New SEPIC Derived Semi-Bridgeless PFC Converter for Battery Charging Application

This paper proposes a novel AC–DC semi-bridgeless dual-switch SEPIC converter tailored for battery charging applications. The proposed design enhances power factor (PF) and significantly reduces total harmonic distortion (THD) in the AC input current by introducing a modified converter topology. Operating in discontinuous conduction mode (DCM), the converter achieves low current THD while enabling a reduction in inductor size. The topology utilizes two power switches to perform power factor correction (PFC), eliminating the need for an additional closed-loop control algorithm. A key innovation lies in the strategic selection and design of the circuit structure, which ensures near-unity power factor and low THD based on the energy balancing of inductors and capacitors. Moreover, the integration of blocking diodes effectively prevents circulating currents through the input inductor, thereby enhancing overall efficiency. This compact and efficient converter offers a promising solution for high-performance battery charging systems.

Keywords: Ac-dc power conversion, SEPIC, power factor correction, total harmonic distortion, discontinuous conduction mode, energy storage system.