Magnetic Bearing Control Study

In this paper,the control effect of H theory used in single degree-of-freedom active magnetic bearing(single DOF AMB) is studied and the digital control system is founded.Firstly,working principle of AMB is introduced and the magnetic force is analysed in this paper.Secondly,we found the mathematical model by concentrated parameter and get the state space equation of AMB. On the base of above,we take into account disturbances of AMB and design the controller which can not noly steady the system but also increase robust ability of the system by choosing suitable weighting sensitivity function. We compare the results of simulation of H controller and PID controller.Lastly,we establish the digital control system which includes signal process circuit,A/D.PWM circuit and amplify circuit,etc. The problem of unsuitable time order between DSP and counter 8254-2 is solved in this paper. We improve the amplify circuit in order to increasing its stability. On the base of the digital control system of single DOF AMB,a digital control system of five degree-of-freedom AMB is designed in this paper.