Converter Technology

Transformer Loss Modelling

Loss in power transformers comprises core and winding loss.

Core Loss

Core loss occurs as a result of eddy currents in the ferrite material and also as a result of moving around the non-linear B-H curve. Both of these loss mechanisms increase with operating frequency (F) and peak to peak flux density variation (B) as well as being dependant on operating temperature.

Loss curves for Kaschke K2006 Material

The effects of eddy current and hysteresis loss can be combined and plotted as a function of frequency and peak to peak flux density variation. Using the curves, an empirical equation can be developed to aid calculation of the loss density:-
Loss Prediction Equation
Fitting the curves to this equation gives the material loss coefficients. The derived coefficients for some of the Kaschke ferrite materials at 100