An energy-efficient optimization method of train group trajectory for metro

Energy-efficient train operation plays an important role on reduction of energy consumption and sustainable development in metro system. the improvement of regenerative energy (rE) utilization through multi-train collaborative optimization is an effective way. however, traditional researches on this problem mainly focus on a two-train system, which cannot be applied to train group. this paper proposes a novel optimization method for multi-train, the complex train group problem is turned into a single-train and multiple two-train problems based on the analysis of the total energy model. then the optimal traction force of the accelerating train related to the braking power of the braking train is deduced to 100% recover the rE. therefore, the train group can be optimized by departure orders, traction energy of the first train is minimized and speed profiles of rest trains are adjusted to maximize the utilization of rE by sequence. specially, optimization of each train is independent, which only needs to focus on the braking power of its previous train, greatly simplifying the multi-train collaborative optimization problem. detailed optimization methods are proposed and the effectiveness are verified by the simulation results based on guangzhou metro.