Generalized finite element based study on the impact of permanent magnets’ imperfections on performance measures of electric machines

This work is about analyzing the impact of permanent magnets’ tolerances on electric machine performance. A generalized model is presented allowing for the analysis of single mmf-harmonics of the permanent excitation or a combination of selected harmonics. The approach can be used both for the standard symmetric case as well as if tolerances are present. It is based on finite element simulations of the machine’s cross section utilizing a thin current layer in the air gap. Results reveal that these investigations can provide general insight in how the harmonics take effect on torque and linked fluxes of the stator coils. Thus, this study can be the basis for evaluating different machine configurations concerning their sensitivity to tolerance-affected permanent magnets.