Improved passive snubbers suitable for single-phase isolated full-bridge boost power factor correction converter

In this study, two novel improved passive snubbers suitable for isolated full-bridge boost topology are proposed. The snubbers are composed of two capacitors, two inductors and four diodes. The voltage spike across the primary side of transformer is absorbed by one capacitor of the snubbers during a charging period, and by the other capacitor in the following charging period. The energy of capacitors can be transferred to the output side of the power factor correction (PFC) converter during one charging period by the resonance of the inductors and capacitors. Taking one improved snubber, for example the operational process of the original and the improved snubbers are analysed in a single-phase isolated full-bridge boost PFC converter. Furthermore, between the original and the improved snubbers, comparative analysis about the voltage and current stress, parameters limitation and the reliability are given. Finally, experimental study has been done on a laboratory-made single-phase PFC prototype, and the feasibility of the proposed method and the validity of the theoretical analysis are verified by the experimental results.