A High Bandwidth, Low Loss Magnetic Suspension System for Turbomachinery

Magnetic bearings, unlike traditional mechanical bearings, consist of a series of components that, when mated together, form a stabilized system. The correct design of the magnetic bearing actuators will provide a cost effective device with low power requirements. The necessity of stability, which a magnetic suspension control system requires in both gain and phase margin, demands the actuators have sufficient bandwidth over the operating range. This paper presents designs for both radial and axial actuators which have attained both high bandwidth and low loss in operation. Test data which verifies the actuator models are presented. Applications of this technology for turbomachinery are described. These include fully magnetically levitated rotor systems, tip clearance control systems and noise and vibration control systems.