The design of barrel-wound foil windings with multiple layers interchanged to balance layer currents

Abstract

This work investigates the performance of multilayer foil windings in which the layers are interchanged to balance the flux linked by each layer and thus the current is shared equally between layers. Prototype transformers were built to confirm how much of the theoretical loss reduction is achievable in practice. The accuracy of the method to determine the location of the interchange is improved by considering individual turn lengths. In addition, the method is extended to any number of layers and several winding configurations. A discussion of the construction and termination of these windings is included as they greatly affect a component's performance.

Comparison between numerical and analytical methods of AC resistance evaluation for Medium Frequency Transformers: Validation on a prototype

“…But, the limits of the analytical models must be established before incorporating them into the design flow-chart. Many works [9], [10] have been carried out to determine the limits of the different theoretical models. These works changed only a limited number of parameters and the discrepancies between their measurements and analytical models suffered from a lack of explanations.…”

Thermal modelling of high-frequency magnetic components for power electronics by Finite Element Analysis

“…Foil barrel-wound magnetics achieve high window filling ratios [41], as square litz bundles do. Then, the procedure to get the effective thermal conductivity of foil winding is relatively easy.…”

“…A magnetic component is a very heterogeneous system. For instance, transformers are made by different coupled windings, which might be made of different types, as the one from [41], whose primary winding is made by litz bundles and secondary winding by foil.…”