access icon free Magnet asymmetry in reduction of cogging torque for integer slot axial flux permanent magnet motors

Cogging torque component is one of the key issues in the design of radial and axial gap permanent magnet motors and the geometry and the position of the magnets plays a critical role in this process. This study presents the influence of magnet asymmetry in minimisation of the cogging torque for axial flux permanent magnet (AFPM) disc motors. Cogging torque minimisation techniques, such as magnet skewing and magnet shifting or groping are examined in detail by using three-dimensional finite element analysis with various types of magnet skewing alternatives since the shaping and the positioning magnets are low cost approaches to minimise or eliminate the cogging component. A prototype AFPM disc motor is built with shifted magnets based on the models which are the results validated with the experimental results for the minimum cogging component and the sinusoidal back-EMF waveform. It is shown in this study that the cogging component in AFPM motors can be practically eliminated by using magnet asymmetry and perfectly sinusoidal back-EMF can also be obtained even for integer slot/pole/phase motors.

Inspec keywords: minimisation; torque; finite element analysis; electric potential; permanent magnet motors; magnetic flux

Other keywords: axial flux permanent magnet motor; integer slot AFPM disc motor; magnet position; integer slot-pole-phase motor; magnet skewing; axial gap permanent magnet motor; radial gap permanent magnet motor; cogging torque minimisation technique; magnet asymmetry; magnet geometry; sinusoidal back-EMF waveform; 3D finite element analysis

Subjects: Finite element analysis; Electrostatics; a.c. machines; d.c. machines; Optimisation techniques

References

    1. 1)
    2. 2)
    3. 3)
    4. 4)
    5. 5)
    6. 6)
    7. 7)
      • 2. Hanselman, D.: ‘Brushless permanent magnet motor design’ (Magna Physics Pub, USA, 2006).
    8. 8)
      • 18. Aydin, M., Qu, R., Lipo, T.A.: ‘Cogging torque minimization technique for multiple-rotor, axial-flux, surface-mounted-PM machines: alternating magnet pole-arcs in facing rotors’. IEEE Industry Applications Society Annual Meeting, Utah, USA, 2003, pp. 555561.
    9. 9)
    10. 10)
    11. 11)
    12. 12)
      • 20. Yolacan, E., Ozyurt, E., Aydin, M.: ‘Magnet shape optimization of a slotted surface-mounted axial gap PM motor for reducing cogging torque’. Int. Conf. on Electric Machines, Rome, Italy, 2010, pp. 16.
    13. 13)
    14. 14)
    15. 15)
      • 1. Hendershot, J.R., Miller, T.J.: ‘Design of brushless permanent magnet motors’ (Clarendon, Oxford, UK, 1994).
    16. 16)
    17. 17)
    18. 18)
    19. 19)
      • 13. Bianchini, C., Immovilli, F., Bellini, A., Davoli, M.: ‘Cogging torque reduction methods for internal permanent magnet motors: review and comparison’. Proc. XIX Int. Conf. on Electrical Machines, Marseille, France, 2010, pp. 16.
    20. 20)
    21. 21)
      • 7. Aydin, M., Huang, S., Lipo, T.A.: ‘Axial flux permanent magnet disc machines: a review’. SPEEDAM, Capri, Italy, 2004.
    22. 22)
      • 17. Caricchi, F., Capponi, F.G., Crescimbini, F., Solero, L.: ‘Experimental study on reducing cogging torque and core power loss in axial-flux permanent-magnet machines with slotted winding’. IEEE Industry Applications Society Annual Meeting, Pittsburgh, USA, 2002, pp. 12951302.
http://iet.metastore.ingenta.com/content/journals/10.1049/iet-epa.2013.0256
Loading

Related content

content/journals/10.1049/iet-epa.2013.0256
pub_keyword,iet_inspecKeyword,pub_concept
6
6
Loading