Energy-efficient Operation Of Medium-low Speed Maglev Train Based On Improved Adaptive Pseudospectral Method

With the opening of two medium-low speed maglev trains commercial operation lines,the energy consumption of medium-low speed maglev trains has attracted more and more attention.Compared with wheel-rail trains,medium-low speed maglev trains not only consume energy in traction,but also introduce levitation energy consumption,which accounts for about 30% of the total energy consumption.The research on energy consumption of medium-low speed maglev trains is still in the preliminary stage.Therefore,to study the energy-efficient driving of medium-low speed maglev trains is of great theoretical significance and of application values.In view of the unique technical characteristics of medium-low speed maglev trains,this thesis borrows the results of energy-efficient operation of wheel-rail trains based on the pseudospectral method and studies the energy-efficient train operation of medium-low speed maglev trains.First,the optimization operation train model of the medium-low speed maglev trains is established.Then,an improved adaptive pseudospectral method based on density function is proposed.In the end,based on the improved adaptive pseudospectral method,the optimal energy-efficient driving curve of the medium-low speed maglev trains is obtained.The main contents of the thesis are as follows:(1)First,force analysis,including traction force,braking force,running resistance and suspension force,of medium-low speed maglev trains is conducted,and the kinematic equation considering single particle point is established.Then,based on the generation mechanism of the traction energy consumption and levitation energy consumption,three cases which meet the constraints of ramp,speed limit,and traction/braking force restrictions for time saving,energy consumption with fixed time and energy consumption without time constraint are established respectively.(2)Based on the global pseudospectral method,an improved adaptive pseudospectral method is proposed.The proposed method uses the ratio of the maximum to the average curvature(excluding the maximum/minimum)in the trajectory as the basis for the adaptive condition.For instance,the degree of the approximating polynomial is increased if the ratio is below the threshold value.Besides,the mesh interval is divided if the ratio is above the threshold value.This algorithm captures the discontinuity and unevenness of the solution well and improves the calculation efficiency.The simulation examples verify the effectiveness and superiority of the algorithm.(3)Based on the improved adaptive pseudospectral method,the energy-efficient operation of medium-low speed maglev trains is studied.On the basis of preprocessing the line data and the maximum traction/braking curve,the train driving curve for the shortest running time,the most energy-efficient with fixed time and the most energy-efficient without time constraints are obtained,the effectiveness of the algorithm is verified.The advantages of this algorithm are analyzed with the case of Beijing S1 line.The results demonstrate that the train driving curve generated by improved adaptive pseudospectral method satisfies the practical constraints,and compared with the unimproved adaptive pseudospectral method,the calculation efficiency is improved.The superiority of the algorithm is verified.