Simplified Steady State Analysis of Stand-Alone Doubly Fed Induction Generator

This paper presents the steady state analysis and characteristics of a doubly-fed induction generator (DFIG) employed in stand-alone wind energy conversion system (WECSs) in a similar way as the synchronous generator. The DFIG is excited through the rotor terminals by a slip-frequency voltage and current injected to the rotor from a battery via rotor side converter. A simplified mathematical model required for evaluation of the steady state analysis and characteristics of the DFIG is presented. The effect of load variation on the rotor voltage, active and reactive power when the generator operated at constant speed is studied. Also, the effect of the generator speed variation when operated at constant load on the rotor voltage, active and reactive power is illustrated. The results show that the parameters affected on the steady state analysis and characteristics of the DFIG by using this method is more clearly and simply.