Power coupling modeling and analysis method of VSG control-based system for quantifying dynamic interaction

In multi-VSG system, there are coupling between the power control loops and among the multiple VSGs, which may deteriorate the control performance and even pose risks to the system stable operation. However, there have been few studies on quantitative index and analysis of power coupling and the dynamic coupling among multiple VSGs. Thus, this paper proposes power coupling modeling and analysis method of VSG control-based system for quantifying dynamic coupling. The established [P Q]-[ω V] model, taking power, frequency and voltage amplitude as variables, is more convenient to characterize power coupling feature. Besides, a quantitative analysis based on relative gain matrix theory is presented to quantify the degree of power coupling and the coupling among multiple VSGs. Further, a modified decentralized damping control method is proposed to help power decoupling and suppress oscillation, which provide more control degree of freedom. Finally, the correctness of the proposed modeling and quantitative analysis method is validated by the control-hardware-in-loop experiment results.