I. Introduction
The Dual Active Bridge (DAB) converter is widely used for bi-directional galvanically isolated conversions owing to its symmetrical structure, few components, and soft-switching functionality [1]. The broad range of applications for DAB converters spans electric vehicles (EV), energy storage systems (ESS), solid-state transformers (SST), solar and wind farms, uninterruptible power supply (UPS), and smart grids [2]. Nevertheless, regardless of the DAB converter topology and application, one or multiple Medium Frequency Transformer (MFT) units are deployed to achieve galvanic isolation. The relatively high fundamental frequency of DAB converter wave-forms fosters MFT size reduction. For any transformer design at a given operating voltage and number of turns, increasing the fundamental frequency decreases the magnetic flux in an inversely proportional fashion, therefore decreasing the required core cross section. While this benefits high-power density applications, it raises prominent challenges in insulation coordination and MFT cooling due to its compact size. Thus, a low computational cost temperature estimation method is crucial to optimize the design procedure while accounting for thermal considerations.