Técnica de projeto de controlador fuzzy aplicada ao acionamento vetorial de motor de indução

Abstract

This paper investigates a strategy for Takagi-Sugeno fuzzy control applied to speed control of induction motor. The strategy implements a weighted interpolation between a set of local controllers previously designed. When changes occur in the operational conditions of the induction motor, the gains of the control law are adjusted automatically to maintain satisfactory performance of the control system. For controller design the fuzzy state space representation of the plant was considered in the form of an augmented system, including a new state variable which in this case, was selected as the integral of speed error. This formulation allowed the design of local controllers with the structure PI, through state feedback with pole placement. As variables of operation for the switching fuzzy controllers local variables were selected angular velocity and stator current component responsible for torque electric, expressed in a frame rotating synchronously with the rotor flux. Then, the stability of Takagi-Sugeno fuzzy controller designed was assured by the Lyapunov criterion, in the form of LMIs. The performance of the Takagi-Sugeno fuzzy controller was assessed through simulation studies and their results compared to the performance of a conventional PI controller, for regulating the rotor speed. The results obtained in simulation tests show that employing the proposed strategy makes the system more robust to parametric variations in the drive system.