An Investigation Study Considering the Effect of Magnet Type, Slot Type and Pole-Arc to Pole-Pitch Ratio Variation on PM Brushless DC Motor Design

This paper deals with a sensitivity study of an outer rotor permanent magnet (PM) brushless DC (BLDC) motor design, concerning the effect of several parameters and factors on its corresponding performance. For the purposes of this study, several design features were considered regarding the type and size of the permanent magnets and the slot geometry. Moreover, the pole-arc to pole-pitch ratio variation was investigated. The primarily aim is to draw useful conclusions for the motor overall performance according to preset requirements, such as the rated speed, motor efficiency, output power, cogging torque, overall motor weight etc. The obtained results were validated through simulations using finite element method (FEM) analysis with the aid of commercial software. The concluded remarks reveal important considerations which have to be taken into account by the designer prior and through the design phase of a BLDC motor.