Internal model control of induction motors based on extended state observer

The conventional internal model control (IMC) has been used widely due to its advantages of less computational burden and simple implementation. Since the internal model controller has a fixed filter, disturbances created by mismatched models, parameter variations and other unstructured dynamic uncertainties in induction motors (IMs) cannot be eliminated by a fixed IMC. To solve these problems, the control strategy of an induction motor using internal model control with an extended state observer (IMC-ESO) was proposed. IM parameter variations and other unstructured dynamic uncertainties are considered in IM drives. Based on this model, an ESO is defined as a hypothetical equivocal function. Then the estimated disturbance is applied as a feed-forward compensation to accurately control the current loop. Since the designed ESO works concurrently with IMC, the fast dynamic response of the IMC is maintained. The feasibility and validity of the proposed method are validated by experimental results.