volume | PIER Journals

Abstract

To effectively simplify system structure and improve power density and efficiency, a design for a motor/generator suitable for flywheel energy storage system (FESS) is proposed. The machine is an outer-rotor and coreless-stator-type bearingless permanent magnet synchronous motor (BPMSM) with a Halbach array. Firstly, the operation principle of the outer-rotor BPMSM is described. Then, the structure and performance of the Halbach permanent magnet (PM) array are analyzed. The airgap magnetic field, back-EMF, suspension force, unilateral magnetic pull force and electromagnetic torque are calculated and analyzed by the finite element analysis (FEA). Finally, it is verified that the magnetic field of the suspension force windings increases the rotor eddy current loss by transient FEA coupled with external circuit. The rotor eddy current losses of BPMSM with different structures are compared. The comparison results show that the rotor eddy current loss of the coreless-stator-type BPMSM with Halbach array is the lowest. The simulation results verify the theoretical analysis and structure design, which can provide reference for the application of the motor in the FESS.

1. Dai, X. J., Z. F. Deng, G. Liu, et al. "Review on advanced flywheel energy storage system with large scale," Transactions of China Electrotechnical Society, Vol. 26, No. 7, 133-140, 2011. Google Scholar

2. Lee, J., S. Jeong, Y. H. Han, et al. "Concept of cold energy storage for superconducting flywheel energy storage system," IEEE Transactions on Applied Superconductivity, Vol. 21, No. 3, 2221-2224, 2010.
doi:10.1109/TASC.2010.2094177 Google Scholar

3. Subkhan, M. and M. Komori, "New concept for flywheel energy storage system using SMB and PMB," IEEE Transactions on Applied Superconductivity, Vol. 21, No. 3, 1485-1488, 2011.
doi:10.1109/TASC.2010.2098470 Google Scholar

4. Zhang, W. Y. and H. Q. Zhu, "Key technologies and development status of flywheel energy storage system," Transactions of China Electrotechnical Society, Vol. 26, No. 7, 141-146, 2011. Google Scholar

5. Pan, Z. and R. A. Bkayrat, "Modular motor/converter system topology with redundancy for high-speed, high-power motor applications," IEEE Transactions on Power Electronics, Vol. 25, No. 2, 408-416, 2010.
doi:10.1109/TPEL.2009.2025948 Google Scholar

6. Ooshima, M., S. Kobayashi, and H. Tanaka, "Magnetic suspension performance of a bearingless motor/generator for flywheel energy storage systems," Proceedings of IEEE Power Engineering Society General Meeting, 1-4, 2010.
doi:10.1109/PES.2010.5589783 Google Scholar

7. Asama, J., M. Amada, N. Tanabe, et al. "Evaluation of a bearingless PM motor with wide magnetic gaps," IEEE Transactions on Energy Conversion, Vol. 25, No. 4, 957-964, 2010.
doi:10.1109/TEC.2010.2040828 Google Scholar

8. Sun, X. D., L. Chen, and Z. B. Yang, "Overview of bearingless permanent magnet synchronous motor," IEEE Transactions on Industrial Electronics, Vol. 60, No. 12, 5528-5538, 2013.
doi:10.1109/TIE.2012.2232253 Google Scholar

9. Nguyen, Q. D. and S. Ueno, "Modeling and control of salient-pole permanent magnet axial-gap self-bearing motor," IEEE/ASME Transactions on Mechatronics, Vol. 16, No. 3, 518-526, 2011.
doi:10.1109/TMECH.2010.2045392 Google Scholar

10. Xu, Y. L. and K. J. Feng, "Analysis on toothless permanent magnet machine with Halbach array," Proceedings of Power Electronics and Motion Control Conference, IPEMC 2006, 1-5, 2006. Google Scholar

11. Zhang, T., H. Q. Zhu, X. D. Sun, et al. "Optimization of permanent magnet type bearingless motor using eddy current loss analysis," Electric Machines and Control, Vol. 16, No. 10, 58-62, 2012. Google Scholar

12. Xia, C. L., L. Y. Guo, and H. M. Wang, "Modeling and analyzing of magnetic field of segmented Halbach array permanent magnet machine considering gap between segments," IEEE Transactions on Magnetics, Vol. 50, No. 12, 2014.
doi:10.1109/TMAG.2014.2336835 Google Scholar

13. Li, H. F. and C. L. Xia, "Halbach array magnet and its application to PM spherical motor," Proceedings of Electrical Machines and Systems, ICEMS 2008, 3064-3069, 2008. Google Scholar

14. Xia, Z. P., Z. Q. Zhu, and D Howe, "Analytical magnetic field analysis of Halbach magnetized permanent-magnet machines," IEEE Transactions on Magnetics, Vol. 40, No. 4, 1864-1872, 2004.
doi:10.1109/TMAG.2004.828933 Google Scholar

Prof. Huangqiu Zhu

Dr. Ronghua Lu