Design and implementation of 1 MHz active-clamped resonant flyback converter

Abstract

This paper aims to study an active-clamped resonant flyback converter. The proposed resonant technique can increase the zero-voltage switching (ZVS) range. Gallium Nitride high electron mobility transistor (GaN HEMT) devices are also applied in this study to reduce the switching losses at high-frequency operation. Synchronous rectifier is designed on secondary side to minimize the conduction losses resulted from the high output current. A planar transformer is designed to achieve low profile and high power density. A 65 W/1 MHz prototype converter is implemented and tested under 90 V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">AC</sub> ~264 V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">AC</sub> input and 19.5 V output condition. The experimental results are shown to verify the feasibility of the studied scheme. The measured efficiency can be up to 90 %.