| As a typical representative of a new type of transportation technology,maglev train has attracted the attention of many scholars at home and abroad because of its advantages such as no mechanical wear,high running speed,safety and reliability.Common magnetic levitation systems are divided into EMS,EDS and HTS according to different vehicle levitation principles and modes.High temperature superconducting maglev has the characteristics of passive stability(stable suspension without active control),but its suspension capacity is low,while the electric suspension system has a larger load control capacity,but the system is more complex.In order to give full play to the advantages of various systems,and obtain a suspension system with stronger load capacity and higher self-stability,In this thesis,In this paper,the magnetic rail relationship and mechanical properties of hybrid magnetic suspension system are studied,and the two magnetic suspension systems are selected for mixed research.The specific research contents are as follows.Firstly,a freezing mirror model was proposed based on the field cooling experiment data of high temperature superconductor through finite element method,and the method of equivalent processing high temperature superconductor into low relative permeability magnet was obtained,so as to obtain the captured magnetic field of high temperature superconductor and the variation law of axial motion suspension force of high temperature superconductor with suspension gap under different field cooling heights.Then the suspension force of the high temperature superconducting block in the permanent magnet orbit in the high temperature superconducting nailing suspension system is studied experimentally and theoretically.The three-dimensional simulation analysis model of the combination pairing of bimodal permanent magnet orbit and high temperature superconducting block was established,and the relationship between the suspension force and suspension gap under different field cooling heights was analyzed.By comparing the simulation results with the experiments,the correctness of the equivalent treatment method was verified,which provided a simple and effective calculation method for the suspension force calculation of high temperature superconducting maglev system.Secondly,according to the parameters of Japan’s MLX01 superconducting electric maglev train,a mechanical simulation analysis model of the superconducting electric maglev system was established.The correctness of the simulation calculation was verified by comparing the calculated guiding force and suspension force with the experimental data.The low-temperature superconducting coil(liquid helium temperature working area)commonly used in Japan’s electric maglev was changed into a high-temperature superconducting coil(liquid nitrogen temperature working area).The size and operating current of the high-temperature superconducting coil were appropriately reduced,and the simulation calculation was carried out.The suspension force,guiding force and magnetic resistance of the system were obtained by using this model.The effects of train speed,transverse distance and vertical distance between coils on suspension force and steering force of the system were studied,and suspension stiffness under different transverse distance and suspension height under different running speed were obtained.Then,by using a permanent magnet array instead of a superconducting coil,a simulation analysis model of a permanent magnet electric maglev system was established based on the finite element method,and the effects of train running speed,transverse and vertical distance between the permanent magnet array and the "8" coil on the suspension force and guiding force were studied.Finally,a hybrid magnetic levitation system is proposed.At the same time,in order to increase the damping of the hybrid magnetic levitation system,the influence of adding copper on the damping of the system is studied.Ansoft finite element software is used to establish the interaction model between the permanent magnet track and the copper.The influences of metal sheet shape,size,velocity and suspension gap on eddy current damping force and unit mass eddy current damping force were studied,and the variation of eddy current force on metal was obtained.After that,the optimal size of the copper sheet is obtained by optimizing the size parameters of the metal sheet.In addition,by fitting the eddy current damping force with the size and velocity of the copper sheet,the empirical formula between the eddy current force,the length of the copper sheet,the suspension gap and the velocity of the copper sheet was obtained.The dynamic model of the hybrid magnetic suspension system was established and verified that adding copper sheet can appropriately increase the damping of the system,which is conducive to the stability of the system. |
