Induction motor magnetizing characteristic identification at standstill with single-phase tests conducted through the inverter

Abstract

In this paper, a magnetizing characteristic identification method for an induction machine at standstill is proposed. The technique is based on machine testing with a single-phase ac supply generated through a standard inverter. This type of test strategy is available in the literature, however, it has been used for parameter identification at a single current level thus ignoring the effects of magnetic saturation. To reproduce accurately the magnetizing curve, the test current level must be varied in order to trace the entire curve. The method presented here takes care of the magnetic saturation and estimates the magnetizing curve for complete current range of the machine. The proposed scheme does not require any external supply, measurement or data acquisition system and works at standstill thus avoiding the need to isolate the machine from its load or to block the rotor. This strategy is suitable for self-commissioning of induction motor drives and for sensorless control applications as well.