Modeling and analysis of a rectifier voltage stress mechanism in PSFB converter

This paper proposes a simple but effectual method to alleviate the voltage stress of the rectifier and improves the overall efficiency of the conventional PSFB converter. This method is based on such a factor that the equivalent circuit of the PSFB converter during the voltage oscillation period can be treated as a fifth-order model, and thus, the amplitude of the voltage ringing across the rectifier can be retrain by adjusting the value of the inductor in the primary-side. Moreover with this method, it is even possible to remove the RC snubber completely to improve the efficiency, but the voltage stresses of the rectifier can still be limited in an acceptable level. The analysis and design process of this method are presented in this paper, and with this method, a reduction of 15V voltage stress and an increment of 2% efficiency can be obtained in the experimental 240 W (10 A, 400 V/24 V) prototype.