CONTROL OF INDUCTION-MOTOR DRIVE FOR IMPROVING OPERATING CHARACTERISTICS AND DYNAMIC-RESPONSE

The control strategies of an indirect field-oriented induction motor d rive for both good operating characteristics and dynamic rotor speed r esponse are presented. The small-signal model representing detuning be havior around the steady-state of an ideal field-oriented induction mo tor is first developed and, according to it, the rotor resistance set in the indirect field-oriented mechanism (IFOM) is adjusted by a propo sed adaptive inverse model controller (IMC) to improve the decoupling characteristic. Furthermore, a stator current minimization controller is designed for fine tuning of the field-orientation characteristic. I n addition, a model following speed controller is proposed. In the pro posed speed controller, the model following gain is tuned according to the control effort and the model following error. The effect of contr ol force saturation is much reduced, and good model following and load regulation speed responses are obtained. The good operating character istics and dynamic speed responses of the motor drive obtained using t he developed controllers are demonstrated by simulated and experimenta l results. (C) 1997 Elsevier Science Ltd.