A new analytical conducted EMI prediction method for SiC motor drive systems

Abstract

Abstract Although silicon carbide (SiC) devices can greatly improve the energy efficiency of electric motor drive systems and increase the power density of inverters as well in electric vehicle applications, fast switching and high-frequency operations of the devices bring more serious electromagnetic compatibility (EMC) problems. It is very important to predict the electromagnetic interference (EMI) level of SiC motor drive systems at design phase. However, since the megahertz resonances caused by the system parasitic parameters can’t be ignored, conventional EMI prediction methods need to be improved. In this paper, the fast switching transient of SiC devices, the power module parasitic parameters, and other detailed circuit parameters are modeled into the EMI sources and propagation paths. In the differential mode (DM) and common mode (CM) EMI sources modeling, both the equivalent switching current sources and the equivalent switching voltage sources of SiC devices are simultaneously taken into account. The proposed analytical method can accurately predict conducted EMI in the SiC motor drive system in frequency range from 150 kHz to 30 MHz. Compared with the previous conventional methods, the proposed method improves DM EMI prediction accuracy of the SiC motor drive system in high frequency range.