Experimental validation of iron loss model for rotating machines based on direct eddy current analysis of electrical steel sheets

In this study, we propose and confirm an accurate estimation method of iron loss in rotating machines. In the method, the eddy-current loss in the electrical steel sheets is directly calculated by a nonlinear time-domain electromagnetic field analysis with a simple approximation of the excess loss. The hysteresis loss is also estimated with the consideration of flux distribution along the thickness of the steel sheet. The advantage of the method is the accuracy of the high-frequency harmonic losses using only several material constants. The validity of the method is confirmed by two experiments. The first experiment is carried out by a ring specimen of the electrical steel sheets. In this case, superimposed fundamental and harmonic fluxes are applied to the specimen. The second experiment is carried out by an induction motor driven by an inverter as well as a sinusoidal power supply. The carrier harmonic loss by the inverter is separated for the purpose of confirming the accuracy of the calculated harmonic losses. The experimental and calculated iron losses in both experiments are found to be in good agreement.