Application of extended Luenberger observer for flux and rotor time-constant estimation in induction motor drives

The synthesis method of an extended state observer for a nonlinear dynamical system is described. A presented observer enables the observation of system state vector and the identification of system parameter simultaneously. This method was adapted to the designing of the extended state and parameter observer for the induction motor. Generally, the proposed observer belongs to the class of time-varying reduced-order estimators. An analysis of the dynamical properties of each observer is presented. It is discovered that this kind of observer enables observation of the rotor flux and the identification of the rotor time-constant simultaneously, in synchronous or asynchronous operation, which greatly improves the computational facility and flexibility in the microprocessor realisation of such a system.