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Quasi 3D modelling and simulation of axial flux machines

Ossi Niemimäki (Department of Electrical Engineering, Tampere University of Technology, Tampere, Finland)
Stefan Kurz (Department of Electrical Engineering, Tampere University of Technology, Tampere, Finland)



The purpose of this paper is to investigate the theoretical foundation of the so-called quasi 3D modelling method of axial flux machines, and the means for the simulation of the resulting models.


Starting from the first principles, a 3D magnetostatic problem is geometrically decomposed into a coupled system of 2D problems. Genuine 2D problems are derived by decoupling the system. The construction of the 2D simulation models is discussed, and their applicability is evaluated by comparing a finite element implementation to an existing industry-used model.


The quasi 3D method relies on the assumption of vanishing radial magnetic flux. The validity of this assumption is reflected in a residual gained from the 3D coupled system. Moreover, under a modification of the metric of the 2D models, an axial flux machine can be presented as a family of radial flux machines.

Research limitations/implications

The evaluation and interpretation of the residual has not been carried out. Furthermore, the inclusion of eddy currents has not been detailed in the present study.


A summary of existing modelling and simulation methods of axial flux machines is provided. As a novel result, proper mathematical context for the quasi 3D method is given and the underlying assumptions are laid out. The implementation of the 2D models is approached from a general angle, strengthening the foundation for future research.



Financial support from KONE Corporation is acknowledged.


Niemimäki, O. and Kurz, S. (2014), "Quasi 3D modelling and simulation of axial flux machines", COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, Vol. 33 No. 4, pp. 1220-1232.



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Copyright © 2014, Emerald Group Publishing Limited

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