Direct Torque Control of Permanent Magnet Synchronous Motor for Reducing Torque Ripple

Traditional direct torque control (DTC) system of permanent magnet synchronous motor has two main problems, one is large torque ripple, and the other is the switching frequency is not constant. To improve the problem of large torque ripple, this paper proposes a new simple torque controller to replace the traditional one, which could be used to reduce torque ripple. At the same time, the extended Kalman filter is used instead of the traditional voltage integral to calculate the flux, which reduces the error of the flux calculation process and makes the flux estimation more accurate. Based on the least variance estimation theory, the extended Kalman filter provides a solution to accurately estimate the state of nonlinear systems and has good dynamic performance, high anti-interference, and accurate estimation ability. Finally, the effectiveness of the proposed method is verified in MATLAB/Simulink based on the built-in PMSM.