In the maritime VSC-HVDC system supplying power to passive network on the island, the dc side of the system is prone to oscillation and even instability, which is resulted from the negative incremental input resistance characteristic of the inverter station. First, a virtual phase-lead impedance stability control strategy aiming at rectifier station is proposed. This control strategy can effectively mitigate the dc-side oscillation of the VSC-HVDC system without affecting the load performance of the inverter station. Then, the dc impedance model of the VSC-HVDC system is built, including the output impedance of the rectifier station, dc cable impedance, and the input impedance of the inverter station. In addition, the oscillation mechanism of the VSC-HVDC system is analyzed by impedance-based Nyquist stability criterion. The reason why rectifier station fails to mitigate the dc-side oscillation using traditional virtual resistance stability control is that the output impedance of the rectifier station exhibits negative damping characteristic outside the control bandwidth of voltage outer loop. For this issue, the proposed control strategy can correct the output impedance of the rectifier station to exhibit positive damping characteristic outside the control bandwidth of voltage outer loop, thus mitigating the dc-side oscillation of the VSC-HVDC system. Finally, simulation and experiment results validate the proposed control strategy and analysis.

中文翻译：

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海上VSC__VDC系统虚拟相位超前阻抗稳定控制策略


在向海岛无源网络供电的海上VSC-HVDC系统中，由于逆变站的负增量输入电阻特性导致系统直流侧容易出现振荡甚至不稳定。首先，提出了一种针对整流站的虚拟相位超前阻抗稳定控制策略。该控制策略能够有效缓解VSC-HVDC系统直流侧振荡，且不影响逆变站的负载性能。然后，建立了VSC-HVDC系统的直流阻抗模型，包括整流站的输出阻抗、直流电缆阻抗和逆变站的输入阻抗。此外，利用基于阻抗的奈奎斯特稳定性判据分析了VSC-HVDC系统的振荡机制。传统的虚拟电阻稳定控制整流站无法抑制直流侧振荡的原因是整流站的输出阻抗在电压外环控制带宽之外表现出负阻尼特性。针对这一问题，所提出的控制策略可以修正整流站的输出阻抗，使其在电压外环控制带宽之外表现出正阻尼特性，从而减轻VSC-HVDC系统的直流侧振荡。最后，仿真和实验结果验证了所提出的控制策略和分析。