Modeling, Analysis, and Control for the Rectifier of Hybrid HVdc Systems for DFIG-Based Wind Farms

In order to improve the dynamic performance of the hybrid HVdc system for doubly fed induction generator wind farms, this paper presents the modeling, analysis, and control methods for its line-commutated rectifier. First, the state variable model of the rectifier subsystem on the dq reference frame is derived considering different control modes of the current source inverter subsystem. Then, the ac current dynamic of the rectifier subsystem is quantitatively analyzed based on the eigenvalue analysis method. According to the analysis results, a double loop control scheme is designed: the inner loop utilizes the inverse system control technique plus a switchable phase-lead compensator, and the outer loop implements an ordinary propotional-integral controller. Finally, the validity of the quantitative analysis method and the superiority of the proposed control scheme are verified by Simulink/SimPowerSystems simulations.