Nowadays, emerging microgrids have been forming fully integrated power and energy systems using multi-infeed ac/dc (MIACDC) power architectures. An MIACDC power architecture easily integrates renewables, battery energy storage systems, fossil-fuel-based generating units, and various types of loads into one coherent microgrid. Therefore, in modernized microgrids (MMGs), time constants (or equivalently bandwidths) of system dynamics are broad; indeed, multiple controls in different parts of grid-connected voltage-sourced converters (GC-VSCs) create them. For the first time, this article takes into account the detailed dynamics of every GC-VSC’s part. It also effectively incorporates their controls to propose “detailed” dynamic dc (DDDC) models for dc-fault simulations. The suggested models are able to simulate dc-fault currents in MMGs’ MIACDC power systems more accurately. This research bridges the gap between VSCs’ controls and their dynamic dc models, which can be used in dc-fault simulation studies associated with MMG protection. It derives DDDC models of GC-VSCs for two fundamental modes of operation, i.e., $P/Q$ -controlled and $V_{\text {DC}}/Q$ -controlled modes. To this end, detailed dynamics of VSCs considering those of ac- and dc-side filters are thoroughly employed using VSCs’ space-phasor representation. After linearization, for creating the models mentioned above, relevant GC-VSCs’ controls are considered. In order to show the validity of the detailed GC-VSC’s dynamic dc models, experimental results are provided. Besides, for studying the models’ response to dc faults, adequate comparisons of time-domain simulations of the proposed models and those of the accurate switching models are made. In this regard, an MMG with an MIACDC structure is simulated in PSCAD/EMTDC software; the MMG is implemented first by the proposed VSC’s DDDC models and second by the switching ones to generate the simulation results with which one can compare. Moreover, in order to reveal the effectiveness of the DDDC models, comparative outputs are produced by simulating conventional models that do not consider dynamics induced by the controllers. Last but not least, comparison outcomes of the DDDC models and those of conventionally adopted models show that this research is able to fill in gaps in the needed models.

中文翻译：

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考虑到现代化微电网保护中直流故障仿真控制的 VSC 详细动态直流模型

如今，新兴的微电网已经使用多馈电交流/直流 (MIACDC) 电源架构形成完全集成的电力和能源系统。MIACDC 电力架构可轻松将可再生能源、电池储能系统、基于化石燃料的发电机组和各种类型的负载集成到一个连贯的微电网中。因此，在现代化微电网 (MMG) 中，系统动力学的时间常数（或等效带宽）很宽；实际上，并网电压源换流器 (GC-VSC) 不同部分的多个控制创建了它们。本文首次考虑了 GC-VSC 各个部分的详细动态。它还有效地结合了他们的控制，为直流故障模拟提出了“详细的”动态直流 (DDDC) 模型。建议的模型能够更准确地模拟 MMG 的 MIACDC 电力系统中的直流故障电流。这项研究弥合了 VSC 的控制与其动态直流模型之间的差距，可用于与 MMG 保护相关的直流故障模拟研究。它为两种基本操作模式推导出 GC-VSC 的 DDDC 模型，即， $P/Q$ - 控制和 $V_{\text {DC}}/Q$ - 控制模式。为此，考虑到交流和直流侧滤波器的 VSC 的详细动态，使用 VSC 的空间相量表示被彻底采用。线性化后，为了创建上述模型，需要考虑相关 GC-VSC 的控制。为了显示详细的 GC-VSC 动态直流模型的有效性，提供了实验结果。此外，为了研究模型对直流故障的响应，对所提出模型的时域仿真和精确开关模型的时域仿真进行了充分的比较。对此，在PSCAD/EMTDC软件中模拟了一个具有MIACDC结构的MMG；MMG 首先由建议的 VSC 的 DDDC 模型实现，其次由切换模型实现，以生成可以与之比较的仿真结果。而且，为了揭示 DDDC 模型的有效性，通过模拟不考虑控制器引起的动力学的传统模型来产生比较输出。最后但并非最不重要的一点是，DDDC 模型与传统采用的模型的比较结果表明，这项研究能够填补所需模型中的空白。