Robust Charging Strategy For Electric Bus Fleet Considering Uncertainty Of Energy Consumption

As one of the green public transportation tools,electric bus has played a key role in saving oil resources,reducing harmful exhaust emissions and reducing noise.However,with the rapid development of new energy bus,a series of practical operational problems have become prominent.For example,charging stations have large spare amount in the daytime and fierce charging competition at night,and other unreasonable resource utilization phenomena.The relatively random charging time sequence makes a large amount of electricity distributed in the period of high electricity price,which leads to high charging cost.Charging plans lack flexibility and ignore the fluctuation of energy consumption during the operation of electric buses.As one of the important links of electric bus operation,the charging optimization has practical significance for accelerating the healthy and stable expansion of electric bus.This study first established the deterministic optimization model of electric bus charging considering the charging resource limitation.According to the fluctuation characteristics of electricity price and the continuous demand of charging,the limited charging power and the optimal charging time are reasonably allocated for each bus,so as to reduce the overall charging cost and improve the economy of electric bus fleet operation.Secondly,since the uncertainty of electric bus energy consumption has a profound impact on the stability of charging plan,this paper further establishes a corresponding robust optimization model,in which the budget uncertainty set is adopted to deal with the uncertainty of operating energy consumption,so as to improve the robustness of charging strategy.Finally,the algorithm based on the column generation framework is proposed to solve the deterministic charging model and robust charging model.The original problem is reformulated as a master problem and several independent sub-problems,which avoided the computational redundancy caused by the direct generation of all charging strategies and improved the solving efficiency.Taking the actual operation data of Zhengzhou,China as a numerical example,the validity of the deterministic charging model and the robust charging model is verified.The results show that the optimal charging strategy obtained by the deterministic model improves the utilization rate of charging resources and reduces the charging cost by 48.7% compared with the disordered charging strategy.The proposed robust model can effectively deal with the problems of low electric quantity and delayed departure caused by uncertain energy consumption,and provide decision support for charging management of electric bus system.