TY - JOUR N2 - This study presents the dependence of the level and harmonic structure of the cogging torque in permanent magnet synchronous motors (PMSM) to imperfections of permanent magnet (PM) dimensions and positions, which can not be avoided in massproduction. Slightly diverse dimensions and misplacements of PMs are introducing asymmetries in magnetic field distribution which cause additional harmonic components. A finite element method (FEM) and Fast Fourier transform (FFT) were used to calculate cogging torque harmonic components with regard to several combinations of PM assembly imperfections. It has been established and proved that unequal PMs cause magnetic asymmetries which give rise to additional cogging torque harmonic components and consequently increase the total cogging torque. It is also shown that in some particular combinations the influence of an individual PM imprecision could compensate with others due to different phase shifts which can result even in the decrease of cogging torque. Considering presented results it is possible to foresee which additional harmonic components will comprise the cogging torque of mass-produced PMSMs due to PM imperfections. In this way the designers are able to predetermine required manufacturing tolerances to keep the level of cogging torque in a admissible level. Simulation results were verified and confirmed by laboratory tests. L1 - http://journals.pan.pl/Content/84831/PDF/08_paper.pdf L2 - http://journals.pan.pl/Content/84831 PY - 2013 IS - No 3 September EP - 461 DO - 10.2478/aee-2013-0036 KW - cogging torque KW - finite element method KW - harmonic components KW - PM synchronous motor A1 - Gašparin, Lovrenc A1 - Fišer, Rastko PB - Polish Academy of Sciences VL - vol. 62 DA - 2013 T1 - Cogging torque sensitivity to permanent magnet tolerance combinations SP - 449 UR - http://journals.pan.pl/dlibra/publication/edition/84831 T2 - Archives of Electrical Engineering ER -