Sensorless Control of Permanent Magnet Synchronous Motor Based on An Improved Sliding Mode Observer

This paper proposes a sensorless speed control method for permanent magnet synchronous motors (PMSMs) based on an improved sensorless sliding mode observer vector control algorithm with dynamic boundary layer, suitable for applications in medium-high speed. Compared with conventional SMO, the signum function is replaced by a saturation function, to reduce the chattering problem. Also, in order to compensate for the position error caused by the low-pass filter, this control method allows the boundary layer to change with speed, making the rotor speed and position estimation more accurate in a wide speed range. The validity of the proposed sensorless velocity control method has been demonstrated with real experiments.