Analysis and calculation of circumferential winding tension in high-speed permanent magnet synchronous motor with a novel composite rotor

The permanent magnets in the rotor of conventional surface-mounted high-speed permanent-magnet synchronous motor (HSPMSM) are vulnerable to centrifugal forces during high-speed rotation, which has long limited their rotational speed. This paper presents a novel composite rotor design for HSPMSMs that significantly improves the allowable rotational speed. The composite rotor is wound around the shaft to replace sintered permanent magnets. Therefore, for stable motor operation, it is crucial to analyze the required tension during the winding of composite magnetic materials (CMM). Based on the elasticity theory, this paper derives the analytical model for the mechanical strength of the composite rotor. According to the strength requirements, a forming calculation method for reducing the circumferential winding tension that meets the strength design requirements of the composite rotor is established. Analytical results confirm that this method accurately predicts the stress distribution of each carbon fiber winding layer. Finally, a composite rotor for high-speed permanent magnet motors was fabricated based on the winding tension analysis and verified through experiments.