Determination of eddy current losses in permanent magnets of SPMSM with concentrated windings: A hybrid loss calculation method and experimental verification

When designing permanent magnet synchronous machines (PMSM) the losses in the magnets should not be neglected. On the one hand these losses could form a proportion of the total loss which can be significant and on the other hand the losses could lead to thermal problems in the magnets. This paper proposes a hybrid eddy current loss calculation method for the determination of the magnet loss which is computationally efficient and relatively easy to use. It combines a transient and two dimensional finite element analysis (FEA) to obtain the time variable distribution of the induction field in the magnets and an analytic eddy current loss calculation approach to determine the resulting eddy current losses. The results are validated by transient 3D FEA computations and, furthermore, by experimental measurements. The loss measurements can be performed by just measuring the electric parameters of the electric drive when operating the machine in a defined operating point.