说明：  本文主要是通过Buck变换器推导出移相全桥变换器的小信号电路模型，接着用MATLAB软件进行仿 真，来判断系统的稳定性。
( This paper is mainly through the Buck converter is deduced the whole bridge converter phase shifting small signal circuit model, then the MATLAB software to copy True, to judge the stability of the system.)