Nonlinear adaptive output feedback control of synchronous motors with damping windings

We design a nonlinear adaptive output feedback control for synchronous motors with damping windings, which, for any motor initial condition, for any unknown constant load torque within known bounds and for any uncertain motor inertia within restricted bounds, guarantees: i) asymptotic rotor speed tracking of arbitrary smooth reference signals; ii) exponential tracking for the rotor flux vector direct axis component of suitable smooth reference signals; iii) exponential regulation to zero of the stator current vector direct axis component (motor field orientation).