Modelling of a Litz-wire planar winding

A rigorous analytical electromagnetic model of a Litz-wire planar winding geometry is presented here. The main objective was the analytical description of the internal structure achieved by setting up a three-dimensional model with parametrical equations. The Litz-wire geometry is used to develop the electromagnetic model of the structure, obtaining a simple circuit formulation of the problem, whose numerical solution allows tocompute all the currents in every strand and also the structure reactance. The comparison with solid-wire spiral is also presented in order to highlight the advantages of the rigorous modelling of Litz-wire structure. To validate this model, different configurations were simulated and compared with measurements.