Verification of PD Suppression by Multi-Level Inverter for Electric Aircraft

This paper investigates the effectiveness of a multi-level inverter in preventing turn-to-turn partial discharge in the high-voltage systems of electric aircraft. First, circuit simulations confirm that using a multi-level inverter reduces the first coil voltage in a three-phase motor winding. Second, partial discharge experiments are conducted using a mock winding circuit and a multi-level inverter. The results suggest that the voltage required to initiate partial discharge in a 7-level multi-level inverter is five times larger than that in a 2-level inverter. Therefore, increasing the number of levels in a multi-level inverter can help prevent turn-to-turn partial discharge of motors, contributing to realizing an electric aircraft with high-voltage systems.