Conflict-free Charging and Real-time Control for an Electric Bus Network

TL;DR

This paper introduces a real-time control strategy for electric bus networks that integrates charging scheduling with speed control, optimizing operations and avoiding conflicts to reduce costs.

Contribution

It presents a novel mixed-integer linear programming approach for conflict-free charging and speed control in electric bus networks, addressing real-time operational challenges.

Findings

Controller anticipates and avoids charging conflicts.

Achieves lower operational costs compared to standard schemes.

Improves service regularity and energy efficiency.

Abstract

The rapid adoption of electric buses by transit agencies around the world is leading to new challenges in the planning and operation of bus networks. In particular, the limited driving range of electric vehicles imposes operational constraints such as the need to charge buses during service. Research on this topic has mostly focused on the strategic and tactical planning aspects until now, and very little work has been done on the real-time operational aspect. To remedy this, we propose integrating the charging scheduling problem with a real-time speed control strategy in this paper. The control problem is formulated as a mixed-integer linear program and solved to optimality with the branch-and-bound method. Simulations are carried out by repeatedly solving the control problem in a receding horizon fashion over a full day of operation. The results show that the proposed controller manages to anticipate and avoid potential conflicts where the charging demand exceeds the charger capacity. This feature makes the controller achieve lower operational costs, both in terms of service regularity and energy consumption, compared to a standard first-come, first-served charging scheme.