Effect of driver to gate coupling circuits on EMI produced by SiC MOSFETS

This work presents a study of the influence of different gate driver circuits on the switching behavior and EMI produced by SiC MOSFET devices used in a boost converter. The paper includes several simulations of switching behavior using different VGS voltage levels and different passive RCD (Resistance Capacitor Diode) circuits to interface the driver to the SiC MOS gate and several tests of conducted and radiated EMI for each one of the interface circuits. The paper also includes a comparison of both aspects (switching and EMI) when using different gate voltage levels. The study reveals that gate voltage has little impact on switching behavior and therefore on conducted and radiated EMI, while gate RCD coupling circuits have a noticeable impact. The EMI reduction, when using the adequate driver-gate circuit may be in the order of 10 dB at certain frequencies in the conducted band and up to 20 dB for certain frequencies in the radiated band.