Analysis on Asynchronous Start Permanent Magnet Synchronous Motor Cogging Torque Optimization Based on Equivalent Magnetic Motive Force

Asynchronous Start Permanent Magnet Synchronous Motor has slots at both sides, so the formation mechanism of its cogging torque is more complex. To avoid influence on analyzing cogging torque by rotor slots, this paper propose a method of making the magnetic motive force generated by rotor bar equivalent to magnetic motive force generated by the permanent magnets, obtaining the analytical expression formula of such motor's cogging torque, to analyze the impact of the rotor tooth width, rotor slots number and rotor teeth shape, and other rotor parameters on motor cogging torque, and gives the method of reducing asynchronous start permanent magnet synchronous motor cogging torque; uses the effectiveness of the method proposed by finite element analysis verification and conducts the comparative analysis of the motor's performance before and after optimization. The results showed that selecting the appropriate rotor tooth width and rotor slots number can effectively weaken the asynchronous start permanent magnet synchronous motor cogging torque.