Prediction of harmonic current frequencies and amplitudes generated in power inductors due to saturation in ferrite and iron powder cores

Reversible and amplitude permeability along with their respective measurement techniques are introduced. They are then used to estimate the current specters resulting from voltage specters applied to cores of power inductors with an AC amplitude high enough to result in saturation. The frequency domain calculation is verified by measurement and it is concluded that when using amplitude permeability the specters can be predicted with satisfying accuracy without time consuming time domain simulation. Reversible permeability is not suitable for modeling inductors under single or multiple AC voltages beyond the nominal current range.