Robust indirect vector control for the induction machine

In the present work, the motion control of an induction machine by indirect field oriented methods is addressed. The computation of the slip frequency, which is traditionally done by a feedforward control structure, is substituted by a feedback loop. The introduction of the slip frequency in the control loop generates a nonlinear model which is also uncertain and nonstationary. Despite the complexity of the model, a simple robust integral control method guarantees the stability of the system all over the operating range of the plant. In order to complete the robustness of the method to parameter variations, a new determination of the stator current references is proposed based on the electromagnetic torque estimation