A Cockcroft-Walton voltage multiplier with PFC using ZC-ZVT auxiliary circuit

This paper proposes a soft-switching technique applying to a single-stage single-phase ac to high voltage dc converter based on Cockcroft-Walton (CW) voltage multiplier circuit. Originally operating under hard-switching, the proposed converter improves switching characteristics by adding an auxiliary circuit for achieving soft-switching. The circuit operation principle of the proposed converter is presented in this paper. The design consideration for determining the values of circuit components used in the implementation is driven as well. For improving the line condition, power factor correction is applied to the proposed converter. Some conventional PFC control methods can be easily adapted to the proposed converter with few modifications. For convenience, this paper employs a commercial PFC IC to implement the controller for the proposed converter. The PWM signal generated form the PFC IC is modified by a simple digital circuit and then sends to the main and auxiliary switches in the power stage. A 500W/1200V prototype is built for test, measurement and evaluation. Finally, the experimental results demonstrate the validity of the proposed converter.