Implementation of sensorless control of radial magnetic bearings
- General Electric Co., Schenectady, NY (United States)
This paper discusses preliminary results of the implementation of sensorless position control of a radial magnetic bearing. The magnetic bearing is controlled using a mutually exclusive excitation scheme; where only one out of the two available actuators in each axis is active at any time. The unused actuator is used for sensorless position estimation. The sensorless position scheme is based on measuring the change of airgap reluctance with the variation of airgap between the actuator and the rotor. The airgap reluctance is measured by driving the unused actuators with short probing pulses and measuring the resultant change of current. The rotor position is controlled using independent Proportional Integral Derivative (PID) control of each axis. This offers a simple and robust controller. The authors present the design of a PID controller. Preliminary experimental results are presented showing levitation at standstill. The sensorless control algorithm has been implemented on a digital controller and levitation of the test-rig rotor with one radial bearing operated without a position sensor has been demonstrated. Due to the inherent double integration from the rotor inertia, the derivative component of the position is required for stabilizing the system. However this also inherently amplifies measurement noise and thus low-noise position estimation is required. Means for reducing the existing noise in the position estimate, in the test-rig system, by increasing the current sensor resolution and using greater filtering are being investigated.
- OSTI ID:
- 390762
- Report Number(s):
- CONF-950852-; TRN: 96:005769-0020
- Resource Relation:
- Conference: 4. industrial conference and exhibition on applications of magnetic bearings, magnetic drives, and dry gas seals, Alexandria, VA (United States), 10-11 Aug 1995; Other Information: PBD: 1995; Related Information: Is Part Of Proceedings of the MAG `95 magnetic bearings, magnetic drives and dry gas seals conference & exhibition; PB: 384 p.
- Country of Publication:
- United States
- Language:
- English
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