高效率CLL谐振变换器的分析与设计

Analysis and Design of High Efficiency CLL Resonant Converter

阐述了CLL谐振变换器的工作原理,该变换器能在全负载范围内实现开关管的零电压开关(ZVS)和次级整流二极管的零电流开关(ZCS),降低了开关管的开关损耗,消除了二极管的反向恢复损耗。与传统LLC谐振变换器相比,CLL谐振电路网络中并联谐振电感上的电压随负载减小而减小,流过并联谐振电感上的电流也因此减小,从而减小了轻载时的环流损耗,改善了轻载效率。采用基波近似(FHA)分析方法分析CLL谐振变换器,得到该变换器的直流增益特性,并给出变换器关键参数的设计原则。通过实验验证了理论分析的正确性。

The working principle of CLL resonant converter is analyzed.This converter can achieve zero voltage sw- itching（ZVS） turning-on for switches from zero load to full load and zero current switching（ZCS） turning-off for sec- ondary rectifier diode, and thus the switching loss of switch is reduced and reverse recovery loss of diode are elimi- nated, and therefore higher efficiency is achieved.Compared with conventional LLC resonant converter,the voltage on the resonant inductor and the current of the resonant inductor are reduced as the load decreases, thereby reducing the circulation loss, and light-load efficiency has been improvd.To obtain the DC characteristic of the converter,the fun- damental harmonic approximation （FHA） analysis method is adopted, the design principle of key parameters of the co- nverter is given.The correctness of the theoretical analysis is verified by the experiment.