Rotor deformation impact on operating characteristics of IPM Motor under High-Speed conditions

This paper investigates effects on permanent magnet motor characteristics of the non-uniform air-gap caused by rotor deformations under high-speed conditions. Particularly, changes in the spatial flux density harmonics, in the flux linkage variations observed in the stator windings and in the electromagnetic torque ripple are evaluated and discussed in the case of a V-type interior permanent magnet synchronous motor. The rotor deformations created by centrifugal forces are analyzed by using static mechanical Finite Element Analysis (FEA). The motor electromagnetic behavior is simulated through an appropriate weak coupling of a 2D FEA with a step-by-step static FEA numerical scheme. The proposed methodology is validated by experimental measurements and enables consideration of interaction amongst electromagnetic and mechanical small time scale phenomena while it can be easily incorporated in design optimization algorithms.