Modeling of doubly-fed induction generator using MATLAB/Simulink
Penetration level of wind units in power systems is increasing rapidly. There are different topologies and configurations of wind units. The most famous configuration is called Doubly-Fed Induction Generator (DFIG). In this configuration, the stator of an induction generator is directly connected to the grid, while the rotor is connected to the grid through an AC/AC converter. The advantage of this topology is the controllability of output active and reactive powers of the generator to some extents. In this thesis, a MATLAB/Simulink modeling of DFIG is presented. Dynamic modeling of all the components of the DFIG is presented here and implemented in Simulink. Moreover, a number of studies on DFIG are performed to carry steady state analysis on DFIG. Then, the design of different controllers for the AC/DC and DC/AC converters is presented. These controllers are designed to ensure extracting maximum power from the wind while keeping the stability of DFIG after different contingencies. Dynamic performances of DFIG controllers are tested through two different studies; the first case is the effect of change in the wind speed over the time and the other case is the effect of grid under-voltage.