Modelling losses in electrical steel laminations

The possibility of obtaining a voltage-driven solution of the diffusion equation by using a history-dependent hysteresis model based on the transplantation principle and a model for excess loss simulation derived from the Landau-Lifshitz-Gilbert equation for magnetic viscosity is presented. The proposed solver appears to be more versatile than existing models and can predict the total losses under arbitrary magnetising conditions as well as reproduce any frequency dependence of the excess losses. The model was tested on nonoriented (NO) and grain-oriented (GO) electrical steels under sinusoidal flux density over a frequency range from 50 to 400 Hz. Initial calculations, performed without viscosity being taken into account, gave underestimated losses with reduced RMS errors which varied from 5% for NO to 10% for GO steels. By introducing viscosity, this error reduced to 1% for both materials. The model parameters are thought to be material dependent so it is reasoned that the model can be used to accurately predict losses in a wide range of materials magnetised under sinusoidal as well as nonsinusoidal flux waveforms.