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Fault Tolerant Homopolar Magnetic Bearings with Flux Coupling  

Na, Uhn-Joo (경남대학교 기계자동화공학부)
Publication Information
Journal of the Korean Society for Precision Engineering / v.25, no.3, 2008 , pp. 83-92 More about this Journal
Abstract
This paper develops the theory for a fault-tolerant, permanent magnet biased, homopolar magnetic bearing. If some of the coils or power amplifiers suddenly fail, the remaining coil currents change via a novel distribution matrix such that the same magnetic forces are maintained before and after failure. Lagrange multiplier optimization with equality constraints is utilized to calculate the optimal distribution matrix that maximizes the load capacity of the failed bearing. Some numerical examples of distribution matrices are provided to illustrate the theory. Simulations show that very much the same dynamic responses (orbits or displacements) are maintained throughout failure events (up to any combination of 3 coils failed for the 6 pole magnetic bearing) while currents and fluxes change significantly. The overall load capacity of the bearing actuator is reduced as coils fail. The same magnetic forces are then preserved up to the load capacity of the failed.
Keywords
Magnetic bearings; Rotor dynamics; Active vibration control;
Citations & Related Records
Times Cited By KSCI : 1  (Citation Analysis)
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1 Na, U. J. and Palazzolo, A. B., "The Fault-Tolerant Control of Magnetic Bearings With Reduced Controller Outputs," ASME Journal of Dynamic Systems, Measurement and Control, Vol. 123, Issue 2, pp. 219-224, 2001   DOI   ScienceOn
2 Sortore, C. K., Allaire, P. E., Maslen, E. H., Humphris, R. R. and Studer, P. A., "Permanent Magnet Biased Magnetic Bearings - Design, Construction and Testing," Proceedings of the Second International Symposium on Magnetic Bearings, pp. 175-182, 1990
3 Maslen, E. H., Allaire, P. E., Noh, M. D. and Sortore, C. K., "Magnetic Bearing Design for Reduced Power Consumption," ASME Journal of Tribology, Vol. 118, Issue 5, pp. 839-846, 1996   DOI   ScienceOn
4 Meeker, D.C., "Optimal Solutions to the Inverse Problem in Quadratic Magnetic Actuators," Ph.D. Dissertation, Mechanical Engineering, University of Virginia, 1996
5 Lee, A. C., Hsiao, F. Z. and Ko, D., "Performance Limits of Permanent-Magnet-Biased Magnetic Bearings," JSME International Journal Series C, Vol. 37, No. 4, pp. 783-794, 1994
6 Kasarda, M. E. F., Allaire, P. E., Norris, P. M., Mastrangelo, C. and Maslen, E.H., "Experimentally Determined Rotor Power Losses in Homopolar and Heteropolar Magnetic Bearings," ASME Journal of Engineering for Gas Turbines and Power, Vol. 121, Issue 4, pp. 697-702, 1999   DOI
7 Maslen, E. H., Sortore, C. K., Gillies, G. T., Williams, R. D., Fedigan, S. J. and Aimone, R. J., "A Fault Tolerant Magnetic Bearings," ASME Journal of Engineering for Gas Turbines and Power, Vol. 121, Issue 3, pp. 504-508, 1999   DOI
8 Allaire, P. E., Maslen, E. H., Humphris, R. R., Sortore, C. K. and Studer, P. A., "Low Power Magnetic Bearing Design for High Speed Rotating Machinery," Proceedings of the NASA International Symposium on Magnetic Suspension Technology Part 1, pp. 317-329, 1992
9 Fan, Y., Lee, A. and Hsiao, F., "Design of a Permanent/Electromagnetic Magnetic Bearing-Controlled Rotor System," Journal of the Franklin Institute, Vol. 334B, Issue 3, pp. 337-356, 1997
10 Maslen, E. H. and Meeker, D. C., "Fault Tolerance of Magnetic Bearings by Generalized Bias Current Linearization," IEEE Transactions on Magnetics, Vol. 31, Issue 3, pp. 2304-2314, 1995   DOI   ScienceOn
11 Lee, A. C., Hsiao, F. Z. and Ko, D., "Analysis and Testing of a Magnetic Bearing with Permanent Magnets for Bias," JSME International Journal Series C, Vol. 37, No. 4, pp. 774-782, 1994
12 Na, U. J., Palazzolo, A. B. and Provenza, A., "Test and Theory Correlation Study for a Flexible Rotor on Fault-Tolerant Magnetic Bearings," ASME Journal of Vibration and Acoustics, Vol. 124, Issue 3, pp. 359-366, 2002   DOI   ScienceOn
13 Na, U. J., "Fault Tolerant Homopolar Magnetic Bearings with Flux Invariant Control," Journal of Mechanical Science and Technology, Vol. 20, No. 5, pp. 643-651, 2006   과학기술학회마을   DOI