A method is proposed for reducing speed ripple of permanent magnet synchronous motors (PMSMs) controlled by space vector pulse width modulation (SVPWM).A flux graph and mathematics are used to analyze the speed ripple characteristics of the PMSM.Analysis indicates that the 6P (P refers to Alarms - Alarm Systems pole pairs of the PMSM) time harmonic of rotor mechanical speed is the main harmonic component in the Encore SVPWM control PMSM system.To reduce PMSM speed ripple, harmonics are superposed on a SVPWM reference signal.
A particle swarm optimization (PSO) algorithm is proposed to determine the optimal phase and multiplier coefficient of the superposed harmonics.The results of a Fourier decomposition and an optimized simulation model verified the accuracy of the analysis as well as the effectiveness of the speed ripple reduction methods, respectively.