MRAS BASED SENSORLESS VECTOR CONTROL OF INDUCTION MOTOR

Abstract

Induction motors are widely used in many industrial applications, represent the starting point and often termed as the workhorse machinery for any electrical drive system, whenever planned to be designed. In correspondence to the modern control theory of electrical machines, the induction motor can be described by more than one mathematical model, in accordance to the employed control method. In the symmetrical three-phase version or in the unsymmetrical two-phase version, this electrical motor type can be associated with vector control strategy. Through this control method, the induction motor operation can be analyzed in a similar way to a separately excited DC motor. The goal of this dissertation is to summarize the existing speed control techniques available through vector control. Starting from vector control principles, the work suggests the d-q axes unified approach for understanding the important concepts of contrast among different techniques of speed control through vector control. However, the vector control or field oriented control is one of the basic modern tools of speed control; the dependence of the technique on mechanical measuring sensors is one of the major areas of concern. The estimation techniques are available to counter this, from which Model Reference Adaptive Control scheme is also discussed and simulated. The MRAC based scheme will not only improve the system efficiency, cost, and maintenance requirement of the mechanical sensing components.