This paper proposes a hybrid adaptive strategy to control virtual inertia of virtual synchronous generators (VSGs). The proposed technique can provide low frequency oscillation (LFO) damping and simultaneously improve primary frequency control (PFC) performance metrics. To this end, a control variable is defined to control extremum values of the VSG inertia during PFC process. The control variable uses an estimation of the grid frequency gradient to identify the PFC process stages following a power deficit event. The extremum of the VSG inertia to provide LFO damping is governed based on the control variable. In particular, the minimum value of the VSG inertia is restricted to its base value during the frequency arresting process in order to moderate the frequency rate of change. In contrast, the maximum value of the VSG inertia is limited to its base value in frequency recovery period to achieve a faster frequency recovery. The efficiency of the suggested method is validated through a power system with VSG penetration level as 50% of the system generation rating. The achieved results verify the superiority of the proposed scheme in the PFC improving and the LFO damping in comparison to the conventional strategy. Moreover, the suggested approach can efficiently decrease the required size of the VSG energy storage by about 50%.

中文翻译：

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一种用于虚拟同步发电机的混合自适应虚拟惯性控制器

本文提出了一种混合自适应策略来控制虚拟同步发电机 (VSG) 的虚拟惯性。所提出的技术可以提供低频振荡 (LFO) 阻尼，同时提高主频率控制 (PFC) 性能指标。为此，定义了一个控制变量来控制 PFC 过程中 VSG 惯性的极值。控制变量使用电网频率梯度的估计来识别功率不足事件之后的 PFC 过程阶段。提供 LFO 阻尼的 VSG 惯性的极值取决于控制变量。特别是在频率停止过程中，VSG惯量的最小值被限制为其基值，以缓和频率变化率。相比之下，VSG 惯量的最大值在频率恢复期间被限制在其基值，以实现更快的频率恢复。建议方法的效率通过 VSG 渗透水平为系统发电额定值的 50% 的电力系统进行验证。与传统策略相比，所取得的结果验证了所提出的方案在 PFC 改进和 LFO 阻尼方面的优越性。此外，所建议的方法可以有效地将 VSG 储能所需的尺寸减少约 50%。与传统策略相比，所取得的结果验证了所提出的方案在 PFC 改进和 LFO 阻尼方面的优越性。此外，所建议的方法可以有效地将 VSG 储能所需的尺寸减少约 50%。与传统策略相比，所取得的结果验证了所提出的方案在 PFC 改进和 LFO 阻尼方面的优越性。此外，所建议的方法可以有效地将 VSG 储能所需的尺寸减少约 50%。