Research On Energy-Efficient Operation Algorithm For Freight Train Based On Optimal Control

With the increasingly prominent role of energy in social development,how to use energy more efficiently has become a widespread focus of the society.The railway is the main artery of national economy,important infrastructure and transportation.The state has put forward new requirements for energy saving and emission reduction of railway transportation system.According to the work plan for energy conservation and emission reduction of the 13 th fiveyear plan,the energy consumption of railway system units by 2020 will be 5% lower than that in 2015.The traction energy consumption in the total energy consumption of freight train is the most part.In order to implement the requirements of the state to accelerate the construction of resource-saving society,it is necessary to study the strategy of optimizing the operation of freight train.This paper is to find energy-efficient train operation strategies based on optimization theory to reduce traction energy consumption.The main research contents in this papser are as follows.First,according to basic regulations of train traction calculation,the optimal control model of train is built,with the target of minimizing traction energy consumption.By applying Pontryagin's Maximum Principle,the necessary conditions for the optimal operation are given.The transformation rules of operation modes and variation of adjoint variable are summarized.Then,the influencing factors of energy comsumption and the relationship of journey time,energy consumption and constant target speed are summarized.Besides,the relationship between the fluctuation of speed and energy consumption is found.On this basis,a new mode of minimizing the fluctuation of speed is proposed and its necessary conditions are developed when there are steep gradients between constand speed sections or being interrupted by neutral sections.The existence and uniqueness of the local optimal connection are proved.In the end,according to the necessary condition and property of local optimal connection between constant speed sections,the search algorithm of local optimal connection is designed.Furthermore,a global solution algorithm for the train saving energy are presented.Taken an actual line as an example,the results show that with the increase of constant target speed,the journey time decreases and the energy consumption increases.Compared with the actual driver control results,the energy saving 3.19% can be realized by using the proposed algorithm based on the speed fluctuation.In addition,the examples demonstrate that the proposed method with less calculation time performs better than the method of adjoint variable.