Validation of eddy current loss models for permanent magnet machines with fractional-slot concentrated windings

Permanent magnet (PM) machines with concentrated windings are increasingly used in industry because of their cost-effectiveness and low production time. Eddy current losses in the rotor of these machines are significant due to a large content of space harmonics in air gap MMF. Analytical and finite element (FE) models have been formulated to predict such losses. This paper presents experimental validation for an analytical and a FE model, in which an openslot and a semi-closed-slot fractional-slot PM machine with 27 slots and 18 poles are modeled. The experiments consist of static tests for both the analytical model and the FE model, and rotary tests only for the FE model. The results show the models can to some extent predict the eddy current losses in the rotor but further improvements such as a three dimensional model may help reduce the deviations between models and experiments.