Design of Zero-crossing Distortion of Boost Power Factor Correction (PFC) Based on Feedforward Current Control Slope Compensation

The method of feedforward current control slope compensation and its circuit structure are proposed. With this method, the zero-crossing distortion of boundary boost Power Factor Correction (PFC) converter is reduced, for improving limits for harmonic current and frequency of the system. Based on boundary boost PFC converter topology, the modulation of Pulse Width Modulation (PWM) signal duty cycle is analyzed theoretically by the feedforward current control slope compensation technology. The relationship between the compensation slope and input line voltage is derived, which forces the current to follow the input voltage in the vicinity of the ac line voltage zero-crossing points. Simulation and experimental results reveal that, the zero-crossing distortion of the system could be suppressed efficiently with this method, as well as improved system dynamic performance, especially under the condition of high frequency or light load. The measured Total Harmonic Distortion (THD) of the Boost PFC converter is only 3.8%, the power factor is 0.988, the load adjust is 3%, the linear adjust rate is less than 1%, and the efficiency is 97.3%. The active die area is 1.611.52 mm2.