Loss Analysis of Permanent Magnet Motors with Concentrated Windings - Variation of Magnet Eddy Current Loss Due to Stator and Rotor Shapes

In this paper, we investigate losses including magnet eddy current loss of permanent magnet synchronous motors with concentrated windings. The 3-D finite element method considering the carrier harmonics of PWM inverters is utilized to calculate the losses in each part of the motor separately. A simple linear magnetic circuit modeling is also introduced to understand the mechanism of the magnet eddy current loss generation. First, the measured and calculated results are compared to verify the validity of the analysis. Next, the variation of the losses due to the stator and rotor shapes are investigated, for instance, concentrated and distributed stator windings, interior and surface mounted permanent magnets. It is clarified that the eddy current loss of the permanent magnet in the concentrated winding motor is much larger than the distributed winding motor. The difference of the loss generation mechanism due to the rotor shape is also clarified.