I. Introduction
With the energy transition, the demand of compact and efficient DC-DC converters is increasing [1] – [3] . Therefore the switching frequency of converters is incremented to reduce the volume of the devices and to achieve high power densities [1] , [4] . With the introduction of wide bandgap semiconductors, switching frequencies up to the MHz range are achieved [1] . For applications which require a galvanic insulation the transformer is an important subcomponent in power converters. For high frequency applications planar transformers are preferred [4] – [6] . Compared to wire-wound transformers planar transformers have a better thermal characteristic and due to the manufacturing process the values for the parasitic elements are more predictable and can be better controlled [1] , [7] .