Analysis of non-uniform circumferential segmentation of magnets to reduce eddy-current losses in SPMSM machines

Eddy current losses generated in the rotor of the permanent magnet machines may lead to an excessive magnet heating. This can cause full demagnetization of the magnets so it is very important to analyze the losses on them to adopt solutions to reduce eddy current losses. The most common technique is the magnet circumferential segmentation. The segmentation of the magnetic poles usually is the same for each magnet segment. In this paper a new concept named nonuniform magnet segmentation is presented, where the length of each segment of a pole is chosen to minimize the losses. This method is tested in three different machines with particular characteristics and the results confirm that fewer losses can be achieved with this segmentation technique.