PMSM Based on Equivalent Magnetic Linkage Super-Twisting Sliding Mode State Observer

In the pursuit of advancing control performance in sensorless control of Permanent Magnet Synchronous Motors (PMSMs), this paper proposes a super-twisting sliding mode observer(STWSMO) based on effective magnetic linkage. The observer is designed to achieve equivalent back-electromotive force (EMF) estimation and mitigate chattering effects commonly associated with sliding-mode observers. Furthermore, the observer allows for filtering and correction of observed values without compromising the phase relationship. Leveraging the estimated equivalent back-EMF, an effective magnetic linkage estimation is realized, facilitating real-time tracking of the electromagnetic torque without the need for sensors. The fractional-order software phase-locked loop (FO-SPLL) is subsequently employed to extract motor speed and rotor position information from the estimated equivalent back-EMF, enabling sensorless identification. Finally, the proposed observer is integrated into the closed-loop Field-Oriented Control (FOC) for motor speed control. The reliability and robustness of the observer are validated through simulation in MATLAB.