Effect of Eddy-Current Loss Reduction by Magnet Segmentation in Synchronous Motors With Concentrated Windings

In this paper, we investigate the effect of eddy-current loss reduction by the magnet segmentation in synchronous motors with concentrated windings in order to understand appropriate segmentation methods. The loss-reduction effects in each harmonic eddy current in the magnets are analyzed by both the theoretical solution and the three-dimensional finite-element analysis with Fourier transformation. The basic experiments using magnet specimens are carried out in order to support the calculated results. It is clarified that the loss-reduction effect varies with the harmonic orders and that the effect depends on the types of the rotors, for instance, interior and surface permanent-magnet rotors.