Nonlinear inductors for active power factor correction circuits

In this paper, a practical method is presented, how to adjust the inductance curve of a nonlinear (saturable) inductor with respect to a desired shape. For these purposes, a nonlinear model was developed based on finite element method (FEM). It is shown how a highly efficient construction with low stray fields and maximum package density can be achieved. Different prototype inductors were realized to illustrate the practical capability for active power factor correction (PFC) applications. All simulation is verified by means of experimental data drawn from electrical measurements.