This paper presents a high dynamic induction motor drive system utiliz
ing a fully digital direct field oriented controller. The drive is cha
racterized by a sliding mode controller and by a stochastic filtering
technique, the latter obtained by an extended Kalman filter (EKF), in
the feedback loop. The EKF, in addition to supplying a reliable estima
tion of state variables, is able to identify and to correct in real-ti
me the values of rotor resistance and of rotor constant time, in effec
t, becoming an adaptive state observer. The system can work both with
or without a speed sensor. Some computer simulations are reported.