Dynamic Vibration Characterastics Of High Temperature Superconducting Maglev In A Ring Low Pressure Tube

Due to the dense air medium in the atmosphere,the large air resistance and aerodynamic noise will be caused when trains run at high speed,which leads to a lot of energy waste and noise pollution.With the development of evacuated tube technology,a new traffic pattern of low pressure is expected to solve the above problems.Depending on the previous studies,the world's first Evacuated Tube High Temperature Superconducting(HTS)Maglev Test Platform was developed successfully in June 2014,using the HTS maglev as the vehicle,which gets wide attention from all over the world.Presently,the investigations mainly focused on the dynamic experiments of the HTS maglev model system in low pressure and the HTS maglev vehicle in atmospheric pressure.However,the tests on the dynamic characteristics of HTS maglev system in low pressure environment is still not to be carried out.Therefore,using the evacuated tube platform,the dynamic vibration characteristics of HTS maglev vehicle in low pressure environment are studied.Firstly,in order to find out a better structure of HTS levitation system,the dynamic experiments of single-cryostat and multi-cryostat are tested in the atmospheric pressure environment.The vertical and lateral vibration acceleration signals of different levitation systems are collected by acceleration sensors,which are used to analyze the change trend of the dynamic parameters and study the relationship between the stability of the HTS maglev vehicle and the number of the cryostat.Secondly,with the acceleration and displacement testing device,the dynamic characteristics of the HTS levitation system are tested with different vacuum and field cooling height(FCH).And the change of tested signals is analyzed from both time domain and frequency domain.Finally,for the levitation drift happened in the long time running process,the influences of the speed,the field cooling height and the air pressure to levitation drift were studied.Meanwhile,to decrease levitation drift and improve the dynamic characteristic of curve negotiating,a magnetic superelevation structure based on Halbach permanent magnetic guideway is proposed,and the adjustment method of the slant angle of magnetic superelevation also be analyzed by simulation.In general,this work provides some basic data for the application of HTS maglev in low pressure tubes.It will be helpful to understand the essential characteristics of HTS maglev vehicle system and beneficial to the future design.