Position and flux linkage tracking

Position and flux linkage tracking control response curves are shown as Fig.1. As can be clearly seen inFig.1 (a): 1) under the action of the backstepping strategy, the position signal θ fails to track the θ∗ due to the existing of the system uncertainties; 2) under the action of the proposed control strategy without NDOs , although the position tracking performance of AC asynchronous motor is improved, there still exists larger chattering; 3) under the action of the proposed control strategy, the position signal θnot only achieves effective tracking for θ∗ , but also has faster dynamic response speed, higher stability precision, and better anti-interference ability. Further, as can be clearly seen in Fig.1 (b): under the action of the proposed control strategy, the flux linkage observation ˆψ r not only realizes effective tracking control for ψ r∗ , but also has faster dynamic response speed and better control precision than the other two control strategies. Observation value curves of the NDOs are shown as Fig.2 (c)-(e). As can be clearly seen that the designed NDOs realize effective dynamic observations for the uncertainties 1 d , 2 d and 3 d , respectively.