volume | PIER Journals

Abstract

Bearingless brushless DC (BBLDC) motor in the flywheel energy storage system has advantages of low energy consumption, high critical speed and better speed adjustment performance. However, torque ripple exists inevitably due to the current commutation of the BBLDC motor and the wide range of speed changes when the flywheel energy storage system charges and discharges. In this frame, an approach of combining the direct torque control (DTC) with the current prediction control (CPC) is proposed to suppress torque ripple in wide speed regulation range. In this paper, the mathematical model of the BBLDC motor is given, and the principle of DTC scheme is introduced. On the basis of analyzing the causes of commutation torque ripple when using DTC scheme, CPC scheme is employed to minimize the commutation torque ripple by controlling the changes of phase current during commutation. During the non-commutation, the DTC is selected, and the CPC is selected during the commutation. Results show that the proposed approach is feasible, and torque ripple is effectively suppressed both in high speed and low speed. Moreover, this method has no effect on the suspension performance.

1. Ooshima, M. and C. Takeuchi, " Magnetic suspension performance of a bearingless brushless DC motor for small liquid pumps ," IEEE Transactions on Industry Applications, Vol. 47, No. 1, 72-78, 2011.
doi:10.1109/TIA.2010.2091233

2. Sun, Y., F. Yang, and Y. Yuan, "Control of out-rotor bearingless brushless DC motor," 2017 32nd Youth Academic Annual Conference of Chinese Association of Automation (YAC), 624-627, IEEE, 2017.
doi:10.1109/YAC.2017.7967485

3. Takahashi, I. and T. Noguchi, "A new quick-response and high-efficiency control strategy of an induction motor," IEEE Transactions on Industry Applications, Vol. 5, 820-827, 1986.
doi:10.1109/TIA.1986.4504799

4. Ozturk, S. B. and H. A. Toliyat, Direct torque and indirect flux control of brushless DC motor, Vol. 16, No. 2, 351-360, IEEE/ASME Transactions on Mechatronics, 2011.

5. Wang, W. H. and H. B. Huang, "Research on commutation fluctuation self-adaptive control suppression strategy for brushless DC motor," 2012 10th World Congress on Intelligent Control and Automation (WCICA), 265-269, IEEE, 2012.
doi:10.1109/WCICA.2012.6357880

6. Kim, D. K., K. W. Lee, and B. I. Kwon, "Commutation torque ripple reduction in a position sensorless brushless DC motor drive," IEEE Transactions on Power Electronics, Vol. 21, No. 6, 1762-1768, 2006.
doi:10.1109/TPEL.2006.882918

7. Fakham, H., M. Djemai, and K. Busawon, "Design and practical implementation of a back-EMF sliding-mode observer for a brushless DC motor ," IET Electric Power Applications, Vol. 2, No. 6, 353-361, 2008.
doi:10.1049/iet-epa:20070242

8. Kumar, B. P. and C. M. C. Krishnan, "Comparative study of different control algorithms on brushless DC motors," 2016 Biennial International Conference on Power and Energy Systems: Towards Sustainable Energy (PESTSE), 1-5, IEEE, 2016.

9. Liu, Y., Z. Q. Zhu, and D. Howe, "Direct torque control of brushless DC drives with reduced torque ripple," IEEE Transactions on Industry Applications, Vol. 41, No. 2, 599-608, 2005.
doi:10.1109/TIA.2005.844853

10. Pan, H., M. Gu, and J. Gu, "A kind of simplified structure direct torque control method for brushless DC motor ," 2013 Third International Conference on Instrumentation, Measurement, Computer, Communication and Control (IMCCC), 1480-1483, IEEE, 2013.

11. Li, D., J. Yang, and Y. Dou, "Comparison analysis for pure torque loop control of brushless DC motor," 2016 19th International Conference on Electrical Machines and Systems (ICEMS), 1-4, IEEE, 2016.

12. Kang, S. J. and S. K. Sul, "Direct torque control of brushless DC motor with no ideal trapezoidal back EMF," IEEE Transactions on Power Electronics, Vol. 10, No. 6, 796-802, 1995.
doi:10.1109/63.471301

13. Lai, Y. S. and J. H. Chen, "new approach to direct torque control of induction motor drives for constant inverter switching frequency and torque ripple reduction," IEEE Transactions on Energy Conversion, Vol. 16, No. 3, 220-227, 2001.
doi:10.1109/60.937200

14. Liu, Y., Z. Q. Zhu, and D. Howe, "Commutation-torque-ripple minimization in direct-torque-controlled PM brushless DC drives," IEEE Transactions on Industry Applications, Vol. 43, No. 4, 1012-1021, 2007.
doi:10.1109/TIA.2007.900474

15. Zhang, J., J. Chai, and X. Sun, "Predictive current control for dual three phase induction machine with phase locked loop based electromotive force prediction," 2014 17th International Conference on Electrical Machines and Systems (ICEMS), 114-117, IEEE, 2014.
doi:10.1109/ICEMS.2014.7013464

16. Park, J., Y. Kwak, and Y. Jo, "Torque ripple reduction of BLDC motor using predicted current control," 2016 IEEE Conference and Expo Transportation Electrification Asia-Pacific (ITEC Asia-Pacific), 407-411, IEEE, 2016.
doi:10.1109/ITEC-AP.2016.7512987

17. Wei, G., C. Zhen, and Z. Jing, "Modified current prediction control strategy for suppressing commutation torque ripple in brushless DC motor," Proceedings 2013 International Conference on Mechatronic Sciences, Electric Engineering and Computer (MEC), 3770-3774, IEEE, 2013.

Dr. Yukun Sun

Dr. Kuan Zhang

Professor Ye Yuan

Dr. Fan Yang