Speed planning for connected electric buses based on battery capacity loss

Abstract

Connected battery electric buses (CBEBs) equipped with Vehicle-to-Infrastructure (V2I) have great potential for improving bus performance, through aspects such as energy saving and travel time reduction. For CBEBs, intelligent speed planning determines the energy consumption, which directly affects the charging or discharging of current to the battery and furthermore affects the battery degradation. This paper develops a speed planning model, aiming to minimize the total battery capacity loss of a battery electric bus by optimizing the bus speed of driving intervals and avoiding stopping delays at intersections along a bus line with a bus lane. Motor modeling, battery modeling, bus operation modeling, and constraints such as cruise time, arrival time, travel speed, acceleration and deceleration are all involved. A Q-Learning-based solution algorithm is proposed to solve the developed model. A case study based on a specific bus line with a bus lane is conducted. Results indicate that the developed method has an obvious advantage in reducing the total battery capacity loss compared with the greedy policy strategy. This study provides potential for future CBEB operation design.