A Hybrid Si/SiC MV Power Conditioning System for Ultra-Fast Electric Vehicle Charging Stations

Ultra-fast charging stations (UFCSs) for electric vehicles (EVs) capable of recharging times as close as those for conventional vehicles with internal combustion engines are necessary to accelerate EV adoption. Most high-power UFCSs are connected to medium-voltage (MV) distribution systems through line-frequency transformers, which are bulky and heavy. However, high-voltage (HV) power modules and multi-level converter topologies eliminate the necessity for these transformers. This paper proposes a 13.8 kV, 6 MVA hybrid Si/SiC medium-voltage power conditioning system (MV-PCS) specifically designed for 800-V dc UFCSs. For the MV ac-dc stage, 3.3 kV Si IGBT modules are utilized. For the MV dc-dc stage, 3.3 kV and 1.2 kV SiC MOSFET modules are used for the MV and low-voltage sides of a MV-DAB, respectively. PLECS software (considering system power losses, volumetric power density, and gravimetric power density) is used to evaluate the design of MV-PCS. Furthermore, an MV building block rated 1.8 kV and 250 kVA is fabricated and tested to validate the simulations provided. The simulation results and experimental waveforms illustrate the potential of the proposed MV-PCS.