ASPL International Journal of Information and Technology journals@arcnjournals.org 74 | Page Review of the Rotor Position and Speed Estimation Method of Induction Motor Drives Musa BabaLawan, Ya’u A. Samaila, Ibrahim Tijjani, Musa Mustapha and Musa A. Sarki Department of Electrical and Electronics Engineering, University of Maiduguri, Borno State, Nigeria Abstract: The electric drive systems used in industrial applications are increasingly required to meet the higher performance and reliability requirement. Today about 90% of all industrial motor applications use three phase induction motors because of their simplicity in design, easier maintenance, and are less costly than other designs. Electromechanical position sensors, e.g., resolvers, optical encoders, and Hall Effect sensors, are commonly used to obtain rotor position/speed in induction motor drives. The use of these sensors is undesirable in a drive because it increases the cost, size, weight, hardware wiring complexity of drive systems and reliability problem, besides the need for a shaft extension and mounting arrangement. To overcome these drawbacks of using position sensors, much research effort has gone into the development of sensorless drives that have comparable dynamic performance with respect to the sensor-based drives during the last decades. It is possible to estimate the position from machine terminal voltages and currents with the help of an intelligent controller. This paper summarizes different sensorless speed control and estimation techniques of induction motor drives system and their corresponding advantages and disadvantages stated. A comparison between different speed estimation methods was also tabulated and presented. Keywords: Induction Motor, Field Oriented Control, Rotor Position, Sensorless Speed Control 1.0 Introduction Induction motors are nonlinear high order dynamic systems of considerable complexity; they are very amenable to a formal mathematical analysis. When operated directly from the line voltages, they operate at a nearly constant speed (Utkin et al, 1999). However, with the help of power electronic converter it is possible to vary the speed of an induction motor. Induction motors are widely used in many residential, commercial, industrial and utility applications due to their manufacturing cost, wide speed range, high efficiency and robustness compared to other types of motors such as brushless DC motors (Farzan , 2004). These advantages have determined an important development of the electrical drives, with induction machine as the execution element, for all related aspects: starting, braking, speed reversal, speed change, etc. Rashidi (2012) stated that they require much more complex methods of control, more expensive and higher rated power converters than DC and permanent magnet machines. The conventional methods of speed control of an induction motor were either too extravagant or too inefficient thus limiting their application to only constant speed drives. Therefore it is of great significance importance to investigate the dynamic control methods of this kind of drives system. ASPL International Journal of Information and Technology ISSN: 2360-9981, Volume 8, Issue 1, (May, 2019) pages 74 – 91 www.arcnjournals.org