Parameter independent sensorless vector control of induction motor

Abstract

The paper propose an improved sensorless stator flux oriented direct vector control of induction motor with parallel estimation of stator resistance and speed, based on an adaptive control algorithm. Conventional field oriented control of induction motor fails to provide satisfactory performance under low speed due to the change in the stator resistance. So the resistance needs to be estimated accurately for better and wide range of speed control. And the sensorless algorithm makes the drive more cost effective and reduces the size. In this paper stator flux oriented control is used to limit the parameter sensitivity only to stator resistance value. And both, the stator resistance and speed estimation are done parallel using a model reference adaptive system, which reduces the complexity and makes the drive more versatile. The motor drive system as well as the control logic and the resistance estimator are simulated and characteristic simulation results are obtained. The simulation results reveal that the proposed method is able to obtain precise speed control for a wide range of operation.