Power Sharing Based Control Strategy for a350 kW Multiport EV Charging System

Due to the immerging market for the ultrafast EV charging solutions to cater the need for EV chargers, multiport charging solutions are nowadays very popular. To reduce the overall footprint size of converter, solid state transformer (SST) based power converter is a preferred choice. The conventional EV chargers can either charge high power EVs or can charge multiple smaller power EVs with the help of multiple DC/DC converters. So, in this research work a 6.6 kV SST based charging solution is proposed, which can charge both the high (350 kW) and low power EVs (50 kW x 7) simultaneously. In the proposed system, the common LV DC-bus can directly charge a high-power EV and it is also shared with other lower power EVs through additional DC/DC converters. The common DC-bus can also be charged from one of the connected EV batteries and it can be shared with other EVs, in case there is a grid failure. Detailed simulation studies are performed to demonstrate the system performance. One of the SST cell unit is also manufactured, and experimental tests are performed to verify the system operation.