New 2D Thermal Model for Shell-Type Medium Frequency Transformers and Experimental Validation Thereof

Medium Frequency Transformers are essential for achieving galvanic isolation in isolated converter topologies, but challenges in insulation and cooling arise due to their compact nature. This study introduces a versatile thermal circuit tailored for shell-type medium frequency transformers. By addressing dielectric losses and incorporating diverse insulation materials, heatsink integration, and air gap considerations, this research enhances the adaptability of thermal modeling in the design process. The derived analytical model is verified against measurements from a 5kW test bench featuring a solid insulated transformer prototype, with a maximum hotspot relative error not exceeding 11.1% at all tested operating conditions.