无整流桥Boost PFC软开关电路的研究

Study of a Soft-Switching Bridgeless Boost PFC

在硬开关条件下,功率器件的开关频率越高,其开关损耗越大,致使变流电路的效率降低,并且功率器件的发热量增大,温升提高,这极大限制了变换电路在大功率场合的应用。据此,文章研究了无整流桥Boost软开关PFC电路。该电路省去了传统PFC电路中的整流桥,导通元件减少,导通损耗降低。同时,该电路引入了谐振网络,仅用一个有源辅助开关管实现了主功率开关管的软开关状态,辅助开关管也工作在软开关状态,提高了电路的效率。文中分析了主拓扑的工作原理及其特性,并进行了仿真试验验证,实验结果验证了理论分析的正确性。

Under the condition of hard switching, higher switching frequency of power devices will bring about more switching loss, which leads to lower efficiency and higher temperature rise. These greatly limit the switching frequency of converters in high power applications. Therefore, a soft switching bridgeless Boost PFC circuit is proposed in this article. It leaves out the rectifier bridge in conventional PFC circuit, and reduces device count and conduction loss. Meanwhile, an active auxiliary switch is added to the main switch to realize soft switching of both the main and auxiliary switches, which improves the efficiency of the circuit. Operating principle and characteristics of the main circuit are analyzed, and simulation results that verify the theoretical analysis are presented.