Parameter Identification Scheme for Induction Motors Using Output Inter-Sampling Approach

This paper shows a parameter identification scheme for speed sensorless vector controlled induction motor using output inter-sampling approach and experimentally evaluates this method. It is well known that both the rotor speed and the rotor time-constant of induction motors cannot be identified under steady state operation. This is because vector control system of induction motors consists of a closed loop system, in which d axis current is always kept constant under steady state operation. In this paper, a novel signal processing method, output intersampling approach, is employed from the viewpoint of the amplitude of high frequency signal injection to realize accurate parameter identification. This paper describes an identification strategy based on output inter-sampling approach and robust estimation method of the d axis using adaptive observer with robust observer design, and finally accuracy of parameter identification is experimentally evaluated using 1.5kW test induction motor.