The Method for Decoupling the Parasitic Inductance of the Laminated Busbar with SiC MOSFETs in Parallel

Abstract

Discrete Silicon Carbide (SiC) MOSFETs are usually used in parallel to enhance the current capability for medium and high-power application. However, the rough design of the busbar structure may lead to an asymmetric parasitic inductance of the parallel branches., which can further cause the current imbalance. Thus, a symmetrical busbar design is critical for the parallel application of the discrete SiC MOSFETs. While, mutual coupling between the parallel branches, and with the increase in the parallel devices can lead to a very complicated inductance network. It is not convenient for the prediction of the current balance and estimating the symmetry of the busbar. Based on it, this paper proposes a decoupling method to acquire the equivalent inductance that can easily evaluate the current balance performance. Meanwhile, it can further provide a basis for the busbar structure design. A specific laminated busbar with six devices in parallel in each bridge arm for an electrical vehicle inverter is used as a case study. And the prosed decoupling method is verified by simulation and experimental tests.