基于GaN器件的有源箝位正激变换器设计

Design of active clamp forward converter based on GaN devices

有源箝位正激变换器因为开关管的软开关控制,可以降低高频下的开关损耗,已是中型功率隔离变换器实现高效率、高功率密度的主流解决方案。文中基于有源箝位正激变换器设计一款输入28 V、输出3.3 V/30 A的电源样机,开关频率为700 kHz,原边主开关管采用低栅极电荷、低输出电容、零反向恢复损耗的氮化镓(GaN)器件,再结合平面变压器技术及次级同步整流(SR)技术,使样机峰值效率达到95.13%。最后通过对样机测试结果分析来验证方案的高效率和高功率密度。

The active clamp forward converter can ruduce the switching loss at high frequency because of the soft-switching control of the switching tube.It has become the mainstream solution for the medium power isolation converter to achieve high efficiency and high power density.Based on an active clamp forward converter,a power supply prototype with an input of 28 V,an output of 3.3 V/30 A,and a switching frequency of 700 kHz is designed.The primary main switch uses gallium nitride(GaN)devices with low gate charge,low output capacitance,and zero reverse recovery loss.In combiantion of planar transformer technology and secondary synchronous rectification(SR) technology,the prototype can realize a peak efficiency of 95.13%.The high efficiency and high power density of the scheme are verified by analyzing the testing results of the prototype.