Sensorless vector control of brushless DC motors using disturbance observer

Abstract

A sensorless drive system using disturbance observers for brushless dc motors is proposed in this paper. There are three observers in the control system, they are a disturbance voltage observer, a speed observer, and a disturbance torque observer. These observers are used not only for a position and speed estimator in the sensorless vector control, but also for a current controller. The rotor position and speed estimator are robust for parameter variations in the e.m.f. constant. The validity of the sensorless vector control of brushless dc motor is confirmed with computer simulations.