Electro-Thermal Design Characterization of a High Power SiC based ANPC Inverter for EV / Aerospace Applications

This paper presents a detailed design of a 1000V, 250 kW Silicon Carbide (SiC) based Active Neutral Point Clamped (ANPC) inverter, adhering to the specifications set forth by the Aviation-Class Synergistically Cooled Electric-motors with Integrated Drives (ASCEND) project, an initiative under the Advanced Research Projects Agency-Energy (ARPA-E).The ANPC inverter utilizes a hybrid combination of high and low thermal resistance commercial off-the-shelf (COTS) SiC modules along with a Hybrid PWM strategy.A thermo-electric evaluation of such an all-SiC hybrid ANPC inverter is discussed in detail. The design methodology integrates PLECS electro-thermal simulation and Finite Element Analysis (FEA) using ANSYS SIWave and Icepak.An experimental inverter prototype was built in which the SiC modules where cooled by a liquid cooling system. Experimental validation was conducted using a pump-back test arrangement of two single-phase ANPC inverter legs with 15.2kVA apparent power and 13.11 kW of active power being circulated between the converters. This represents the equivalent cruise power per phase for the ASCEND flight profile.Furthermore, a procedure was established to estimate the junction temperature of a COTS SiC module.