PM-machines with an additional shielding sleeve to reduce the rotor losses

Rotor losses have a major impact on the performance of high-speed permanent magnet synchronous machines. Therefore a way to reduce rotor losses by using shielding cylinders is proposed and the effects of these measure are discussed according to the main causes of the rotor losses, which are current harmonics and winding harmonics. The loss minimisation will be demonstrated a for a specific high-speed motor design.