A novel mixed cascade finite-time switching control design for induction motor

This paper presents a novel cascade Proportional-Integral (PI) continuous second-order Sliding Mode Control (SMC) for induction motor in the presence of operational constraints. The inner-loop SMC is designed to control the current dynamics of the motor, while the outer-loop control is the PI control of speed. The main advantage of the proposed method is that the PI control provides the reference to the inner-loop SMC with constraints according to the system requirements in terms of maximum current and speed limits. Moreover, because the inner-loop dynamics of the motor are non-linear, SMC design has more importance in terms of robustness and disturbance rejection capability. The proposed control is a continuous time design strategy with fixed-time convergence while its discretization is performed at the implementation stage. The performance of the developed controller is validated by carrying out real-time experimental studies on an industrial size induction machine. Experimental results demonstrate remarkable robust tracking performance of the controller in terms of transient speed response and steady-state accuracy.