Replacing Stator of Existing Three-phase Synchronous Reluctance Machines towards Improved Multiphase Machines Performance

Abstract

This paper researches the possibility of changing the stator of existing three phase synchronous reluctance motors to achieve improved multiphase machines performance, keeping the same rotor. An optimal design for the stator is proposed. Thus, several geometrical constraints are imposed such as fixed inner stator bore diameter, air gap length and axial stack length. Analysis and discussion to select the optimal dimensions of the proposed multiphase stator with no extra cost in both iron and copper are provided, considering a main goal to achieve a higher torque gain and a minimum torque ripple. By means of finite element magnetic simulation, two stator designs (60 and 40 slots) are simulated and compared with the 3-phase (36 slots) SynRM. It has been found that a 5-phase SynRM with 60 slots stator gives better performance compared to a 3-phase SynRM: the average torque is increased by 11.78%, the efficiency and the power factor are increased by around 0.72% and 5.54% respectively compared to 3-phase. However, the torque ripple becomes slightly higher, but within the permitted range (<; 10%). This proves that it is possible to use the same rotor of existing 3-phase SynRMs and design a multiphase stator to achieve an improved machine performance.