Observer-Based Online Parameter Estimation of Doubly Fed Induction Generators Based on the Gradient Descent Method

Abstract:
This paper deals with the online parameter estimation of doubly fed induction generators (DFIG) using the Gradient Descent Method (GDM) and one flux observer for each winding system. Stator resistance, rotor resistance and mutual inductance can be estimated simultaneously in real time. The presented approach is applicable for standard variable speed DFIG with an inverter at the rotor side including a stator and rotor current measurement, a stator voltage detection and a rotor position feedback. The adaptation algorithm is described with simple analytical terms. The performance has been demonstrated by simulation and experiments. Furthermore, the influences of secondary effects like the nonlinear behavior of the inverter, incorrectly assumed leakage inductances and iron losses are discussed.