Effects of manufacturing dissymmetry in axial flux PM machines

Abstract

The paper discusses the effects that various kinds of manufacturing dissymmetry can cause in axial flux PM machines. A case study is considered, and, in particular, two effects are investigated: the circulation current in parallel paths at no load and the mechanical stresses together with the resulting axial force and bending torques on the machine shaft.

Effects of Manufacturing Imperfections in Concentrated Coil Axial Flux PM Machines: Evaluation and Tests

“…Moreover, it provides the validation of the method and of the analysis presented in [13] and [24], by comparing the theoretical predictions and the test results concerning the prototype. Finally, some additional results concerning the stresses on the middle rotor disk and the forces on the bearings are included.…”

“…In [13], such field functions have been identified by selective FEM analyses, even if they could be also analytically deduced [23]. In [24], the same method has been used to perform a sensitivity analysis on the effects of various kinds of manufacturing imperfections in a concentrated coil AF PMSM; the considered geometrical defects were concerning the offset and the tilt of the rotor disks, and an evaluation of the resultant forces and torques on the rotor disk was carried out. However, these results have been validated only by the FEM analyses.…”

Effect of unbalanced and inclined air-gap in double-stator inner-rotor axial flux permanent magnet machine

“…In [9] relevant mechanical stresses due to the electromagnetic attraction between the stator and the rotor parts due to slight air-gap asymmetries were analyzed based a simplified 2D rectified geometry using a circuit model. Manufacturing imperfections including phase displacement, rotor offset and three kinds of rotor tilts in concentrated coil axial flux PM machines were studied in [17][18][19], where calculation results of stresses, force, circulating current and bending torque is illustrated and discussed.…”

“…Static eccentricity changed the amplitude of back electromotive force (EMF) and it was proposed to use EMF curve for fault detection during manufacturing and assembling. The air-gap asymmetry arisen from offset or inclination in an inner-stator double outer-rotor AF machine is studied in [9,[17][18][19]. In [9] relevant mechanical stresses due to the electromagnetic attraction between the stator and the rotor parts due to slight air-gap asymmetries were analyzed based a simplified 2D rectified geometry using a circuit model.…”