Graded Surface Modification of Electric Vehicles Motor Insulating Material by using Plasma to Tailor Surface Charges

Insulation challenges in power frequency converters arise from electric stresses on motor winding slots and overhang junctions, leading to erosion of stress-grading insulation due to partial discharge and heat. Additionally, nonuniform electric field distribution and thermal transients at the slot-coil interface pose challenges. This study focuses on modifying the surface of polyimide-based composite varnishing to achieve uniform electric field distribution. A novel fluorescence-enhanced hexamethyldisiloxane atmospheric pressure plasma jet is used to modify the surface, enhancing surface conductivity and converting deep traps into shallow traps. Samples treated with plasma demonstrate accelerated dissipation of accumulated charges, signifying enhanced electrical properties. This improvement can help to improve other electrical characteristics like flashover and breakdown strength. Furthermore, the integration of graphene oxide enhances thermal properties, facilitating the efficient dissipation of heat generated during electric motor operation.