슈퍼커패시터용 양방향 DC-DC 컨버터의 충방전시 효율을 고려한 변압기권선비 설계

Abstract

This paper describes the design of a transformer turn-ratio with the consideration of converter efficiency. Usually, the turn-ratio is determined according to the input and output voltage level of the converter. However, in case of energy storage system with supercapacitor, the supercapacitor vaoltage varies widely. In this case the turn-ratio can be determined with the maximum supercapacitor voltage. This paper suggests a new design method for the turn-ratio with the considerations of not only the maximum voltage but also an efficiency of the power converter. A 3-kW bidirectional DC-DC converter with transformer is designed for a superapacitor which has the voltage variation range of 50-80V. Swithching characteristics and on-state V-I characteristics of all the switches charging and discharging models. Through the analysis and simulation it is found that the most avaliable turn-ratio is 400:100 for the maximized converter efficiency. It is expected that the proposed method can be used for a high efficient power converter design.