A centralized EV charging scheme based on user satisfaction fairness and cost

Recently, the penetration of electric vehicles (EVs) has been expected to increase rapidly. From the power grid point of view, a large number of EVs could act as a large amount of load as well as energy storage. To avoid jeopardizing the electric power grid stability, a charging mechanism for EVs should be properly managed. Many researchers have investigated several centralized charging algorithms. However, to the best of our knowledge, none of them have discussed about the satisfaction fairness among EV users. In this paper, we propose a new metric to represent the EV user satisfaction fairness. We investigate a tradeoff between the user satisfaction fairness and the total cost of electricity for charging. Results show that we may need higher total electricity cost even with a smaller deviation of EV users´ satisfaction, especially with higher fairness among EV users at a given time. Through the proposed scheme, EV users can achieve a much higher satisfaction level for almost all the times compared to the conventional scheme. The proposed scheme can also ensure a higher level of battery state-of-charge (SOC). The new proposed metric can be further used for evaluating the performance of various charging algorithms.