The inverter-interfaced distributed generation (IIDG) units are operated either in grid-forming or grid-feeding modes. To this end, the inner control loops are embedded into the inverters’ control system to achieve the control objectives. However, the dynamic performance of IIDG units are greatly affected by their control system and also by the grid's impedance characteristics. Optimal voltage regulator (OVR) previously has been proposed where the conventional inner loops have been replaced by the state feedback loop to compensate for the LC filter dynamics in order to achieve the desired dynamic performance. Utilizing the OVR, a universal model is proposed in this article which is useful for both grid-feeding and grid-forming modes. Each mode of operation is achieved through impedance shaping as a feedback gain adjustment. To this end, the optimal impedance shaping for the universal model is determined based on the desired dynamic performance, control objectives and grid's impedance characteristics. Eigenvalue-analysis and simulation results prove the effectiveness of the universal model in the grid-feeding and grid-forming modes, in unbalanced and harmonic conditions as well as being able to suppress circulating, transient and fault currents in autonomous networked MGs.

中文翻译：

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逆变器接口分布式发电机组的最佳稳压器第二部分：应用

逆变器接口的分布式发电（IIDG）单元以网格形成或网格馈送模式运行。为此，将内部控制回路嵌入到变频器的控制系统中以实现控制目标。但是，IIDG装置的动态性能受其控制系统以及电网阻抗特性的很大影响。先前已经提出了最佳电压调节器（OVR），其中传统的内部环路已由状态反馈环路代替，以补偿LC滤波器的动态特性，以实现所需的动态性能。利用OVR，本文提出了一个通用模型，该模型对于网格馈送和网格形成模式都非常有用。通过阻抗整形作为反馈增益调整，可以实现每种工作模式。为此，根据所需的动态性能，控制目标和电网的阻抗特性，确定通用模型的最佳阻抗整形。特征值分析和仿真结果证明了通用模型在电网馈送和电网形成模式下，在不平衡和谐波条件下的有效性，并且能够抑制自主网络MG中的循环，瞬态和故障电流。