Research On The Performance Characteristics Of Magnetic Suspended Vehicle Under Ultimate Load Conditions

Based on the levitation theory of the conventional maglev train, the structure andcontrol of the magnetic suspended vehicle are greatly simplified. Compared withconventional maglev train, there are two main innovations for the magneticsuspended vehicle: one is that the control principle is simplified from theconventional maglev train control of five degrees of freedom to two degrees offreedom control based on its structural features, which simplifies the structure,reduces the difficulty of control, improves reliability and saves cost; the other is thatair propeller replaces the linear motor in the conventional maglev train in terms of thedrive system, which reduces the cost, simplifies the structure of the rail and avoids themutual interference between drive and suspension magnetic field.This paper, firstly, introduces the characteristics and main applications ofmagnetic bearing system briefly and analyzes the research status related to this paper.Secondly, it introduces the design principle, structural features and control system ofthe magnetic suspended vehicle. Then, the equivalent friction of the magneticsuspended vehicle is defined from the perspective of the energy loss; the equivalentfriction of selected magnetic bearings, whose structure size and material propertiesare fixed, is only determined by the average magnetic induction intensity of airgap magnetic field at any rate when the coil current is maximum. Finally, it analyzesthe performance characteristics of magnetic suspended vehicle under ultimate loadcondition through two methods: experimental determination and ANSYS simulation,which mainly includes the influence law of equivalent friction due to the changes ofbearing capacity and speed in magnetic suspended vehicle, and analyzes thefeasibility of PID control in magnetic suspended vehicle system under ultimate loadcondition.From the results, under the condition of close to magnetic suspended vehicleultimate load, the current in the coil of U-shaped electromagnet increases with theincrease of suspended load and speed, resulting in the increase of in air gapmagnetic field, which makes the equivalent friction of vehicle increase. The ultimateload of magnetic suspended vehicle is504N. When the suspended load exceeds ultimate load, PID control loses function for the magnetic suspended vehicle system;the small disturbance outside can make the vehicle fall or absorb on the guide rail andit can’t restore suspension. Therefore, it should be avoided that the magneticsuspended vehicle works under ultimate load condition to reduce electromagneticfriction and improve the stability of magnetic suspended vehicle system.