Design and Mechanical Property Analysis of Permanent Magnet Spring with Attractive Force used in PMSM with a Conical Rotor

To balance the axial force of a permanent magnet synchronous motor with a conical rotor (CR-PMSM) between the stator and the rotor, a permanent magnet (PM) spring with attractive force is designed. The magnetic circuit method is adopted to calculate the effective air-gap permeance, flux linkage and flux density. Then the magnetic force in axial direction is calculated by the virtual displacement method. The theoretical model of magnetic force – deformation is established to reveal the impact of different configurations adjustments on magnetic field distribution and stiffness coefficient. The static performance of the PM spring are analyzed by theoretical model and 2-D axial symmetry model of finite element method (FEM). A prototype of the PM spring is designed and manufactured together with the CR-PMSM. The simulation and experimental results show that the designed PM spring can meet the technical specification of axial force requirement of the CR-PMSM.