Model Predictive Control of A Speed Sensorless Linear Induction Motor Drive

In this paper, the model predictive control (MPC) technique has been used to control the speed of the linear induction motor (LIM) drive. The mathematical model of the LIM has been described in the stationary frame. The longitudinal end effects of the linear induction motor are taken into account as external load.The concept of field orientation is used to decouple the mover speed from the secondary flux. The MPC technique has been designed such that the effect of the uncertainty due to motor parameters variation and load disturbance could be reduced. A simplified LIM model is introduced in the MPC structure so as to minimize the computational load. To decrease the associated maintenance cost, and increase reliability, the most common model reference adaptive system (MRAS) structure is used to estimate the motor speed. An adaptive full-order observer based on LIM equation is used to estimate the primary current and secondary flux. Lyapunov’s stability criterion is employed to estimate the motor speed. The same algorithm deduced from Lyapunov’s stability criterion is given to estimate the stator resistance, which results in the speed estimation error. Digital simulations are provided to validate the effectiveness of the proposed scheme. The results show that the proposed system possesses the advantages of good transient performance and robustness in face of uncertainties. A performance comparison between the proposed MPC controller and both of sliding mode and PI control schemes is carried out confirming the superiority of the proposed MPC technique. The proposed system has the advantages of increased reliability, and low cost due to the elimination of the mechanical speed sensor .