Asymmetrical half-bridge converter with an improved coupled inductor rectifier for high efficiency under light-load condition

Abstract

In this paper, a high efficiency asymmetrical half-bridge (AHB) converter with an improved coupled inductor rectifier is proposed. The proposed circuit can eliminate a DC-offset current in the transformer using a coupled inductor at the rectifier stage. Furthermore, because one diode of the conventional CIR is removed in the proposed converter, conduction loss can be reduced. Moreover, proposed converter can reduce diode snubber loss as the voltage stress of diode decreases. In addition, the proposed converter has wide zero voltage switching (ZVS) range of primary switches, which improves light and medium load efficiency. In order to demonstrate the feasibility of the proposed converter, experiments were conducted with a 200W prototype of 250-400 V and 48 V output conditions.