Design of an extended luenberger observer for sensorless vector control of induction machines under regenerating mode

Within this work we present a method of choosing the proportionality coefficient between the eigenvalues of the motor and the eigenvalues of the Luenberger Observer. The choosing of this coefficient is made based on the Routh - Hurwitz criterion considering that the controller within the adjustment mechanism is an adaptive type one. The tuning of the PI controller within the adjustment mechanism is made based on the proportionality coefficient between the eigenvalues of the motor and the eigenvalues of the observer. All these research are made in order to stabilize the control system at low speed both in motor and in regenerating mode running. On the other hand within this work we present in details the current, flux, torque and speed controllers´ tuning within the control system. In the end paper we analyze the asymptotic stability of a vector control system for an induction motor with short-circuited rotor that contains in its loop an extended Luenberger observer. The studied control system is based on the direct rotor flux orientation method (DFOC) and the stability study is based upon the linearization theorem around the equilibrium points of the control system, emphasizing the estimated variation domain of the rotor resistance for which the control system remains asymptotically stable.