An Improved Sliding Mode Observer for Sensorless Vector Control of PMSM — A Simulation Study

In recent years, high-speed permanent magnet synchronous motor (PMSM) has been extensively investigated for the driving of a flywheel energy storage system, and sliding mode observer (SMO) has been widely utilized to implement the sensorless vector control of PMSM. To overcome several defects of the conventional SMO, an improved sliding mode observer is investigated via a simulation approach, where the conventional sign function is replaced by the hyperbolic tangent function. Several simulation experiments are carried out to demonstrate the superiority of the improved SMO, which can outperform the conventional SMO on the estimation of both speed and position of the rotor.