Estimation and Analysis of Iron Losses in Induction Motors under Sinusoidal and PWM Excitation

In this paper the iron losses in induction motors are estimated and analysed using time-stepping Finite Element Method (FEM) both with sinusoidal and PWM supply. The iron losses calculation has been carried out by add up the iron losses produced by orthogonal components of the flux density, as if the iron losses produced by these components were independent phenomena. The rotational hysteresis loss has been calculated applying a correction factor based on experimental data. This factor is a function of the peak flux density value and of the major and minor axis of the B loci. The experimental validations are provided for several frequencies and saturation levels.