Analytical modeling of coreless stator axial flux permanent magnet machines under no-load condition

This paper presents three analytical techniques for 3D modeling and analysis of coreless stator axial flux permanent-magnet (CS-AFPM) machines under no-load condition. Quasi 3D analytical model based on Hague's solution, magnetic equivalent circuit (MEC) model, and analytical model based on Fourier-Bessel series are used to calculate the components of air-gap magnetic flux density. In quasi 3D analytical model, the 3D geometry of CS-AFPM machine is transformed into the 2D geometries in different radii. Hague's solution is used to calculate the tangential and axial components of air-gap flux density in corresponding radius. The law of superposition is then used to calculate the flux-linkage of stator phase. In the MEC model, the non-linear permeance network is used to calculate the axial component of air-gap flux density while considering the curvature effect, the fringing effect, and the leakage magnetic fluxes. In the proposed 3D analytical model, all components of air-gap flux density are calculated while considering the edge effect, the curvature effect, fringing and leakage fluxes, the magnetic saturation, and the skewed PMs. In final, the accuracy and capabilities of these techniques are verified through comparing with corresponding results obtained from 3D finite element method (FEM) and the experiment set-up.