Digital-controlled power factor corrector with transition current mode control without zero current detection

It is well known that transition current mode control for power factor corrector can reduce the reversal recovery loss for the diode. This method can be realized using discrete control integrated circuit which requires zero-crossing detection circuit. In this paper, a novel control technique for digital-controlled power factor corrector to achieve transition current mode control is proposed. The switching period to retain zero current switching is predicted and the turn-on period is determined by the voltage controller. Experimental results derived from a DSP-based controller are presented for confirmation. The power factor corrector is with 100 V/AC input and 400 V/DC output. Its power rating is 250 W. Experimental results show that the power factor is higher than 0.98, efficiency is greater than 94% and current total harmonics distortion (THDi) is smaller than 4% under full load condition and confirms the above-mentioned claims very well.