Input voltage estimation method and suppression of distortion caused by DC voltage ripple for input current control of PFC

Abstract

This paper proposes a new method for input current control of power factor correction (PFC) with continuous conduction mode (CCM), which does not require input voltage detection. As a control method that does not use input voltage detection, pulse width modulation (PWM) with the inductor current as the modulated signal is already in practical use however, this approach has limitations for the range of inductance values used. In CCM-PFC, the input rectified voltage and low-frequency component of the voltage of the switching circuit are approximately equal in the stable state as well as proportional to the PWM signal. This study uses the previous modulated signal as the estimated voltage value to generate an instantaneous current command for feedback control. In addition, a method to suppress the influence of the DC voltage ripple by changing the voltage control gain according to the value of the DC voltage was employed. From the evaluation, it was confirmed that the harmonics of the input current were suppressed within the specified range of values. K E Y W O R D S current control, PFC, voltage detection 1 Similar methods based on the same principles are sometimes called one cycle control or peak current mode control. In the paper, we use the collective term modulated carrier control.