基于分裂电容结构的无电解电容PFC变换器功率解耦电路

PFC converter has inherent double frequency ripple problem. The traditional solution is to filter by connecting large electrolytic capacitors in parallel at the DC side. However, because of the short life and poor safety performance of electrolytic capacitors, it has become the most inefficient device in the converter. In order to remove the electrolytic capacitor and improve the service life and reliability of the converter, this paper proposes a power decoupling circuit of PFC converter based on split capacitor structure. Compared with the basic bidirectional converter type decoupling circuit, this decoupling circuit can significantly improve the ripple absorption capacity of the decoupling circuit. In addition, the structure of split capacitor on the DC side can eliminate the need for additional DC side filter capacitor and improve the utilization rate of capacitor. In addition, a voltage-mode control method based on duty cycle compensation is proposed for the decoupling circuit. This method does not need additional sampling links, which is conducive to reducing the volume and cost of the converter. Finally, the proposed decoupling circuit and control method are experimentally verified, and the experimental results prove the correctness of the theory.