Dynamic Performance Analysis And Structural Optimization Of Suspension Electromagnets

As a safe,efficient,quiet and environmentally friendly rail transit,the medium and low speed maglev train has gradually become an important means of transportation connecting the city.The horizontal thrust of the medium and low speed maglev train is provided by the asynchronous induction linear motor,while the suspension force is provided by the suspension electromagnets.The dynamic performance of the suspension electromagnet determines whether the maglev train can operate stably and efficiently.During the acceleration of the maglev train,the levitation electromagnet moves relative to the rail,and eddy current is generated in the rail through electromagnetic induction.The external magnetic field generated by eddy current will counteract the original magnetic field generated by some levitation electromagnets,so the levitation force is weakened.With the increase of train speed,the eddy current effect will become obvious.When the suspension force is attenuated by the eddy current effect,a larger current input is needed to keep the suspension air gap between the electromagnet and the rail constant.However,when the train is running at high speed,if a large current is applied to the electromagnet for a long time,it will lead to the continuous heating inside the electromagnet winding,accelerate the aging of the insulation layer between the windings.If the insulation layer is damaged,it will lead to the reduction of the winding ampere turns and further weaken the suspension force.Therefore,it is urgent to study the dynamic coupling characteristics between the suspension electromagnet and the rail.In this paper,the dynamic coupling mechanism of electromagnet and rail is studied,the dynamic law of eddy current effect with the change of speed is analyzed,and the optimal matching method of electromagnet and rail to restrain eddy current effect is proposed.In this paper,starting from the levitation principle of the levitation electromagnet,the key factors affecting the levitation performance of the electromagnet are analyzed,and then the dynamic coupling model of "levitation electromagnet rail" is constructed,and the change rule of the levitation force of the levitation electromagnet under the effect of eddy current under different operating speeds is analyzed.At the same time,the typical working conditions of the suspension electromagnet are studied,including pitch,roll,lateral offset and swing,and the dynamic characteristics of the suspension force under four working conditions are analyzed.Then,in order to restrain the weakening effect of eddy current on the suspension force,this paper improves the structure of the suspension electromagnet and the rail by using the lamination method,and compares it with the suspension electromagnet without lamination structure.Through comparative analysis,the use of laminated structure of the electromagnet can effectively reduce the impact of the track eddy current on the suspension electromagnet of the medium and low-speed maglev train in the moving state,and has a better inhibition effect on the attenuation of the suspension force of the electromagnet.Its dynamic suspension performance is better than that of the non laminated structure of the suspension electromagnet.Finally,in order to improve the magnetic field distribution at the end of the electromagnet and weaken the influence of the eddy current generated by the electromagnet in the rail when the train moves,this paper adopts the improved scheme for the end structure of the electromagnet,and analyzes and compares it with the prototype of the suspension electromagnet.The simulation results show that the improved triangle structure at the end of the electromagnet can restrain the influence of the end effect on the levitation force to a certain extent,and further improve the levitation performance of the suspension electromagnet.