A Single-stage Boost-Flyback PFC Converter

This paper presents a novel single-stage single-switch power factor correction (PFC) converter. The proposed topology is derived by combining a boost cell and a flyback cell into one power stage. In this converter, the transformer in the flyback cell has two-coupling primary windings, which have the same turns. Two bulk storage capacitors are used to store the power energy from the input source, and then feed one primary winding of the transformer respectively. In addition, the two capacitors can absorb the leakage inductances energy and clamp the voltage of power switch. Compared with using one bulk capacitor, the voltage across each capacitor here is lower, only half of the line voltage. This converter will potentially have low switch voltage stress, good regulation capability and high efficiency. To verify the performance of the proposed converter, a design example is given with its experimental results.