Full-Order Terminal Sliding-Mode-Based Sensorless Control of Induction Motor With Gain Adaptation

This article proposes a sensorless speed control approach of Induction motor (IM) applying full-order terminal sliding-mode (FOTSM) control theory. The speed control system consists of three feedback control loops, i.e., the speed-, flux-, and current-loops. The related controllers in these three feedback loops are designed using FOTSM to enhance the robustness and dynamic performance, eliminate the singularity, and attenuate the chattering. The virtual control technique is utilized in the outer-loop speed controller to compensate unmatched uncertainties in the system, such as load disturbance and some parameter variations. The integral-type continuous control law with gain adaptation algorithm guarantees that the current references are smooth. In the inner-loop controllers, the actual voltage control signals can force the tracking errors of the currents to converge to its equilibrium point within finite time. Meanwhile, the FOTSM observer is designed for estimating the flux and speed of the motor simultaneously. Finally, the experiment results have demonstrated the effectiveness and feasibility of the proposed sliding-mode controllers and observers for the sensorless speed control of IM.