Decreasing eddy current is very important for the realization of stability control of HoMB system. In order to improve the dynamic performance precision of HoMB in the design stage, the dynamics and stiffness analysis of a homopolar magnetic bearing (HoMB) has been studied in this paper. Because the polarities of the magnetic poles were not changed during the rotation of rotor, the effect of eddy-currents was often ignored in the previous researches. However, when the frequencies of vibration caused by external disturbance and control currents are very high, eddy-current effects have significant influence on the performance of HoMB. In order to predict the HoMB performance, guide the HoMB design and control of the HoMB system in high frequency, a dynamics model was built on the equivalent circuit method. Parameters of dynamic Modeling are frequency-dependent. The effect of eddy-currents on the current stiffness was studied. The analysis results show that the eddy current effect on HoMB can be reduced by increasing the air gap, decreasing the laminations thickness and decreasing the laminations conductivity.
2. Xu, S. L. and J. C. Fang, "A novel conical active magnetic bearing with claw structure," IEEE Transactions on Magnetics, Vol. 50, No. 5, 8101108, 2014.
3. Ren, X. J., et al., "Magnetic flux leakage modeling and optimization of a combined radial-axial hybrid magnetic bearing for DC motor," IET Electric Power Applications, DOI: 10.1049/iet-epa.2016.0259, to be published.
4. Huang, Z., J. Fang, X. Liu, , and B. Han, "Loss calculation and thermal analysis of rotors supported by active magnetic bearings for high-speed permanent magnet electrical machines," IEEE Transactions on Industrial Electronics, Vol. 63, No. 4, 2027-2035, 2016.
5. Bai, J. G., X. Z. Zhang, and L. M. Wang, "A flywheel energy storage system with active magnetic bearings," Proc. 2012 Int. Conf. Future Energy, Environ., Mater., Vol. 16, 1124-1128, pt. B, 2012.
6. Tang, J., et al., "Low eddy loss axial hybrid magnetic bearing with gimballing control ability for momentum flywheel," Journal of Magnetism & Magnetic Materials, Vol. 329, No. 2, 153-164, 2013.
7. Fang, J. C., S. Q. Zheng, and B. C. Han, "AMB vibration control for structural resonance of double-gimbal control moment gyro with high-speed magnetically suspended rotor," IEEE/ASME Transactions on Mechatronics, Vol. 18, No. 1, 32-43, 2013.
8. Fang, J., Y. Le, J. Sun, and K. Wang, "Analysis and design of passive magnetic bearing and damping system for high-speed compressor," IEEE Transactions on Magnetics, Vol. 48, No. 9, 2528-2537, 2012.
9. Noh, M. D., S. Cho, J. Kyung, S. Ro, and J. Park, "Design and implementation of a fault-tolerant magnetic bearing system for turbo molecular vacuum pump," IEEE/ASME Transactions on Mechatronics, Vol. 10, No. 6, 626-631, 2005.
10. Gilchrist, U., et al., "Robot drive with magnetic spindle bearings,", USA Patent, US20090243413 A1, 2009.
11. Hollis, Jr., R. L., "Magnetically levitated fine motion robot wrist with programmable compliance,", USA Patent, US4874998 A, 1987.
12. Beniak, R. and T. Pyka, "An energy-consumption analysis of a tri-wheel mobile robot," International Journal of Robotics and Automation, Vol. 31, No. 1, 2016, DOI: 10.2316/Journal.206.2016.1.206-4079.
13. Liang, L., et al., "Dynamical modelling and structural parameter optimization of a novel spiral in-pipe robot," International Journal of Robotics and Automation, Vol. 31, No. 1, 2016, DOI: 10.2316/Journal.206. 2016.1.206-4170.
14. Zhu, Y., X. Sun, and X. Wang, "Locomotion system design and dynamics analysis of a new telescopic miniature in-pipe robot," International Journal of Robotics and Automation, Vol. 31, No. 2, 2016, DOI: 10.2316/Journal.206.2016.2.206-4361.
15. Higuchi, T., K. Oka, and H. Sugawara, "Clean room robot with noncontact joints using magnetic bearings," Advanced Robotics, Vol. 7, No. 2, 105-119, 1993.
16. Selmy, M., M. Fanni, and A. M. M. Mohamed, "Design and control of a novel contactless active robotic joint using AMB," 2015 IEEE International Conference on Autonomous Robot Systems and Competitions (ICARSC), 144-149, Dec. 2015, DOI: 10.1109/ICARSC.
17. Schweitzer, G. and E. H. Maslen, Magnetic Bearings Theory, Design and Application to Rotating Machinery, Springer-Verlag, Berlin, 2009.
18. Zhang, W. and H. Zhu, "Improved model and experiment for AC-DC three-degree-of-freedom hybrid magnetic bearing," IEEE Transactions on Magnetics, Vol. 49, No. 11, 5554-5565, 2013.
19. Fang, J. C., et al., "Homopolar 2-pole radial permanent-magnet biased magnetic bearing with low rotating loss," IEEE Transactions on Magnetics, Vol. 48, No. 8, 2293-2303, 2012.
20. Eryong, H. and L. Kun, "A novel structure for low-loss radial hybrid magnetic bearing," IEEE Transactions on Magnetics, Vol. 47, No. 12, 4725-4733, 2011.
21. Kim, H.-Y. and C.-W. Lee, "Analysis of eddy-current loss for design of small active magnetic bearings with solid core and rotor," IEEE Transactions on Magnetics, Vol. 40, No. 5, 3293-3301, 2004.
22. Muramatsu, K., T. Shimizu, A. Kameari, I. Yanagisawa, S. Tokura, O. Saito, and C. Kaido, "Analysis of eddy currents in surface layer of laminated core in magnetic bearing system using leaf edge elements," IEEE Transactions on Magnetics, Vol. 42, No. 4, 883-886, 2006.
23. Tian, Y., Y. Sun, and L. Yu, "Modeling of switching ripple currents (SRCs) for magnetic bearings including eddy current effects," International Journal of Applied Electromagnetics and Mechanics, Vol. 33, 791-799, 2012.
24. Wang, J., H. Lin, Y. Huang, and L. Huang, "Numerical analysis of 3D eddy current fields in laminated media under various frequencies," IEEE Transactions on Magnetics, Vol. 48, No. 2, 267-270, 2012.
25. Bachovchin, K. D., J. F. Hoburg, and R. F. Post, "Magnetic fields and forces in permanent magnet levitated bearings," IEEE Transactions on Magnetics, Vol. 48, No. 7, 2112-2120, 2012.