桥式变换器的瞬态共同导通分析及解决方案

The Analysis and Solution of Transient Through in Bridge Converter

在双端变换器,如全桥、半桥、推挽和同步整流器中,共同导通将是最严重的故障之一。常规的由驱动信号的重叠或MOSFET的关断延迟而造成的共同导通问题已得以解决。在此提出了MOSFET应用于桥式变换器中常见而又不易查出的故障,即瞬态共同导通现象。分析了产生瞬态共同导通的主要原因和条件,指出采用非对称驱动或双极性电压驱动,可以很好地解决瞬态共同导通问题,采用先进的MOSFET或零电压开关则可彻底消除共同导通现象。

Among the double end converters （full bilge, half brige, push-pull and synchronous rectify）, shoot-through will be one of the most serious faults.The normal and general shoot-through caused by the superposition of the drive signals or turn-off delay of MOSFET, which has already been solved easily.Some frequent faults are proposed which are not easy to find out in the application of MOSFET for brige converter-transient shoot-through.The main reason of causing the transient shoot-through is also analyzed.The peak voltage is the cause of transient shoot-through.And then the condition of causing the transient shoot-through is analyzed.Finally it suggests that adopting unsymmetry drive or bipolar voltage drive could solve the problem by the transient shoot-through effectively,and adopting advanced MOSFET or ZVS could remove the phenomenon of the transient shoot-through entirely.