Disturbance Observer-Based Speed Estimator for Controlling Speed Sensorless Induction Motor

Abstract

In this research, speed sensorless control is designed for induction motors by simulation. When the induction motor operates using the speed sensorless technique, the speed sensor is eliminated. Information about speed is obtained from an estimation algorithm based on the voltage and current entering the motor. In this study the estimation algorithm used is a Disturbance Observer. While the control method to control the speed of the induction motor in this study uses the Direct Torque Control (DTC) method. So the purpose in this research is to build a speed sensorless control system for induction motors with a disturbance observer as speed estimator and a DTC control scheme. The speed sensorless control system that has been designed can work well for the speed range of 50 rpm - 300 rpm, while for speeds of 350 rpm or speeds above 300 rpm the system is less able to work properly. The system produces a steady state error response for all variations of the set point in the speed range of 50 rpm - 300 rpm none of which is above 5%.