The calculation of the classical loss as well as the excess loss in the soft magnetic materials under the rotational magnetisation

Abstract

PurposeThe calculation of the power loss in the core of the electrical machines is a special problem. In some areas of the electrical machine core the magnetic fields are neither unidirectional nor sinusoidal. This paper seeks to discuss the rotational power loss calculation methodology.Design/methodology/approachThe proposed methodology is based on the calculation of the field quantities Bx and By. In this methodology the rotational power losses are calculated employing the empirical approach directly from these quantities. Moreover, the computational model is the most important element of the proposed methodology because it utilises the FEM to the calculations of the hodographs of the flux density vector in each mesh element.FindingsThe paper formulates the dependence of the rotational power losses from the B vector hodograph shape.Research limitations/implicationsExperimental verification will still be needed as to the accuracy of the model and the applicability to the various magnetic materials.Practical implicationsThe paper provides an easy mathematical method to the iron loss calculation, under the rotational magnetisation, the excess loss included.Originality/valueThe analytical model, as presented here, is applicable to the iron loss calculation under the rotational magnetisation in devices that have complicated geometrical shapes.