Analytical model including rotor eccentricity for bearingless synchronous reluctance motors

Seppo E. Saarakkala, Victor Mukherjee, Maksim Sokolov, Marko Hinkkanen, Anouar Belahcen

Research output: Chapter in Book/Report/Conference proceedingConference contributionScientificpeer-review

2 Citations (Scopus)
130 Downloads (Pure)


This paper deals with modelling of rotor eccentricity in a dual three-phase winding bearingless synchronous reluctance motors (BSyRMs). The motor includes two separate sets of three-phase windings: one for torque production and the other one for radial force production. For this motor, an improved analytical model with linear magnetic material is presented. The accuracy of the model depends on the accuracy of the inverse-airgap function. Typically, a series expansion is used for approximating the inverse-airgap function. In order to make the main-winding inductances depend on the radial position, at least the first two terms have to be included in the expansion, enabling calculation of the radial forces caused by unbalanced magnetic pull. The improved model is applicable, e.g., for stability analysis, time-domain simulations, or developing real-time control methods.
Original languageEnglish
Title of host publicationProceedings of the 23rd International Conference on Electrical Machines, ICEM 2018
Number of pages7
ISBN (Electronic)978-1-5386-2477-7
Publication statusPublished - 3 Sep 2018
MoE publication typeA4 Article in a conference publication
EventInternational Conference on Electrical Machines - Ramada Plaza Thraki, Alexandroupoli, Greece
Duration: 3 Sep 20186 Sep 2018
Conference number: 23


ConferenceInternational Conference on Electrical Machines
Abbreviated titleICEM
Internet address


  • dual-winding motor
  • eccentricity
  • inductance
  • inverse-airgap function
  • open-loop stability
  • radial force
  • unbalanced magnetic pull


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