Sensitivity to Demagnetization in Interior and Surface PM Electric Machines for Line-start Applications

Design and optimization of Line-Start Permanent-Magnet Synchronous Motors (LSPMSM) considering demagnetization is explored in this study. Two topologies with 36 slots 4 Pole are investigated: Interior Permanent Magnet (IPM) and Surface Mounted Permanent Magnet (SMPM) with squirrel cage rotor bars. Both designs utilize identical packaging dimensions. A comprehensive parametric sweep is performed to analyze the influence of the magnet and rotor bar parameters on motor performance under constant load operation. Transient performance is evaluated using starting torque and settling time, while steady-state performance is determined by the steady-state phase current. The insights obtained guide the Multi-objective optimization process for design of these two topologies. Transient and steady- state performance and demagnetization analysis of these machines at different operating temperatures have been performed in FEA.