Optimal Security Charging Service for Electric Vehicles by Mobile Charging Stations: Dynamic Contract-based Approach

Electric vehicles (EVs) are designed to improve the power efficiency as well as it prevents the environment from being polluted, and thus they are widely and reasonably used in the power market. Thanks to mobile charging stations (MCSs), it provides the charging service to EVs more easily with higher payoff and lower consumption, compared with the fixed charging stations (FCSs). In this paper, we propose a dynamic contract-based strategy to apply the secured charging service from MCS in Internet of things (IoTs), considering incomplete information of EV users. Firstly, considering this charging system composed of multiple EV users and MCSs, we design the utility function of each one, where non-contract power are supplied to EV users besides the power in contract items in IoTs. Then, in order to maximize MCS's profits, an optimization problem is formulated to obtain the optimal contract items satisfying EV users' power demand. Thirdly, the optimal solution of this problem is efficiently achieved through the presented iterative search algorithm, considering the different types of EV users with different contract items. Finally, simulation results validate the effectiveness of our proposal and each of them in this charging system can be benefited.