Sequence Impedance Modeling and Stability Assessment for Load Converters in Weak Grids
Sequence Impedance Modeling and Stability Assessment for Load Converters in Weak Grids
复制标题
弱电网中负载转换器的序列阻抗建模和稳定性评估
DOI：
10.1109/tie.2020.2987257
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发表时间：
2021-05
影响因子：
7.7
通讯作者：
Wenhua Wu
中科院分区：
文献类型：
--
作者：
Yifeng Liu;Xiaoping Zhou;Haoqi Yu;Lerong Hong;Haitao Xia;Hanhang Yin;Y;ong Chen;Leming Zhou;Wenhua Wu
负载变换器在弱电网中运行时，由于阻抗的相互作用，可能会产生谐波振荡问题。在本文中，考虑直流母线电压动态和频率耦合效应，精确的顺序阻抗模型推导出传统的负载转换器（TLC）和负载虚拟同步机（LVSM）。在此基础上，分析比较了它们的序阻抗特性。分析表明，在中低频段，低压同步电动机的正序阻抗一般为感性，这与电网阻抗特性基本一致。相反，TLC的正序阻抗是负阻容性的（即，相位角在-180° ~-90°之间），其幅频曲线易与电网阻抗幅频曲线相交，在弱电网中易引起谐波振荡。在此基础上，基于所建立的模型和Nyquist稳定判据，分析了电网阻抗和负载功率对TLC和LVSM稳定性的影响，结果表明，在弱电网条件下，LVSM的稳定性优于TLC。最后通过实验验证了理论分析的正确性。
Load converter operating in the weak grid potentially suffers harmonic oscillation problems due to the impedance interaction. In this article, considering dc-link voltage dynamics and frequency-coupling effects, the precise sequence impedance models are derived for the traditional load converter (TLC) and the load virtual synchronous machine (LVSM). Based on the derived models, their sequence impedance characteristics are analyzed and compared. The analysis shows that the positive-sequence impedance of the LVSM is generally inductive in the middle- and low-frequency bands, which is basically consistent with the grid impedance characteristics. In contrast, the positive-sequence impedance of the TLC is negative-resistive-capacitive (i.e., phase angle is between -180° and -90°) in the middle- and low-frequency bands and its amplitude-frequency curve is easy to intersect with the amplitude-frequency curve of the grid impedance, which may lead to harmonic oscillation in the weak grid. Furthermore, based on the derived model and Nyquist stability criterion, the effects of the grid impedance and load power on the stability are analyzed for TLC and LVSM, which indicates that the LVSM has better stability in the weak grid than the TLC. Finally, the experimental results validate the correctness of the theoretical analyses.
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影响因子：
6.7
作者：
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通讯作者：
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影响因子：
6.7
作者：
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影响因子：
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作者：
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影响因子：
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作者：
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通讯作者：
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DOI：
10.1109/pesgm.2017.8274585
发表时间：
2017-07
期刊：
2017 IEEE Power & Energy Society General Meeting
影响因子：
--
作者：
Raouia Aouini;B. Marinescu;Khadija Ben Kilani;M. Elleuch
通讯作者：
Raouia Aouini;B. Marinescu;Khadija Ben Kilani;M. Elleuch