Experimental studies on reducing permanent magnet losses through segmentation in a fractional slot PMSM with high power density

The paper presents the results of numerical calculations and experimental tests on reducing eddy current losses in permanent magnets by means of segmentation in a high-power fractional slot PMSM. This type of motor allows for obtaining a high value of specific power (kW/kg), but at the same time they are characterized by the problem of eddy current losses in rotor elements. Thus designed and manufactured model of motor, which is the subject of this work, has a maximum power of 50 kW (at 4800 rpm) and a mass of 10.5 kg. Reducing eddy current losses by segmentation of permanent magnets is a well-known and widely described method, but there is a lack of papers showing the results of experimental studies, in particular of high-power density motors. This article presents results of the effectiveness of reducing eddy current losses for several variants of axial and circumferential segmentation. The results of experimental studies were verified and compared with the results of numerical calculations performed in the ANSYS Motor-CAD software.