Operation Characteristic Analysis of an Asymmetrical Half-Bridge Converter with Half-Wave Rectifier

Abstract

Generally, when designing a symmetrical half-bridge converter, the rectifier on the secondary side is composed of a full-bridge rectifier or a center-tap rectifier to take advantage of the full-wave rectifier (FWR). However, when driving with asymmetrical PWM, the benefit of full-wave rectification due to symmetric operation is lost, so a half-wave rectifier (HWR) can be introduced to cope with low-voltage and high-current applications. Furthermore, if an HWR is used with an asymmetrical half-bridge converter (AHBC), the soft switching characteristics of the AHBC can be improved while maintaining appropriate conduction loss. It is because the transformer current has a negative average with the reduced duty cycle loss due to the operation characteristics of HWR. Accordingly, this study examines the superiority of an AHBC with HWR in an efficiency aspect compared to the case of using FWR through the operation characteristic analysis. The validity of the analysis is verified through experiments with a 360-W prototype.