Calculating the Temperature Rise during the Starting Process of a Large-capacity Line Start Permanent Magnet Synchronous Motor

This paper investigates the effect of the starting process on the temperature distribution of a large-capacity line-start permanent magnet synchronous motor (LSPMSM). An electromagnetic model for a 630 kW LSPMSM is developed, and the variations in different losses during the starting process are analyzed. The starting process is divided into multiple stages, with the transient temperature rise for each stage approximated as a steady-state temperature rise for calculation purposes. By integrating these results, the overall temperature rise and distribution of the motor are determined. Finite element analysis (FEA) software is utilized to simulate temperature variations throughout the starting process. Experimental findings confirm the temperature rise profile during startup, offering valuable insights into the risk of irreversible demagnetization in permanent magnets and providing a reference for motor design and optimization.