Influence of shaft relative permeability on rotor losses in 2-pole slotless high-speed motor

This paper presents a time-efficient transient numerical method for three-dimensional analysis of rotor losses in a three-phase 2-pole high-speed permanent-magnet synchronous machine. The motor has axially stacked ring shaped permanent magnets (PM). The influence of shaft material properties on rotor harmonic losses and loss distribution between the rotor shaft and magnets is investigated in the frequency range 10-100 kHz. It is found that the shaft magnetic properties have a significant impact not only on the total rotor losses, but on the magnet losses and inductance as well.