Φ AbstractUsually In the speed sensorless of the induction motor, the machine parameters (especially rotor resistance R r ) have a strong influence on the speed estimation. This paper presents simultaneous estimation of speed and rotor resistance in sensorless ISFOC induction Motor drive based on a Model Reference System (MRAS). The MRAS has been formed to estimate the rotor speed and the rotor resistance which are tuned to obtain high-performance ISFOC induction motor drive. The error between the reference and adjustable models, developed in stationary stator reference frame, is used to drive a suitable adaptation mechanism that generates the estimate ω r and R r from measured terminal voltages and currents. The proposed algorithm has been tested by numerical simulation, showing the capability of driving active load and stability is preserved. Experimental results for the simultaneous estimation are presented in order to validate the effectiveness of the proposed scheme. The control algorithm has been implemented using a digital signal processor based on dSPACE DS1104. Index Terms  Induction motor drive, indirect stator field oriented control (ISFOC), model reference adaptive system (MRAS), rotor speed estimation, rotor resistance estimation. I. NOMENCLATURE , ds qs v v d, q-axis stator voltage components , ds qs i i , , dr qr i i d, q-axis stator and rotor current components , ds qs φ φ d, q-axis stator flux components , dr qr φ φ d, q-axis rotor flux components , s r φ φ Stator and rotor flux , s r R R Stator and rotor winding resistance , s r L L ,M Stator, rotor and mutual self inductance p N Number of pole pairs , s r ω ω Synchronous and rotor angular speed sl ω Slip angular speed , e l T T Electromagnetic and load torque J Moment of inertia f Friction constant σ Leakage coefficient , s r τ τ Stator and rotor time constant. d p dt = Differential operator Y. Agrebi Zorgani is with Laboratory of Sciences and Techniques of Automatic control & computer engineering (Lab-STA), National School of Engineering of Sfax, University of Sfax-Postal Box 1173, 3038 Sfax, Tunisia and Laboratoire des Sciences de l’Information et des Systèmes (LSIS) – UMR CNRS 6168 Ecole Centrale de Marseille (ECM) – Technopôle de Château Gombert,13451 Marseille cedex 20 – France (Email: agrebi69@yahoo.fr). Y. Koubaa is with Laboratory of Sciences and Techniques of Automatic control & computer engineering (Lab-STA), National School of Engineering of Sfax, University of Sfax-Postal Box 1173, 3038 Sfax, Tunisia (Email: yassine.koubaa@enis.rnu.tn). M. Boussak is with the Laboratoire des Sciences de l’Information et des Systèmes (LSIS), UMR CNRS 7296 – Ecole Centrale Marseille (ECM) – 38 rue Joliot Curie, Technopôle de Château Gombert, 13451 Marseille Cedex 20, France (Email: mohamed.boussak@centrale-marseille.fr). II. INTRODUCTION ndirect field oriented control (IFOC) [1], [2] has become an industry standard for control of induction motor in high performance drive application. The use of vector controlled induction motor drives allows obtaining several advantages compared to the DC motor in terms of robustness, size, lack of brushes, and reducing cost and maintenance. Unfortunately the IFOC induction motor drive technique requires an accurate rotational speed sensor for good operation. However, speed sensor has several disadvantages, such as reduced reliability, susceptibility to noise, additional cost and weight, and increased complexity of the drive system. Therefore sensorless IFOC induction motor drive eliminates the need for speed sensor, overcoming these challenges. Moreover, a high performance sensorless induction motor drive needs speed estimation in addition to estimating machines parameters from which the rotor resistance is the most important and which change with temperature and skin effects. The stator flux for speed sensorless IFOC of an induction motor drive has been receiving wide attention because it has been less influenced by parameter variation effect. Different solutions for simultaneous estimation of speed and rotor resistance have been presented. In [3] the simultaneous estimation of the rotor speed and the rotor resistance were estimated from the transient state without signal injection to the stator current. The method is not used for the machine which is driven at the constant speed. In references [4], [5], [6], the rotor resistance was estimated from the higher order harmonics of the rotor slots, but it is difficult to estimate this resistance in the low speed because it becomes difficult to measure the highest order harmonics in the low speed range. In [7] the rotor resistance was estimated with adding small alternating current to the rotor flux so that is fluctuated, but the ripple of the torque and the real speed oscillation were caused. In [8], [9], [10], [11], the rotor resistance was estimated using the extended Kalman filter. The method used is limited to the provision for the estimator which is designed on the basis of a linear induction motor. This paper presents a simultaneous estimation of the speed and the rotor resistance based on MRAS scheme using only stator currents and voltages measurement. A full description and justification of the proposed algorithm is given, and its performances are tested by simulations and experimental results. Although related algorithms have been presented previously, the following contributions are believed to be new. First, the dynamic and steady-state performance are analyzed. Excellent behaviour is verified in most cases. Second, the use of the ISFOC induction motor drive and a general framework are developed. This paper is organized as follows. Section II formulates the stator flux orientation modeling, while section III presents the simultaneous estimation of speed and rotor resistance using MRAS technique. Simulation results are proposed in section IV. In section V the theoretical analysis is confirmed by experimental tests of sensorless drive system with estimation of the rotor resistance and finally section VI draws the final conclusions. I Sensorless Speed Control With MRAS for Induction Motor Drive Y. Agrebi Zorgani, Y. Koubaa, M. Boussak, Senior Member, IEEE I ＹＷＸＭＱＭＴＶＷＳＭＰＱＴＱＭＱＯＱＲＯＤＲＶＮＰＰ＠ﾩＲＰＱＲ＠ｉｅｅｅ ＲＲＵＷ