Abstract
This study presents the design optimization and experimental validation of a Line-Start Permanent Magnet Synchronous Motor (LSPMSM) aimed at achieving IE4 efficiency class. An IE1 class induction motor (IM) was used as a reference. Only the rotor structure was modified, while the stator geometry, winding, and mechanical components were kept unchanged. The optimization process focused on rotor slot geometry, magnet placement, magnet dimensions, and core length, employing a Multi-Objective Genetic Algorithm (MOGA) to maximize efficiency while maintaining cost-effectiveness. Following the optimization, six candidate designs were evaluated based on demagnetization prediction, synchronization performance, and starting torque capability. Among them, Design C demonstrated the highest overall performance. Finite Element Analysis (FEA) confirmed that Design C met IE4 efficiency standards with a calculated efficiency of 92.15%. This result was later experimentally verified at 91.95% through thermal testing. The study further examined the cost and payback period scenarios for adopting LSPMSMs in industrial applications. Three implementation strategies were analyzed: replacing only the rotor, purchasing a new IE4 LSPMSM instead of an IE1 motor, and replacing an operational IE1 motor with an IE4 LSPMSM. The results indicated that efficiency improvement could be achieved with minimal modifications. The payback period varied depending on the investment strategy. The findings demonstrate that high-efficiency LSPMSMs can serve as direct replacements for induction motors, offering energy savings and improved performance while maintaining compatibility with existing motor housings and components.