Research on transient reconfiguration and low voltage ride-through control for a doubly fed induction generator wind turbine with energy storage device

Abstract

Doubly fed induction generator (DFIG) is extremely sensitive to grid voltage dips, which has restricted it from connecting with the grid at large scale. This paper proposes a novel transient reconfiguration solution and control strategy, based on the principle of stator voltage compensation, to enhance the low voltage ride-through (LVRT) capabilities of a doubly fed induction generator (DFIG) with an energy storage device (ESD). During a grid fault, the grid side converter (GSC) is reconfigured and is in series between the DFIG's stator and the grid through the series path. It is acted as a dynamic voltage restorer (DVR) with the energy storage device through the series path together. Based on the transient configuration, the positive and negative sequence controllers are employed to compensate the stator voltage of DFIG during grid faults. ESD is controlled to maintain the DC-link voltage via the DC-DC converter. Thus, the DFIG can be against the effects of grid faults, and still output active and reactive power steadily as normal. Simulations on a 1.5 MW DFIG system with ESD under severe unsymmetrical grid faults have been carried out, and the results demonstrate the effectiveness of the proposed transient configuration and control strategy in improving the LVRT capabilities, by comparing with the traditional control strategy.