Design and implementation of a fault-tolerant magnetic bearing system for turbo-molecular vacuum pump

One of the obstacles for a magnetic bearing for use in a wide range of industrial applications is the failure modes associated with magnetic bearings, which are not expected for conventional passive hearings. These failure modes include electric power outage, power amplifier faults, position sensor faults, and the malfunction of controllers. Fault tolerant magnetic bearing systems have been proposed so that the system can operate in spite of some faults in the system. In this paper, we describe the design and implementation of a fault tolerant magnetic bearing system for a turbo-molecular vacuum pump. The system can cope with actuator/amplifier faults, as well as faults in position sensors, which are the two major fault modes in a magnetic bearing system.