Analytical Procedure for the Performance Prediction of Single-sided Axial Flux PM Machines with Coreless and Slotless Stator

The paper presents the application of an analytical procedure to the design of axial flux permanent magnet machines (AFPMMs) with coreless (CL) and slotless (SL) stator. The enhancement of formulations proposed in the literature enables a more accurate and faster calculation of the axial flux density at no-load and of the related electromagnetic quantities. The analysis is focused on an AFPMM with a 3-phase lumped coil winding, sized for a flywheel energy storage system. After a proper tuning of the formulation parameters, the procedure accuracy is validated by verifying the results with both 3D finite element analyses and measurements on a preliminary prototype. Thanks to its computational effectiveness, some favorable configurations for both the CL- and SL-AFPMMs are identified by a parametric analysis, with a significant reduction of the voltage THD without detriment to the rms value and to the axial force.