Abstract: The sensorless control of PMSM based on control algorithm is a research hotspot in the field of

motor control. A PMSM sensorless control system based on low-speed pulse and high-frequency stator flux injection

was proposed，and the traditional stator flux estimator was improved and the high-frequency signal was introduced

into the low-pass filter to improve the accuracy of the stator flux estimator when the motor is running at low speed. In view of the fact that the sensorless control system is easily affected by torque ripple when PMSM is running at

medium and low speed，the disturbance torque observer was used to suppress the voltage error caused by the torque disturbance. The effectiveness and feasibility of the proposed scheme were verified by experiments.

    Key words: permanent magnet synchronous motor（PMSM）；sensorless；stator flux estimator；low pass filter；disturbance torque observer