Adaptive Robust Sensorless Control for PMSM Based on Super-Twisting Algorithm Back EMF Observer and Extended State Observer

The estimation of the back electromotive force (EMF) signal of the permanent magnet synchronous motor (PMSM) using sliding mode observer (SMO) has a large number of high-frequency chattering, which cannot be directly applied to the sensorless control system of PMSM. This article proposes a robust sensorless control scheme based on an improved back EMF observer (BEO) and an extended state observer (ESO). First, a super-twisting algorithm back EMF observer (STABEO) is proposed by combining the back EMF model and the super twisting algorithm, in which the equivalent signal of the back EMF is estimated through the traditional SMO. The STABEO takes into account the uncertainty and unmodelled dynamics in the back EMF model, which leads to smaller chattering, better estimation, and faster convergence. Then, an ESO is constructed to calculate the rotor position, the rotor speed, and the total interference, and after that, a robust speed controller is designed. In addition, the stability is proved through the Lyapunov stability theory. Finally, the effectiveness and feasibility of the proposed control scheme were verified through experiments. The proposed robust sensorless control scheme has the characteristics of strong anti-interference ability, faster convergence, smaller high-frequency chattering, and without losing its robustness.