A method for the calculation of an apparent time invarying inductance for an iron core inductor

A method for measurement of the instantaneous inductance L(t) of an iron core inductor is presented as function of the inductor current i, the rate of change di/dt of this current and the past history of the iron core at that moment. The inductance of a filter inductor is shown as a function of unidirectional continuous and discontinuous currents. The concept of an equivalent time invarying inductance L_egu is formulated for purpose of piecewise linear time domain analysis of switching networks and a method for its calculation is indicated. The usefulness of this new tool of analysis is confirmed by agreement of calculated and experimentally obtained data.