Winding loss calculation with multiple windings, arbitrary waveforms, and two-dimensional field geometry

A method for calculating eddy-current (proximity-effect) losses in transformer and inductor windings is introduced. The new method is capable of analyzing losses due to two- and three-dimensional field effects in multiple windings with arbitrary waveforms in each winding. It uses a simple set of numerical magnetostatic field calculations to derive a matrix describing the transformer or inductor. This is combined with a second matrix calculated from derivatives of winding currents to computer total AC loss. Experiments show the method is accurate for coils that are not in or close to self-resonance.