Torque ripple minimization of switched reluctance motors

This thesis introduces firstly a mathematical model of 6/4 switched reluctance motor using MA TLAB/SIMULfNK software package. Simulation is based on the motordifferential equations. Two models are built one for high speed operation using single- pulse control and another for low speed operation using hysteresis current control. Depending on the developed model, factors that influence torque ripple related to motor design such as rotor pole arc, maximum and minimum inductances are studied. Winding inductance has a considerable effect on torque ripple. If the aligned inductance (Lmax) is increased while the unaligned inductance (Lmin) is kept constant, both of torque ripple and starting torque are going to increase and the no-load speed will be decreased. If the unaligned inductance (Lmin) is increased while the aligned inductance is keptconstant, the starting torque decreases and the no-load speed increases. The effect of this factor on torque ripple can be explained as follows: the torque ripple will decrease to a minimum value as Lmin is going to increase, after which, increasing Lmin will increase torque ripple again. Changing the length of stator or rotor pole arcs has the same effect on torque ripple.