Decentralized PID Control of Magnetic Bearings in a Rotor System

The decentralized PID controller design for a permanent/electromagnetic magnetic bearing CPEMB) system that suspends a high-speed rigid horizontal rotor is investigated in this paper. Two types of decentralized PID controllers are proposed. Considering the gyroscopic effect, a design procedure is presented. Simulation results show that the larger the ratio of polar mass moment of inertia to transverse mass moment of inertia in a rotor, the more significant the gyroscopic effect will affect the system stability. To facilitate implementation, we developed a controller together with bipolar linear current amplifiers for the PEMBs. Experiments show that the rotor's whirling orbits can be maintained within an acceptable small range (30 flm) when the rotor operates in the speed range from 0 to 12,000 rpm.