Optimal tuning of PI coefficients by using fuzzy-genetic for V/f controlled induction motor

Abstract

This paper presents a novel speed control scheme of an induction motor using genetic-fuzzy logic. The aim of this paper is to improve a new method of the optimal tuning of proportional integral controller coefficients in the off-line control of a induction motor. The V/f control, which realizes a low cost and simple design, is advantageous in the middle to high-speed range. Its torque response depends on the electrical time constant of the motor and adjustments of the control parameters are not need. Therefore, V/f control of induction motor is carried out. Space vector pulse width modulation with V/f is used for controlling the motor. Because, it includes minimum harmonics according to the other PWM techniques. In this paper, the first step is the identification of the system via fuzzy logic, using performance value (1/(1 + maximum overshoot and settling time)) obtained from the application circuit for different K-p-K-i pairs. In the second step, the purpose is to find the optimum controller coefficients using the fuzzy model as the objective function via genetic algorithms. A digital signal processor controller (dsPIC3OF6010) was used to carry out control applications. Then, the proposed method is compared with Ziegler-Nichols method.