Torque ripple improvement for brushless DC miniature motors

An analytical investigation of the brushless DC miniature motor with permanent magnets is presented. Fundamental equations are derived, and the torque ripple is evaluated by utilizing the performance index, which is defined to be in proportion to the peak-to-peak pulsation of the motor velocity. The torque ripple arising from the flux distributions in a magnet is investigated, and the optimal distribution to minimize the torque ripple is presented. In order to develop a practical method of reducing the torque ripple, the overlapping method and the pulse-width modulation method are used, and the optimal values of the parameters are discussed.<
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