Thermal Management of planar magnetics for Spacecrafts: characterization and modeling

The dissipation of the generated power losses of on-board magnetic components is a major concern regarding the thermal management of the power systems. In this study, two planar transformers designed for common space power converters are chosen as representative samples to analyze the effect of different elements on heat transfer (vias, connectors to a baseplate, gap filler pads, glue, integration in the main PCB). 3D thermal simulations are used to quantify it. It has been found out that the contribution of vias to heat transfer can reach a 8.9%, and the use of metallic connectors, window filling or gap filler pads can reduce the maximum temperature rise between 18.4% and 57.4%. Additionally, a simplified 2D model is proposed as a fast solution to characterize the thermal behavior of planar transformers and determine if a design is valid or if it requires any modification. Finally, some guidelines to address the thermal management of these components are explained.