Design Considerations of High-Speed PMSM With Nonuniform Two-Segment Halbach Magnet Array

Halbach magnet array has been widely used in high-speed permanent magnet synchronous machines (PMSM) due to the possibility of creating a highly sinusoidal air gap magnetic field. However, conventional Halbach arrays often adopt magnet segments with uniform thickness which limits the optimization space. In this paper, the Halbach array composed of magnet segments with nonuniform thicknesses is considered to further expand the optimization space. Both electromagnetic and mechanical analyses have been conducted, considering design parameters such as the span angle and thickness of the magnet segments. Characteristics including the fundamental air gap flux density, demagnetization status, and mechanical stress of the rotor are analyzed in detail. The conclusions obtained can be used as the design guidelines for the optimization of PMSM with a two-segment Halbach array.