Experimental Investigation on Electromagnetic Interference (EMI) in Motor Drive Using Silicon Carbide (SiC) MOSFET

The motor drive is widely applied in industry applications. With the emergency of the next generation wide bandgap semiconductor device, such as silicon carbide (SiC) MOSFET, performance of the motor drive can be improved. However, the fast switching speed and serious switching ringing brought by SiC MOSFET can cause unwanted high-frequency (HF) electromagnetic interference (EMI), which may significantly reduce the reliability of the motor drive in many aspects. In order to reveal mechanism of the EMI existing in the motor drive, this paper has analyzed the influences of both HF impedance of the motor and switching characteristics of the SiC MOSFET based on relative experiment results. Influences of motor impedance on EMI have been elaborated through spectra analysis of the drain-source voltage of the SiC MOSFET, phase to ground voltage of the motor, CM voltage, phase current of the motor, and CM current. Additionally, impacts of switching performance of the SiC MOSFET on EMI are also discussed in detail. Based on the analysis above, the relationship between motor impedance, switching performance of the SiC MOSFET, and HF EMI can be figured out, which is able to provide much helpful assistance in motor drive applications.