QUANTIFICATION OF THE ACCURACY OF DIFFERENT APPROACHES TO MODELING ANISOTROPY OF GRAIN-ORIENTED ELECTRICAL STEELS

In order to accurately model the anisotropy of grain-oriented electric al steel it is necessary to consider the variation of magnetisation ch aracteristics at various angles to the rolling direction. This affects the accuracy to which localised loss and flux distributions can be ca lculated in laminated cores. Many approaches have been attempted inclu ding modelling the spacial phase difference between B and H at differe nt angles to the rolling direction. This is a close representation of the manner in which internal magnetisation occurs in practice and it h as been shown to produce good agreement between experiment and calcula tion in relatively simple geometries. In this paper various approaches of the past 5 years are summarised before considering the particular geometry of a 3 phase transformer core in which the flux distribution has been measured experimentally and by the basic and the complex mode lling approaches. The accuracy of the two approaches is compared and i t is shown that large differences still occur between experimental and computed flux distributions even using the more accurate representati on of the magnetisation process. This shows that further development i s needed to predict losses sufficiently accurately for machine core de signs.