Investigation of losses in permanent magnet synchronous motor under different operation conditions

The operation condition of line-start permanent magnet synchronous motor(PMSM) varies frequently,and its losses change correspondingly.In order to investigate the main factor which affects losses and its variation,Time-Stepping Finite Element Method(T-S FEM) was employed to calculate the loss density in different part of PMSM considering the harmonic magnetic field and current,then the copper and iron losses under different voltage and load conditions were obtained,and it's harmonic component was analyzed based on Fourier analysis of stator current,current density in rotor bar and magnetic density in the core,furthermore the main factor which affects the losses of PMSM and its variation was obtained.The results indicate that there is a significant influence of slot harmonic field to the rotor losses.The rationality of calculation is validated by comparing with the experiment result.