Torque ripple reduction of switched reluctance motor by optimising switch angle based on analytical modelling

Abstract

To reveal the torque ripple mechanism of switched reluctance motors (SRMs), an analytical instantaneous torque model considering current harmonics is established based on the analysis of the air-gap magnetic field. The results show that torque ripple contains third-order harmonic components in a three-phase SRM and mainly comes from the current harmonic, the rotor slotting, and their interaction. Then, the influence of main current harmonics on the torque ripple is investigated based on an analytical calculation method and it is found that the filtering of the second-order current harmonic is more conducive to reducing the torque ripple. Finally, the influence of the turn-on/turn-off angle on each harmonic current is fully analysed by means of the analytical modelling of current, based on which the second-order current harmonic and torque ripple is reduced by optimising the turn-on/turn-off angle. Also, it is found that the suitable prior turn-on angle and delayed turn-off angle is helpful to reduce the torque ripple.