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PIERS Online
Vol. 3
No. 5
2007
pp: 666-671Optimization Method for Passive Pole Pieces DesignLe Wang, Haitao Zhu, Xiaoyu Song, Zhe Jin, Xin Tang, and Weiming Wang doi:10.2529/PIERS061007111313 Downloads: 873 Abstract:The pole pieces of permanent magnet require precise design since the highly uniform magnetic field are needed for nuclear magnetic resonance imaging. A new method has been introduced in this paper to optimize the shape of passive pole pieces. Based on Filter Equation [1, 3] a field alteration function is proposed in this method to indicate the magnetic field change according to the pole pieces variation. And this function is optimized with BFGS method to determine the shape of pole pieces which produce the most uniform magnetic field. Simulation indicates that this method is much better than the optimization methods in previous published papers with respect to the speed and field uniformity.References:1. Abele, M. G. and J. H. Jensen, "Hybrid pole pieces for permanent magnets," J. Appl. Phys., Vol. 79, No. 8, 5199-5201, 1996. 2. Abele, M. G., Structures of Permanent Magnets, Wiley, New York, 1993. 3. Abele, M. G., J. H. Jensen, and H. Rusinek, 13th International Workshop on Rare-earth Magnets and Their Applications, 167-176, Birmingham, U.K., September, 1994. 4. Molfino, P. and M. Repetto, "Design of an axisymmetric permanent magnet structure for magnetic resonance tomography," IEEE Transactions on Magnetics, Vol. 24, No. 2, 994-997, 1988. 5. Miyamoto, T., H. Sakurai, H. Takabayashi, and et al., "A development of a permanent magnet assembly for MRI devices using Nd-Fe-B material," IEEE Transactions on Magnetics, Vol. 25, No. 5, 3907-3909, 1989. 6. Zhang, Y., D. Xie, and P. Xia, "Passive shimming and shape optimization of an unconventional permanent magnet for MRI, electrical machines and systems, 2003," Sixth International Conference on ICEMS 2003, Vol. 28, 99-902, Nov. 9-11, 2003. 7. Leonard, P. J. and A. M. Connor, "Pole shape optimization using a tabu search scheme," IEEE Transactions on Magnetics, Vol. 36, No. 4, July, 2000. |
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