Winding insulation improvement by thin film metalized winding head support for fast switching SiC-voltage inverter drives

Abstract

This paper proposes a winding head support design with a thin film surface metallization for edge rounding to avoid high electric field strengths and thereby winding insulation failures. Base materials of the winding head support are high performance plastics like polyetheretherketone (PEEK) or high temperature resins with good heat resistance capabilities and a low electrical conductivity to minimize eddy current losses. The metallization layer of the support is manufactured in thin film technology for the same purpose. The main focus of the work lies on investigating the improvement of dielectric strength of the insulation system. Electrostatic FEM-calculations are being conducted to estimate the distribution of the electric field strength in the area of the stator edges. Within this work eddy current losses inside the metallization layer are also considered. Although the conductive film of the support is with a thickness fewer than 100 microns [1] very thin, heating, especially in the area of the winding head, may cause structural and lifetime issues. On this account, FEM-simulations regarding eddy current losses and thermal distributions are being progressed.