PEEC-like analytical calculation of static leakage inductances of H.F. transformers

FEM simulations carried out on several two windings transformers having different shapes show that, when the Ampere turn sum of the two windings equals zero, only a negligible part of the magnetic energy reach the core. Moreover, 2D approximations of induction and energy density are very close to 3D simulation results. It enables to compute transformer leakage inductance from equations giving the induction created by a straight rectangular cross-section wire, as used in the PEEC method. Weak magnetic core effects are accounted for, using magnetic images of the currents flowing in the windings. Comparison between the calculations carried out and measurements is provided.