Nonlinear Magnetics Model for Permanent Magnet Synchronous Machines Capturing Saturation and Temperature Effects

This paper proposes a nonlinear magnetics model for Permanent Magnet Synchronous Machines that accurately captures the effects of magnetic saturation in the machine iron and variations in rotor temperature on the permanent magnet excitation. The proposed model considers the permanent magnet excitation as a current source rather than the more commonly used flux-linkage source. A comparison of the two modeling approaches is conducted using Finite Element Analysis for different machine designs as well as experimental validation, where it is shown that the proposed model has substantially better accuracy. The proposed model decouples the effects of magnetic saturation and rotor temperature variations on the current/flux-linkage relationship, allowing for adaptive estimation of a single parameter to account for rotor temperature changes.