Magnetic bearings are coming into increasing use in industry with advanced control and measurement techniques and magnetic material development today. They are primarily used to replace either rolling element or fluid film bearings in rotating machinery.
The primary objective of this work is to design a magnetic bearing system and its analog control circuits. The system consists of a rotor and two radial magnetic bearings with four electromagnets arranged radially to support the rotor. The rotor consists of a shaft and two laminated silicon steel disks to reduce eddy current. Each radial bearing is equipped with two gap sensors to measure the vertical and horizontal displacements of the rotor and a ball bearing for emergency operation. The controllers are designed such that the proportional and derivative actions can stabilize the system. The magnetic properties are measured experimentally and compared with theoretical results. Finally, the control gains are tuned, using the experimentally identified system parameters, such that the system stability and performance are satisfactory.