高效率准谐振Buck变换器设计与研究  

Design and study of high efficiency quasi resonant Buck converter

作　　者：王金龙[1] 张方华[1] 张帅[1] 

机构地区：[1]南京航空航天大学江苏省新能源发电与电能变换重点实验室,江苏南京210016

出　　处：《电工电能新技术》2014年第4期11-15,共5页Advanced Technology of Electrical Engineering and Energy

基　　金：国家高技术研究发展计划(863计划;项目编号2011AA11A249)

摘　　要：电感电流临界连续工作模式(BCM)Buck变换器,在电感电流下降到零时,输出滤波电感和开关管并联电容谐振即准谐振(Quasi Resonant)(QR)。在开关管两端电压谐振到零的时候开通开关管,则可以实现零电压零电流开通(ZVS/ZCS)。本文通过详细分析输出电感与开关管并联电容的谐振过程,得出开关管两端电压为零的时间,并且通过设计延时电路,以保证输入电压变化时依然能够实现零电压和零电流开通(ZVS/ZCS)。在开关管关断时由于开关管两端并联了谐振电容,可近似认为是零电压关断。而且Buck变换器工作于BCM模式时输出滤波电感体积小,动态响应速度变快,二极管自然关断,没有反向恢复损耗。最后设计了一台3kW的原理样机,最高效率可以达到98.7%。When the inductor current of boundary conduction mode （BCM） Buck converter falls to zero, the output filter inductor will resonate with the capacitor across the switch called Quasi Resonant. If the switch is turned on when the voltage of resonant capacitor is zero, ZVS and ZCS turn-on can he achieved, and the switching loss is e- liminated. This thesis analyses the resonance between output inductor and the capacitor in detail, and find out the time when the voltage across the switch is zero. Then by using a proper delay circuit, zero voltage switching and ze- ro current switching of switch are assured. When the Buck converter works in BCM mode the output filter inductor is small, and the reverse recovery loss of diode is eliminated, so dynamic performance can be improved. And there is a capacitor across the switch when it is turned off, and ZVS turn-off is achieved. At last a 3kw prototype is de- signed, and the highest efficiency is 98.7%.

关 键 词：临界连续 准谐振 延时电路 

分 类 号：TM46[电气工程—电器]