Average Current Mode Control in Digitally Controlled Discontinuous-Conduction-Mode PFC Rectifier for Improved Line Current Distortion

Abstract

This paper proposes a digital average current mode control method in discontinuous conduction mode (DCM) power factor correction (PFC) rectifier. The proposed control technique can directly sense the average value of the inductor current in each switching cycle digitally by employing a conventional current sensing circuit. Thanks to the current control loop, high speed analog-to-digital converters (ADC's) or high performance digital IC's are not needed. The technique achieves lower total harmonic distortion (THD) and higher power factor (PF) than conventional DCM PFC rectifiers. Experimental results using prototype hardware verify the feasibility and performance of the proposed sensing method.