Analytic separation of the factors contributing to the eddy-current loss in magnetically nonlinear steel

Abstract

Many approximate solutions for eddy-current loss in solid steel have been published, but little attention has been given to identifying the effects of magnetic nonlinearity on the loss and electromagnetic-field distribution. An analytic solution is described in which these effects are identified, and defined by simple factors which are determined from the B/H-curve for the steel; this curve is represented by the function B = aHb. Saturation harmonics are accounted for approximately by the use of the single derived function B1 = AHb1 this is validated by a separate analytic investigation. Comparison with the limiting nonlinear theory, for which B = ±BS, leads to a definition of BS which relates it to the shape of the B/H-curve. An experimental investigation to test the theory is also described.