Adaptive Stator Current Controller for Subordinate IM Drive Scalar Control System

This paper deals with stator current control in scalar control system of frequency controlled induction motor drives and describes mathematical model of induction motor's stator current unit taking into account induction motor's electromagnetic transient responses. Several stator current controller's with signal adaptation structures have been tested, such as based on both constant and variable parameters PID-controller. Also an approach to controller's parameters synthesis is described. For the proposed control system's properties estimation the following time-domain criteria were selected: transient response time, overshoot, maximum reaching time. Reactions for both reference and disturbing influences have been tested. It is shown that application of PID-controller with variable parameters and signal adaptation provides high performance combined with robustness toward disturbances, as which internal electromotive force inducted in rotor circuit are taken into account. Rational field of use for proposed current controller with signal adaptation are scalar control system with enhanced electromagnetic torque forming ability.