Detailed electromagnetic analysis of a coreless axial flux permanent magnet machine using field solution and finite element method

Axial Flux Permanent Magnet (AFPM) machines, also referred to as dysc-type machines, have attracted significant attention in recent decades due to their reduced axial encumbrance and higher torque density compared to Radial Flux Permanent Magnet (RFPM) machines, their more mainstream cylindrical counterparts. In particular, Coreless AFPM (C-AFPM) machines, where stator windings are encased in non-magnetic materials, offer even better performances, eliminating cogging torque and iron losses, in addition to being lighter. These characteristics make C-AFPM machines uniquely suited for applications where space is limited and torque-to-weight ratio is crucial, such as aerospace and drone propulsion. In this work, an analytical quasi-3D electromagnetic model of C-AFPM machines with surface-mounted magnets is developed by solving the governing field equations through Fourier series expansion, and then validated using Finite Element (FE) method. To that end a MatLab code is developed in order to calculate the performance and characteristics of any double-rotor Fractional Slot Concentrated Winding (FSCW) C-AFPM machine under any load condition, both by analytical Field Solution and FE analysis. Finally, a parametric analysis is performed using Field Solution in order to determine the optimal machine design for any performance requirement.