Torque Ripple Investigation on Line-start Permanent Magnet Synchronous Motors

This paper proposes a torque calculation method based on analytical equations. This method is used to investigate the torque ripple of line-start permanent magnet synchronous motors (LSPMSM). The comparison with the results of the finite element method (FEM) illustrates that the method is able to explore the interaction between magnetic potential and permeance. By calculating torque in two cases, without rotor bar and with rotor bar, the effect of rotor slotting and rotor bar on torque ripple is discussed. The calculation results indicate that rotor slotting is the main source of torque ripple in LSPMSM.