一种高效率无桥双谐振功率因数校正变换器

摘要

在无桥Flyback功率因数校正(PFC)变换器中引入二次侧谐振电路,提出一种无桥双谐振PFC变换器.该变换器利用变压器二次侧漏感与谐振电容的谐振,减小了开关管关断电流,从而降低了开关管的关断损耗.同时,二次侧二极管实现零电流关断,有效抑制二极管的电压尖峰和振荡.接着分析变换器工作于临界连续模式(CRM)的工作原理和工作特性,给出变换器关键参数的设计原则.最后通过实验验证了理论分析的正确性.%A secondary resonant circuit is introduced into the bridgeless Flyback power factor correction (PFC) converter,and a bridgeless dual resonant PFC converter is proposed in this paper.The turn-off current of switch decreases due to the resonance between the secondary leakage inductance of the transformer and the resonant capacitor.Therefore,the turn-off losses of switch are greatly reduced.Meanwhile,the secondary diodes turn off at zero current,which effectively suppressed the voltage spike and oscillation.The operation principle and characteristics of the proposed converter working in critical conduction mode (CRM) are analyzed.The design principles of the key parameters in the converter are also presented.Finally,experimental results verify the theoretical analysis of the proposed converter.