A Critical Aspect of Dynamic Stability in Autonomous Microgrids: Interaction of Droop Controllers Through the Power Network
A Critical Aspect of Dynamic Stability in Autonomous Microgrids: Interaction of Droop Controllers Through the Power Network
复制标题
自主微电网动态稳定性的一个关键方面：下垂控制器通过电力网络的交互
DOI：
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发表时间：
2022
影响因子：
12.3
通讯作者：
A. Savkin
中科院分区：
文献类型：
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作者：
Mohsen Eskandari;A. Savkin
在这篇文章中，下垂控制器通过电力网络（IDCPN）的相互作用是影响自主网络化微电网（ANMG）的动态稳定性的主导因素，并开发了新的模型来支持IDCPN。该模型被开发来分析三个部分对IDCPN的影响：1）电力网络阻抗的X/R比; 2）包括低通滤波器的下垂控制器;以及3）并网电压源逆变器（VSI）的阻抗特性。低频振荡（LFO），激发IDCPN，识别和量化建模的第一和第二部分。阐明了低X/R比对放大LFO的关键影响。然后，包括虚拟电感回路（VIL）的网格形成VSI的输出阻抗的开发和严格观察，揭示了低效的性能。结果表明，VIL通过提供足够的阻尼来抑制LFO，而不是通过有效地提高VSI输出阻抗的X/R来提高动态性能。然而，这在电流限制中是有问题的，由于VSI的电容-电容阻抗特性，电流限制使ANMG处于不稳定风险。关于我们oldsymbol{H}}_infty }$鲁棒控制器代替VIL抑制LFO和稳定ANMG。数值/仿真结果证明了模型的准确性。
It is explored in this article that the interaction of droop controllers through the power network (IDCPN) is the dominant factor affecting the dynamic stability of an autonomous networked microgrid (ANMG) and new models are developed to support the IDCPN. The models are developed to analyze the impacts of three parts on the IDCPN: 1) the X/R ratio of the power network impedance; 2) the droop controllers including low-pass filters, and 3) the impedance characteristics of the grid-forming voltage source inverters (VSIs). The low-frequency oscillations (LFO), excited by IDCPN, is identified and quantified by modeling the first and second parts. The critical impact of the low X/R ratio on amplifying the LFO is clarified. Then, the output impedance of the grid-forming VSI, including the virtual inductance loop (VIL), is developed and rigorously observed that reveals inefficient performance. It is shown that the VIL improves dynamic performance by providing sufficient damping to suppress LFOs and not by effectively boosting the X/R of the VSI output impedance. This, however, is problematic in the current limiting that puts the ANMG at instability risk because of the resistive–capacitive impedance characteristics of the VSIs. A ${{oldsymbol{H}}_infty }$ robust controller is proposed to replace VIL for suppressing LFO and stabilizing ANMG. Numerical/simulation results are provided to prove the accuracy of the models.