Sensorless control of PMSM based on linear super-twisting sliding mode observer and SOGI-PLL

Abstract

In PMSM sensorless control systems, conventional sliding mode observers are prone to chattering and noise during backEMF estimation, which negatively affects speed stability and estimation accuracy. To mitigate these issues, a sensorless control scheme that combines a linear super-twisting sliding mode observer with a SOGI-PLL framework is presented. A linear correction component is embedded within the super-twisting structure to suppress chattering and improve the quality of back-EMF estimation, while preserving finite-time convergence properties. Moreover, the SOGI-PLL allows for smooth and reliable extraction of rotor speed and position. Under no-load startup conditions, simulation studies show that the proposed approach reduces speed variation from 330 r/min to 20 r/min and decreases chattering from 16.5% to 1%, with improved waveform smoothness. These findings demonstrate that the method enhances estimation accuracy and overall performance of PMSM sensorless control systems.