Numerical approach for estimation of the rotor speed of the asynchronous machine

Abstract : This paper presents a new method for speed-sensorless estimation of the induction motor by considering estimation algorithm as a nonlinear optimal control. The proposed estimation approach uses an approximate numerical one-step time discretization of the nonlinear plant model behavior obtained from offline simulations. Then the speed of the induction motor is estimated by minimizing the distance between the plant output and the predicted output, leading the system to adopt its dynamical behavior. Since the prediction horizon is limited to one time-step, the execution time of the algorithm can be completely bounded. It can thus easily be implemented and used to observe the speed of the real induction motor system. Experimental results obtained from some simulations show the performance and robustness of the proposed estimator.