Research On Levitation Controller Based On Electromagnetic Force Feedback Control Strategy

To establish the mathematical model of the single electromagnet levitation system and to design reasonable control strategy is the basis of the stable control of maglev trains. The traditional voltage and current control model of single electromagnet levitation system is established by using the linearization method based on Taylor Series. The accuracy of control model is limited, and the effect of control is easily affected. In order to overcoming the shortcomings of traditional control models, this paper mainly focuses on improvement of the control model of single electromagnet levitation system.In this paper, the dynamic equations of the single electromagnet levitation system are established, and the modeling process of the traditional voltage and current control models is given, and the limitations of the traditional linearization models are discussed. Aiming at the shortcomings of the linearization model, the electromagnetic levitation force is regarded as the control object, and the electromagnetic force control model of the single electromagnet levitation system is established. The model is not linearized and retains the nonlinearity of the levitation system. Based on the electromagnetic force control model and the electromagnetic force analytical formula, the electromagnetic force feedback control strategy is established by adopting state feedback control method. Comparison is give between electromagnetic force feedback control strategy and the traditional control strategies by Simulation.For further verification of the effectiveness of the electromagnetic force feedback control strategy, the controller based on the electromagnetic force feedback is realized on the TMS320F28335 digital signal processor. For typical working conditions of maglev trains, such as levitating-up & landing-down, load changes, disturbance of external force, gap interference caused by track joint gaps, experiments are done in maglev vehicle model experimental platform for comparative purpose between electromagnetic force feedback control strategy and the traditional control strategies. The experimental results show that the electromagnetic force feedback control strategy has better levitation stability, load adaptive ability and adaptability of gap interference compared with the traditional control strategies. Due to the measurement of load before levitating-up by the electromagnetic force feedback control strategy, the adaptability of load increase of electromagnetic force feedback control strategy shows obvious advantages., the control characteristics are effectively enhanced in the load increasing state, the range of the control stability is expanded. In the condition of 165% load-up in the experimental platform, the electromagnetic force feedback control strategy can still keep the system stable, compared with the traditional voltage and current control strategies, the data respectively is 90% and 125% load-up, in which the system becomes instable. The result shows that the stable range of electromagnetic force feedback control strategy is expanded by nearly 30%.