一种带有变压器辅助绕组的推挽正激软开关电路

Novel Zero-Current-Switching (ZCS) Push-Pull Forward PWM Converter Using Transformer Auxiliary Winding

在原有推挽正激软开关电路的基础上 ,提出了一种新颖的软开关电路拓扑 ,使主管开关实现了零电流关断 ,减小了开关管的关断损耗 ;谐振网络不处于主功率回路中 ,谐振回路环流能量小 ;同时通过改变变压器辅助绕组的匝比 ,使主管电流应力和副边整流管电压应力在实现 ZCS的前提下尽可能低 ,提高了变换器的可靠性。文中具体说明了该变换器的工作原理 ,谐振网络参数的设计准则 ,并给出了对比实验波形和详细的分析过程。通过样机实验 。

A novel soft switching circuit is proposed based on the previous zero-current-switching (ZCS) and zero-current-transition (ZCT) for the push-pull forward converters. It can make the main switch turn off with ZCS; its resonant network does not lie in main power loop so that the resonant current is very low. Compared with the previous circuit, the current of the main switch is decreased and the converter losses are reduced because of the soft-switch; adjusting the turns ratio of the auxiliary winding can decrease the voltage of the rectifier. The reliability and the efficiency of the converter are largely improved. The ZCS push-pull forward converter using transformer auxiliary winding and design guidance of resonant parameters are analyzed. The operation and the analysis are verified on a 76 V/1 kW/80 kHz MOSFET based on the experimental circuit.