Improved air-gap flux in axial flux induction machine through shaping of radial slot opening

Abstract

Axial flux machines (AFM) have inherent non-uniform flux density distribution in radial direction leading to improper utilisation of iron part. The objective of this paper is to shape the edges of tooth lamination along radial direction to achieve uniformity in radial flux density distribution using multi-slice analytical approach. The machine considered is an axial flux induction machine (AFIM) with single stator and single rotor. The machine’s core and tooth are laminated perpendicular to each other and the approach makes use of multiple 2-D non-linear lumped parameter flux models along the radial direction representing each tooth lamination. For a given magneto-motive force, the laminations provide many parallel paths. Effective air gap length which is a function of tooth opening is adjusted to level air-gap flux density. The process results in further improvement in net flux per pole. The results of performance enhancement are validated through analytical equations, quasi 3-D FEA, 3-D FEA and a 3 kVA laboratory prototype machine.