Hysteresis modeling in transient analysis of electric motors with AlNiCo magnets

Electric motors fabricated with aluminum-nickel-cobalt (AlNiCo) permanent magnets (PMs) can be operated over a wide speed range, as the strong nonlinear demagnetization characteristics of AlNiCo allow effective and efficient airgap flux control. This paper presents a linear hysteresis model which is derived from the Preisach model for AlNiCo PMs, to be incorporated into the time-stepping finite element method to study the motor performance, especially transient performance, accurately and effectively. The proposed method can significantly reduce the computing time without scarifying the accuracy of the Preisach model. The validity and accuracy of the proposed method are verified by both simulation and experimentation.