Experimental validation of slot Effects in 2D Axial Flux motors via Conformal Mapping

This paper presents an analytical and experimental investigation of the magnetic field distribution in the air gap of a single-stator, single-rotor axial flux permanent magnet (AFPM) machine under no-load conditions. To simplify the problem, the model is rectified using quasi-3D modeling techniques at the machine’s mean radius. A quasi-static analytical Fourier based formulation is developed to describe the magnetic field produced by a classical North-South permanent magnet array. In addition, the influence of stator slotting on the air-gap field waveform is assessed through the Schwarz–Christoffel conformal transformation, enabling an accurate representation of slot-induced distortions. The resulting methodology provides a clear analytical framework for evaluating and quantifying harmonic distortion in the field distribution due to geometric discontinuities. To validate the model, experimental measurements are performed using a custom-designed four-degree-of-freedom scanning test bench equipped with a three-axial Hall-effect sensor capable of capturing detailed field profiles across the air gap. The comparison between analytical results, finite element method (FEM) simulations and experimental results demonstrates good agreement, confirming the reliability of the proposed approach for AFPM machines.