Demagnetization characteristics analysis of propulsion Halbach-PMSM

The partial demagnetization characteristics of Halbach permanent magnet synchronous motor (Halbach-PMSM) are investigated in this paper. First, a 2-D finite-element model of an 8-pole 48-slot motor is built, four different degree demagnetization cases are simulated, and the severe and moderate radial/tangential magnetization losses are shown in the results. Second, the air-gap flux density, no-load induced electromotive force (EMF), and electromagnetic torque are analyzed to evaluate the performance deviations, and the results show that the radial and tangential demagnetization affect motor performance differently. Finally, the experiment and simulation results show that the no-load induced EMF harmonics and elevated torque ripple coefficients can well characterize and distinguish the different local demagnetization of Halbach permanent magnets.