Autonomous Robot-Like Mobile Chargers for Electric Vehicles at Public Parking Facilities

At a public parking facility, only electric vehicles (EVs) that are parked at dedicated parking spaces with charging points can enjoy charging services. Installing a charging point at each parking space is an expensive way to support increasing EV penetration. As an alternative, this paper proposes the novel idea of autonomous robot-like mobile charger, which can move freely to visit different parking spaces to charge vehicles. Mobile charger decouples EV charging requirement from parking requirement. A Markov chain model is developed to describe the mobile charger operation in a parking facility, which is shared by EVs and non-EVs with stochastic arrivals and departures. The model is used to study performance of the charger, in terms of system throughput, charging delay, and blocking probability. Accuracy of the proposed model has been verified through extensive simulations. It is found that the maximum throughput of a mobile charger is dependent only on the effective charging powers, which may be affected by the size of parking facility. As a system planning criterion, EV arrival rate must not exceed the maximum charger throughput.