• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.335-336
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• 2016

This paper introduces a bidirectional full-bridge converter with new active damp structure. The proposed active damp circuit can damp the oscillating voltage across the rectifier diodes with a smaller voltage stress of the damping capacitor and eliminate the circulating current. In addition, the proposed converter can achieve additional advantages such as nearly ZCS switching for leading-leg switches and no recovery current for rectifier-bridge by the suitable design of the damp capacitor to resonate with leakage inductor. Since the ZVS is achieved for both leading-leg and lagging-leg switches by the magnetizing current of the transformer, it can be achieved regardless of the load variation. A 3.3 kW prototype converter is implemented for vehicle-to-grid (V2G) application and the advantages of the proposed converter are verified by the experiments. The maximum efficiencies of 98.2% and 97.6% have been achieved for the buck mode and boost mode operation, respectively.

• Journal of the Korean Society for Railway
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• v.14 no.5
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• pp.411-415
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• 2011

DC/DC switching power converters are commonly used to generate a regulated DC output voltages with high efficiencies from different DC input sources. The voltage mode DC/DC converter utilizes MOSFET (metal-oxide semiconductor field effect transistor), inductor, and a PWM (pulse-width modulation) controller with oscillator, amplifier, and comparator, etc. to efficiently transfer energy from the input to the output at periodic intervals. The fundamental boost converter and a buck converter containing a switched-mode power supply are studied. In this paper, the electrical characteristics of DC/DC power converters are simulated by program of SPICE, and the PWM controller is implemented to check the operation. In addition, power efficiency is analyzed based on the specification of each component.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1997.10a
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• pp.88-92
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• 1997

Power conversion system must be increased swiching frequency in order to achieve a small size, a light weight and a low noise, However, the swiches of converter are subjected to high switching power losses and switching stresses. As a result of those, the power system brings on a low efficiency. In this paper, the authors propose a DC-DC boost converter of high power by partial resonant switch method (PRSM). The switching devices in a proposed circuit are operated with soft swiching and the control technique of those is simplified for switch to drive in constant duty cycle. The partial resonant circuit makes use of a inductor suing step up and a condenser of loss-less snubber. Also the circuit has a merit which is taken to increase of efficiency, as if makes to a regeneration at input source of accumulated energy in snubber condenser without loss of snubber in conventional cirvuit. The result is the the switching loss is very low and the efficiency of system is high. The proposed converter is deemed the most suitable for high power applications where the power switching devices are used.

• Journal of IKEEE
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• v.23 no.1
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• pp.254-260
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• 2019

The failure rate of bidirectional dc-to-dc converter is predicted through the failure mode and effect analysis (FMEA) and the fault-tree analysis (FTA) considering the operational risk. In order to increase the driving voltage of the electric vehicle efficiently, the bidirectional converter is attached to the front of the inverter. It has a boost mode for discharging battery power to the dc-link capacitor and a buck mode for charging the regenerative power to the battery. Based on the results of the FMEA considering the operating characteristics of the bidirectional converter, the fault-tree is designed considering the risk of the converter. After setting the design parameters for the MCU for the electric vehicle, we analyze the failure rate of the capacitor due to the output voltage ripple and the inductor component failure rate due to the inductor current ripple. In addition, we obtain the failure rate of major parts according to operating temperature using MIL-HDBK-217F. Finally, the failure rate and the mean time between failures (MTBF) of the converter are predicted by reflecting the part failure rate to the basic event of the fault-tree.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.7
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• pp.111-121
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• 2014

A bi-directional DC-DC converter has been developed for a wireless power transceiver which enables a device to receive and transmit power wireless. Generally, the wireless power transceiver requires two DC-DC covnerter and two external inductors. However, the proposed wireless power transceiver requires only one DC-DC converter and one inductor, allowing small form-factor. The bi-directional DC-DC converter implemented in $0.35{\mu}m$ BCDMOS process operates as a buck converter at the wireless power receiving mode and the power efficiency is 91% when the ouput power is 3W. In the wireless power transmitter mode, the DC-DC converter operates as a boost converter. With the bi-directional DC-DC converter and the proposed efficiency maximizing techniques, the power efficiency of wireless power transceiver is 81.7% in receiver mode and 76.5% in transmitter mode.