The grid-forming and grid-following controls are adopted in three-phase voltage source converters according to different grid conditions. However, the basic operation principle of the two kinds of control is different and will lead to the instability of the grid-connected system through various paths. In this article, the energy function model of the grid-forming and grid-following controlled converters are established and compared in detail. The influence of system parameters is studied, and the large-signal stability boundaries are derived through a general method. Moreover, compared to the grid-forming controlled converter, the grid-following converter will lose stability by exhibiting a varying damping coefficient transient. The equivalent damping coefficient can be used as a criterion of whether the grid-forming/following control is suitable for the weak/strong grid condition. The simulation and experiment results show the difference of the transient process and validate the control criterion for different grid strength under large-signal disturbance.

中文翻译：

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电压源换流器中电网形成和电网跟随控制的大信号稳定性：比较研究

根据不同的电网条件，在三相电压源转换器中采用了电网形成和电网跟随控制。但是，这两种控制的基本操作原理是不同的，并且将导致并网系统通过各种路径不稳定。在本文中，建立并详细比较了网格形成和网格跟随受控变换器的能量函数模型。研究了系统参数的影响，并通过通用方法推导了大信号稳定边界。此外，与形成网格的受控变换器相比，跟随网格的变换器将通过表现出变化的阻尼系数瞬变而失去稳定性。等效阻尼系数可以用作判断网格形成/跟随控制是否适合于弱/强网格条件的标准。仿真和实验结果表明了瞬态过程的差异，并验证了大信号扰动下不同电网强度的控制准则。