Performance analysis of un-equal rotor and stator length switched reluctance motor

Abstract

The performance of the SRM motor is influenced by several design parameters, including the lengths of the rotor stack and stator stack. Typically, the SRM is designed with equal rotor and stator lengths. However, there are some limited exceptions where the motor has a rotor that is longer or shorter than the stator; such a motor can achieve a reduction in one or more of the following: iron loss, copper loss, weight, inertia, and cost. To evaluate the performance of the SRM when the stator and rotor lengths are unequal, a 3D-model of the 6/4 SRM was developed using Ansys Motor-CAD software. In this work, two cases were investigated: the first case involved configurations where the stator was shorter than the rotor, and the second case involved configurations where the rotor was shorter than the stator. In both cases, other motor dimensions and variables were held constant. The simulation results show that certain performance indicators of the motor are not negatively affected, where they remain almost constant or even change positively, while other performance indicators are negatively changed, these changes are not significant when the differences between the stator and rotor lengths are within 10%. The cases of unequal length of stator and rotor can be considered as a new option that is manipulated to achieve the optimal design of the SRM, especially for low cost, low inertia, and high-speed applications.