Investigation of Delphi compact thermal model style for modeling surface-mounted Soft Magnetic Composite inductor

Abstract

Recent works on System-In-Package component pointed out that its in-package inductor is the hottest part. It occurs that thermal stresses due to joule heating and magnetic losses can be damaging. The present study focuses on low profile, surface-mounted, Soft Magnetic Composite inductors to define their thermal behaviour and then to propose a guideline to create pertinent models.Results highlight the impact of thermal conductivity of composite core on temperatures and the lack of properties data of iron-resin mixtures. Using mixture model, a calculation of effective thermal conductivity is proposed.To minimize the expensive meshing of the fine detailed simulations and the computation time, a novel Compact Thermal Model for inductor, based on DELPHI methodology, was established. The predictions of CTM model show good agreement, less than 10% of divergence. Further works must be done to really master the coupled interaction of magnetic, joule effect, thermal phenomenon as well as material properties.