Feed-forward control scheme to improve light-load power factor for single-stage flyback PFC converters

In this Letter, the author proposes a new feed-forward controller for single-stage flyback power factor correction (PFC) converters. By compensating the phase-lead effect caused by input capacitor current, the proposed feed-forward control duty improves the displacement factor as well as the distortion factor, and so the flyback PFC converter has high power quality. By means of the synchronous rectification circuit, the flyback PFC converter can operate in reverse when the negative current is required. To confirm the theoretical analysis and validity of the proposed control scheme, the author demonstrated the proposed control algorithm with 80 W flyback PFC converter prototype.