Buck Converter의 Switching-Power Loss 감소를 위한 Passive Snubber에 관한 연구

Abstract

This thesis presents a passive snubber for a dc-dc buck converter. The snubber consists of an inductor, two capacitors, and a diode. It reduces the switching power loss significantly by eliminating reverse recovery current of a freewheeling diode and providing zero-current turn on and zero-voltage turn off conditions for a switch, without increasing the voltage stress of a switch. When the snubber was adapted to the conventional dc-dc buck converter and tested at an output power of 200 W, and a switching frequency of 188 kHz, the snubber reduced power loss in a switch by ~ 72.3 %. Thus, the power conversion efficiency increased by ~ 2.8 %. Also, the temperature of a switch decreased by ~ 73 °C and the temperature of a diode decreased by ~ 20 °C. These experimental results show that the proposed passive snubber is useful for improving power conversion efficiency and reliability of conventional dc-dc buck converters operating at a high frequency.