Transient Control of Grid-forming Doubly-fed Induction Generator Considering Power Angle Stability and Fault Current Limitation

Grid-forming doubly-fed induction generators (GFM-DFIGs) exhibit similar active grid-forming capabilities as synchronous generators. However, under grid fault conditions, GFM-DFIGs are prone to transient power angle instability and fault overcurrent issues, which pose significant threats to their safe and stable operation. For GFM-DFIGs, both power angle stability and fault current limitation are essential. Despite this, most existing studies overlook the complex interaction between power angle and fault current, treating them as independent issues. This approach makes it challenging to achieve a balance between the two. To address this, this paper first investigates the power angle instability mechanism in GFM-DFIGs, then analyzes the interactive coupling relationship between power angle characteristics and fault current characteristics. Finally, a transient control strategy is proposed that accounts for both power angle stability and fault current limitation. The effectiveness of the proposed strategy is verified through simulations.