Energy-efficient Operation Method Based On The Train With Discrete Control

Railway is the one of the most important modes of transportation,providing huge support for the development of the social and economic.However,with the increasing scale of railway transportation in recent years,its energy consumption has been deeply concerned by the public.With the development of the western China,the diesel locomotive it still the best choice in some areas where there is a lack of capacity and electricity.Even in the initial stage of medium capacity lines,it is appropriate to choose the diesel locomotive as the traction power.Because of its multiple control degrees and discrete control characteristics,the diesel locomotive has lower adaptability to the complex railway lines and it needs more skills to operate.Therefore,it is significant to research the energy-efficient operation of the discrete-controlled trains on complex lines which composed of steep sections,long steep down grades and complex speed limits.On the basis of domestic and international achievements,this paper probes into the energy-efficient operation of discrete-controlled train on complex railway lines.The following components are involved:(1)Based on the energy consumption model of discrete controlled train,an energy-efficient optimization model of train under complex speed limits is established by defining the relationship among control change points,gradient change points,speed limit change points.By applying the Lagrange method and the Kuhn-Tucker condition,the key equation of energy-efficient operation under complex speed limits is obtained and the analytical method for solving the energy-efficient operation problem is deduced.(2)In view of the shortcoming of the inadequacy of the analytical method when there are steep sections in the track,the discrete controlled model is transformed into the continuous controlled model,and the maximum principle is introduced to obtain the optimal principle of control switching.After analyzing the optimal control switching form when train passing through the steep down section,the steep up section,and the long step down grade,we conclude that the form of control switching which is used by the continuous model to travel through the steep section is also applicable for the discrete model.(3)The key point of energy-efficient operation of discrete controlled train on complex lines lies in the reasonable selection of the control switching of trains passing through the steep section.In this paper,an optimal connection algorithm is designed to solve the energy-efficient operation problem under complex lines.The lines are divided into steep sections and non-steep sections.For steep section,a graphic method based on the principle of the optimal control switching of the continuous control mode is designed to obtain its optimal speed profile.For the non-steep section,the energy-efficient speed profile is obtained by the analytical method.Finally,the effectiveness of the algorithm is verified by computer simulations.The algorithm provides a theoretical basis for practical engineering application of energy-efficient operation of discrete-controlled train on complex railway lines.