Modelling of the Hotspot Temperature in Gapped Single Layer Inductor Windings Using a Conductor Homogenisation Technique

Abstract:
In gapped inductors, which are often operated at high frequencies, the magnetic fringing field emanating from the air gap induces local eddy currents in the windings. Macroscopically, this leads to significantly increased overall winding losses of the component. Microscopically, the local eddy current losses also lead to a locally increased loss density in the conductors, which leads to a thermal hotspot in the conductors in close vicinity to the air gap. This article explores this currently unexplored phenomenon in terms of measurements, analytical modelling and FEA analyses. In order to enable faster 3D FEA analyses, this article presents an analytical method to homogenise the circular conductors, that is capable of reducing the computational cost of intensive 3D FEA eddy current simulations by over 90 %.