Research On Electromagnetic Characteristics Of Superconducting Linear Motor For High-speed Maglev

Due to its high speed upper limit,excellent acceleration and deceleration performance and strong climbing ability,the high-speed maglev system plays an increasingly important role in rail transit.Maglev has no contact with the ground track and consists of multiple linear motors to drive and levitation,the current more mature high-speed maglev train technology mainly includes Germany’s TR series constant conductive electromagnetic maglev and Japan’s ML series superconducting electric maglev.The stator and mover sides of constant conducting linear synchronous motor(LSM)adopt the iron core structure,which can produce a large excitation magnetic field to ensure large electromagnetic force output,but there is a saturation phenomenon of iron core.In this thesis,taking the constant conducting LSM as the design basis,the high-temperature superconducting(HTS)winding is used to replace the aluminum wire winding and remove the core structure on the mover side.The large current in the superconducting coil provides a strong magnetic field to drive the operation of the HTS LSM.The research contents of this thesis are as follows:The finite element model of the constant conducting LSM is established,and the accuracy of the simulation model is verified by comparing it with the operation data of the test sample vehicle.The material characteristics of HTS tape are introduced,and the electromagnetic field of runway type HTS coil is analyzed and calculated.On the basis of the normal conducting LSM,the excitation coil is changed into HTS coil,and the HTS LSM model is established,and the electromagnetic field and operating characteristics of normal conducting and superconducting LSM are compared and analyzed.The effects of stator side with and without iron core on electromagnetic field,traction force and levitation force are studied.The results show that under the same excitation conditions,the iron core structure can significantly improve the air gap magnetic density and electromagnetic force output.Secondly,the effects of the transverse coupling length of stator and mover as well as air gap height on the performance of the HTS LSM are studied.Finally,the influence of the number of mover side poles and the pole pitch on the output characteristics are calculated and analyzed.The influences of the operating parameters of HTS linear motor on the output characteristics are analyzed,the changes of electromagnetic force and electrical parameters under different armature currents,excitation currents,power angles and operating speeds are studied.On this basis,the obvious differences between normal conducting LSM and superconducting LSM with the changes of operating parameters are compared and analyzed.The field-circuit coupling model based on inverter is established,aiming at the problem of large fluctuation of traction and levitation force,the filter circuit is introduced to improve the electromagnetic force fluctuation of superconducting LSM.