Design of a bridgeless PFC with Line-Modulated Fixed Off-Time current control and zero-voltage switching

In this paper, the Line-Modulated Fixed Off-Time method is used as the current control strategy for a Power Factor Corrector (PFC) pre-regulator. A zero voltage switching PWM (ZVS-PWM) auxiliary circuit is configured to perform ZVS in the switches. Soft commutation of the main switch is achieved without additional current stress. A significant reduction in the total conduction loss is achieved, since the circulating current for the soft switching flows only through the auxiliary circuit and a minimum number of switching devices are involved in the circulating current path. The proposed rectifier uses a single converter instead of the conventional configuration composed of a four-diode front-end rectifier followed by a boost converter. A 250W, with an input ac voltage of 90-265 Vrms, output voltage of 400 Vdc and switching frequency of 100 kHz is designed and simulated to verify the system performance.