Infulencing Factors And Experimental Research On The Performance Of Permanent Magnet Electric High-speed Maglev Suspension

The permanent magnet electric maglev system induces eddy current in the induction track through the relative movement of the permanent magnet and the induction track,and interacts with the source magnetic field to generate electromagnetic force to make the vehicle levitate.It has the advantages of low energy consumption,large suspension air gap,low requirements for track construction,and simple structure,and has broad application prospects in the fields of maglev transportation and electromagnetic ejection.Developed countries led by the United States found in the process of tackling key problems in this technology that the suspension performance in the full-speed range,especially in the high-speed section,is still poor,which is mainly reflected in the relatively small floating resistance caused by the excessive magnetic resistance,and the floating weight caused by the weight of the permanent magnet.It is relatively small.In the final analysis,it is necessary to study the suspension characteristics of the system to improve the suspension performance.In the process of tackling this technology,developed countries led by the United States found that the suspension performance in the full speed domain,especially in the high-speed section,is still poor,which is mainly reflected in the small floating resistance caused by excessive magnetic resistance and the small floating weight caused by the self weight of permanent magnet.In the final analysis,it is necessary to study the suspension characteristics of the system to improve the suspension performance.In this thesis,the parameters affecting the suspension performance of the system are studied one by one.Combined with the planning and engineering practice requirements of the Provincial Department of science and technology,this thesis takes the permanent magnet electric high-speed maglev suspension system as the research object,and analyzes its structural characteristics and engineering principle.The spatial distribution of magnetic field of permanent magnet array source is analyzed by means of theoretical derivation,Mathematica numerical analysis,Ansoft Maxwell two-dimensional and three-dimensional electromagnetic simulation and field test.The theoretical model of electric levitation considering track thickness is established.The effects of permanent magnet array structure,induction track parameters,system dynamic parameters and special structure on the levitation performance of the system are deeply studied,and the optimization design suggestions of each influencing factor are put forward.Finally,a permanent magnet test-bed with a speed of 450 km/h is built to verify the correctness of the model and the effectiveness of the design suggestions.The main research work of the thesis is as follows:(1)The distribution characteristics of the external magnetic field of the Halbach array are analyzed,and the difference between the Halbach array and the ordinary array is compared by the method of finite element calculation.Analytical expressions are used to analyze the spatial distribution of the external magnetic field,and then the correctness of the model is verified by means of experimental measurement and finite element calculation.(2)An ideal electric suspension theoretical model considering the thickness of the track is established,the analytical relationship between the electromagnetic force and the source magnetic field is studied,and the influence of the typical dynamic parameters operating speed on the electromagnetic force is analyzed,and the theoretical model is verified by finite element simulation.The results are basically consistent with the change trend of the theoretical calculation values,which verifies the correctness of the theoretical calculation results.(3)The two-dimensional and three-dimensional transient electromagnetic simulation models of the permanent magnet electric suspension system are established.The permanent magnet array parameters such as the width length ratio,height length ratio and different types of magnetic blocks,the track parameters such as the thickness,width and material of the induction plate,the dynamic parameters such as running speed and suspension clearance,and the influence of special structural forms on the suspension performance of the system are studied.The design and selection suggestions of various influencing parameters are put forward.(4)The first counter rotating permanent magnet electric suspension test-bed with a test speed of 450 km/h is designed.The design idea and parts selection of the test-bed are introduced.The changes of electromagnetic force under different speed,air gap and permanent magnet array are tested.By comparing the calculation results of the model established in this thesis,a high degree of agreement is achieved.It is proved that the model established in this thesis is accurate and effective,and the design of the test platform and the setting of test conditions are reasonable.