Study on the control of DFIG and its responses to grid disturbances

The paper presents the dynamic model of doubly fed induction generator (DFIG) including the mechanical model, the generator model and the PWM voltage source converter model. The mechanical model uses two-mass model, and the generator model includes both the stator side and the rotor side dynamics. The PWM voltage source converter is modeled as an average model in which the action of power electronic switches is neglected. The paper features vector control of DFIG. On the rotor side converter, the control scheme enables the independent control of speed and reactive power from the stator. On the grid side converter, the control scheme is implemented to regulate the DC voltage and reactive power from the grid as well. In order to study the influence of the grid disturbances on the DFIG, grid voltage dip and quick frequency change are simulated with the engineering software, MATLAB/Simulink. Meanwhile, in the paper the pole-placement method and internal model control method are implemented for designing the PI controllers