State feedback control of invertor fed induction motor drives

A pole assignment technique by state feedback can be used to control an induction motor drive to produce the required transient performance with zero error in steady state. However, decoupled control of the rotor flux and the output torque cannot be ideally achieved if as VSI (voltage source invertor) is used, though the interaction between the two control loops can be partly compensated. In order to carry out the state feedback, a rotor flux estimation technique is necessary and other motor state variables can also be estimated, thus achieving better performance. Closed loop estimators provide controllable and flexible performance