Novel configuration and control of DFIG-based FESS associated to a wind turbine connected to power grid

The power output of wind turbine (WT) is unpredicted and irregular, large scale wind power integrated to power grid influences the power system stability heavily. The multi-functional flexible power conditioner (FPC) is a flywheel energy storage system (FESS) based on doubly-fed induction generator (DFIG), which can perform functions including energy storage, active and reactive power generation. To enhance the power output characteristics of WT, a novel configuration of FPC associated to WT (WT-FPC) is proposed. According to the configuration and control targets of WT-FPC, the control strategies are studied. The active power of the associated system is regulated based on a fuzzy logic inference system, and machine terminal voltage was controlled by regulating the reactive power of FPC. The model of WT-FPC is established and the time-domain simulations are performed using MATLAB/Simulink. The simulation results show the feasibility and effectiveness of the proposed WT-FPC and its control strategies, and the operation characteristics of the WT connected to the grid are enhanced evidently.