Design and analysis of a sensorless magnetic damper

Journal Article · Wed Jan 01 04:00:00 EST 1997 · Journal of Engineering for Gas Turbines and Power

DOI:https://doi.org/10.1115/1.2815544· OSTI ID:483762

Chen, H M ^[1]

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1. Mechanical Technology Inc., Latham, NY (United States)

An industrial vertical rotor supported by rolling element bearings was originally designed to operate below its first critical speed. Since the rotor accumulated unbalance during operation, which was a potential problem, it was proposed that a soft magnetic bearing replace the lower rolling element bearing. The magnetic bearing (hereafter referred to as a damper) tends to make the rotor spin at its mass center and reduces the unbalance force to ground by an order of magnitude. The damper is an actively controlled electromagnetic device, and its desires stiffness and damping properties can be readily achieved by using a conventional PID controller with displacement sensors. However, because these sensors are expensive and unreliable in the hot, hostile environment around the rotor, there is a high incentive to design a sensorless controller. An analytical method for designing magnetic bearing controllers with no displacement sensors has been developed and laboratory tested. The method was applied to the design of a sensorless magnetic damper for replacing a rolling element bearing of a vertical rotor with a large unbalance. The synchronous vibration force transmitted to ground was predicted to be reduced by a factor of ten.

• Sponsoring Organization: USDOE
• OSTI ID: 483762
• Report Number(s): CONF-950629--
• Journal Information: Journal of Engineering for Gas Turbines and Power, Journal Name: Journal of Engineering for Gas Turbines and Power Journal Issue: 1 Vol. 119; ISSN JETPEZ; ISSN 0742-4795
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
CONTROL SYSTEMS
DAMPING
MAGNETIC BEARINGS
MECHANICAL VIBRATIONS
ORIENTATION
ROTORS