Electromagnetic Performance Analysis of Asymmetric Hybrid-SPPMSM After Demagnetization Considering Nonlinear Demagnetization Curve

The demagnetization fault of salient-pole permanent magnet synchronous motor (SPPMSM) can reduce the motor’s output performance and load capacity, which can severely affect its service life. Therefore, this paper investigates the electromagnetic performance and the degree of demagnetization of an asymmetric hybrid-SPPMSM after a demagnetization fault. First, an iterative analysis model for motor demagnetization faults considering the nonlinearity of the demagnetization curve is proposed. Based on a subdomain analysis model of the demagnetization as a function of the spatial angle, this model can quickly predict the no-load back electromotive force (BEMF) and electromagnetic torque. The demagnetization model is analyzed using the finite element method and compared with the analytical model. At the same time, the demagnetization rate is used as one of the optimization objectives to optimize the dimensional parameters of the N-pole permanent magnet. The resulting optimized solution can increase the average torque by 1%. Subsequently, the study analyses the peak current of the motor when it reaches the maximum demagnetization rate compared to the reference motor, the proposed asymmetric hybrid-SPPMSM demonstrates robust resistance to irreversible demagnetization. A prototype is developed and tested to verify the correctness of the theoretical analysis.