Adaptive Damping Control for Stability Enhancement of Grid-Following Converters Based on q-Axis Voltage Magnitude Feedback

Grid-following converters are prone to transient synchronization instability during grid faults, which may lead to the disconnection of renewable energy devices and threaten the security and stability of power systems. To address this issue, this paper first establishes a second-order nonlinear reduced-order model centered on phase-locked loop dynamics and constructs an energy function to analyze the instability mechanism, revealing the decisive role of equivalent damping in the energy dissipation process. On this basis, an adaptive damping stabilization control strategy based on q-axis voltage feedback is proposed. By introducing the amplitude of the q-axis voltage into the feedback loop to reshape the damping path, the strategy can adaptively adjust the damping according to the fault severity. This control strategy significantly enhances the synchronization stability of grid-following converters: it suppresses oscillations and achieves fault ride-through during transient instability, while limiting the divergence of the power angle during static instability to buy time for fault clearing. Finally, hardware-in-the-loop experiments validate the effectiveness of the proposed strategy.