Sensorless speed tracking of induction motor with unknown torque base on maximum power transfer

In this paper, a nonlinear indirect adaptive sensorless speed tracking controller for induction motor with the maximum power transfer is proposed. In this controller, only the stator currents are assumed to be measurable. The rotor flux and speed observers are designed to relax the need of flux and speed measurement. Besides, the rotor resistance estimator is also designed to cope with the problem of the fluctuation of rotor resistance. Stability analysis based on Lyapunov theory is also performed to guarantee that the controller design here is stable. Finally, the computer simulations and experiments are done to demonstrate the tracking performance of our design subject to maximum power transfer