Fuzzy logic-based charging strategy for Electric Vehicles plugged into a smart grid

The smart grid allows its consumers to participate in producing cost effective, sustainable, and environmentally friendly electricity. The consumers in a smart grid, for example, can plug their Electric Vehicles (EVs) into the grid to charge and discharge their vehicles´ batteries. However, charging of the electric vehicles, especially during the peak periods, can adversely impact the grid performance. Thus, in this paper, the coordinated charging of the electric vehicles problem is tackled. A fuzzy logic-based approach is developed to coordinate the electric vehicle charging such that the system minimum voltage is within the allowable limits. The inputs to the Fuzzy Charging Controller (FCC) include the States of Charge (SOC) of the electric vehicles, the grid parameters represented in the system minimum voltage, and the hourly energy price. The output of the FCC is the charging levels of the electric vehicles´ batteries. The developed fuzzy logic-based charging strategy was validated on the 69-bus test system. The Fuzzy Charging (FC) was compared with three modes of uncoordinated charging, namely Slow Charging (SC), Medium Charging (MC), and Fast Charging (FC). The results of the comparative study prove the superiority of the developed fuzzy charging approach over uncoordinated charging schemes.