Design of Rotor Side Current Regulator for a Doubly-Fed Induction Generator

Design of rotor side current regulator of a doubly-fed induction generator (DFIG) connected to a power system is investigated in this thesis. In conventional design of the decoupled direct-axis and quadrature-axis current regulators for the rotor side converter of a DFIG, the derivative of the stator flux was usually neglected. In this thesis, a new feedforward compensator and a new proportional-integral (PI) regulator are derived by taking the derivative of the stator flux into account. By using the new rotor-side feedforward compensator and the new PI regulator, the dynamic responses of the generator subject to wind speed change and different voltage dips are studied. The MATLAB/Simulink simulation software is used to simulate the dynamic performance of the grid-connected DFIG. The control parameters of the rotor-side PI regulator were designed by using pole-zero cancellation. The simulation results indicate that the proposed compensator and PI regulator offer better dynamic responses than the conventional current regulator neglecting stator flux transient when the DFIG is subjected to wind speed change and different voltage dips.