Model predictive levitation control for single levitation system of EMS maglev trains

Maglev traffic has a broad application prospect. However, the traditional levitation controller is difficult to deal with the system constraints, resulting in the decline of system stability when the constraints are triggered. To solve above problems, a levitation controller based on MPC (model predictive control) is designed to achieve stable levitation under the condition of satisfying the electromagnet current saturation constraints. Firstly, the dynamic model of single levitation system is established, and the stability, observability and controllability of the levitation system are analyzed. Then, based on the linearized discrete model, the predicted output trajectory of the levitation system is calculated. The cost functions which considering tracking error and control quantity fluctuation are designed, and the corresponding quadratic programming problem under the constraint of current saturation is formed. Finally, the designed MPC control algorithm and PID method are compared and simulated. The simulation results show that the designed control method can significantly improve the robustness of the levitation system under the premise of meeting the constraints.