Modeling and optimization of PHEV charging queues

The use of PHEVs (Plug-in Hybrid Electric Vehicles) is fast expanding due to their low energy cost and low environmental pollution. However, the biggest hurdle is that PHEVs have short driving range and long battery charging time even when using supercharging stations. Therefore, better queuing models are necessary to improve the quality of services using public charging stations. In this paper, first the PHEV queue is simulated based on the M/M/1 queuing model, where M denotes a Markov process for both inter-arrival time and service times. Then, the electrical consumption of PHEVs is simulated for urban driving standard (FTP-72) to better understand of the behavior the battery state of charge (SOC). In addition, discharging characteristics of the PHEVs´ batteries in urban city are analyzed using different cycles. Moreover, a computer model is implemented to study waiting time of PHEV at public charging stations. Simulation results suggest that, assigning charging stations by considering the queue length at each charging nodes (station), as well as the distance, considerably reduces the queue length at each station.