An Adaptive Active Damper for Improving the Stability of Grid-Connected Inverters Under Weak Grid
An Adaptive Active Damper for Improving the Stability of Grid-Connected Inverters Under Weak Grid
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DOI：
10.1109/tpel.2018.2793242
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发表时间：
2018-01
影响因子：
6.7
通讯作者：
L. Jia;X. Ruan;Wenxin Zhao;Zhiheng Lin;Xuehua Wang
中科院分区：
文献类型：
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作者：
L. Jia;X. Ruan;Wenxin Zhao;Zhiheng Lin;Xuehua Wang
当并网逆变器连接到弱电网时，系统可能不稳定。一个主动阻尼器可以连接到公共耦合点（PCC），它模拟一个虚拟电阻来抑制谐振，从而稳定系统。本文提出了一种虚拟电阻自适应整定方法，该方法可以自动将虚拟电阻调整到临界值，以稳定系统，从而降低功率损耗。此外，主动阻尼器被设计成不响应由电网背景谐波引入的PCC电压中的主导低频谐波分量，从而可以进一步降低其功率损耗。为了使主动阻尼器在较宽的频率范围内更准确地模拟虚拟电阻，提出了一种谐波参考电流补偿方法。搭建了6 kW并网逆变器和1 kVA主动阻尼器的样机，并进行了试验，验证了所提出的主动阻尼器控制方案的有效性。
When a grid-connected inverter is connected to a weak grid, the system may be unstable. An active damper can be connected to the point of common coupling (PCC), which simulates a virtual resistor to dampen the resonance and thus stabilize the system. In this paper, an adaptive tuning method of the virtual resistor is proposed, which can automatically regulate the virtual resistor to the critical value to stabilize the system, and thus reduce the power loss. Furthermore, the active damper is designed not to respond to the dominant low-frequency harmonic components in the PCC voltage introduced by the grid background harmonics, so that its power loss can be further reduced. In order to make the active damper more accurately simulate the virtual resistor in a wide frequency range, a harmonic-current-reference compensation method is proposed. The prototypes of a 6-kW grid-connected inverter and a 1-kVA active damper are built and tested to verify the effectiveness of the proposed control scheme of the active damper.