Improving induction motors speed and flux control using Fuzzy-SMC-PI

This paper addresses the usage of the boundary-layer concept in removing the chatter that occurs in sliding mode control applications in the area of controlling the speed and flux of induction motors. Although this concept succeeds in removing the chatter from the system, it introduces a stability problem. This paper proposes a fuzzy controller that acts as a supervisory controller for a sliding mode controller and a classical PI controller. Lyapunov functions are used to ensure the stability of the overall system. The proposed regulator solves the problems of overshoot and slow transient responses associated with fast response PI controllers in transient state and the chattering problem associated with robust sliding mode controllers in the steady state. Simulations of the proposed Fuzzy-SMC-PI strategy on the flux and speed controllers display diminished chatter, overshoot and significant reduction of settling time. One other significant result of applying Fuzzy-SMC-PI strategy on the flux component of the system is that optimum flux level is attained fairly quicker. This results in faster rise and settling times.