Model-free Predictive Direct Speed Control for Maglev Transportation Long Stator Linear Motor

Maglev trains adopt long cable power supply, and the length of the cables changes with the position of the train, resulting in changes in the motor's parameters. Meanwhile, load disturbances and unmodeled dynamics also bring negative effects to the control of the long stator linear motor (LSLM). This paper proposes a model-free predictive direct speed control (MFPDSC) strategy for the three-level inverter LSLM traction system. The method simplifies the traditional dual-loop control system into a single controller, further improving dynamic performance. Integrates a Moving Horizon Estimation (MHE) observer to estimate and compensate for load disturbances and dq-axis voltage disturbances, enhancing robustness. This method is simple in design and simultaneously achieve the neutral-point potential balance control of the three-level inverter. The simulation results show that the proposed method can simultaneously achieve the tracking control of the neutral point voltage, velocity and current, and has better dynamic performance and robustness compared with the conventional methods.