This paper introduces a sensorless nonlinear control scheme for controlling
the speed of a permanent magnet synchronous motor (PNSM) driving an unknow
n load torque. The states of the motor and disturbance torque are estimated
via an extended nonlinear observer avoiding the use of mechanical sensors.
The control strategy is an exact feedback linearization law, with trajecto
ry tracking evaluated on estimated values of the PMSM states and the distur
bance torque. The system performance is evaluated by simulations.