Realization of High-Speed Cast Copper Cage Induction Machines for Electric Mobility

Regarding the availability of resources as well as advantageous operating characteristics, the use of induction machines in the high-speed range is desirable, especially in electric mobility applications. In this paper, the main features of the electromagnetical and structural-mechanical design of squirrel-cage induction machines with die-cast cage winding are discussed with the aim of achieving a high power density and high-speed strength. Different conductor materials for the cage (copper, aluminum, copper alloys with optimized yield strength and conductivity) as well as electrical steel sheets with high yield strength and low magnetic losses are considered with regard to their effect on the speed strength and the losses dependent on the working point. In addition, aspects of rotor production, especially with regard to the die-casting process, are presented. The realization of the drive and the performance are discussed based on electromagnetical and mechanical measurements on different rotor prototypes.