Sensorless linear induction motor control using fuzzy observers for speed tracking

In this paper, a sensorless speed controller for linear induction motor (LIM) is developed based on a fuzzy observer. First, the LIM is represented by a T-S fuzzy model. Next, the fuzzy observer is constructed to estimate the immeasurable states including the mover speed and secondary flux, where the observer gains are obtained by computationally solving a set of linear matrix inequalities. Based on the fuzzy observer, the synthesis using the virtual desired variable concept is applied to design the control law. Then, the exponential convergence for both estimation error and tracking error is concluded. This indicates that the proposed sensorless speed control possesses the feature with fast transient response and high robustness. Finally, experiments are carried out to verify the theoretical results and show satisfactory performance.