Computation of driving profiles for high-speed trains powered by on-board energy storage systems

Traction power supply system (TPSS) sometimes suffers a short interruption, which will lead trains losing power during their operations. In this emergency situation, to ensure passenger safety, an effective way is to drive the train to a nearest station using on-board energy storage systems (OESS). This paper presents two methods to compute emergency driving profiles subjected to the power and energy limitations of OESS. The emergency driving problem is formulated as an optimal control problem (OCP) by considering energy consumption of traction systems and auxiliary systems in the cost function, and the trip time is free. Firstly, a heuristic algorithm is designed to solve the OCP, which aims at maximizing the utilization of the potential energy related to gradients. Furthermore, to obtain a global optimal solution, the OCP is transformed into a multiple-phase decision problem, and a dynamic program (DP) method is proposed. Extensive comparisons are provided to investigate the performance of the two methods. Numerical results show that both of the two methods can generate feasible driving strategies. The operational energy consumption of the DP algorithm is lower than the heuristic algorithm, but the trip time of the heuristic algorithm is shorter than it of the DP.