Measurement and calculation of rotating anomalous loss in electrical steel sheets considering harmonics and skin effect

In order to accurately calculate the rotating anomalous loss in electrical steel sheets, sheets finite element model was simulated by adopting time-stepping finite element method based on Fourier analysis. Then, the key loss coefficients of the sheets were obtained by experimental measurement at low to medium frequencies with considering the influence of eddy current skin effect to the loss coefficients on the basis of rotating core losses calculation model. So, the calculation formula of rotating anomalous loss in electrical steel sheets was deducd indirectly. By using a novel 3-D magnetic properties testing system, the total broadband core losses under elliptical rotation and alternating excitations were carried out for a typical electrical steel laminated specimen. Meanwhile, losses characteristics of the two excitation modes were compared and analyzed quantitatively. The results show that both the losses variations are analogous, but varieties of elliptical rotation excitation losses are bigger than the corresponding alternating losses, so it is necessary to consider the influences of harmonic, skin effect and rotating excitation, etc, to the materials properties seriously. The calculation of rotating anomalous loss is relatively small and is not accounted for 5% of the total rotating core losses up to 1 k Hz. Thus, it validates the correctness and feasibility of the calculation formula and measurement means.