Design and Analysis of an Active Adaptive and Regenerative Snubber for PSFB Converter

This paper presents a detailed design and analysis of an active adaptive and regenerative snubber for a phase shifted full bridge converter. A high voltage overshoot at the full bridge rectifier diodes of a PSFB converter occurs due to parasitic components such as transformer leakage inductance and diode capacitance. A snubber is essential in this converter to limit the voltage overshoot and the stress on the diodes. A control methodology for the snubber is proposed that reduces the snubber switching frequency and makes the clamping voltage a function of input voltage that helps in reducing voltage stress, voltage ringing magnitude on the secondary diodes, and hence the EMI. The energy efficiency of the snubber is determined, and theoretical energy efficiency and power loss comparisons with other approaches in the literature are presented.