Digitally Implemented Average Current-Mode Control in Discontinuous Conduction Mode PFC Rectifier

This paper proposes a digital average current-mode control method in discontinuous conduction mode (DCM) power factor correction rectifier. The proposed control technique does not estimate, but directly senses the average value of the inductor current in each switching cycle. It is implemented by means of a conventional current sensing circuit and a microcontroller. The calculation burden of the microcontroller is the same with that of conventional two-loop-controlled converter because the additional calculation process is not required. The control method achieves lower total harmonic distortion and higher power factor than the conventional technique. Experimental results with a 200-W prototype verify the feasibility and performance of the proposed control method.