Magnetic Flux Feedback Strategy to Suppress the Gap Fluctuation of Low Speed Maglev Train Caused by Track Steps

Magnetically levitated (maglev) train achieves non-contact operation by maintaining a constant suspension gap between the electromagnet and the track. The gap is generally 8-10mm. Such a small suspension gap makes a limited range of the suspension gap, which affects the riding comfort and stability of the train. There exits rough suspension gap fluctuation while low speed maglev train running through some track steps. The electromagnet may hit the track under some severe conditions, which makes loud noise and weakens the riding comfort. In this paper, in order to suppress the gap fluctuation caused by track steps, we propose a linearized coupled model of the suspension module and the track. The analysis shows that the differences between the suspension gap signals and mean gap signals of the two suspension points lead to the large fluctuation of the rear suspension point. In order to solve this problem, we propose a control strategy using feedback of magnetic flux signals. Numerical simulations and experiment results show that the strategy can reduce the fluctuation amplitude of the suspension gap and weaken the difference of the gap response between the front and rear suspension points.