Digital Control Method Of Electromagnetic Suspension System And Its Realization

Maglev train has been put into practice successfully which act as a new ground transit system. Due to the inherent nonlinearities and open-loop instability of the electromagnetic suspension (EMS) systems, control of its stability is accomplished either through analog controllers or by using digital systems. With the .availability of low-cost, high-speed and high-precision VLSI devices, digital control is being a new aiming direction of maglev control instead of widely used analog technique.Based on the nonlinear dynamic of single magnetic levitation system (SMLS,) two linear models are designed through the methods of 1 inearizing around the equilibrium and feedback linearization in this thesis. And close-loop control rules are given by using state-feedback on the base of the linear models. Because of the influence of the system' s nonl inear, different control rules designed according to the corresponding linearization models will result different close-loop responses. And this is illustrated by simulation. Transformation from s domain to z domain is needed in order to apply the continuous-time control rules to discrete control systems. The close-loop system' s stability under different sampling rates and the disturbance of noise is illustrated through the simulation based on discrete control model. Arid (lie feasibility of using digital control is demonstrated. Depending on the request of the digital control, a controller is designed using the digital signal processor (DSP) TMS320C31. Its functions include signal' s sampling, signal processing and operating result' s output. It is bare out through the experiment that the SMLS' s stable suspension can be obtained by using the digital controller mentioned above.