A Synchronous Rectification Method of Bidirectional CLLC Resonant Converter Based on Phase and Duty Cycle Regulation

Abstract

In bidirectional CLLC resonant converter, if the parasitic inverse diodes of MOSFETs are used for rectification without driving signals at the secondary side, there will have a larger conduction loss when current flows through them. Therefore, the driving signals of MOSFETs at the secondary side of the converter for synchronous rectification can be modulated to reduce the circuit conduction loss. To solve this issue, in this paper, a synchronous rectification method based on regulating phase and duty cycle of the secondary side MOSFETs driving signals in bidirectional CLLC resonant converter is proposed to reduce the conduction loss. According to the relationship between the switching frequency and the first resonant frequency, the driving signals of synchronous rectifier can be achieved. Then the feasibility and validity are verified by simulation.