Analytical modelling of the magnetic field in axial flux permanent magnet machines with semi-closed slots at no load

This paper presents an analytical solution for prediction of the no-load magnetic field in slotted semi-closed permanent magnet axial flux synchronous machines. The technique is based on 2-D solution of the Maxwell's equations using the separation of variables method, this technique is validated for two different machines. The magnetic field expressions are developed in slots regions, magnetic airgap region, slot opening region and permanent magnet region leading to an exact calculation of the slot effects on the airgap magnetic quantities. Results from this analytical model are compared to corresponding finite element analyses (FEA).