Accurate Modeling of the Effective Parasitic Parameters for the Laminated Busbar Connected With Paralleled SiC MOSFETs

Silicon Carbide (SiC) MOSFETs are usually paralleled to increase the current capability for high power applications. While, the asymmetrical parasitic parameters of the wide-used laminated busbar can cause current imbalance for paralleled MOSFETs. The fast switching of SiC devices can further deteriorate the imbalance. However, the complex current paths and their mutual effects are seldom considered and effectively modeled for the parasitics of the busbar, which is not accurate enough to evaluate the current imbalance for the busbar connected with SiC devices. This paper proposes accurate modeling of the effective parasitic parameter of laminated busbars with paralleled SiC MOSFETs. The model incorporates not only the self-inductance and resistance but also the complex mutual coupling effect of all the current paths. Moreover, a switching period is divided into two durations for accurate effective parasitic models, in which the busbar can have different effective models regarding one physical structure. Furthermore, for easy evaluation of the current balance, a single effective model, namely equivalent model, is derived for a physical structure by replacing the complex mutual network. A specific laminated busbar for EV inverter is analyzed to prove the above theory, which is validated by simulation and experiment separately.