Design and Torque Analysis of Double-Slot Surface and Spoke-Type BLDC Motor Using Finite Element Method

The aim of this paper is to investigate the impact of second slot in stator tooth on performance of two commonly used rotor structures, namely Surface-type and Spoke-type, for a brushless direct current (BLDC) motor. The comparative results are reported for different closing slot conditions. Afterwards by inserting a direct current driven winding or permanent magnets (PMs) into the stator tooth slots of best performed model of previous stage, two hybrid-brushless direct current (HBLDC) motors are introduced and studied. The results demonstrated that slot-closing strategy has high impact on torque fluctuations while the torque produced remain almost constant. For HBLDC, the auxiliary Electro-Magnetic field, placed in stator slot, developed torque performance of the motors. The finite element method (FEM) is used in stages of study.