Minimizing Torque Ripple in Synchronous Reluctance Motors Through Rotor Shape Optimization with Particle Swarm Algorithm

In this paper, the torque ripple of the synchronous reluctance motor (SynRM) is suppressed by optimizing the geometry of the rotor. A new method based on the particle swarm optimization (PSO) evolutionary algorithm is used to optimize highlighted rotor parameters, such as the size of iron parts and barrier widths along the d and q axes and the angle of the rotor end barriers. At the same time, the insulation factor and rib thickness remain the same during the optimization. The main goal of optimization is to get a pure sinusoidal airgap flux density by manipulating the rotor parameters, resulting in reducing the torque ripple. The Finite element analysis (FEA) and comparative study are conducted for conventional and optimization design to reveal the optimization effect on the motor characteristics such as average torque, torque ripple, and flux density distribution. The results indicated that the torque ripple of the optimized rotor is reduced from 21.81% to 5.02% compared to the conventional design, while the average torque is improved by 0.45 N.m. By considering the identical stator structure for the induction motor (IM) and SynRM, the SynRM with the optimized rotor is fabricated by utilizing the stator of the 1-hp IM motor. Then, the prototype is tested, and experimental results are derived to verify the simulation results. The results indicated a strong correlation between the simulation results and the experimental test results.