Dynamic evaluation of two configurations for a hybrid DFIG-based wind turbine integrating battery energy storage system

Abstract

Hybrid systems comprising battery energy storage systems (BESSs) and wind power generation entail considerable advances on the grid integration of renewable energy. Doubly fed induction generators (DFIGs) stand out among differentwind turbine (WT) technologies. On the other hand, electrochemical batteries have proved to be valid for these purposes.In this paper, a comparative analysis is carried out between two alternative configurations for hybrid WT-BESS systems,where the BESS is connected either outside or inside the DFIG. The modeling of these two configurations and the controlsystems applied for achieving the coordinate operation of the energy sources (DFIG and batteries) are illustrated. The hybridsystems under study are evaluated by simulation under normal operation (wind speed fluctuations and grid demand changes)and grid faults. Simulation results show that both configurations improve the grid integration capability of the WT, althoughthe configuration with external BESS presents better results since it can provide additional active/reactive power injection.