Analytical model and characteristics of current-observer-based induction motor speed-sensorless vector control system taking into account iron loss

We have proposed a current‐observer‐based speed‐sensorless vector control system that is in a rotating reference frame and takes into account iron loss. By deriving a linear model and by computing the trajectories of poles and zeros, the system stability on various parameters such as operating points, observer gain, controller gain, and stator resistance has been investigated. Furthermore, an exact analytical model including PWM control, dead time, and nonideal features of power devices is developed. The characteristic improvement and stability limit of the proposed system are discussed by simulation and experiment. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 180(1): 46–56, 2012; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.21301