A two-step approach to optimal management of electric vehicle parking lots

Abstract

In this paper, a two-step approach is presented for optimal energy management in electric vehicle parking lots. In the first step, a new scheduling method is proposed for charge and discharge of electric vehicles which bases upon identification of joint time interval and the optimal number of charge and discharge time intervals. This method is able to determine the time of charge and discharge accurately through an efficient mechanism. In addition, a modified approach is presented to ensure the maximum profit to be gained by the electric vehicle owners. Based on this approach, electric vehicle owners announce their maximum acceptable cost for the charging process or their minimum desired profit from discharging the electric vehicle as their preferences to the parking lot operator. Satisfying these preferences by the parking lot operator means the maximum profit for the EV owners referring to a parking lot. In the second step, an innovative approach is presented to optimal management of the parking lot that is based on the set of equations governing parking lot and encouragement and punishment policies. In this regard, fine due to the mismatching of power flow direction and profit due to the matching of power flow direction of the electric vehicles with that of the parking lot have been introduced and modeled. Finally, the approach proposed is implemented in a parking lot with real world data and the results are discussed. Results show that the proposed approach is able to determine accurately the time of charge/discharge of electric vehicles even in the joint time interval. Moreover, this approach will fulfill both technical and financial preferences of the electric vehicle owners to increase their profit with respect to the previous approaches. Also, using the encouragement and punishment mechanisms, the optimal parking lot scheduling and calculating optimum time intervals for power absorption from and power injection to the grid; the total parking lot operator’s profit is increased.