| Abstract |
Sensorless speed control of AC motors has been intensively investigated over the last few decadesusing multiple strategies. In particular, stable operation around zero speed can only be guaranteed sofar by the so-called signal injection methods, which extract motor saliencies to acquire a rotor flux orrotor position.Research on issues of induction motor saliency extraction at first put into service is quite limited butnecessary. In certain induction machine drives, cogging torques or torque harmonics are unavoidablypresent, causing undesired effects such as vibrations, noise and losses. Several torque harmonicspossess a mechanical periodicity and magnitude, which is not known when the sensorless drive is putinto service. Such harmonics can hampering thus the identification of the motor saliencies, especiallyat start-up. In this sense, this paper proposes a method to estimate machine saliencies for sensorlessspeed control under presence of torque harmonics without any position sensor. Thus, the methodidentifies and compensates simultaneously cogging torques and motor saliencies in an iterativescheme, ensuring smooth sensorless speed operation based on rotor slotting saliency.Experimental results extracting machine saliencies from an induction motor that shows rotor-relatedcogging torques will be provided. |
