| Speed is the eternal theme of social development and the driving force for the continuous progress of human society.With the development of superconducting technology,the hightemperature superconducting magnetic levitation(HTS Maglev)technology with the main characteristics of frictionless,low energy consumption and low pollution has great potential to become a new mode of high-speed rail transportation.In recent years,researches on the application of HTS Maglev vehicle systems have become more and more abundant.However,with the further research and the completion of medium and long-distance test lines,the safety of the levitation system and performance of dynamic stability under moving conditions,especially in high-speed operation scene,higher requirements are put forward.Based on the situation above,with the goal of levitation force improvement and dynamic characteristics enhancement,this thesis proposes a levitation force compensation scheme based on electromagnetic force.By applying the electromagnetic coil to the HTS Maglev system,the electromagnetic force is used to provide compensation for the levitation force of the system.At the same time,the electromagnetic coil is used as a shunt damping system to improve the dynamic characteristics of the system.Based on the characteristics of the scheme,the basic principle and the feasibility of implement to HTS Maglev system are analyzed,and the research on the levitation force and the dynamic characteristics of the levitation system under vibration conditions have been carried out.Aiming at providing design ideas and references for the optimization and practical application of the HTS Maglev vehicle systems.Research on levitation force compensation based on coil electromagnetic force,the relationship between the levitation force and the intensity of current of current-loaded coils is conducted via the combination of simulation and experiment respectively.And the coupling performance between the electromagnetic force and the high-temperature superconductor levitation force is verified.At the same time,the effect of the magnetic field of the currentcarrying coil on the levitation force of the superconductor under long-term working conditions is studied.The results demonstrate that as the current intensity of the current-carrying coil increases,the effect of increasing the maximum levitation force becomes more obvious.Under the field cooling height(FCH)of 20 mm and 30 mm,the levitation performance is increased by 146.65% and 106.92% respectively when the current intensity is 20 A.After considering the influence of the fluctuation of liquid nitrogen,the maximum proportion of the levitation force change at the two FCHs is 3.38%.In the research on vibration reduction characteristics of shunt damping system,the optimal values of resistance of the shunt damping system are calculated according to theoretical analysis.Based on the built-up vibration test platform,the influence of the shunt damping system on the dynamic characteristics of the levitation system under vertical and horizontal vibration conditions is studied.The experimental results show that the R shunt damping system can effectively enhance the anti-interference ability of the HTS Maglev system,especially in the natural frequency range of the system.In the forced vibration conditions,the maximum vibration reduction efficiency of the shunt damping system reaches78.58% and 81.73% under the FCH of 20 mm and 30 mm,respectively;under free vibration conditions,the time required for the levitation system to stabilize after the addition of the shunt damping system has been reduced by 88.24% and 83.33%,respectively.Finally,based on the finite element electromagnetic simulation software,the electromagnetic coil model was established,and the relationship between different excitation frequencies and induced current and damping force under vibration conditions is further studied.The results show that as the excitation frequency increases,the maximum value of the induced current generated by the electromagnetic coil increases first and then gradually stabilizes.The higher the excitation frequency and the lower the working height,the greater the damping force generated by the system and is always greater than the inertial force of the system.These experiments and simulation work show that the application of electromagnetic coils to the HTS Maglev system can not only provide compensation for the levitation force,but also effectively improve the dynamic characteristics of the levitation system. |
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