低共模噪声图腾柱SEPIC PFC变换器研究

Research on Low Common-mode Noise Totem Pole SEPIC PFC Converter

传统图腾柱SEPIC功率因数校正(PFC)变换器具有低输入电流纹波、高效率、可实现升降压转换的优点,但由于电路在输入电压负半周工作时,其输出电压相对于输入电压开关周期浮动导致了严重的电磁干扰(EMI)问题,从而限制了该拓扑的应用。基于传统图腾柱SEPIC PFC变换器拓扑,分析了共模噪声的产生机理,并提出采用耦合电感以及隔离变压器结构来解决共模噪声以及输出浮动的问题,该变换器不仅实现了低共模噪声,且实现了图腾柱式单级隔离转换。最后搭建了一台200 W实验样机验证了理论分析的正确性与可行性。

The traditional totem pole SEPIC power factor correction(PFC)converter has the advantages of low input current ripple,high efficiency and voltage rise and fall conversion.However,when the circuit works in the negative half cycle of the input voltage,its output voltage fluctuates relative to the input voltage switching cycle,resulting in serious electromagnetic interference(EMI)problems,which limits the application of this topology.Based on the traditional totem pole SEPIC PFC converter topology,the generation mechanism of common-mode noise is analyzed,and to use coupling inductance and isolation transformer structure to solve the problems of common-mode noise and output floating is proposed.This converter not only realizes low common-mode noise,but also realizes totem pole single-stage isolation conversion.Finally,a 200 W experimental prototype is built to verify the correctness and feasibility of the theoretical analysis.