Sensorless rotor velocity tracking control for induction motors

In this paper, we present a sensorless control algorithm that achieves semi global exponential rotor velocity tracking for the full-order nonlinear dyn amic model of an induction motor actuating a mechanical subsystem, The prop osed controller utilizes stator current measurements but is termed sensorle ss due to the fact that no mechanical sensors are required and that stator current measurements can be obtained in an inexpensive/simplistic manner (e ,g,, relatively inexpensive Hall effect current sensors can be used to obta in current measurements). The control strategy utilizes a novel rotor veloc ity observer which facilitates the potential for improved rotor velocity tr acking transient performance. In addition, the observed integrator backstep ping technique is utilized to ensure that the observer-based controller rem ains bounded. Experimental results are included to verify the effectiveness of the controller,