Analytical approach for spoke-type permanent magnet machine including finite permeability of iron core

Purpose The purpose of this study is the introduction of finite permeability of ferromagnetic core in analytical approach for slotted spoke-type permanent magnet machine. Design/methodology/approach A two-dimensional analytical approach of magnetic field distribution is established for spoke-type permanent magnet machine to calculate the flux density distribution in the middle of airgap. The paper presents an analytical subdomain model accounting for stator slotting effect. The governing equations are obtained from Maxwell's equations by using vector potential in all regions of the machine, i.e. magnet, airgap, stator slots and rotor/stator yoke. The finite element analysis is used to validate the analytical results. Findings It is found that the developed subdomain model including finite permeability of ferromagnetic core is accurate and is applicable for spoke-type permanent magnet machine for no-load and on-load condition. The analytical results are in accurate agreement with the numerical simulation. Originality/value Some assumptions and conditions are presented to improve and simplify the analytical method for analyzing the global saturation for spoke-type permanent magnet machine.