Nonlinear adaptive control of induction motor with unknown rotor resistance

The paper proposes an adaptive speed/position tracking control of an induction motor subject to unknown load torque. The controller is developed based on a dynamic model obtained from the d-q-axis model (w.r.t. the stationary reference frame) of the motor under a special nonlinear coordinate transform so that either speed or position control objective can be fulfilled. The underlying design concepts is to endow the close-loop system with so-called maximal power transfer property while under lack of knowledge of some key system parameters, such as the rotor resistance, motor inertia and motor damping coefficient: To be rigorous, the proposed control scheme comes along with a thorough proof derived based on Lyapunov stability theory. Numerical simulations and experimental results are also given to validate the effectiveness of the presented control scheme.