Off-line tuning of fractional order PI lambda controller by using response surface method for induction motor speed control

Abstract

In this study, fractional order PI lambda (FOPI lambda) speed control of induction motor is realized with dsPIC30F4011 microcontroller which is suitable for industrial applications. Voltage/frequency (V/f) control method is used for induction motor. Integer order PI (IOPI) controller and fractional order PI lambda controller coefficients are optimized by using response surface method. The main advantage of FOPI controller is to provide more adjustable time and frequency responses of the control system allowing fulfillment of better as well as robust performance. FOPI controller is less sensitive than a classical PI controller when the parameter of the controlled system changes. FOPI has an extra variable to tune. This provides extra degrees of freedom to the dynamic properties of fractional order system. IOPI and FOPI lambda controller results are compared. FOPI and IOPI settling times are obtained as 0.65 and 1.15 second, respectively. FOPI and IOPI overshoots are approximately obtained as the same value (Less than 1 %). Fractional order PI lambda controller results are better than integer order PI controller.