Suppression of conducted, high frequency signals in aerospace DC/AC converters designed with SiC MOSFETs

This paper presents the impact of voltage fall time of SiC MOSFETs, applied in converters of aerospace DC fed AC drives, on a HF conducted EMI signals. Simple frequency domain behavioral model is proposed for the use. Simulation results and real system measurements are successfully compared. It was shown that appropriate tuning of MOSFET voltage fall time by means of gate driver design allows to selectively suppress common mode noise in the high frequency range. Associated EMI filter design is showing that such suggestion can be used to compensate negative impact of equivalent parallel capacitance of the common mode chokes, leading to simplified filter structure. Resulting impact on the switching energy loss per one commutation cycle is also discussed.