Design Of Controllers For Active Magnetic Bearing Rotor System

Active magnetic bearings(AMBs),use controllable electro-magnetic force to realize the rotor suspension.Rotating machinery supported with the active magnetic bearings can not only achieve higher rotation speed,have longer service life,but also feature better preventive maintenance,no lubrication,and no friction-related mechanical damage.The main problem in the AMB rotor systems is that the AMB is an inherent unstable,nonlinear system and variable-time,so a control system must be installed in order to realize the system stability。A single degree-of-freedom AMB model and a four degree-of-freedoms model were built based on the analysis of the AMB rotor system working principle.The basic control theories of the PD controller,fuzzy controller,fuzzy PD controller and H_∞controller that suited for active magnetic bearing systems are analyzed.Their performances are simulated through MATLAB Simulink.An interface built by MATLAB GUI is proposed to choose a proper control parameter for PD controller and H_∞controllerA PCB motherboard with TMS320F2812 as its central processor was designed and manufactured to realize the ontrollers.Base on the motherboard,the four degree-of-freedom of rotor suspension was stably achieved.The step responses of the four controllers,the rotor's static and dynamic performance at the speed of 1500rpm and 3000rpm were measured and analyzed.Finally,Kalman filter was introduced to overcome the random disturbance signal in the control system,and experimental results show the effectiveness of the Kalman filter in suppressing the random disturbance.