Novel Approach to the Extraction of Delphi-like Boundary-Condition-Independent Compact Thermal Models of Planar Transformer Devices

Planar Magnetic Components are new alternatives to classic transformers. Based on the combination of a low profile high frequency magnetic core and a Printed Circuit Board, these devices allow large reduction in terms of weight and size, which exacerbates power density constraints. To circumvent the potential issues of a multi-layer embedding of flatten high-current-density copper windings at the heart of a substrate, a set of analyses were conducted to characterize electro-thermo-magnetic combined effects with the purpose of elaborating a pertinent thermal model. Using a set of numerical simulations, several concepts of multi-source surrogate thermal model were derived with the prospect of shortening the expensive computation time of the fine Detailed Thermal Model. These approximated models permit to monitor the sensitive temperatures of the primary and secondary windings as well as core ones. Designers can therefore perform trivial calculations to analyse the thermal behaviour of planar transformers for various boundary conditions.