Experimental Comparison of Radiated EMI in Si MOSFETs and WBG GaN for Low Voltage Motor Drives

This paper compares the radiated EMI of Si MOSFET and GaN HEMT-based low voltage (LV) batterypowered VSIs. Key differences between the technologies such as slew rate, reverse recovery (Qrr), switching frequency, and parasitics are analysed to investigate variances in emission spectra. Bench testing extracts switching events for varying slew rates. Models for Radiated EMI are produced from these extracted waveforms. Practical measurements occur in a semi-anechoic chamber under various operational conditions. The results provide insights into emission origins and device behaviour, highlighting the differences between GaN and Si technologies for switching up to 150kHz.