3D FEA investigation of the PM segmentation on the iron loss of fractional-slot machines

The estimation of PM eddy current loss in fractional slot PM machines (FSPMMs) is of great importance since it is closely related to the prediction of their efficiency. This issue turns to be critical accounting for the FSPMMs capability to achieve a wide speed range. The paper is devoted to a 3D FEA-based investigation of the effect of PM segmentation on the variation of their eddy current losses at load operation constant power and flux weakening range operating points in a 12 slot/10 pole FSPMM. The developed study considers three different segmentation configurations, such that: (i) the radial segmentation, (ii) the axial segmentation, and (iii) the axial-skewed segmentation. The postprocessing of FEA models yields the time variation of eddy current loss in each PM segment as well as the loss density maps in the PMs for each segmentation configuration. It has been found that the radial segmentation is more effective than the other configurations.