C-filter LCC断续工作模式逆变桥损耗分析

Analysis of Inverter IGBT Losses of C-filter LCC Operating in DCM

工作于谐振电流断续模式(DCM)的容性滤波LCC谐振变换器易实现软开关,能可靠高效地工作。同时,它具有优良的调压特性,拓扑上无需输出滤波电感,适用于高压大功率场合。然而,目前缺少开关管损耗的分析和计算方法,导致工程上难以实现可靠的系统热设计。针对工作于DCM下的容性滤波LCC谐振变换器,进行了逆变桥部分的开关管损耗分析。利用谐振电流的封闭表达式及开关管的特性数据,得到了开关管损耗的理论计算方法。最后,以一个输出指标为直流3.6 kV/0.3 A的谐振变换器为例,给出了逆变桥IGBT的理论计算和实验测量损耗结果,验证了理论计算的有正确性。

The C-filter LCC resonant converter operating in discontinuous conducting mode （DCM） can realize soft-switch- ing easily and has valued features such as high reliability and efficiency.Also, the C-filter LCC resonant converter has a good voltage regulation ability and no inductor is needed in the output side, making it suitable for high power and high voltage applications.However,there lacks a method to analyze and calculate the IGBT power losses, which is es- sential for heat sink design.This paper analyzes the inverter losses of the C-filter LCC resonant converter which is op- erating in DCM.A method to calculate the power losses of the switches is also given based on the closed-form func- tion of the resonant current and the characteristics of the IGBT.Finally, a DC/DC 3.6 kV/0.3 A C-filter LCC resonant converter is taken as an example.The experimental results are given to verify the proposed analysis.