Performance Improvement in Vector Controlled Induction Motor Drive by Combining the Principle of Hybrid Pwm and Anfis

The complexity involved in the designing of a conventional PI type speed controller for an induction motor is replaced by fuzzy logic controller, synthesized by adaptive neural fuzzy interference system (ANFIS) method. This paper presents a hybrid pulse width modulation (HPWM) algorithm to reduce the steady state ripple in current. The conventional space vector pulse width modulation (CSVPWM) method with equal division of zero state time is modified. To avoid the complex coordinate transformations, trigonometric calculations and sector identification involved in CSVPWM, the concept of imaginary switching times is utilized. The proposed PWM algorithm is designed based on the notion of stator flux ripple. Modulation index and duty cycle dependent expression for rms value of the stator flux over a sampling interval is calculated. Moreover, the rms flux ripple characteristics are graphically illustrated, from which the proposed hybrid PWM algorithm is developed. To validate the proposed algorithm, simulation studies have been carried out and compared with PI controller based vector control of induction motor.