Science Journal of Circuits, Systems and Signal Processing 2017; 6(6): 57-64 http://www.sciencepublishinggroup.com/j/cssp doi: 10.11648/j.cssp.20170606.12 ISSN: 2326-9065 (Print); ISSN: 2326-9073 (Online) Rotor Speed and Parameters Identification Scheme for Sensorless Induction Motor Drives Djamila Cherifi * , Yahia Miloud Electrical Engineering Department, Faculty of technology, Dr Moulay Tahar University, Saida, Algeria Email address: * Corresponding author To cite this article: Djamila Cherifi, Yahia Miloud. Rotor Speed and Parameters Identification Scheme for Sensorless Induction Motor Drives. Science Journal of Circuits, Systems and Signal Processing. Vol. 6, No. 6, 2017, pp. 57-64. doi: 10.11648/j.cssp.20170606.12 Received: December 15, 2017; Accepted: December 28, 2017; Published: January 18, 2018 Abstract: Most industrial processes have time-varying parameters, the Induction Motor IM is a typical example, in fact the rotor resistance (Rr) can vary and reach 100% of its nominal value during operation because of the heating of the rotor, the effect of the variation of the stator resistance (Rs) is very influential at low speed for our case because it can go up to 50% of its initial value, it is proposed in this work to developed a method that involves the observation of the speed and the simultaneous estimation of the principal parameters varying in time, and in particular the estimation of the stator resistance Rs and rotor Rr of the induction motor using sliding-mode observer when only the stator currents and voltages are accessible by measurement. After the theoretical study we will validate the method proposed by the simulation results where we will show the fairly fast convergence of this method as well as its robustness. Keywords: IM Control, Sliding Mode Observer, Parameter Estimation, Field Oriented Controller 1. Introduction The field-oriented control technique has been widely used for high-performance induction motor (IM) drive With this technique, the decoupling of torque and flux control commands of the induction motors is guaranteed and the induction motor can be controlled linearly as a separated excited dc motor. Indirect field-oriented control (IFOC) is one of the most effective vector controls of IM due to the simplicity of design and implementation [1]. But, the knowledge of the rotor speed is necessary, this necessity requires additional speed sensor which adds to the cost and the complexity of the drive system. Over the past few years, ongoing research has concentrated on the elimination of the speed sensor at the machine shaft without deteriorating the dynamic performance of the drive control system. The advantages of speed sensorless induction motor drives are reduced hardware complexity and lower cost, reduces size of the drive machine, elimination of the sensor cable, better noise immunity, increased reliability and less maintenance requirements, [2]. In order to achieve good performance of sensorless vector control, different speed estimation schemes have been proposed, and a variety of speed estimators exist nowdays [3]. Such as direct calculation method, model reference adaptive system (MRAS), Extended Kalman Filters (EKF), Extended Luenberger observer (ELO), ect. Out of various approaches, Luenberger observer based speed sensorless estimation has been recently used, due to its good performance and case of implementation. The Luenberger observer (LO) belongs to the group of closed loop observers. It is a deterministic type of observer because it is based on a deterministic model of the system, [4]. Therefore, parameter errors can degrade the speed control performance. However, the rotor and the stator resistance variation has a great influence on the speed estimation [2], [5]. So, online adaptation of the stator resistance can improve the performance of sensorless IFOC drive at the low speed region. So, a simultaneous estimation of rotor speed with stator and stator resistance is presented based on a luenberger observer. This paper is organized as follows. In Section 2, dynamic model of induction motor is reported; principle of field- oriented controller is given in Section 3. The proposed solution is presented in Section 4. In Section 5, results of