并联H桥DC/DC变换器软开关技术研究

Research on Soft Switching Technology of Parallel H-Bridge DC/DC Converter

与传统的Buck电路相比,基于H桥并联的DC/DC变换器可以实现电压的双极性输出和故障时的冗余控制,非常适合用于大功率电动机正反转控制的场合。分析了并联H桥型DC/DC变换器的结构组成和双脉宽调制(PWM)模式。为了降低双脉宽调制下H桥型DC/DC变换器的开通和关断损耗,对无源软开关技术进行了分析,重点探讨了RCD缓冲电路和最小应力缓冲电路之间的性能差异,指出最小应力软开关技术可以获得更好的软开关性能,并就将其用于双脉宽调制下的并联H桥DC/DC变换器进行了仿真研究。仿真结果表明:最小应力软开关技术用于双脉宽调制下并联H桥DC/DC变换器时,可以实现开关管的零电压开通和零电流关断。

Compared with the traditional buck circuit, the DC/DC converter based on H-bridge parallel connection can realize the bipolar output of voltage and redundancy control in case of failure, so it is very suitable for the situation that large power motor needs positive and negative rotation control. The structure of the parallel H-bridge DC/DC converter and the mode of dual pulse width modulation (PWM) were analyzed. To reduce the switching loss of H-bridge DC/DC converter under dual PWM, the passive soft switching technology was analyzed, and the performance difference between the RCD buffer circuit and the minimum stress buffer circuit was emphatically discussed. It was found that the minimum stress soft switching technology could obtain better soft switching performance. The minimum stress soft switch was used to simulate the parallel H-bridge DC/DC converter with dual PWM. Simulation results showed that the soft switching technology based on the minimum stress snubber circuit could be used in the parallel H-bridge DC/DC converter with dual PWM to achieve zero voltage switching on and zero current switching off.