Modeling and simulation play a vital role in the design and testing of modular multilevel converter (MMC) high voltage direct current (HVDC) systems. Detailed equivalent model (DEM) and switching-function-based average value model (SFB-AVM) are two major types of accurate and efficient models to represent the dynamic response of the MMCs. However, the DEM and the SFB-AVM possess unique benefits depending on the purpose of the simulation studies. The DEM provides a detailed representation of submodule (SM) switching events and individual capacitor ripples. The SFB-AVM provides faster simulation speed by using arm equivalent capacitance. Combining both models in a universal arm equivalent circuit gives the users the choice of selecting the most appropriate modeling method during dynamic simulation. This paper proposes a universal modeling framework combining the DEM with the SFB-AVM which allows the DEM and the SFB-AVM smoothly switch from one to the other during dynamic simulation. The proposed SFB-AVM can accurately represent the MMCs with different SM types. The proposed models are validated in offline and real-time simulation studies which demonstrate the improved simulation speeds of the proposed SFB-AVM over the DEM especially for large numbers of SMs.

中文翻译：

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将详细等效模型与基于开关函数的平均值模型相结合，实现 MMC 的快速准确仿真

建模和仿真在模块化多电平转换器 (MMC) 高压直流 (HVDC) 系统的设计和测试中起着至关重要的作用。详细等效模型 (DEM) 和基于开关函数的平均值模型 (SFB-AVM) 是表示 MMC 动态响应的两种主要类型的准确有效模型。然而，根据模拟研究的目的，DEM 和 SFB-AVM 具有独特的优势。DEM 提供了子模块 (SM) 开关事件和单个电容器纹波的详细表示。SFB-AVM 通过使用臂等效电容提供更快的仿真速度。在通用臂等效电路中结合这两种模型使用户可以在动态仿真期间选择最合适的建模方法。本文提出了一种将 DEM 与 SFB-AVM 相结合的通用建模框架，该框架允许 DEM 和 SFB-AVM 在动态仿真过程中从一个平滑切换到另一个。所提出的 SFB-AVM 可以准确地表示具有不同 SM 类型的 MMC。所提出的模型在离线和实时仿真研究中得到验证，这证明了所提出的 SFB-AVM 比 DEM 的仿真速度有所提高，尤其是对于大量 SM。