Electrical aging characteristics of Aramid paper under nanosecond impulse and AC voltages for the stator slot of electric vehicle motors

Abstract

Abstract Electric vehicles (EVs) have been helping to alleviate the pressure of the world energy crisis. However, the insulation of EV driving motors usually suffers from the electrical stress caused by partial discharge (PD) during the operation. Aramid paper in the stator can reduce the incidence of electrical degradation. In this context, PD characteristics, topography and chemical group changes of Aramid paper under AC and repetitive nanosecond impulse voltages were compared. The results illustrated that the increase of ambient temperature will promote the activity of PD under AC voltage. The PD magnitude under nanosecond impulse voltage is almost 100-fold that under AC voltage. PD caused by nanosecond impulse voltage leads to more severe destruction of chemical groups and higher roughness. This investigation offers an important reference for exploring the electrical aging of Aramid paper for the slot of the stator in EVs motor.