A single stage single switch power factor correction converter

The flyback-flyback single stage converter operated in DCM+DCM is easy to control bus voltage, but hard to control switch stress. We propose a new converter having low voltage stress on its switch. The flyback converter is simplified into buck-boost form. Also, the PFC flyback transformer is replaced by an inductor. The switches of both PFC and DC/DC stages are merged, and a diode is used to force the direction of power flow. A 30 W prototype is built to evaluate the performance.