The virtual synchronous generator (VSG) was proposed to emulate a synchronous machine's dynamics when integrating power electronic converter-based distributed energy resources to the power grid. However, the VSG's synchronization stability during grid faults is not fully explored. The underlying mechanism of loss of synchronization still needs to be further revealed due to VSG's nonlinear characteristics. In this article, a step-by-step analytical method based on combining the linear and nonlinear models is proposed to analyze VSG's dynamic behaviors during a large disturbance. The relationship between the linear and nonlinear models is first brought to light, showing that the linear model is suitable for qualitative analysis to give an intuitive physical insight. Simultaneously, the latter is adopted for quantitative analysis to assess stability after a grid fault. Moreover, to avoid the conflict of the synchronization stability and the inertia response, a transient damping method is added in the active power control loop, which can simultaneously improve the synchronization stability and frequency stability. Design guidelines are also proposed to identify the parameter of the transient damping with different inertia requirements. Finally, the experimental results verify the analytical method and the theoretical analysis.

中文翻译：

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提高虚拟同步发电机同步稳定性的瞬态阻尼方法


虚拟同步发电机（VSG）的提出是为了在将基于电力电子转换器的分布式能源集成到电网时模拟同步机的动态。然而，VSG 在电网故障期间的同步稳定性尚未得到充分研究。由于VSG的非线性特性，失同步的根本机制仍需要进一步揭示。本文提出了一种基于线性和非线性模型相结合的逐步分析方法来分析 VSG 在大扰动期间的动态行为。首先揭示了线性模型和非线性模型之间的关系，表明线性模型适合进行定性分析，以提供直观的物理洞察。同时，采用后者进行定量分析，评估电网故障后的稳定性。此外，为了避免同步稳定性和惯性响应的冲突，在有功功率控制环中加入暂态阻尼方法，可以同时提高同步稳定性和频率稳定性。还提出了设计指南，以确定具有不同惯性要求的瞬态阻尼参数。最后，实验结果验证了分析方法和理论分析。