Computation of transformer iron losses under saturation using the Fourier method Part 2: Stray loss

Computation of iron losses is a heavy numerical task, and the problem is further complicated by magnetic nonlinearity when saturation is considered. In an accompanying paper, a Fourier method for calculation of the transformer core loss under saturation is presented. In this paper, the influence of the permeability definition of the core material on leakage field and the associated stray loss calculation is studied. Based on the relationship between magnetic field and input current, a waveform correction factor is introduced which enables stray loss estimation of nonsinusoidal excitations. The results obtained by this method are compared to those given by a time domain calculation to evaluate the accuracy of the method.