A Peak Current Mode Control Method for PFC

Abstract:
A peak current mode control method for a power factor correction (PFC) is introduced in this paper: the inductor peak current is modulated by a special sawtooth wave, the peak value of the sawtooth wave is a function of voltage loop output and PWM on time, and its magnitude linearly drops to 0 V at the end of the switching period. PWM turns on at the beginning of the switching cycle, and turns off when the inductor current value exceeds the sawtooth wave. This control method can achieve a unity power factor and low total harmonics distortion (THD) for both continuous conduction mode (CCM) and discontinuous conduction mode (DCM) operation, it also brings many advantages over the traditional average current mode control. The proposed peak current mode control method is proved through mathematical analysis, then verified on a PFC converter.