Motivated by the emergence of power systems that consist of HVAC and HVDC subgrids this work focuses on grid-forming (GFM) control of Interconnecting Power Converters (IPCs) that are the key elements for connecting HVAC and HVDC systems. We introduce the concept of dual-port GFM control that leverages the ability of Modular Multilevel Converters (MMCs) to simultaneously form its AC and DC terminal voltage and present two dual-port GFM MMC controls. We provide analytical results and high-fidelity simulations that demonstrate that (i) dual-port GFM control is more resilient to contingencies (i.e., line and generator outages) than state-of-the-art single-port GFM control, and (ii) unlike single-port GFM control, dual-port GFM control does not require assigning grid-forming and grid-following (GFL) roles to the IPC terminals in grids of grids. Finally, we provide an in-depth discussion and comparison of single-port GFM control and the proposed dual-port GFM controls.

中文翻译：

---

MMCs的双端口并网控制及其在网格中的应用

受由 HVAC 和 HVDC 子电网组成的电力系统出现的推动，这项工作的重点是互连电力转换器 (IPC) 的电网形成 (GFM) 控制，IPC 是连接 HVAC 和 HVDC 系统的关键要素。我们介绍了双端口 GFM 控制的概念，它利用模块化多电平转换器 (MMC) 的能力同时形成其 AC 和 DC 端电压，并提供两个双端口 GFM MMC 控制。我们提供了分析结果和高保真模拟，证明 (i) 双端口 GFM 控制比最先进的单端口 GFM 控制更能应对突发事件（即线路和发电机停电），以及 (ii) ) 与单端口 GFM 控制不同，双端口 GFM 控制不需要为网格网格中的 IPC 终端分配网格形成和网格跟随 (GFL) 角色。最后，