关键词: 交通工程；电动公交车；空驶时间；充电时隙；联合优化

Abstract: Reducing the deadhead time of electric bus (EB) from terminals to charging stations can effectively reduce hidden costs such as additional driver staffing and improve charging efficiency. In light of this, firstly, the deadhead time was minimized based on the cost objectives of existing research, balancing both cost and efficiency requirements. Secondly, based on the analysis of the charging time characteristics of EB under slow and fast charging modes, two charging time slot parameters were set for slow and fast charging, addressing the shortcomings of existing studies that considered only a single charging method and treating it as an unbalanced assignment problem at the meanwhile. Then, by fully considering constraints such as uncertainty in vehicle speed and the latest charging time limit for vehicles, a joint optimization study on charging facility layout and scheduling was conducted, and a multi-objective optimization model was constructed. Finally, the genetic algorithm was improved with the first come first served (FCFS) strategy and the Metropolis criterion, which was applied to a case study to validate the effectiveness of the model and algorithm. The results show that considering only the cost objective causes the drawback of excessively long deadhead time, whereas the established multi-objective model can effectively reduce the maximum deadhead time per EB and improve charging efficiency. Shortening charging time slots can reduce the costs of EB charging facility layout and scheduling. Increasing EB driving speed can effectively reduce deadhead time. In the initial stage of bus system operation, a higher weight should be given to the cost objective to address the issue of financial constraints, while in the middle and later stages, a higher weight can be given to the deadhead time objective to improve charging efficiency. Compared to a single slow/fast charging method, considering both slow and fast charging methods simultaneously yields the best overall effect.

Key words: traffic engineering; electric bus; deadhead time; charging time slot; joint optimization