Utilizing Active Rotor-Current References for Smooth Grid Connection of a DFIG-Based Wind-Power System

Abstract

Large inrush currents emerge abruptly whenever a doubly fed induction generator (DFIG) attempts to connect with the grid. Moreover, a DFIG is highly vulnerable to grid disturbances owing to its direct stator-grid contact, which induces a sizable electromotive force in its rotor circuit. Therefore, to ensure reliable and stable system operations, it is unavoidable to improve system performance through suitable and corrective control actions to counteract such issues effectively. In this context, this study focuses on establishing a stable and smooth grid connection for a DFIG by developing dynamic models of the rotor-side converter controls that generate suitable rotor-current references for both the synchronizing and running modes of a DFIG. Furthermore, a smooth transition between both modes is also precisely made with trivial inrush currents. Dynamic simulations confirm the validity of the proposed synchronization method in MATLAB/SIMULINK. Finally, a comparative study with a conventional synchronization method is also performed.

Keywords

• current control
• power converters
• generators
• power grids
• wind energy integration