Modeling and Energy-Optimal Control for High-Speed Trains

This article presents a microscopic simulation model and corresponding energy-optimal control method for high-speed trains. The vehicle-line-coupled longitudinal dynamics model and nonlinear power loss model of the traction transmission system (TTS) for different traction force and speed pairs are discussed. Based on these detailed models, an energy-optimal control problem is formulated by systematically considering speed limitations, punctuality, and control force constraints in neutral sections of contact wire. Then, the formulation is transformed into a multiple phases' optimal control model based on some key positions, and the hp-adaptive pseudospectral method is applied to obtain the optimal results. The proposed dynamics model and the energy consumption model are validated by the comparison of model predictions and measured data. The simulation results show that the energy efficiency of the optimal results with a nonlinear power loss model is improved compared to the traditional method with constant efficiency of the TTS. The energy consumption can be reduced by 12.67%, comparing optimal speed profiles against measured results on commercial lines of China. Finally, the influences of gradients are analyzed, and the coast-traction pairs can replace cruising strategy on downhill sections.