Interior permanent magnet synchronous machines show a good range of behaviours, which make these kinds of machines good candidates for an electromechanical energy conversion. However, in order to improve their accuracy in their torque responses, the cogging torque and torque ripple phenomena should be mitigated to obtain better performance of the machine. In order to reduce the cogging torque and torque ripple, control techniques as well as geometric parameters of the machine have to be improved. In this thesis, geometric parameters such as the use of the fractional slot windings, the improvement of the pole-arc to pole-pitch ratio and the dimensions of the stator slots are considered for the better minimization of the cogging torque and torque ripple. The results are presented to show the performance of the IPMSM with fractional slot windings as well as the reduction of the cogging torque and torque ripple. Furthermore, four models of IPMSM with fractional and integer slot windings are going to be compared with the aim of the attenuation of the cogging torque phenomenon.