Abstract The transient stability of power-electronic dominated systems such as wind farms and photo-voltaic power plants depends on the control settings of the involved converters, the grid resonances and the system’s operating conditions. This paper focuses on investigating the impact of converter control algorithms on possible interactions that could endanger the overall stability of these kinds of systems. Mainly, two control approaches namely the conventional cascaded control structure, consisting of an inner current-control loop and various outer-loop controls, and the immediate voltage control structure which generates the converter voltage directly from the power and voltage controllers without necessarily including a current-control loop, are compared. The latter control structure falls in the class of grid-forming control strategies and the impact of different variants of this control structure will also be investigated. For this purpose, the ac-side input admittance of a grid-connected converter is derived for the two approaches and passivity-based frequency-domain stability analysis is used to assess their impact on system stability. Finally, the analytical findings are verified through time-domain simulations and recommendations to increase system stability are given accordingly.

中文翻译：

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变流器控制策略对电力电子主导系统中低频和高频谐振相互作用的影响

摘要 风电场、光伏电站等电力电子主导系统的暂态稳定性取决于相关变流器的控制设置、电网谐振和系统的运行条件。本文重点研究转换器控制算法对可能危及此类系统整体稳定性的可能交互的影响。主要有两种控制方法，即传统的级联控制结构，由内部电流控制环和各种外环控制组成，以及直接从功率和电压控制器产生转换器电压而不必包括电流的即时电压控制结构。 -控制循环，进行比较。后一种控制结构属于网格形成控制策略，还将研究这种控制结构的不同变体的影响。为此，推导出两种方法的并网转换器的交流侧输入导纳，并使用基于无源性的频域稳定性分析来评估它们对系统稳定性的影响。最后，通过时域模拟验证了分析结果，并相应地给出了提高系统稳定性的建议。