A Field Oriented Adaptive Controller Using EKF for Asynchronous Drives

This paper presents a high dynamic induction motor drive system utilizing a fully digital direct field oriented controller. The drive is characterized 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 estimation of state variables, is able to identify and to correct in real-time the values of rotor resistance and of rotor constant time, in effect, becoming an adaptive state observer. The system can work both with or without a speed sensor. Some computer simulations are reported.