Calculation of rotor eddy-current loss in high-speed PM alternators

This paper is concerned with the calculation of rotor eddy-current power losses in high-speed permanent magnet (PM) alternators. The work described covers the no-load tooth-ripple losses due to the distortion of the fundamental flux density wave by the stator slotting (making the flux density stronger under teeth and weaker under slots), and the on-load losses which include the additional effects of the MMF winding harmonics, including particularly the important slot order harmonics. Significant eddy-current losses may occur in the magnet material, in the steel hub underlying the magnets, and in the retaining sleeve over the magnets if that is conducting.