  In this paper we address the problems of flux and speed observer design for
voltage-fed induction motors with unknown rotor resistance and load torque. The
only measured signals are stator current and control voltage. Invoking the
recently reported Dynamic Regressor Extension and Mixing-Based Adaptive
Observer (DREMBAO) we provide the first global solution to this problem. The
proposed DREMBAO achieve asymptotic convergence under an excitation condition
that is strictly weaker than persistent excitation. If the latter condition is
assumed the convergence is exponential.
