Investigation of Ceramic-like Composite Systems for the Winding Insulation of a Permanent Magnet Excited Synchronous Machine in Outer Rotor Construction for an Electric Vehicle Drive

Abstract:
When designing electrical machines for electric vehicle drives, one goal is to achieve a high level of electromagnetic utilization of the active part of the electrical machine. This is possible by increasing the current loading, whereby the application limit is resulting from the maximum permissible temperature of the insulation materials of the winding. Because of the low specific thermal conductivity of conventional insulating materials, large temperature gradients arise in the winding cross-section and hotspots are generated e.g. in the end windings. The article presents the development and characterization of ceramic-like polysiloxane composite materials for the dip coating of lamination stacks as well as the impregnation of the winding of electrical machines. The potential for increasing the power density resulting from the improvement of the heat dissipation ability is demonstrated based on an experimental investigation of a permanent magnet excited synchronous machine (PSM) with outer rotor for an electric motorcycle drive.