Automatic generation of accurate low-order models for magnetic devices

A method to automatically create low order state-space models for magnetic devices is set forth. The method begins with geometrical and materials data from which the finite element analysis (FEA) is used to build a high order state-space model. It is shown that this model contains far more state variables than are necessary to achieve the nearly the same results in the frequency band of interest. It is shown that the full-order model can be reduced methodically without additional physical assumptions. The reduction method is applicable directly to magnetically linear systems, but applies to a wide range of power electronics applications and can be a basis for future nonlinear device modeling. The method reduced an example inductor model from 882 state variables to two. To confirm correct model derivation, the full-order model is checked against and agrees with experimental data to the extent that the FEA and materials data are accurate. The reduced-order model agrees very well with the full-order model, particularly in computing impedance.