On optimization of the mixed charging infrastructure of electric buses for urban routes

Abstract

Objectives. When transition from a fleet of diesel buses to a fleet of electric buses, it is important to optimize the charging infrastructure, which combines the slow-charging technologies at the depot overnight and fast recharging at the terminals of the routes. The purpose of the study is to create models and methods for developing the cost-effective solutions for selecting this type of charging infrastructure for a fleet of electric buses serving the city route system, taking into account a number of specific conditions. The operation of the fleet and charging infrastructure is modeled both for the depot at night and for the terminal stops in the most representative period of the day, characterized by the highest intensity of passenger traffic and maximum power consumption.Methods. Methods of set theory, graph theory and linear approximation are used.Results. A mathematical model has been developed for the problem of optimizing a mixed-type charging infrastructure for an electric bus fleet. The total daily cost of charging stations, degradation of electric bus batteries and consumed electricity was chosen as the objective function. The model is formulated as a mixed integer linear programming problem.Conclusion. To solve the formulated problem, standard solvers like IBM ILOG CPLEX can be used. The solution of the problem lies in the choice of durations and schedules for charging electric buses at low-capacity charging stations in the depot at night and at high-capacity charging stations of terminal stops in a given range of peak hours.

Keywords

• electric bus
• battery
• charging station
• optimization
• mixed integer linear programming