A Comparative Study of a High Gain Observer and a Nonlinear Observer based on the Circle Criterion for Sensorless Induction Motor Control

This paper compares between a High-Gain Observer (HGO) with a nonlinear observer based on the Circle Criteria Observer (CCO) for sensorless control of induction motor (IM) drives.The circle criterion method is better for making nonlinear observers because it doesn't require as strict conditions as other methods that try to get rid of system nonlinearities using a transformation nonlinear state.However, the high gain observer makes an effort to dominate the nonlinearities in the system with a high-gain output adjustment term.The suggested study uses the backstepping control method and looks at three performance criteria: tracking the trajectory, rejecting disturbances, and maintaining steady-state stability.It was found that the circle-based nonlinear estimator works better than the interconnected observer, based on the results and the comparison criteria already mentioned.