Active control of linear motor suspension systems in high-temperature superconducting maglev trains

High-temperature superconducting (HTS) maglev trains are subjected to random track irregularities and normal forces from onboard linear motors during operation, leading to vibrational coupling among the train bodies, maglev frames, and motors. These motor vibrations cause changes to the air gap, which in turn result in variations in the normal forces. The altered normal forces react on the motor suspension systems, affecting the vibrations of both the maglev frames and the train bodies. A dynamic model was established for HTS maglev trains equipped with an active controller. This model incorporated an additional suspension system between the motor rotor and the maglev frame to mitigate the effects of air gap variations, and introduced an active control technique to the suspension system. Under external excitations composed of random track irregularities and normal forces from the linear motor, the dynamic responses of the motor rotor were simulated using MATLAB/Simulink with both PID and Fuzzy-PID controllers. Comparisons were made with passive suspension systems to verify the feasibility of the proposed control approach. Simulation results show that, compared to passive suspension systems, both control methods effectively suppressed air gap fluctuations in the motor, with Fuzzy-PID demonstrating significantly better control performance than PID. This approach offers a novel solution for suppressing linear motor vibrations, and its feasibility has been confirmed through simulations.