An optimal charging/discharging strategy for smart electrical car parks

This paper presents a smart electrical car park model where the power flows among electrical vehicles(EVs) as well as between EVs and the main grid. Based on this model, an optimal charging/discharging scheme is proposed. The fluctuation of hourly electricity rates is considered in this strategy to select a proper charging/discharging rate for each EV with less expenditure during each charging period. The proposed smart electrical car park is able to buy or sell electricity in the form of active and/or reactive power, i.e. kWh and/or kVARh, from or to the main grid to improve the power quality. According to the current state of charge of the EV's battery bank, customers and the grid demands, a control center makes the decisions and sends the instructions of specific charging/discharging mode to each charging station. The performance of the proposed charging/discharging algorithm is simulated in Matlab. A comparison between the proposed and the unregulated charging/discharging strategies has been implemented. The results demonstrate that the proposed scheme can achieve better economic profits for EV customers and increase the commercial benefits for the car park owner.