Representation of soft magnetic materials

Soft magnetic materials have symmetrical B/H characteristics which form closed loops for alternating magnetisation between positive and negative saturation levels of flux density, B. The model suggested here produces these `nesting? characteristics by making the coercive force proportion to the maximum flux density. The deviations between ascending and descending curves are modelled in a single expression in which the B/H curve and a defined hysteresis parameter are used. The simplicity of the model makes it valuable for use in electromagnetic applications in which soft iron materials are used, and the representation of hysteresis is crucial. It is primarily intended for the representation of high magnetisation, but can be amended to represent cycles of low magnetisation. The inrush current of a single-phase transformer is calculated, and the method is suitable for obtaining inrush current in any power equipment.