Analysis of a novel boundary conduction mode (BCM) and voltage control of buck capacitor in single-stage PFC circuit

In single stage, power factor correction circuits, the high voltage of the bulk capacitor is a common problem. This paper analyses the reason for this problem and then proposes a novel boundary conduction mode (BCM) of PFC circuit to solve the problem. Based on the analysis of the boundary point of the PFC converter and the DC-DC converter, the analytic formulation of the working principle of the BCM is obtained and the control method to decrease the high voltage of the bulk capacitor is presented. The circuit uses a common IC to realize the high power factor, control the voltage of the capacitor, decrease the stress of the switches and increase the stability of the circuit. In this paper, the equation for the power factor of the circuit based on the analysis of the distortion of the input current is derived. Finally, the circuit performance was verified experimentally