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An electromagnetic suspension (EMS) magnetic levitation (Maglev) vehicle runs between a guideway and electromagnet at a certain distance, usually called the "airgap". To maintain the vertical airgap, the electric current of the electromagnet must be controlled. A lateral restoring force is generated by a component force in the vertical direction but is not controlled. So, the EMS Maglev vehicle must be operated at appropriate speeds around curves to prevent contact with the track. This is particularly important at track sections with a small radius of curvature such as at a switch. The segmented switch system developed and employed in Korea is entirely made of steel, which may cause instabilities in the levitation system in the presence of an airgap due to its greater susceptibility to vibration compared to concrete. Therefore, it is necessary to evaluate the stability of levitation using computational simulation when the maglev vehicle ran over a segmented switch. In this paper, a dynamic model of a Maglev vehicle was developed based on multibody dynamics that accounts for the flexibility of the segmented switch track. Using the developed analytical model, levitation stability and operational safety simulations were carried out. [ABSTRACT FROM AUTHOR]

In the literature related to maglev vehicles, most studies have primarily discussed the trade-off between a levitation system and guideway smoothness, such as deflection and surface roughness, and the optimization of a levitation controller. A dynamic model integrated with a kinematic vehicle, electromagnetic suspension system, guideway profile, and levitation controller model has been widely used for this purpose. However, in addition to guideway smoothness and stiffness, the normal force of a Linear induction motor (LIM) that is installed in the same bogie frame and drives the maglev vehicle can be regarded as a disturbance element affecting a levitation system. In addition, a linear model of an electromagnetic force is usually used in linear approximations around the nominal equilibrium point, in spite of its nonlinear characteristics. In this study, to analyze the interaction between electromagnetic and normal forces of the LIM, a dynamic model coupled with the normal force calculated from finite element analysis was developed. In addition, to comparatively analyze levitation stability by considering the linear and nonlinear characteristics of electromagnets, the non-linear electromagnetic forces measured in the experiment are coupled to the dynamic model. From the simulation results, it was confirmed that although a slight increase in current was observed with the LIM model when compared to without the LIM model, it produced no adverse effect on levitation stability. In simulation, considering the non-linear characteristics of an electromagnet, it was confirmed that the nominal current of the linear model converged to a higher value than the designed nominal current when the vehicle was standing still, whereas the nominal current of the non-linear was similar to the designed one. [ABSTRACT FROM AUTHOR]