Small-Signal Modeling and Stability Prediction of Parallel Droop-Controlled Inverters Based on Terminal Characteristics of Individual Inverters
Small-Signal Modeling and Stability Prediction of Parallel Droop-Controlled Inverters Based on Terminal Characteristics of Individual Inverters
复制标题
DOI：
10.1109/tpel.2019.2914176
复制
发表时间：
2020
影响因子：
6.7
通讯作者：
Shike Wang;Zeng Liu;Jinjun Liu;D. Boroyevich;R. Burgos
中科院分区：
文献类型：
--
作者：
Shike Wang;Zeng Liu;Jinjun Liu;D. Boroyevich;R. Burgos
并联下垂控制逆变器与可再生能源广泛应用于孤岛式交流微电网，其中它们之间的动态相互作用可能会导致小信号稳定性问题。由于采用了有功功率频率下垂方案，逆变器之间的动态相互作用不仅存在于母线电压和传输电流，而且还存在于可变的系统基频。提出了一种新的下垂控制逆变器小信号终端特性模型。除了传统的阻抗和导纳，一组新的终端特性被提出来表征基频的动态。此外，小信号模型的并联逆变器的基础上，单个逆变器的终端特性。针对下垂控制逆变器并联系统，提出了一种基于广义奈奎斯特判据的稳定性预测方法。除了阻抗和导纳的乘积之外，在系统返回比中添加了一个附加项，该附加项由与基频相关联的拟议终端特性组成。最后，实验结果验证了该方法的有效性。
Parallel droop-controlled inverters with renewable energy sources are widely employed in islanded ac microgrids, where dynamic interactions among them may cause small-signal stability issues. Since the active power-frequency droop scheme is applied, the dynamic interactions among inverters exist not only in bus voltage and transmitted current, but also in variable system fundamental frequency. This paper introduces a novel small-signal terminal characteristic model for droop-controlled inverter. Besides conventional impedance and admittance, a new set of terminal characteristics is proposed to characterize the dynamics of fundamental frequency. Furthermore, the small-signal model of parallel inverters is constructed based on the terminal characteristics of individual inverters. Covering the fundamental frequency interactions, a stability prediction approach based on generalized Nyquist criterion is proposed for parallel droop-controlled inverters. Besides the product of impedance and admittance, an additional term is added in the system return ratio, which consists of the proposed terminal characteristics associated with the fundamental frequency. Finally, experimental results validate the effectiveness of this proposed stability prediction approach.