Calculation of the Rotor Mechanical Stress of Bridgeless Interior Permanent-Magnet Synchronous Machines with a High-Strength Sleeve

This paper proposes an analytical method for calculating the mechanical stress on the rotor of bridgeless interior permanent-magnet synchronous machines (IPMSMs) with a high-strength pre-tightened sleeve. First of all, the one-pole model of the V-shaped rotor with sleeve and some assumptions are introduced, and the calculation method based on stress and deformation compatibility condition is analyzed. Besides, the finite element method (FEM) is applied to verify the accuracy of the proposed calculation model. By extracting the contact stress between the sleeve and the pole shoe, the reliability of the model is verified. After applying the fitting method, the calculation model can accurately predict the average stress on the center rib when some basic parameters of the rotor are changed and the calculation model passes the accuracy verification of the FEM with an error under 5%, which has positive significance for the future electromagnetic-mechanical joint optimization and design of high-speed IPMSMs.