Analysis of the Flux-Lag Effect in an Iron Core.

Power electronic converters, such as dc choppers and inverters, generate a pulsating current. The magnetic flux lags behind the current, because of eddy currents in the solid part of an electrical machine. This paper analyzes magnetic flux transients, which are closely related to such delayed responses caused by eddy currents in iron cores, and proposes a method for estimating magnetic responses on the basis of an equivalent circuit model for an iron-cored winding. The model parameters can be determined by measuring the de resistance and testing the impedance at a commercial frequency. The calculated results agree well with the experimental results. The method can be used to estimate the electromagnetic response of windings such as those used in electrical machines.