An adaptive controller for speed-sensorless current-fed induction motors with unknown load torque

The problem of controlling a sensorless current-fed induction motor (i.e. without rotor speed measurements) is addressed. Smooth reference signals for rotor speed and rotor flux modulus are required to be tracked for any initial condition and unknown constant value of load torque. A new control scheme is presented which guarantees local exponential stability and global asymptotic stability of the closed loop system.