The Study of Switched Reluctance Motor for 4-DOF Bearingless Motor

  • Ye Yuan
  • Yukun SunEmail author
  • Qianwen Xiang
  • Yuan Ren
  • Qiang Liu
Original Article


High integration, low loss and high-reliability are the main development trends of flywheel battery. Thus this study presents the first prototype of a novel high-integration four degrees of freedom (4-DOF) bearingless motor with the advantages of weak coupling and low power consumption. The proposed bearingless motor can realize energy conversion and produce 4-DOF radial forces compared with the conventional bearingless motor for improving the integration of system. A biased flux for producing radial levitation forces is provided by the permanent magnets, which reduce the power consumption of the system. Moreover, a decoupling between the torque and the suspension systems is realized through a structural design, thereby improving the controllability. Structure and winding configurations are introduced and the operation principle of the 4-DOF bearingless motor is discussed. Magnetic circuits analysis and parameter design method are present and a three-dimensional finite element model is established. Electromagnetic characteristics that focus on the high integration, low loss and high reliability are discussed and validated comprehensively. Finally, a favorable controllability of radial suspension forces are verified using finite-element analysis and some experimental results.


Flywheel battery Bearingless motor Degrees of freedom Radial force 



This work was supported by the National Natural Science Foundation of China (51707082, 51877101, 51475452), Natural Science Foundation of Jiangsu Province (BK20170546, BK20150510), China Postdoctoral Science Foundation (2017M620192) and the Priority Academic Program Development of Jiangsu Higher Education Institutions.


  1. 1.
    Severson E, Nilssen R, Undeland T et al (2015) Magnetic equivalent circuit modeling of the AC homopolar machine for flywheel energy storage. IEEE Trans Energy Convers 30(4):1670–1678CrossRefGoogle Scholar
  2. 2.
    Sarkar S, Ajjarapu V (2011) MW resource assessment model for a hybrid energy conversion system with wind and solar resources. IEEE Trans Sustain Energy 2(4):383–391CrossRefGoogle Scholar
  3. 3.
    Casella F (2004) Modeling, simulation, control, and optimization of a geothermal power plant. IEEE Trans Energy Convers 19(1):170–178MathSciNetCrossRefGoogle Scholar
  4. 4.
    Yuan Y, Sun Y, Huang Y (2016) Accurate mathematical model of bearingless flywheel motor based on Maxwell tensor method. Electron Lett 52(11):950–952CrossRefGoogle Scholar
  5. 5.
    Zhan C, Tseng K (2007) A novel flywheel energy storage system with partially-self-bearing flywheel-rotor. IEEE Trans Energy Convers 22(2):477–487CrossRefGoogle Scholar
  6. 6.
    Subkhan M, Komori M (2011) New concept for flywheel energy storage system using SMB and PMB. IEEE Trans Appl Supercond 21(3):1485–1488CrossRefGoogle Scholar
  7. 7.
    Wei K, Liu D, Meng J (2010) Design and Simulation of a 12-Phase flywheel energy storage generator system with linearly dynamic load. IEEE Trans Appl Supercond 20(3):1050–1055CrossRefGoogle Scholar
  8. 8.
    Cimuca G, Breban S, Mircea M (2010) Design and control strategies of an induction-machine-based flywheel energy storage system associated to a variable-speed wind generator. IEEE Trans Energy Convers 25(2):526–534CrossRefGoogle Scholar
  9. 9.
    Lin C, Wang S, Moallem M et al (2017) Analysis of vibration in permanent magnet synchronous machines due to variable speed drives. IEEE Trans Energy Convers 32(2):582–590CrossRefGoogle Scholar
  10. 10.
    Dong J, Jiang J, Howey B et al (2017) Hybrid acoustic noise analysis approach of conventional and mutually coupled switched reluctance motors. IEEE Trans Energy Convers 32(3):1042–1051CrossRefGoogle Scholar
  11. 11.
    Eric S, Robert N, Tore U et al (2015) Magnetic equivalent circuit modeling of the AC homopolar machine for flywheel energy storage. IEEE Trans Energy Convers 30(4):1670–1678CrossRefGoogle Scholar
  12. 12.
    Yuan Y, Sun Y, Huang Y (2016) Design and analysis of bearingless flywheel motor specially for flywheel energy storage. Electron Lett 52(1):60–62CrossRefGoogle Scholar
  13. 13.
    Morrison C, Siebert M, Ho E (2008) electromagnetic forces in a hybrid magnetic-bearing switched-reluctance motor. IEEE Trans Magn 44(12):4626–4638CrossRefGoogle Scholar
  14. 14.
    Takemoto M, Chiba A, Akagi H (2004) Radial force and torque of a bearingless switched reluctance motor operating in a region of magnetic saturation. IEEE Trans Ind Appl 40(1):103–112CrossRefGoogle Scholar
  15. 15.
    Chen L, Hofmann W (2010) Design procedure of bearingless high speed switched reluctance motors. In: Int. Symp. on power electronics electrical drives automation and motion, Pisa, Italy, pp 1442–1447, June 2010Google Scholar
  16. 16.
    Liu W, Yang S (2005) Modeling and control of a self-bearing switched reluctance motor. In: Proc. IEEE IAS annual meeting, Kowloon, Hong Kong, pp 2720–2725, 2005Google Scholar
  17. 17.
    Cao X, Zhou J, Liu C (2017) Advanced control method for single-winding bearingless switched reluctance motor to reduce torque ripple and radial displacement. IEEE Trans Energy Convers 32(4):1533–1543CrossRefGoogle Scholar
  18. 18.
    Wang H, Wang Y, Liu X (2012) Design of novel bearingless switched reluctance motor. IET Electr Power Appl 6(2):73–81CrossRefGoogle Scholar
  19. 19.
    Xu Z, Lee D, Zhang F (2011) Hybrid pole type bearingless switched reluctance motor with short flux path. In: 2011 Int. Conf. on electrical machines and systems, Yichang, China, pp 1–6, 2011Google Scholar

Copyright information

© The Korean Institute of Electrical Engineers 2019

Authors and Affiliations

  • Ye Yuan
    • 1
  • Yukun Sun
    • 1
    Email author
  • Qianwen Xiang
    • 1
  • Yuan Ren
    • 2
  • Qiang Liu
    • 3
  1. 1.School of Electrical and Information EngineeringJiangsu UniversityZhenjiangChina
  2. 2.Department of Astronautics Science and TechnologySpace Engineering UniversityBeijingChina
  3. 3.Institute of Precision Electromagnetic Equipment and Advanced Measurement TechnologyBeijing Institute of Petrochemical TechnologyBeijingChina

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