Design an Improved Sensorless Sliding Mode Observer for PMSM

In order to reduce the imprecision of the sliding mode observer to the sensor-less permanent magnet synchronous motor a new switching function is used instead of the traditional symbolic function. The variable cut-off frequency low-pass filter is used to replace the common low-pass filter to compensate the motor phase to estimate the rotor position. Finally, the simulation model of PMSM vector control system based on the new sliding mode observer is built in Matlab/Simulink. It is proved that the new sliding mode observer can effectively estimate the rotor position and speed, also achieve good dynamic and static performance. The reliability and robustness of the system are verified by simulation experiments.