VANET based online charging strategy for electric vehicles

An online charging strategy is an efficient approach to provide charging plans for electric vehicles (EVs) from a global point of view, aiming to improve energy efficiency while avoiding overloading of an electric power system. However, designing an efficient online charging strategy to achieve optimal energy utilization remains a challenging problem, especially when the coordinated behaviors of both EVs and charging stations are taken into consideration. In this paper, we first introduce an intelligent power distribution system which utilizes vehicular ad-hoc networks (VANETs) to enable communication among EVs on roads, road-side units (RSUs), and a vehicle-traffic server. Then, we propose a globally optimal online EV charging strategy, which not only improves energy utilization of the whole system but also prevents charging stations from overloading, which may cause a voltage drop in the power distribution system. Lagrange duality optimization techniques are exploited to address the associated optimal EV charging problem. The performance of our proposed strategy is evaluated by extensive simulations, and the results are compared with that of the traditional autonomous offline charging strategy.