PWM–PFM hybrid controlled LCC resonant converter with wide ZVS range and narrow switching frequency variation

摘要

Variable frequency controlled LCC resonant converter suffers from wide variation of switching frequency. Although fixed frequency controlled LCC resonant converter benefits from constant switching frequency, it suffers from narrow zero voltage switching (ZVS) range of power switch and high circulating energy. A pulse width modulation - pulse frequency modulation (PWM-PFM) hybrid controlled LCC resonant converter is proposed to achieve wide ZVS range of power switch with narrow variation of switching frequency. Experiment results of a 500 W prototype are provided to verify theoretical analysis of the proposed converter.