Optimum Design of an IE4 Line-Start Synchronous Reluctance Motor Considering Manufacturing Process Loss Effect

As a kind of direct-on-line motor, super premium efficiency (IE4) line-start synchronous reluctance motors (LS-SynRMs) were developed recently and are now used in many applications, including fans, pumps, and compressors. This paper presents an optimum design and comparative study of LS-SynRMs with additional losses and impact during the manufacturing process (electrical steel cutting/punching damage as well as squirrel-cage die-casting with bubble effects). The work results indicate that the LS-SynRM design with the "manufacturing process loss" effect should be considered and compensated for the design in order to achieve an IE4 class efficiency and ensure synchronization. Furthermore, the LS-SynRM rotor with multilayer flux barriers and rotor slots is investigated in detail. The influences of optimum design geometrical parameters (flux barriers thickness, segments thickness, length of rotor slots, etc.) on the performances of the basic model and optimum design model are evaluated with finite-element analysis (FEA) results. For more accurate results, the effects of saturation, saliency ratio, inductance difference, and the change in the B-H/B-P curve in damaged motor core edges are considered. Meanwhile, in the squirrel cage, the porosity rate distributions are considered. The copper loss, iron loss, starting torque, power factor, efficiency, and synchronization ability are investigated. The experimental results verify the accuracy of the process presented in this paper.This work was supported in part by the Human Resources Program in Energy Technology of the Korea Institute of Energy Technology Evaluation and Planning under Grant 20154030200900 and in part by the Basic Science Research Program through the National Research Foundation of Korea under Grant 2015R1C1A1A01055013