The Role of Magnet Segmentation in a High-Speed IPMSM: Torque and Loss Reduction

This paper presents a detailed investigation of magnet segmentation for the circumferential and axial direction for a high-speed interior permanent-magnet-synchronous machine with a double-layer U-shaped rotor geometry. The simulations are performed in 2-dimensional as well as in 3-dimensional finite element analysis with sinusoidal excitation. The analysis is carried out for various machine lengths, taking into account the change in segmentation effectivity for axial scaling. For a reduction of the simulation time in 3D finite element analysis, carrier harmonics and slots harmonics will be considered in relation to the loss reduction through segmentation in 2 D. In conclusion, the results are specifically analyzed in terms of magnet mass loss under various segmentation scenarios and isolation thicknesses. This analysis uniquely enables the prediction of both loss reduction and torque reduction across a wide range of machine geometries.