Identification of the machine parameters in a vector controlled induction motor drive

A method for the online identification of the parameters of an induction machine is described. This method requires the actual value of the rotor time constant as essential system information, on the basis of which the magnitude and the position of the rotor flux is calculated. An online identification technique for the rotor time constant and other machine parameters is described. The identification is based on an evaluation of the stator current trajectory as the dynamic response of the induction motor to the pulse-width modulation (PWM) switching sequence. An analytical machine model is operated in parallel with the stator voltages and the mechanical speed of the induction motor as input signals. The coincidence of the two stator current trajectories of the model and the machine serves as an error indicator for the parameter identification scheme, permitting repetitive updates of the model parameters.<>