss than that of a unidirectional buck and boost converter, and to improve the converter efficiency, both the power stage design and power conversion architecture are described in detail. The conduction and switching losses are compared among three different SiC devices in this paper. In addition, the thermal analysis using Maxwell software of each switching device supports the loss analyses, in which both the 2 kW prototype analyses and experimental results show very good agreement.

• The Transactions of the Korean Institute of Power Electronics
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• v.10 no.5
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• pp.428-435
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• 2005

In this paper a power controller is proposed to accurately control the commanded power for charge and discharge operation of a bidirectional DC-DC converter so that durability is improved in hybrid systems such as fuel cell vehicles. Also, a control algorithm for charge and discharge operation is proposed to improve fuel utilization and keep battery SOC constant so that energy is effectively utilized.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.320-321
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• 2018

A non-isolated high voltage gain bidirectional DC-DC converter for battery storage system has been presented in this paper. The topology is composed of boost converter and traditional SEPIC converter. The proposed converter can achieve higher voltage conversion ratio with reduced voltage and current stresses in the switches. In additional, a reduced number of components are included in this topology. The PSIM simulation is carried to validate the analysis and operation of the converter.

• The Transactions of the Korean Institute of Power Electronics
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• v.17 no.6
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• pp.523-531
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• 2012

This paper proposes a high efficiency power conversion system for battery-ultracapacitor hybrid energy storages. The proposed system has only one bidirectional dc-dc converter for hybrid power source with batteries and ultracapacitors. The hybrid power source has bidirectional switching circuits for selecting one energy storage device. Bidirectional power flow between the energy storage device and high voltage capacitor can be controlled by one bidirectional converter. An asymmetrical switching method is applied to the bidirectional converter for high power efficiency. Switching power losses are reduced by zero-voltage switching of power switches. System operation and design considerations are presented. The experimental results are provided to verify the performance of the proposed system.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.1
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• pp.65-72
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• 2016

In this paper, we developed a bidirectional LDC(Low DC-DC converter) for vehicle which is composed of a full bridge converter and a current doubler at the second side. The LDC is a converter that converts DC input from one side to DC output on the other side, and the converter which was developed in this thesis is capable of transferring power in both directions. It has been verified that the developed LDC has 90% efficiency at 1400W and approximately 85% efficiency at 2KW.

• Proceedings of the KIPE Conference
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• 2010.07a
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• pp.29-30
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• 2010

This paper proposed bidirectional DC-DC converter applying soft switching technique. Compared with conventional bidirectional converter, the main switches of proposed converter are operated without switching losses, and auxiliary switches were run under soft switching condition using quasi-resonant current mode. To verify the validity of the proposed converter, mode analysis and simulation results are presented.