Design and Simulation of a Single Stage Control Strategy for Power Factor Correction based on Soft Switched Flyback Converter

This work proposes a control strategy for power factor correction utilizing soft switched flyback converter. The conventional system fed by AC source consists of two stages for output power greater than 100 watts. Power factor correction (PFC) is the first stage and second is DC-DC converter for output regulation. Isolation is desired between input and output for most applications. Flyback converter is the simplest SMPS topology with isolation. Energy stored in leakage inductance is recycled for soft switching by incorporating active snubber (or clamp) instead of RCD network. Hence, zero voltage switching (ZVS) is achieved. This paper proposes a control scheme for flyback converter with active snubber that combines PFC and output regulation in a single stage. The number of active and passive components is reduced by combining these two stages. Further, Total Harmonic Distortion (THD) of input current is presented in this work.