The Influence of Parasitic Parameters of Power Modules on CM Current During Switching Oscillation

The penetration rate of SiC MOSFETs gradually increases due to excellent electrical and thermal characteristics. However, the wide-bandgap devices exacerbate switching oscillations, making the conducted electromagnetic interference (EMI) problem more serious. The effect mechanism of parasitic parameters of power module on oscillation common mode (OCM) current is unclear, which is usually not considered. This paper establishes an accurate oscillation CM EMI (OEMI) model considering parasitic parameters. The equivalent voltage source and impedance of OEMI model are given. The model reveals the effect of parasitic inductances and capacitances at different positions on equivalent voltage sources of OEMI model. The OCM current can be completely canceled by parasitic parameters matching without adding other components. The double pulse test (DPT) with power module CAS300M12BM2 is established to verify the amplitude and phase of OEMI model.