2.1.2. Fast-Charging-Stations

According to safety standards [12], galvanic isolation must be guaranteed between the main distribution 3-phase AC-grid and the charging station. This can either be realised by utilizing a low frequency (LF-) transformer or an isolating DC-DC converter (MFtransformer), which operates in the medium frequency (MF) range. These two possibilities are visualised in Figure 1 as "Topology 1" and "Topology 2". Higher frequencies allow for lower material effort, and hence the size of the passive devices. Therefore, Topology 2 provides benefits over Topology 1 in the form of a less "bulky" transformer. However, a transformer connects the regional airport to the medium-voltage grid. Accordingly, "Topology 1" is considered in this study.

**Figure 1.** Basic topologies for DC-Fast-Charging of electric vehicles.
