A bi-flyback PFC converter with low intermediate bus voltage and tight output voltage regulation for universal input applications

A single-stage bi-flyback power factor correction topology is proposed in this paper. By adding a secondary winding to BIFRED choke inductor, there are two discharging paths for the choke inductor: to load or to intermediate capacitor. In this topology, the intermediate bus voltage is limited to below 400 VDC for universal voltage applications, and DC/DC conversion cell can operate in CCM. A 150 W prototype unit based on this topology has been built and tested in the lab with experimental results that show good performance.