Investigation of SiC Current Source Inverter for Medium-Voltage High-Frequency Electric Aircraft Propulsion Applications

High efficiency, high power density, and high reliability are three essential criteria for evaluating aircraft propulsion drives. In this paper, a current source inverter (CSI) based on Silicon Carbide (SiC) normally-on MOSFETs is proposed for electric aircraft propulsion drives. The high-frequency operation of the SiC CSI enables lower value of dc-link inductance. Additionally, unlike the conventional voltage source inverters (VSI), the inherently sinusoidal line-to-line voltages waveforms output from the CSI waives the necessity of having a bulky sinewave filter or dv/dt filter, even for long-cable-fed motor drive applications. Therefore, high efficiency and high power density can be concurrently achieved for the proposed propulsion drive. Moreover, differing from the VSI, CSI with normally-on semiconductor switches can tolerate uncontrolled generator fault in which the microcontroller is tripped by electromagnetic inter-ference or other causes when the permanent magnet synchronous machine is operating at high speed with large induced back electromotive force. Simulation results are presented to confirm the high performance of such a SiC CSI based aircraft propulsion drive.