High Temperature Motor Drive

The goal of this proposal is to develop a WBG based motor drive that can interface with military 600 Vdc power systems, provide 18 kW of output power, and have full power capability with ambient air temperatures of 71 °C and liquid coolant temperatures of 105 °C. Building upon an existing 105 °C coolant SiC based motor drive, Mainstream Engineering proposes a revised SiC based motor drive that is smaller and lighter than our legacy system. The proposed SiC based motor drive is built around custom SiC modules built in collaboration with WolfSpeed, where the optimum number of MOSFETs and anti-parallel diodes is selected for the specific application. This allows for a reduction in SiC module footprint by more than 50% as compared to Mainstream existing SiC based motor drive. The SiC device switching frequency was selected to be 25 kHz (above the audio frequency range), thus minimizing the system detectability in the field. Even at this high switching frequency, the proposed motor drive is 98.8% efficient, weighs only 13 lbs, and has a high power density with almost a 2x improvement over Mainstream existing SiC based VFD.