Ecological Velocity Planning of Plug-in Hybrid Electric Bus Through Signalized Intersections

This work focuses on the velocity planning problem for Plug-in Hybrid Electric Bus (PHEB). Based on communication with transportation infrastructures, the traffic information like Signal Phase and Times (SPaT) of traffic signals or stop time of bus stations over the entire route will be known precisely in advance. A spatial PHEB velocity optimization formulation with communication to traffic information is proposed to minimize the energy consumption or travel time. Two procedures are used for optimizing the objective, first, a State-of-Charge (SOC) curve is obtained from optimization with known road conditions for replacing empirical data to avoid the heavy computational duty of solving three-dimension dynamic programming. Then the optimized velocity profiles are calculated via a two-dimension dynamic programming model. Finally, the simulation results validate the energy savings and time savings of the proposed velocity planning strategy.