An IRFO System with Stator and Rotor Resistance Identification for the Induction Motor

This paper presents a new online identification method for the stator and rotor resistance Of an induction motor operating in an indirect rotor field oriented (IRFO) control system. The rotor resistance is identified using the MRAS (model reference adaptive system) principle due to the estimated magnitude of the rotor flux. The rotor flux magnitude is estimated in the stationary reference frame (alpha,beta) using the voltage model and the current model. The error signal of the rotor flux magnitude obtained from the two models provides the identification of the rotor resistance. In order to estimate the rotor flux from the voltage model, a new method for elimination of the DC drift based on the observer theory is presented and compared with two very commonly used methods. The stator resistance is identified through two methods. The first method is based on the MRAS procedure. The second method is derived in the d,q reference frame aligned to the stator current vector. This paper investigates the possibility that the stator resistance, identified by either the first or second method, could be used as an input parameter for the rotor resistance identification method The validity of the proposed approach is verified by realistic simulation and experimentation. Copyright (C) 2008 Praise Worthy Prize S.r.l. - All rights reserved.