Nonlinear Control for Speed-Sensorless Synchronous Motors with Damping Windings

A nonlinear control for speed-sensorless synchronous motors with damping windings is designed. Assuming that flux initial values are known, exponential rotor angle tracking of arbitrary smooth bounded reference signals, rotor flux vector direct axis component tracking of suitable smooth bounded reference signals and stator current vector direct axis component regulation to zero (motor field orientation) are guaranteed for any initial condition and for any unknown constant load torque. In the case of non-exact knowledge of flux initial conditions, a local result holds.