Speed sensorless control of PMSM motors implemented in real-time simulator

The paper presents a method for determining the transition region between rotor position estimators applied to permanent-magnet synchronous motors. A speed sensorless control scheme is implemented by combining the voltage injection method in low speed region, and back-emf estimation in the high speed region. The transition region is evaluated from the rms AC content level of the command current. Besides, based on this criteria, is established the bandwidths of the observers in function of the speed. Simulation are shown to verify the proposed technique. Results of the control system implemented in a real-time simulator are presented.