Transient Stability Enhancement Strategy of GFM-PMSG Considering Fault Current Limitation

When the grid voltage sags significantly, the power angle stability of grid forming-permanent magnet synchronous generator (GFM-PMSG) may be damaged, and overcurrent phenomenon may also occur. Both will seriously reduce the ability of GFM-PMSG to support the grid voltage. However, most of the existing research studied these two aspects as independent issues. In order to solve the above problems, an improved grid-forming control strategy is proposed for GFM-PMSG that take into account the power angle stabilization and fault current limitation. First, the output power angle is changed by adjusting the active regulation coefficient for various fault degrees, which enhances the transient margin while avoiding power angle destabilization. Then, according to the expected power angle, the reactive power regulation coefficient is changed to limit the fault current. Finally, simulation tests indicate that the power angle can be maintained stable under different fault degrees, and the fault current is kept within the threshold, which verifies the effectiveness and applicability to enhance the GFM-PMSG transient stability.