| Active magnetic bearing (AMB) make rotor suspended by magnetic force in the realization of non-contact support. Since magnetic suspended bearings have many advantages of no friction, no abrasion, no lubricated, lasting life, maintenance-free to the traditional bearings, they are attracting more attention gradually. However, the mathematical model of magnetic suspension bearing is difficulty to be determined accurately , the load is always in the change and the working conditions is quite complex.Therefore ,it is very essential to do research on the control algorithm which has strong antijamming ability and is insensitive to the model parameter. In this paper, magnetic suspended bearing is researched and the electromagnetic parameter is designed. The coupling of the system is analyzed and the mathematics mode has been elected. System control algorithm is also researched deeply in this paper. The main contents of this paper are follows:The structure and the relation of five-freedom-degree magnetic suspended bearing are described in detail. Based on the basic idea of the magnetic circuit, system requirements and relevant experience, main electromagnetic parameters of system is calculated. Also current response rate of power amplifier and the impact of bias current are analyzed. It provides theoretical guidance for the actual electromagnetic parameters design and system modeling.Coupling of magnetic bearing system's sensor is analyzed and electric decoupling mean is researched. It is deduced that the movement of rotor is approximate to be independent respectively, have no coupling and be controlled all alone without affects. It is probability that five-freedom-degree magnetic suspended bearing can regard as five single-freedom-degree magnetic suspended bearing. The rationality for the model of the single-freedom-degree AMB is verified.Functional components and working principle of magnetic suspended bearing system are described. The capacity of magnetic suspended bearing is analyzed. On this basis mathematical model of magnetic suspended bearing is deduced. And the model of system control object is deduced on the basis of the analysis of power amplifier, displacement Sensor, D/A and A/D. It provides theoretical basis for design and simulation of control algorithm.The application of state-feedback control, PID control and optimal control in the magnetic bearing system are analyzed. Multi-modal control algorithm of magnetic suspended bearing is deduced. Fuzzy adaptive algorithm is regarded as upper control algorithm of switching rules. Expert control, single neuron PID control, state-feedback control and maintain control are introduced to Lower control mode. And from top to bottom they are divided into four levels. Lower control mode is changed through fuzzy adaptive control. The simulation results show that the algorithm can be achieved better control results and fast, stable and precise suspension, which is a highly adaptive control strategy. |
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