变短路比下GFM与GFL逆变器混合系统的功率振荡分析及双互阻尼控制

Active power oscillation in the hybrid grid-connected system with grid-forming (GFM) and grid-following (GFL) inverters can threaten its safe operation. In this paper, considering the coupling between GFM and GFL inverters, the small signal model of the heterogeneous system is established. Based on the model, the influence mechanism of control parameters on the power oscillation under varying short-circuit ratio (SCR) is qualitatively and quantitatively revealed. In particular, the damping of the GFM inverter has a dominant effect compared with other parameters. Therefore, dual mutual damping control (DMDC), containing angular frequency and active power mutual damping, is integrated into the GFM inverter to enhance system damping. Its stability analysis and key parameters design are also presented. Finally, the experimental results validate the effectiveness of the DMDC, demonstrating a reduction in the interaction power oscillation amplitudes by 38.5% and 29.4% under strong and weak grid conditions, respectively.