Modal analysis concerning the control mode of doubly-fed induction generator

The paper deals with the impact of wind power integration on power system small signal stability. The DFIG wind turbine consisting of a back-to-back PWM converter is introduced. Generator model is given first, ignoring the transient of stator. The converter control, shaft and pitch angle control diagrams are picked out for a detailed study subsequently. A case study is performed in part three, eigen-analysis of a modified IEEE 14 system is conducted considering the PF and VT control modes of wind farm. The pole map gives an intuitionistic view that DFIG introduces two oscillation modes related to the shaft and VAR controller model respectively. Eigen-structure depicts the electromechanical oscillation modes, and comparison of DFIG and SG case was studied which gives an overall conclusion that DFIG can have a favorable performance. Also the influence of increased penetration of wind power is examined.