A Comparative Study of Two Widely Used Grid-Forming Droop Controls on Microgrid Small-Signal Stability
A Comparative Study of Two Widely Used Grid-Forming Droop Controls on Microgrid Small-Signal Stability
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两种广泛使用的成网下垂控制对微电网小信号稳定性的比较研究
DOI：
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发表时间：
2020
影响因子：
5.5
通讯作者：
Soumya Kundu
中科院分区：
文献类型：
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作者：
W. Du;Zhe Chen;K. Schneider;R. Lasseter;Sai Pushpak Nandanoori;F. Tuffner;Soumya Kundu
历史上，两个类似的网格形成下垂控制被广泛报道的文献-单回路和多回路下垂控制。虽然非常相似，但作者发现，在微电网中，每种控制方法的动态性能和稳定特性是非常不同的。与单回路下垂控制相比，多回路下垂控制在某些情况下更容易出现阻尼小、失稳等问题。这篇文章提供了一个新的见解不同的动态响应的两个基本控制。它指出，这两个类似的控制调整逆变器内不同位置的角频率和电压幅值，导致不同的耦合电抗，不同的影响微电网的动态响应和稳定性。单环下垂控制的使用导致较大的耦合电抗，这有助于改善动态响应和稳定性。通过全阶小信号分析、离线电磁暂态仿真和实时半实物仿真实验验证了这一新的见解。结果表明，微电网有一个更大的小信号稳定边界时，使用单环下垂控制，这种差异随着逆变器的内部滤波电感值的增加而增加。
Historically, two similar grid-forming droop controls are widely reported in literature—the single-loop and multi-loop droop controls. Although being very similar, the authors find that the dynamic performance and stability characteristics of each control method are very different in a microgrid. Compared with the single-loop droop control, the multi-loop droop control is prone to be less damped and loses stability more easily under some circumstances. This article provides a novel insight into the different dynamic responses of the two basic controls. It points out that the two similar controls adjust the angular frequency and voltage magnitude at different locations within the inverter, resulting in different coupling reactances that impact the dynamic response and stability of microgrids differently. The use of the single-loop droop control results in a larger coupling reactance, which helps improve the dynamic response and stability. This novel insight is verified through full-order small-signal analysis, offline electromagnetic transient simulation, and real-time hardware-in-the-loop simulation experiments. The results show that the microgrid has a larger small-signal stability boundary when using single-loop droop control, and this difference increases as the value of an inverter’s inner filter inductance increases.