Comparison of Demagnetization Models for Finite-Element Analysis of Permanent-Magnet Synchronous Machines

We have studied a few simple demagnetization models, which are quick and easy to implement in finite-element calculations, and compared them with measured recoil behavior of Nd-Fe-B magnet material, also using a hysteresis model for comparison. The models are used to estimate post-demagnetization performance of an overloaded surface magnet synchronous machine. Two of the simple models, the sloped linear model and the exponent function model, give the most accurate results without significantly increasing the computation time.