Research on rotor harmonic copper losses of line-start REPMSM based on FEM

As the rotor temperature rise of line-start rare earth permanent magnet synchronous motor (REPMSM) is much higher than tradition expected theoretically during the synchronous operation, in order to analyze the reason in-depth, in this paper, the dynamic starting process of the line-start REPMSM in the load and no-load conditions was simulated by two-dimensional finite element method (FEM) using MagNet software. Results of the simulation show that the great actual harmonic currents exist in rotor cage bars, and then the rotor harmonic copper losses must be produced and cause the heating problem of rotor; To be precise, transient solver of MagNet was used for calculating the rotor harmonic currents. Finally, the tests proved the validity of the computing results of simulation; and it is practical value for the reasonable design of REPMSM.