Using the induction motor as a flux sensor: new control perspectives for zero-speed operation of standard drives

Although sensorless techniques are among the preferred topics of many researchers around the world, the challenge they represent in terms of finding a robust and effective solution for sensor elimination in AC machine drives has not yet been completely solved. This is especially true for induction motor (IM) drives that still remain the "drive choice" for most of the lowand medium-performance applications. This paper discusses how standard control methods of IM drives can be improved by adopting a sensorless flux estimation procedure.