Robust control of induction motor drive with rotor time-constant adaptation

In this paper, an indirect field-oriented induction motor drive with a rotor time-constant adaptation is presented. Since the deviated rotor time-constant of an induction motor makes the indirect field-orientation inaccurate, an adaptation mechanism is proposed to tune the rotor time-constant to establish a complete indirect field-oriented control for an induction motor drive. With the rotor time -constant adaptation, the indirect field-oriented control has the robustness property for decoupling torque and flux components. In order to further insure the robustness of the servo control, a novel variable-structure speed controller is proposed under the adaptive field-orientation operation. A novel sliding surface with an integral component for the variable structure speed controller is designed, and exponential convergence in speed-tracking control is obtained. Using the proposed variable-structure speed controller, the insensitivity for parameter uncertainty and disturbance load is provided. Finally, a simulation and experimental results are demonstrated.