Current phase lag issue and the compensation scheme for OCC PFC converter

Abstract

A new equivalent input circuit of one-cycle-controlled (OCC)PFC converter is built, based on which, the current phase lag issue especially outstanding at low ratio of switching frequency to line frequency is analyzed, and a novel current phase lag compensation scheme by controlling the voltage across the switch is proposed to reduce the phase lag of line current relative to line voltage. Implementation method of the compensation scheme with digital control is introduced, and a design example is given. The stability of the system using the compensation scheme is verified by frequency-domain analysis. The newly built equivalent input circuit can more preciously reflect input characteristics of the OCC PFC converter, and the proposed compensation scheme can reduce the current phase lag, and increase the displacement power factor, which has been verified by experimental results.