On line rotor parameter determination of three phase induction motors

This paper discusses the developments on the implementation of a rapid online rotor parameter determination method for three-phase induction motors without the need to connect a mechanical load or drive to the machine´s output shaft. The technique is based on data sampling and at the same instance calculating and recording the necessary parameter determination input such as currents, voltages, power, power factor and speed whilst the machine runs up to speed. In this paper, a method is proposed whereby the no-load and zero-speed data are also measured from the run-up test. Furthermore the technique takes into account rotor parameter variations with frequency due to skin effect, and other nonlinear imperfections such as heating, main flux path saturation, leakage variation or flux migration due to rotor skew