Thermal survey of core losses in permanent magnet micro-motor☆

This paper presents a new approach for improving performance of a permanent magnet micro-motor. A finite element (FE) model was presented for a basic permanent magnet micro-motor which was then experimentally validated. The effect of adding back iron to the basic micro-motor was then investigated, showing an increase in mechanical torque of up to 60%. A side effect of the back iron was eddy current loss, for which two lamination methods (radial and circular) were presented and their effectiveness was examined by coupled thermal and electromagnetic FE analysis. The former decreased core loss by about 60%, while the latter decreased the same by up to 80%. Results indicated that compared to no-lamination, both applied laminations employed in this study, did not affect the back-EMF, and hence, did not decrease the mechanical torque.

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