Reduced-order observers for rotor flux, rotor resistance and speed estimation for vector controlled induction motor drives using the extended Kalman filter technique

The paper deals with robust parameter estimation (rotor and slater resistan ces), shaft speed estimation, and flux observation of induction motors usin g the extended Kalman filter (EKF) technique. The novelty of the paper is t hat it develops the EKF in a frame rotating synchronously with the staler c urrent vector with the use of a reduced dynamic motor model in order to eco nomise the computational requirements of the EKF. Different problems have b een studied. First, the EKF technique is applied to the estimation of the r otor and stator resistances. This is used for the indirect field-oriented c ontrol of the induction machine. Next, the EKF technique is applied to the estimation of the induction machine rotor fluxes and rotor resistance, and is used to perform the direct field oriented control of the induction machi ne. Finally, speed sensorless control is carried out. In this case, the rot or flux and the motor shaft speed are estimated. Computer simulations and e xperimental tests have been carried out to show the effectiveness of the pr oposed methods.