Study On Electromechanical System Structure And Digital Control System Of Magnetic Thrust Bearing

The life of mechanical thrust bearing will be hard shortened, due to the severe wear at high speed rotation, so the requirements of modern high-speed rotating machinery can not be satisfied. Therefore, a magnetic thrust bearing, including the mechanical structure and digital control system, is design here basing on maglev technique, and the suspended experiment is carried out.Generally, a magnetic thrust bearing system is composed of mechanical structure,detection unit and control system, which are designed separately in this thesis. The rationality and machining accuracy of mechanical structure is so important that the control precision and even the success of the system will be affected directly. Besides, the sizes of bearing, air gap, bias current, coil turn, maximum current, diameter of wire and other related parameters are designed according to the actual requirements.The performance of the control system will be influenced by the detection precision and real-time performance of displacement sensors, which are required to be of non-contacted type, high sensitivity, wide linear range, good stability and high immunity. The eddy current displacement sensor is selected here, and the related circuits are designed and tested satisfactorily in the experiment.The actual condition of the system can not be described accurately, due to the nonlinearity model of magnetic thrust bearing, so PID controller is adopted here, which will not require excess precision mathematics of controlled object and be of strong suitability and flexibility. Furthermore, the experiment based on the simulation of PID algorithm using MATLAB is carried on, and the steady suspension of magnetic thrust bearing is achieved, as will lay a useful foundation for further study.