基于虚拟振荡器控制的变流器暂态稳定性提升策略OA

When the power grid experiences voltage sags due to large disturbances,converters controlled by virtual oscillators face dual risks of power angle instability and overcurrent,indicating insufficient fault ride-through capability.To address this issue,the transient characteristics of virtual oscillators are analyzed from three dimensions:the mechanism of power angle stability,the impact of voltage dynamics on power angle stability,and fault current dynamics.The necessary conditions for effective fault ride-through are also explored.Based on the above analysis,a transient power angle control scheme based on the synergetic control theory is proposed to enhance power angle stability.To tackle the overcurrent issue,a joint control architecture combining adaptive reference voltage and virtual impedance with decaying characteristics is designed to dynamically optimize the current response.Furthermore,a transient integrated control architecture is proposed,enabling efficient coordination between the solutions to these two issues through their control loops.This allows the converter to rapidly stabilize the power angle during transients while simultaneously limiting the transient current within safe thresholds.Simulation analysis and hardware-in-the-loop experimental results demonstrate that the proposed strategy enhances the converter fault ride-through capability,providing an effective technical solution for enhancing the operation stability of the power grid.