Objective During the operation of EMS (electromagnetic suspension) maglev trains, the electromagnets carry large energizing currents, leading to high energy consumption and severe heat generation. The permanent magnet - electromagnetic hybrid suspension technology is expected to address such problems. Therefore, it is necessary to conduct a comparative study on the magnetic force characteristics of the above two maglev modes to clarify the performance of the hybrid suspension system in terms of levitation force, guidance force, and other aspects.
Method Based on the principles of hybrid suspension and EMS, the theoretical model of the electromagnetic field is derived, and a nonlinear finite-element simulation model is established. Under different suspension gaps and excitation currents, the variations of suspension force in the two maglev modes are investigated. When the maglev vehicle undergoes different lateral displacements, the variations of guidance force in the two modes are studied. Finally, the performance differences in the characteristics of suspension force and guidance force, and stability control between the two modes are analyzed in detail.
Result & Conclusion Under the same rated suspension mass, the required excitation current of hybrid suspension is significantly lower than that of EMS, which enables effective control of system energy consumption and heating. The suspension force of hybrid suspension mode exhibits smaller negative stiffness, and varies more gently with the suspension gap change. However, its lower current sensitivity is unfavorable for stable control of the levitation system. There is little difference in the suspension stability between the two modes at lower train speed. With the increase of the train speed, the EMS system demonstrates better suspension stability. The guidance force characteristics of both hybrid suspension and EMS are basically consistent. The guidance force rises with the increase of the vehicle lateral displacement, while the guidance stiffness gradually decreases due to magnetic flux leakage of the system.
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