Models of Magnetic Anisotropy for Nonoriented Silicon Steel Laminations of Electrical Machines

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School of Electrical Engineering | Doctoral thesis (article-based) | Defence date: 2022-10-21
Degree programme
117 + app. 69
Aalto University publication series DOCTORAL THESES, 137/2022
This dissertation deals with magnetic anisotropy and its impact on the flux density and loss distribution for non-oriented silicon steel laminations. Magnetic material models, such as anhysteretic reluctivity, Bergqvist’s vector Jiles-Atherton and energy-based hysteresis models, are considered in this work. The vector hysteresis models mentioned above are extended: first, to account for magnetic anisotropy observed in non-oriented silicon steel, and second, to predict hysteresis losses for the input excitation rotating in the plane of the sheet, as well as alternating in different directions. Non-oriented silicon steel lamination, commonly used in a rotating electrical machine’s magnetic core, shows a significant level of magnetic anisotropy. Numerical analysis tools often assume the laminated core is isotropic. Preliminary investigations reveal that the anisotropy alters the distribution of magnetic flux density in the core. Thus, some core parts get saturated, which may adversely affect the core losses. Hence, determining how the losses predicted by the anisotropic models differ from their isotropic counterparts is paramount. Firstly, an extension of the isotropic anhysteretic reluctivity model is proposed to account for magnetic anisotropy. After preliminary investigations, the ideas from the anisotropic reluctivity model are then incorporated into the advanced hysteresis models. Hysteresis models, such as Bergqvist's vector Jiles-Atherton and energy-based models, rely upon the anhysteretic properties for quantitatively describing the intrinsic anisotropy. Anhysteretic magnetic characteristics are identified from unidirectional alternating measurements in several directions to include intrinsic anisotropy in the models. Moreover, to reasonably predict the hysteresis losses, the model parameters are allowed to depend on the magnitude and polar direction of the flux density vector. Secondly, the anisotropic models are coupled with the finite element method. This coupling is then applied to simulate magnetic fields and associated losses in the commonly used measurement setups such as a toroidal inductor, round rotational single sheet tester, and a transformer-like device. The results of the finite element simulations are briefly compared and discussed. Furthermore, the material level validation of the proposed hysteresis models is in the peer-reviewed articles at the end of this thesis.
Supervising professor
Belahcen, Anouar, Prof., Aalto University, Department of Electrical Engineering and Automation, Finland
Thesis advisor
Rasilo, Paavo, Assoc. Prof., Tampere University, Finland
anisotropic reluctivity, energy-based model, finite element method, Jiles-Atherton model, magnetic anisotropy, nonoriented silicon steel
Other note
  • [Publication 1]: Brijesh Upadhaya, Floran Martin, Paavo Rasilo, Paul Handgruber, Anouar Belahcen, and Antero Arkkio. Modelling magnetic anisotropy innon-oriented silicon steel using vector Jiles-Atherton model. COMPEL - The international journal for computation and mathematics in electricaland electronic engineering, Vol. 36, No. 3, pp. 764-773, May 2017.
    Full text in Acris/Aaltodoc:
    DOI: 10.1108/COMPEL-09-2016-0399 View at publisher
  • [Publication 2]: Brijesh Upadhaya, Paavo Rasilo, Lauri Perkkiö, Paul Handgruber, Anouar Belahcen, and Antero Arkkio. Comparison of anisotropic energy-based and Jiles-Atherton models of ferromagnetic hysteresis. IEEE Transactions on Magnetics, Vol. 56, No. 4, pp. 1-7, April 2020.
    Full text in Acris/Aaltodoc:
    DOI: 10.1109/TMAG.2020.2964745 View at publisher
  • [Publication 3]: Brijesh Upadhaya, Lauri Perkkiö, Paavo Rasilo, Anouar Belahcen, Paul Handgruber, and Antero Arkkio. Representation of anisotropic magnetic characteristics observed in a non-oriented silicon steel sheet. AIP Advances, Vol. 10, No. 6, pp. 1-12, June 2020.
    Full text in Acris/Aaltodoc:
    DOI: 10.1063/5.0009554 View at publisher
  • [Publication 4]: Brijesh Upadhaya, Paavo Rasilo, Lauri Perkkiö, Paul Handgruber, Anouar Belahcen, and Antero Arkkio. A constraint-based optimization technique for estimating physical parameters of Jiles-Atherton hysteresis model. COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, Vol. 39, No. 6, pp. 1281-1298, August 2020.
    Full text in Acris/Aaltodoc:
    DOI: 10.1108/COMPEL-08-2019-0332 View at publisher
  • [Publication 5]: Brijesh Upadhaya, Paavo Rasilo, Lauri Perkkiö, Paul Handgruber, Abdelkader Benabou, Anouar Belahcen, and Antero Arkkio. Alternating and rotational loss prediction accuracy of vector Jiles-Atherton model Journal of magnetism and magnetic materials, Vol. 527, pp. 167690. January 2021.
    Full text in Acris/Aaltodoc:
    DOI: 10.1016/j.jmmm.2020.167690 View at publisher