Sensorless Control of a Linearized Induction Motor Drive

Abstract

This paper presents an input-output linearizing and decoupling control scheme for speed control of an induction motor drive. In this scheme, the motor model is linearized, and torque and flux are decoupled by use of nonlinear control. Proportional-cum-integral controllers are used for the linear electrical and mechanical subsystems. A reduced order rotor flux observer is designed, eliminating the need of flux sensor for control purpose. A stator flux based algorithm is used to estimate the synchronous speed and then rotor speed, leading to sensorless control. Also, rotor flux and speed are estimated using Kalman filter. The control scheme is implemented and tested in laboratory.