For the virtual synchronous generator (VSG) connected to the distorted grid, it is difficult to address the distorted grid current issue by the conventional harmonic suppression methods. To address this issue, in this article, we propose an impedance-based harmonic current distortion suppression method without closed-loop control to improve the adaptability of VSG connected to the distorted grid, mainly consisting of the passive and active approaches. The passive branch separated from the decentralized filter inductor is installed between the point of comment connection (PCC) and grid to introduce an additional voltage variable, which will not add the system power consumption and cost. Meanwhile, through the proper feed-forward of the PCC voltage and the additional voltage variable, the active branch can increase the harmonic impedance viewed from the grid side to the VSG, and also reduce the output impedance viewed from the PCC to the VSG, which effectively solves the grid current distortion. Moreover, with a proper parameters design, the proposed method can adapt to a wide range of grid impedance variation. Finally, experiment results validate the proposed control method.

中文翻译：

---

基于阻抗的VSG并网谐波电流抑制方法

对于连接到畸变电网的虚拟同步发电机（VSG），传统的谐波抑制方法难以解决畸变电网电流问题。针对这一问题，本文提出了一种基于阻抗的无闭环控制谐波电流畸变抑制方法，以提高VSG接入畸变电网的适应性，主要包括无源和有源两种方法。与分散滤波电感分离的无源支路安装在连接点（PCC）和电网之间，以引入额外的电压变量，不会增加系统功耗和成本。同时，通过PCC电压和附加电压变量的适当前馈，有源支路可以增加电网侧到VSG的谐波阻抗，也可以降低PCC到VSG的输出阻抗，有效解决电网电流畸变。此外，通过适当的参数设计，所提出的方法可以适应广泛的电网阻抗变化。最后，实验结果验证了所提出的控制方法。