Stability analysis and PI controller tuning for a speed-sensorless vector-controlled induction motor drive

The purpose of this paper is to determine the controller parameter tuning range for a speed sensorless vector-controlled induction motor drive from the system stability point-of-view. The tuning rules for conventional PI controllers are mostly based on experience, Trial-and-error procedures are used to tune the values of the controller parameters. The relationship between the tuned controller parameters and the stable operating range of the control system is generally not known. The approach of this paper starts from establishing the complete dynamic models for a sensorless vector-controlled induction motor drive. The nonlinear dynamic models are linearized around a chosen operating point The characteristic equation is then derived, which is used to determine the values of the controller parameters corresponding to the marginal system stability. Based on these critical values, the tuning range of the controller parameters is obtained, which assures stable operation of the drive in the entire operating region and provides a reference for controller parameter tuning.