Design and Optimization of 2×211-kW SiC-Based Aircraft Propulsion Inverter System with High Power Density and High Efficiency

The power rating of the motor drive system in more electric aircrafts is continuously increasing and the Silicon Carbide (SiC) device enables the higher power density and higher efficiency. This paper introduces the design and optimization of a 2×211-kW SiC-based aircraft motor drive system, including the topology selection, parameter optimization, busbar design, device current sampling, phase current reconstruction, short-circuit protection, EMI filter design, insulation and thermal design at high altitudes, and control schemes. Three-level (3-L) T -Type is selected due to the smaller EMI filter compared to the conventional two-level (2-L) inverter. To achieve a high density, the conventional laminated busbar, bulky hall sensors, shunt resistor, and de-sat short-circuit protection are eliminated in this design, and these functions are integrated into a gate driver board, which includes the decoupling path, PCB-based Rogowski coil current sensor, and gate driver circuits. Planar EMI filters on DC and AC sides are designed to suppress the bearing current and meet the standard DO-160. The insulation and thermal design should be paid special attention for the high-altitude operation and the design rules are discussed in this paper. A neutral point (NP) potential balance scheme is designed to mitigate the NP ripple for high-speed operation, and a loss-balance scheme is proposed to solve the overheating issue of clamping switches caused by the breakaway torque. All the performances of the 2×211-kW SiC-based motor drive system are verified with experiments. The power density and efficiency of the motor drive system are up to 19.5 kW/kg and 99 % respectively.