Common-Mode EMI Mathematical Modeling Based on Inductive Coupling Theory in a Power Module with Parallel-Connected SiC MOSFETs

Parallelization of silicon carbide (SiC) metal-oxide-semiconductor field-effect transistor (MOSFET) could significantly improve the current capability and power rating of power converters. However, the inductive coupling effect of parasitic inductance between the paralleled branches is a critical challenge for the mathematical modeling of electromagnetic interference (EMI) in a power module with parallel-connected SiC MOSFETs (PMPSM). In this article, first, an EMI source generation mathematical modeling method for PMPSM is proposed. The quantitative analysis of EMI interference source caused by inductive coupling of PMPSM is introduced. Second, a common mode (CM) interference propagation mathematical modeling method for PMPSM is proposed. Through the equivalent CM interference source and equivalent impedance model, the strong and weak inductive coupling theory of CM interference equivalent circuit based on parallel-connected SiC MOSFETs is proposed. Third the effect of different decoupling capacitance values on EMI source is compared and analyzed and the influence of changing the ratio of coupling inductance inside and outside the decoupling branch on EMI source of parallel-connected switches is analyzed. Finally, a self-made 1.2-kV 160-A PMPSM based on EMI optimized layout is proposed and tested via an experimental platform of synchronous buck converter, which can verify the feasibility and validity of the proposed power module and the theoretical analysis.