In this paper, the effect caused by the suspension force windings on the torque windings in a bearingless synchronous reluctance slice motor (BsynRSM) is analyzed, and a new slide model observer is proposed to reduce the speed estimation vibration caused by this effect. Firstly, the effect of suspension force windings is analyzed in a Maxwell model. The suspension force windings will generate an asynchronous torque and current, which are similar to superimposing an asynchronous motor on the original motor. And a special Matlab/Simulink model is built. Secondly, the effect of current and torque generated by suspension force windings on speed sensorless is analyzed. The sliding mode observer (SMO) is studied considering the effect of suspension force windings. Simulation result shows that the current generated by suspension force windings of the BsynRSM will cause the estimate speed vibrating with the rotor vibration, and the frequency of speed estimation vibration is much higher than the additional current and torque generated by the suspension force windings. Thirdly, an improved SMO is proposed. By using the improved SMO, the amplitude and frequency of the speed estimation are obviously reduced. Finally, the improved SMO is verified on the experimental platform, which proves the feasibility of the method.
1. Sun, X., L. Chen, and Z. Yang, "Overview of bearingless permanent-magnet synchronous motors," IEEE Transactions on Industrial Electronics, Vol. 60, No. 12, 5528-5538, 2013. doi:10.1109/TIE.2012.2232253
2. Sawada, M., et al., "A study on a bearingless drive of a surface permanent magnet synchronous motor," 15th International Conference on Electrical Machines and Systems, 1-4, Sapporo, Japan, 2012.
3. Steinert, D., T. Nussbaumer, and J. Kolar, "Slotless bearingless disk drive for high-speed and high-purity applications," IEEE Transactions on Industrial Electronics, Vol. 61, No. 11, 5974-5986, 2014. doi:10.1109/TIE.2014.2311379
4. Puentener, P., M. Schuck, J. W. Kolar, and D. Steinert, "Comparison of bearingless slice motor topologies for pump applications," 2019 IEEE International Electric Machines & Drives Conference, 9-16, Santiago, Chile, 2019.
5. Gruber, W., "Bearingless slice motors: General overview and the special case of novel magnet-free rotors," Innovative Small Drives and Micro-Motor Systems, 1-6, Nuremberg, Germany, 2013.
6. Takemoto, M., K. Yoshida, N. Itasaka, Y. Tanaka, A. Chiba, and T. Fukao, "Synchronous reluctance type bearingless motors with multi-flux barriers," 2007 Power Conversion Conference, 1559-1564, Nagoya, Japan, 2007.
7. Mukherjee, V., J. Pippuri, S. E. Saarakkala, A. Belahcen, M. Hinkkanen, and K. Tammi, "Finite element analysis for bearingless operation of a multi flux barrier synchronous reluctance motor," 18th International Conference on Electrical Machines and Systems, 688-691, Pattaya, Thailand, 2015.
8. Ding, H., H. Zhu, and Y. Hua, "Optimization design of bearingless synchronous reluctance motor," IEEE Transactions on Applied Superconductivity, Vol. 28, No. 3, 1-5, April 2018.
9. Mukherjee, V., P. Rasilo, F. Martin, and A. Belahcen, "Analysis of electromagnetic force ripple in a bearingless synchronous reluctance motor," IEEE Transactions on Magnetics, Vol. 57, No. 2, 1-8, 2021. doi:10.1109/TMAG.2020.3041703
10. Diao, X., H. Zhu, Y. Qin, and Y. Hua, "Torque ripple minimization for bearingless synchronous reluctance motor," IEEE Transactions on Applied Superconductivity, Vol. 28, No. 3, 1-5, April 2018. doi:10.1109/TASC.2018.2798632
11. Holenstein, T., T. Nussbaumer, and J. W. Kolar, "A bearingless synchronous reluctance slice motor with rotor flux barriers," 2018 International Power Electronics Conference, 3619-3626, Niigata, Japan, 2018.
12. Sokolov, M., W. Gruber, S. E. Saarakkala, and M. Hinkkanen, "Modeling of a bearingless synchronous reluctance motor with combined windings," 2019 IEEE Energy Conversion Congress and Exposition, 7084-7090, Baltimore, Maryland, USA, 2019.
13. Holenstein, T., M. Schuck, and J. W. Kolar, "Performance benchmarking of a novel magnet-free bearingless synchronous reluctance slice motor," IEEE Open Journal of the Industrial Electronics Society, Vol. 1, 184-193, 2020. doi:10.1109/OJIES.2020.3011926
14. Chiba, A., K. Chiba, and T. Fukao, "Principles and characteristics of a reluctance motor with windings of magnetic bearing," Proc. of IPEC, 919-926, Tokyo, 1990.
15. Belahcen, A., V. Mukhrejee, F. Martin, and P. Rasilo, "Computation of hysteresis torque and losses in a bearingless synchronous reluctance machine," IEEE Transactions on Magnetics, Vol. 54, No. 3, 1-4, 2018. doi:10.1109/TMAG.2017.2765080
16. Li, P., L. Zhang, and Y. Yu, "A novel sensorless for switched reluctance motor based on sliding mode observer," IEEE 2nd Advanced Information Technology, Electronic and Automation Control Conference, 1560-1564, Chongqing, China, 2017.
17. Foo, G. H. B. and M. F. Rahman, "Direct torque control of an IPM-synchronous motor drive at very low speed using a sliding-mode stator flux observer," IEEE Transactions on Power Electronics, Vol. 25, No. 4, 933-942, 2010. doi:10.1109/TPEL.2009.2036354