双向全桥串联谐振DC/DC变换器回流功率特性优化

The Backflow Power Optimization of Dual Bridge Series Resonant DC/DC Converter

双向全桥串联谐振DC/DC变换器(dual bridge series resonant DC/DC converter,DBSRC)具有控制简单、损耗低等优点,在电力电子牵引变压器场合具有应用前景。然而若系统参数选择不当,会产生较大回流功率,使开关管的损耗增大,系统效率降低。为了降低系统运行时的回流功率,该文分析DBSRC的工作原理及换流过程,利用微分方程得到系统模型,进而总结DBSRC的3种稳态工作模式及回流功率在不同工作模式的表达式。通过优化电压增益(M)、开关频率谐振频率比(F)、谐振回路的特性阻抗(Zr)参数,达到在宽负载范围内降低系统回流功率的目的。最后,构建一个35 kW实验样机,实验结果证明了DBSRC模型的正确性及回流功率特性优化和有效性。

Dual bridge series resonant DC/DC converter(DBSRC)has the advantages of simple control and low power loss,which is a promising topology in power electronic traction transformer(PETT).However,if the system parameters are selected improperly,the large backflow power will be generated,which can lead to the increase of power switches’loss and the decrease of system efficiency.In order to reduce the backflow power,the working principle and commutation process of DBSRC were analyzed,and then the converter model was derived from two second-order differential equations.The steady states of DBSRC were divided into three working mods,at which the expression of backflow power were calculated,respectively.By optimizing the system parameters,such as the voltage gain(M),the ratio of switching frequency and resonant frequency(F)and characteristic impedance(Zr),the backflow power of converter was reduced significantly over a wide load range.Finally,a 35 kW DBSRC prototype was constructed,whose experimental results proved the correctness of DBSRC model and effectiveness of backflow power optimization.