Study of improving low frequency torque ripple in low speed and high torque PMSM

The paper introduces the crucial technical difficulty of the low-speed and high-torque gearless drive system is the waveform sinusoidal design of internal potential electromotive force in the Permanent Magnetic Synchronous Machine (PMSM), thereby reduces the ripple torque of PMSM of transmission systems. The paper take the low-speed and high-torque Permanent Magnetic Synchronous Machine of 12 type pumping units drive system as an example, through theoretical analysis and calculation of specific project, MATLAB software is used for the optimum design, ANSOFT software is used for the finite element analysis of the air gap magnetic field, no load back electromotive force and the torque of teeth groove. The distortion rate of the sine waveform of internal potential electromotive force is reduced to less than 3%, the steady running frequency of PMSM reaches 0.2Hz under the rated torque.