Experimental evaluation on parameter identification of induction motor using output inter-sampling approach

This paper evaluates parameter identification of speed sensorless vector controlled induction motor using output inter-sampling approach. It is well-known that the rotor speed and the rotor time constant of induction motors at steady state operation cannot be simultaneously identified. In order to avoid this problem, many researches have already proposed some kinds of strategies such as high frequency signal injection to obtain the parameter knowledge from only stator quantities, which would cause the torque vibration and the degradation of efficiency. Hence, it is desirable to decrease the amplitude of the injected signal. Although M sequence (maximum-length linear shift register sequence) signal is injected as an exogenous signal for parameter identification in this paper, the method of signal processing is discussed from the viewpoint of M sequence amplitude to achieve accurate parameter identification. To solve this problem, some literatures describe that output inter-sampling approach can result in the improvement of parameter identification accuracy. So, this motivates us to identify d-axis model of induction motors in steady state. In this paper, identification mechanism based on output inter-sampling approach is shown, and accuracy of identified parameters is experimentally evaluated.