Active and reactive power distribution under steady-state and transient conditions in doubly-fed induction generator (DFIG)

Doubly fed induction generator (DFIG) represents one of the more used generators for the conversion of wind energy, whose operation is based on the capacity to adapt their excitation to obtain grid-frequency voltage. An experimental study of a 4 kW DFIG is presented, together with the corresponding behavior modeling when interconnected to a grid of infinite power, under steady-state and transient conditions. The distribution of the active and reactive power is analyzed. The phenomenon is studied in both the stator and rotor circuits of DFIG. An approximate physical analysis is carried out using the theorem of constant linked flux that is widely used to study the synchronous machine transients. The cited theorem has been found to be a very good tool to explain the phenomenon that takes place in DFIG, and the necessity of a deeper analysis to explain other phenomena not analyzed in this work.