Strategies for Power-frequency Fluctuation Suppression of Multiple Virtual Synchronous Generators Under Different Operating Conditions

Introduction: When multiple Virtual Synchronous Generators (VSG) operate in parallel in a grid-connected control system, the system tends to experience power-frequency fluctuation due to low inherent disturbance rejection and the interaction of multiple parameters, which affects the stability of the power system. To address this issue, this paper proposes a method based on Center Of Inertia (COI) parameters and high-pass filter feedback. The proposed method aims to enhance the dynamic response speed of the multi-VSG parallel system and suppress overshoot. Methods: First, a mathematical model of the multi-VSG parallel control system is established, considering the influence mechanism of different parameters of multi-VSG. Next, the inertia center model is introduced to calculate the inertia center values of each VSG parameter and control the error with the original values, dynamically adjusting the parameters to ensure consistency and minimize the impact of parameter differences. Then, high-pass filter feedback is introduced to optimize the parameters in the low-frequency band, improving the response capability and reducing communication delay. This approach can effectively reduce the interaction between parameters, thereby improving disturbance rejection and dynamic response capabilities. Results: Simulation experiments under various operating conditions demonstrate that the proposed method can enhance the dynamic response speed of the system';s power, frequency, and voltage, suppress overshoot, and make the parameters more consistent, thereby reducing their mutual influence and outperforming traditional methods. Discussion: Through comparisons under different operating conditions, it is evident that the proposed control strategy can be effectively applied to various scenarios and solve the power-frequency fluctuation problems in the system under multi-VSG parallel control. Conclusion: Compared with traditional VSG control, the proposed method demonstrates higher dynamic response capability and improves the disturbance rejection ability of the multi-VSG parallel system, providing theoretical and simulation basis for practical engineering applications.