Calculation of Leakage Inductance in Toroidal Core Transformer With Non-Interleaved Windings

Recently, transformers with toroidal core have received much attention. The compactness and weight of these kinds of transformers make them suitable for power electronics applications. In some areas, it is necessary to have a toroidal transformer with particular parasitic elements such as leakage inductance. So, there is a need for a precise method to calculate the exact amount of leakage inductance for designing the desired system. This article presents a pure analytical method based on Maxwell's equations to accurately determine the leakage inductance of a toroidal transformer which its windings are wounded separately. The proposed expression for the leakage inductance calculation considers the influence of the core specifications, such as dimensions and material. In order to validate the presented method, 3-D finite-element simulation and experimental results of the prototype transformer have been done.