Comparative study of speed estimation techniques for sensorless vector control of induction machine

Sensorless vector control is applied to variable speed (AC) motor drives where speed estimators and observers are used instead of the costly speed or position sensors. Eliminating speed and position sensors reduces hardware complexity and cost, increases the mechanical robustness and reliability of the drive, and leads to a better noise immunity. However, some of these speed estimation techniques could be used only in low-cost drive applications not requiring high dynamic performance. The paper presents analytical study and simulation results of induction machine speed sensorless vector control where various speed estimation techniques are discussed.