Kyo-Beum Lee, Jooho Song, Joong-Ho Song, and Ick Choy, “Sensorless Vector Control of Induction Motors Using a New Reduced-Order Extended Luenberger Observer,” The Transactions of the Korean Institute of Electrical Engineers, vol. 53, no. 3, pp. 173–179, M > Paper

A synthesis method of the reduced-order extended Luenberger observer (ROELO) and its design procedure for a nonlinear

dynamic system are presented. This paper proposes a method to reduce the order of the observer and to select the observer gain

matrix. The proposed algorithm is applied for high performance induction motor drives without a speed sensor. The simulation and

experiment results show that the proposed ROELF provides both rotor flux and rotor speed estimation with good performance.