Research on the characteristics of vertical electromagnetic force in EMS maglev trains based on hysteresis effect

The vertical component of the electromagnetic force between the electromagnet and the track is a key factor for the levitation and support of the EMS (Electromagnetic Suspension) maglev train. The hysteresis effect of the levitation electromagnet has a direct impact on the variation of the electromagnetic force. To investigate the influence of the hysteresis effect on the vertical component of the magnetic force in the EMS levitation system, a single electromagnet was first taken as the research object, and a vertical electromagnetic force model of the EMS levitation system was established based on the equivalent magnetic circuit method. A model was established by introducing changes in relative permeability considering magnetic saturation, and a model was established based on the Jiles-Atherton hysteresis theory, considering the hysteresis effect and a bench test of a single electromagnet was carried out. Secondly, a comparative analysis was conducted on the magnetic characteristics of the three vertical electromagnetic force models under static conditions, and levitation control was introduced to compare and analyze the magnetic characteristics of the three vertical electromagnetic force models under dynamic conditions. Finally, a vertical electromagnetic force model suitable for numerical calculation based on the hysteresis effect was proposed. The results show that under static conditions, the model considering the hysteresis effect is closer to the experimental results, and the calculation results are more accurate. Under dynamic conditions, the model considering the hysteresis effect can cause a strong noise interference in the dynamic response of levitation electromagnet and the magnetic flux density will exhibits a disordered and chaotic motion at the top of the limiting hysteresis loop.