The small - signal model in main circuit are built by using average circuit model . the relationship of each small signal and efficiency duty cycle are described completely . magnitude - frequency characteristics and phase - frequency characteristics of each main transfer function are got 本文分析了全桥移相zvspwmdc - dc变换器的基本原理，运用平均等效电路法建立了主电路小信号模型，并详细分析了各小信号变量与有效占空比之间的关系，得到了各主要传递函数的幅度和相位频率特性。
