Research On Super High Speed Levitation And Guidance Technology

With the development of economy and society and the increasing requirement of speed,the research of ultra-high speed systems such as Hyperloop has become a hot topic in recent years.In order to reduce the friction,vibration,speed limitation and high energy consumption caused by the contact structure such as slide block and wheel rail,the super high speed system usually adopts the magnetic suspension structure to realize vertical support and lateral guidance.Hyperloop is taken as the research object in this paper,and a whole structure with functions of suspension,guidance and propulsion is proposed.The research is mainly focused on the structural design and realization of the suspension and guidance system.Based on the characteristic analysis and performance comparison between the plate type and the null-flux coil type structures,a suspension and guidance structure is designed and the system characteristic is researched.The main work of this paper is as following:Firstly,special requirements of the suspension and guidance structure are studied considering the operation characteristics of Hyperloop.The comparison of EMS attractive type suspension structure,EDS repulsive suspension structure and flux pinning effect high temperature superconducting maglev structure is conducted.Through the comparative analysis of the working principles and the operation characteristics of the different structures,it shows that EDS suspension structure has unique advantages in the application of ultra-high speed system.Combined with the linear synchronous air core motor propulsion system,an ultra-high speed system scheme with the function of suspension,guidance and propulsion is designed.The magnet selection is studied and performance indexes of the suspension and guidance system are clarified.Secondly,on the basis of the proposed super high speed system,the inductive plate type EDS structure is designed and analyzed.Different from the symmetrical structure of the magnet and the inductive plate in the Magplane system,the inductive plate is placed vertically in the proposed structure,and the center-lines of the magnet and the inductive plate are asymmetric.The double Fourier series method is used to model the plate structure,and the analytical results of electromagnetic force are verified by three-dimensional finite element simulation.According to the order from single plate to double plates,the suspension and guidance characteristics of the plate type suspension structure are studied,including the effects of magnet speed and suspension height on the system performances,the calculation of guidance stiffness,the design of permanent magnet and inductive plate,and the uneven force on the front and the back magnets.On the basis of design and analysis,a small plate type EDS structure experimental platform is built and tests at different speeds are conducted.The experimental data are in good agreement with the calculation results,which verifies the analysis of the proposed plate type EDS structure.Then,the null-flux figure eight coil EDS structure is studied.The structure of null-flux coil is modeled by dynamic circuit theory,and the electromagnetic forces between the magnet and the coil are obtained by energy method.Based on the analysis of the working principle of the null-flux coil and the effects of the system time constant on the system performance,the figure eight coil is designed with the electromagnetic force amplitude and the suspension force fluctuation as the indexes.The working characteristics of the coil structure are studied,including the influence of the magnet speed on the system performance,the selection of the suspension working point,the analysis of the levitation-drag ratio,the calculation of the guidance stiffness and the analysis of the system damping.A small figure eight coil platform is built and the experimental results have verified the effect analysis of levitation height and lateral gap on the system performance.Finally,on the basis of the requirement of operation speed and suspension guidance ability,a kind of permanent magnet and plate type EDS structure is designed.And the quantitative calculation results of speed effect,suspension stiffness,guidance stiffness and suspension-drag ratio have shown the rationality of the proposed structure.As the key component of the super speed transport system,the suspension and guidance structure is critical for the stable and safe operation of the system.The research of super speed suspension guidance structure in China is still at the initial stage and the analysis results of this paper will promote the development of super high speed transport system in theory and application.