A High Efficiency Zero-Voltage-Switching Boost Voltage Doubler With Low Conduction Losses

high efficiency zero-voltage-switching three level boost converter for power factor pre-regulator is proposed in this paper. The topology can perform ZVS in the main switches and the passive switches, and zero-current switching in the auxiliary switch. Furthermore, soft commutation of the main switch is achieved without additional current stress by the presented ZVS-PWM auxiliary circuit. A significant reduction in the conduction losses 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, and the proposed rectifier is suit for low line voltage and high power applications. A prototype rated at 600 W, operating 50 kHz, with an input ac voltage of 120 Vrms and an output voltage of 400 Vdc has been implemented in the laboratory. An efficiency up to 97% and power factor over 0.99 has been measured.