Analysis of Rotor Saturation in Synchronous Reluctance and PM-Assisted Reluctance Motors

The design of synchronous reluctance (REL) machines is complex and involves a lot of variables. It is difficult to design proper rotor flux-barrier geometry that yields satisfactory performance, in terms of torque ripple, average torque, etc. Geometry optimization is often necessary to find optimum solutions on the basis of some objective functions. However, it is not easy to determine the main impact of each geometry variable on the machine performance. The main contribution of this paper is to investigate the effect of a different level of saturation of the magnetic rotor path, comparing the performance of some synchronous REL machines. The effect of the insertion of permanent magnets is also investigated. The comparison has been carried out on the basis of finite-element analysis, considering average torque, torque ripple, power factor, torque and power versus speed curves and efficiency. A prototype has been tested to compare the simulation results with the experimental measurements.