Research on stability performance of speed estimation for induction motors based on adaptive full-order observer

To assure the stability performance of the speed estimation in the speed sensorless induction motor drives, the design strategy of feedback gain matrix for an adaptive full-order observer is a necessary issue. In this paper, the major cause of instability phenomenon based on adaptive full-order observer is analyzed, and a novel design of observer´s feedback gain matrix is proposed to achieve the stability over the whole operating range especially in the low speed region, including the regenerating mode. Besides, the Popov hyper-stability theory is used to prove the stability improvement based on the proposed method. Some simulation results are given to demonstrate the effectiveness of the proposed solution.