An improved nonlinear control strategy for induction motor drive

In this paper, a new configuration called the auto disturbance rejection controller (ADRC) is used in induction motor speed control. The key part of the ADRC is the extended state observer (ESO). By using ESO, the ADRC can estimate accurately the derivative signals and accurate decoupling of the induction motor is also achieved. In addition, the external disturbances and parameter variations could also be estimated and compensated by ADRC, so that the closed loop motor drive system under ADRC control does not depend on the accurate mathematical model of induction motors. Therefore, the robustness and adaptability of the control system is improved too. The simulation and experiment results show that the controller operates quite robustly under modeling uncertainty and external disturbance, and it can provide good dynamic performance such as small overshoot and fast transient time in the speed control