Multiobjective optimization for torque ripple suppression in brushless DC motors with a hybrid magnet
摘要
To address the torque ripple issue of brushless direct current motors under square wave control, this study proposes a multiobjective optimization design method on the basis of hybrid poles to achieve torque ripple suppression and reduce manufacturing costs. The method optimizes the interior flat permanent-magnet motor by combining neodymium–iron–boron and ferrite magnets with the improved Kepler optimization algorithm. The optimization process modulates the rotor flux linkage to improve the interaction between back electromotive force and phase current time-domain waveforms, thereby effectively suppressing torque ripple under six-step square wave control. Finite element analysis and prototype testing results indicate that under various operating conditions, the optimized model achieves a maximum torque ripple reduction of 25.6% at the cost of a 13.8% decrease in the average torque output, and the use of rare-earth permanent-magnet materials is reduced by about 26.7%, substantially enhancing cost effectiveness.