A New Method for Torque Optimization of a BLDC Motor Based on Commutation Ripple

High efficiency and ease of speed control make BLDC a suitable choice for fans and pumps. By now, cogging torque reduction and airgap flux density increase have been the common objectives in motor design to achieve a reasonable torque profile. Commutation torque ripple is a major factor in torque ripple, and significant error is caused by ignoring it. A design method is suggested in this paper that considers the effect of non-ideal back EMF in torque calculation. After discussing the commutation point, electric loading based on current density and motor dimensions, torque optimization is done by Ansys FEM software. A procedure for determining the coil turn number that ensures matching between the motor operating point and power supply is also suggested. Detailed dynamic simulation is done to validate the proposed procedure.