Scheduling of Merchant-Owned EV Charging at a Charging Facility with Multiple Chargers

Merchant-owned charging stations will replace gasoline stations in the near future. As charging times of electric vehicles (EV) may be significant, without optimization, customers will wait to get charged without knowing the actual period of charging. In addition, the charging facility will not be aware of optimum charging power levels and the charging time to minimize costs. In this paper, an optimal EV charging method is proposed that minimizes the total cost for a merchant-owned charging facility with multiple chargers. The formulation considers energy costs, demand charge, connected transformer capacity, charger capacities and EV power capacities. The optimal schedule for the day can be determined ahead of time such that the customers can be informed of the cost and charging schedule. This is a complex mixed-integer linear optimization challenge with three-dimensional matrices. In this paper several cases are studied using the proposed algorithm. It is fast and efficient. This methodology would be highly useful for merchant-owned EV charging facilities and it is ready for the industrial applications.