Effect of voltage harmonics on iron losses in magnetic cores with hysteresis

The effect of distorted voltage waveforms on the iron losses, considering the magnetic hysteresis, is quantitatively studied, using an accurate losses separation method and a time-integration for each component. The model parameters, including the Preisach hysteresis function, are identified by magnetic measurements. A case-study, implying measured electric power quality data in a metal processing and thermal treatment facility, is presented to outline the consequences of a non-sinusoidal regime on iron losses in high power low-voltage motors with rated power between 132 kW and 200 kW. Three sorts of standard FeSi non-oriented electrical sheets (M330-50A, M400-65A and M700-65A) were considered for the motor magnetic core. The iron losses, estimated both for non-saturated and saturated core regions, rise with 11-35 % for the measured non-sinusoidal voltage having 7.6% total harmonic distortion.