| The Urban rail transit system can provide safe and efficient service for passengers,which has the advantages of lower energy consumption of per unit and high volume.However,due to the large-scale operation of the urban rail transit system and the high frequency service,the overall energy consumption of the subway system is very huge and it is imperative to reduce the energy consumption.The energy conversion efficiency of regenerative braking in urban rail system is high and its utilization potential is great.As a result,the utilization of the regenerative energy has become one of the most popular energy-saving methods in recent years.Based on the traditional energy-efficient driving strategy of trains,this paper analyzes the effect of on-board and wayside energy storage device on the train traction energy consumption with combining of the utilization of regenerative braking energy.Models and alogorithms for the optimal utilization of regenerative braking energy are also established.The main contents of this thesis are as follows:(1)Firstly,this paper proposes an energy-efficient driving model for trains.In the proposed model,the constraints are considered,such as the maximum traction and braking force,the basic resistance,the ramp additional resistance which is related to the position and the speed limit,the running time,the comfort degree.This thesis puts forward a solution approach of the energy-efficient train driving strategy with the dynamic programming method.According to the actual operation experience,the method effectively reduces the space complexity and decreases the computation time by limiting the number of stage and states.(2)In this paper,an optimization model of energy-efficient driving strategy under the condition of energy storage system is formulated.And a numerical algorithm is designed to obtain the optimal utilization of regenerative braking energy in on-board energy storage system through dividing the available regenerative braking energy and distributing to different locations in the interval.Based on this numerical algorithm,another numerical algorithm is designed in this paper.A better performance of utilizing the regenerative energy is achieved with optimizing the location of wayside energy storage system on line.(3)This paper conducts the case studies by using the operation data of Beijing Subway Yizhuang Line.In the Case 1,this paper firstly obtains the energy-efficient driving strategy in the given interval.Then,the effect of the velocity and the distance interval on the settlement results in the dynamic programming is analyzed by the control variable method The optimal utilization method of regenerative braking energy in the on-board energy storage system is obtained and the mass and the capacity of the on-board energy storage system are optimized in Case 2.The traction energy consumption of the train decrease by 30.66%compared with that of the unloaded onborad energy storage system.Furthermore,comparing to the case that without considering the utilizing the regenerative energy,the proposed numerical algorithm that optimizes the utilization of the regenerative energy can increase the energy reduction by 9.90%.The Case 3 make research on the optimal utilization method of regenerative braking energy in the wayside energy storage system.The result shows that the traction energy consumption of the train is 21.7%lower than that of the train before the wayside energy storage system is installed.The examples in Case 3 also analyzes the influence of the capacity and the installation location of the wayside energy storage system on energy-efficient performance,which provide a reference for practical application and has a certain application prospect. |
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