Improved Quasi 3D Modelling and Simulation of Axial Flux Machines
Niemimäki, Ossi (2012)
2012
Sähkötekniikan koulutusohjelma
Tieto- ja sähkötekniikan tiedekunta - Faculty of Computing and Electrical Engineering
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Hyväksymispäivämäärä
2012-09-05
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tty-201209101276
https://urn.fi/URN:NBN:fi:tty-201209101276
Tiivistelmä
Permanent magnet axial flux machines have become to enjoy increasingly widespread usage during the past two decades. While the basic type of axial flux machines has been known for over a century, the electromagnetic design of these machines is still in its development. Several design methods have been proposed; one of them being the so-called quasi 3D method, in which the inherently 3D machine geometry is sliced into separate 2D surfaces in order to simplify the modelling of the electromagnetic behaviour of the machine.
In modern electromagnetic modelling, solid mathematical framework is crucial. In this thesis, the quasi 3D method is given a formal and mathematically rigorous treatment. The 3D electromagnetic field problem concerning axial flux machines is formulated using the tools of differential geometry, and geometrically decomposed to a set of (2+1)D problems with the aid of an observer structure. The assumptions leading to the dimensional reduction underlying the quasi 3D method are pointed out, and their justification is discussed. Following the dimensional reduction, the resulting 2D problems are reformulated to models suitable for computation, and these models are then implemented with a commercial software and compared to an already existing industry-used model.
The formal approach is shown to make the modelling method more accurate and reliable, as the theoretical foundation is strengthened. Furthermore, the implementation of the derived models clarifies the effect of the prevailing inaccuracies in the already existing models.
In modern electromagnetic modelling, solid mathematical framework is crucial. In this thesis, the quasi 3D method is given a formal and mathematically rigorous treatment. The 3D electromagnetic field problem concerning axial flux machines is formulated using the tools of differential geometry, and geometrically decomposed to a set of (2+1)D problems with the aid of an observer structure. The assumptions leading to the dimensional reduction underlying the quasi 3D method are pointed out, and their justification is discussed. Following the dimensional reduction, the resulting 2D problems are reformulated to models suitable for computation, and these models are then implemented with a commercial software and compared to an already existing industry-used model.
The formal approach is shown to make the modelling method more accurate and reliable, as the theoretical foundation is strengthened. Furthermore, the implementation of the derived models clarifies the effect of the prevailing inaccuracies in the already existing models.