Distributed Electric Vehicle Charging Mechanism: A Game-Theoretical Approach

To reduce the overloading of the power system due to the increasing use of electric vehicles (EVs), the power system operators employ dynamic cost plans depending on the number of EVs being charged. In this situation, the charging cost of an EV can be reduced by considering other EVs' charging strategies and avoiding simultaneous charging. In this paper, we develop a distributed EV charging mechanism (D-EVCM) where each EV possesses some information, such as the charging probabilities of other EVs, electricity price, current energy level, and expected departure time. Based on the information, an EV periodically decides whether to charge its battery in a distributed manner. To minimize the average charging cost of EV while avoiding the situation where an EV departs from a charging station with insufficient energy level, a constrained stochastic game model is formulated and its solution is obtained using a best response dynamics-based algorithm. The evaluation results show that D-EVCM can reduce the average charging cost by up to <formula><tex>$89\%$</tex></formula> with a sufficient low battery outage probability (e.g., <formula><tex>$0.01\%$</tex></formula>) compared to a threshold-based charging scheme.