Sensorless Control for Induction Motors via Fuzzy Observer Design

In this paper, sensorless control for induction motors is developed based on fuzzy observer design. First, the T-S fuzzy model is used to exactly represent the induction motor. Then, the fuzzy observer of the induction motor is straight-forwardly constructed to estimate the immeasurable states of rotor speed and rotor flux, where the estimation gains are obtained by solving a set of linear matrix inequalities (LMIs). This observer scheme gives the estimated states converging to the real states exponentially. For the controller design, in light of the principles of vector control, a new concept, namely virtual-desired-variable synthesis is introduced to design the control law. Finally, numerical simulations and experiments are carried out to verify the theoretical results and show satisfactory performance