Comparison of Si and SiC EMI and Efficiency in a Two-Level Aerospace Motor Drive Application

Power electronics are crucial elements in more-electric aircraft (MEA) applications. Existing hardware is almost exclusively silicon (Si)-based. However, recent advances in semiconductor technology yielded silicon carbide (SiC) components with current ratings suitable for aerospace applications. These devices have much strength that can increase power density and improve performance over Si-based hardware. High switching speeds are characteristic of SiC devices, and there is much concern about their impact on electromagnetic interference (EMI). This may necessitate larger EMI filters to comply with EMI standards, which would decrease power density and negate some of SiC's benefits. The following research explores the tradeoff between efficiency and EMI. It compares the performance of two high-power three-phase converters: one built from SiC MOSFETs and the other from Si IGBTs. The test setup consists of a 250-kW drive stand capable of sourcing and regeneratively sinking power as well as a 40-kVA aerospace rated machine. Experimental results are obtained at a bus voltage of 270-Vdc with power levels exceeding 1.5 p.u. The findings demonstrate comparable EMI performance for Si and SiC under MIL-STD-461 with the SiC converter achieving higher efficiency.