Analysis and modeling of airgap & zigzag leakage fluxes in a surface-mounted-PM machine

In this paper the magnetic characteristics of surface-mounted permanent magnet machines are analyzed and modeled. The airgap and zigzag leakage fluxes are analytically expressed in terms of the magnetic material properties and the motor dimensions. Both factors are essential quantities for the accurate prediction of the flux distribution within the machine and of the machine torque. Therefore, they are desired for the purpose of machine design and optimization. In order to evaluate the validity of the proposed models, the finite element method (FEM) analysis is used. The results show that the errors between the FEM results and analytical predictions are less than 1% for both the airgap and zigzag leakage fluxes. This accuracy is also proven by the prototype measurements.