Abstract
Vector controlled induction motor (field oriented control of induction motor) is very prospective actuator instead of direct current motor because of the robust construction, non-expensive and maintenance-free actuator etc. Until now, the vector controlled induction motor system is mainly designed and producted by power electronics technique only. Consideration from the control theory point of view is necessary in order to examine the transient performance as well as the steady state performance because this system is very effective in the control engineering field as well as in the field of energy conversion machine. In this paper, adaptive control system realizing the vector controlled induction motor is synthesized on the basis of nonlinear state equation of induction motor. Under an assumption that secondary flux is detectable, continuous nonlinear compensation inputs are applied to the nonlinear state equation of induction motor and the linearized induction motor model is obtained. Model reference adaptive control system for the speed control is synthesized on the basis of the linearized model in order to construct the robust control system for the parameter variations of induction motor during the operation and the disturbance change. Moreover, the position control system is synthesized and applied to the robot manipulator control to show the effectiveness. Next, under the assumption of non-detectable secondary flux, the similar procedure as before is applied. Since the secondary flux detection is not easy in the industrial field application of the induction motor, a practical method to construct near-vector controlled system is expected. Near-vector controlled induction motor synthesized by the method is compared with the well-known vector control technique (slip frequency control type vector comtrol method). Good transient and steady state performance are shown by the simulation studies.
