Choice of Pole Spacer Materials for a High-Speed PMSM Based on the Temperature Rise and Thermal Stress

This paper investigates the choice of pole spacer materials for a high-speed surface-mounted PMSM based on the temperature rise and thermal stress. For a rotor without copper shield, the influences of pole spacer materials on the rotor losses, temperature rise, and thermal stress are analyzed. After that, the rules for selecting pole spacer materials are concluded. For a rotor with copper shield, the effects of copper shield's positions and thickness on the rotor losses are studied. Then the variation of temperature rise of the rotor with copper shield thickness is described. Finally, the influences of pole spacer materials on the temperature rise and thermal stress of the rotor are compared and the rules for choosing pole spacer materials are summarized.