Research and implementation of a new sensorless control method for permanent magnet synchronous motor based on sliding mode observer

In this paper, a sensorless control method based on sliding mode observer (SMO) is proposed for permanent magnet synchronous motor (PMSM), in which continuous Sigmoid function is substituted for saturation function as switching function. A sliding mode observer is used to identify and determine the rotor position instead of the traditional position coding plate, and the operation system is started through I/F. Finally an experimental platform was built, and the test results were analyzed. It was verified that the proposed method has the advantages of smooth starting, accurate current observation model establishment and improved robustness of SMO control.