Robust control of induction motor using fuzzy sliding adaptive controller with sliding mode torque observer

In this paper, a robust speed controller for an induction motor is proposed. The speed controller consists of a fuzzy sliding adaptive controller (FSAC) and a sliding mode torque observer (SMTO). The FSAC removes the problem of oscillations caused by discontinuous inputs of the sliding mode controller. The controller also provides robust characteristics against parameter and sampling time variations. Although, however, the performance of FSAC is better than the PI controller and fuzzy controller in robustness, it generates the problem of slow response time. To alleviate this problem, a compensator, which performs feedforward control using torque signals produced by the SMTO, is added. The simulation and hardware implementation results show that the proposed system is robust to the load disturbance, parameter variations, and measurement noises.