Load Management Strategy for DC Fast Charging Stations

DC fast charging reduces the time for charging electric vehicles, however, it requires large power demand from the grid during each EV charging. DC fast charging is random in nature. At peak load demand periods of the distribution network, the energy requirement may become as high as five times the normal peak load, due to DC fast charging loads. This paper proposes a load management strategy for integrating fast charging infrastructure with the grid. An energy management system with a charge scheduling algorithm is proposed to control the charging rate of the electric vehicles in the DC fast-charging station, effectively decreasing the stress on the grid during peak load. The results of the load management strategy are compared with rule-based system and DC fast charging station devoid of any energy management system. The main contribution of the paper includes an optimized energy management system framework for a DC fast charging station connected to a low voltage distribution network. The performance of the centralized energy management system is tested on a given network - peak charging power due to fast charging on the grid is reduced, the voltage constraints are satisfied (confined within +/- 5% band of the system base voltage), and voltage deviation is minimized, without integrating additional ESS or PV system.