A Fuzzy Logic Approach for Speed Controller Design of A.C. Voltage Controller Fed Induction Motor Drive

Induction motors constitute a theoretically challenging control problem due to non-linearity of the dynamical system, motor parameter variation and the difficulty in measuring rotor variables. Incorporation of thyristorised a. c. voltage controller for speed control of the induction motor aggravates the non-linearity of the system. The use of conventional PI controller will not guarantee optimum dynamic response at different operating points of the drive. This paper presents the design and simulation of a fuzzy logic controller for speed regulation of voltage controlled induction motor drive. The fuzzy algorithms in the proposed controller are systematically obtained from the intuition and experience about the motor drive dynamics. A linearized incremental model of a. c. voltage controller fed induction motor drive is derived from the fifth order d-q axis model and is used for simulation study. The nullifying effect of parameter variation and disturbance rejection property of fuzzy logic controller is evidenced through simulation results.