Power Factor Corrector with Bridgeless Flyback Converter for DC Loads Applications

Abstract

Since power systems with a DC distribution method has many advantages, such as conversion efficiency increase of about 5–10%, cost reducing by about 15–20% and so on, the AC distribution power system will be replaced by a DC distribution one. This paper presents a DC load power system for a DC distribution application. The proposed power system includes two converters: DC/DC converter with battery source and power factor corrector (PFC) with a line source to increase the reliability of the power system when renewable energy or energy storage equipment are adopted. The proposed PFC adopts a bridgeless flyback converter to achieve power factor correction for supplying power to DC loads. When the bridgeless flyback converter is used to achieve PFC, it needs two transformers to process positive and negative half periods, respectively. In order to increase conversion efficiency, the flyback one can add two sets of the active clamp circuit to recover energies stored in leakage inductances of transformers in the converter. Therefore, the proposed bridgeless flyback converter can not only integrate two transformers into a single transformer, but also share a clamp capacitor to achieve energy recovery of leakage inductances and to operate switches with zero-voltage switching (ZVS) at the turn-on transition. With this approach, the proposed converter can increase conversion efficiency and decrease component counts, where it results in a higher conversion efficiency, lower cost, easier design and so on. Finally, a prototype with a universal input voltage source (AC 90–265 V) under output voltage of 48 V and maximum output power of 300 W has been implemented to verify the feasibility of the proposed bridgeless flyback converter. Furthermore, the proposed power system can be operated at different cases among load power PL, output power PDC1 of DC/DC converter and output power PDC2 of the proposed PFC for supplying power to DC loads.