Abstract
This paper is concerned with the occurrence of chaotic motion in velocity control system of induction motor. Though the control of induction motor is very difficult, it is currently used by realization of so-called vector control method. The reason is that the induction motor is superior to a dc motor in maintenance. But, the stability of the Velocity control system is not established, neither is robustness. The dynamics of the induction motor is represented by nonlinear equations with three inputs and three outputs. Though precise parameters are necessary for the vector control method, it is difficult to obtain the precise values. Therefore, there are often identified errors in parameters and then the effect of the nonlinear terms remains. On this occasion, it is known that chaotic motions may occur in the system. In this paper, the existence of chaotic motion in such system can be verified using the concept of Lyapunov exponent, and the generating conditions of chaotic motion are found, when the desired value and load conditions are given.
