基于紧凑型耦合电感的并联SiC MOSFET电流均衡与电压振荡抑制

Parallel connection of SiC MOSFETs is a cost-effective application for high-capacity and high-frequency power converters. But voltage oscillations and imbalanced currents during the switching operation significantly impair the high-reliability deployment of parallel SiC MOSFETs. In this article, a novel method of using compact coupled inductors to suppress both voltage oscillation and imbalance current is proposed. First, a mathematical model is established to investigate the operating principle of the coupled coil inductance to suppress the imbalance current. Second, the characteristic equations are built via the two-port network and the high-frequency distribution model of a coupled inductor, and the influence of the model parameters on the system stability is analyzed. Finally, the associated parasitic parameters are extracted from the selected representative devices to provide design guidelines for the coupling coils. The parallel-connected SiC MOSFETs with PCB coupling inductors are constructed. The experimental results show that the peak current difference between parallel SiC MOSFETs can be reduced from 40% to less than 2% concurrently with effective suppression of voltage oscillation.