Energy-based modeling and control for grid-side converter of doubly fed wind generator

To avoid dealing with the zero dynamics limitation brought by the bidirectional power flow through the back-to-back converter in a doubly fed wind generator, a new energy-based modeling and control approach for the grid-side converter is presented. During the modeling process, the grid-side converter is divided into two subsystems with the feedback interconnection structure, and the interactive matrix of the model takes into account the concrete port structure. Then, an energy-based controller is proposed to realize the grid-side control objectives based on the new model. Simulation studies are carried out in MATLAB/Simulink. Comparative results between the proportional-integral controller and the energy-based controller show that the latter one can obtain faster convergence rate and global stability as the load current varies. Moreover, the energy-based controller is also competent for grid-side control when simulated in a 2 MW wind energy conversion system with random wind. © 2012 South China University of Technology, Academy of Mathematics and Systems Science, Chinese Academy of Sciences and Springer-Verlag Berlin Heidelberg.