Optimum pole arcs for a switched reluctance motor for higher torque with reduced ripple

In this paper, the results of a two-dimensional (2-D) finite element (FE) analysis carried out on a 8/6 switched reluctance motor with a view to arrive at the optimum pole arcs for the stator and rotor teeth are presented. The authors have put forward a new method for calculating the average torque for comparison of static torque profiles to identity the optimum one. In this new method, 15degrees of the static torque profile, where the developed torque is nearly constant is considered for calculating the average torque. Operating the motor in this range instead of the first quarter cycle of the static torque profile will ensure higher average torque with minimum ripple. This average torque is considered as the parameter for comparison of different torque profiles of various pole arcs for the stator and rotor. It is observed that the geometry with the existing stator pole arc of 20.2degrees and a changed rotor pole arc of 30degrees, instead of the existing 23.5degrees will be the optimum for this motor, as it gives the highest average torque with the minimum ripple.