Design of ac/dc converter for bidirectional on-board battery charger with minimizing the amount of SiC MOSFET

This paper is mainly focus on bidirectional on-board charger with high performance and low cost. With SiC MOSFET, it is possible to make the on-board charger high efficiency, high power density and light weight. However, the price of the SiC MOSFET is higher than Si based MOSFET. Therefore, a high performance on-board charger with a small number of SiC MOSFET is the key factor to limit the cost of the bidirectional AC/DC converter. This paper analyzes the inverter mode and PFC mode to find out the way to decrease the number of SiC MOSFET without affecting the performance. Ultimately, unipolar PWM and totem PFC control strategies are adopted. Besides a LCL filter is also used to increase the power density. A 3KW bidirectional AC/DC prototype verifies the methods.