The unique advantages of modular multilevel converters (MMCs) have led to wide adoption of the converter topology in high voltage dc (HVDC) transmission systems, with great potential for use in medium voltage motor drive and dc grid applications. Inspired by the structure of the MMC, many extended converter topologies have been developed in the literature. These include, in addition to conventional parallel multiphase connection, a variety of series-connected topologies. Extended MMCs integrate the modular nature of cascaded SMs of the MMC but with different topology structure leading to substantially different operating principles. Given the growing number of such topologies, this paper provides a critical review of MMC derived topologies and summarizes individual advantages and disadvantages. The control schemes and application fields of these different topologies are analysed. This review facilitates the classification and understanding of extended MMCs and provides the necessary scaffold for the development of a general framework for new topologies and applications based on the MMC.

中文翻译：

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超越 MMC：扩展模块化多电平转换器拓扑和应用


模块化多电平转换器 (MMC) 的独特优势导致该转换器拓扑在高压直流 (HVDC) 输电系统中得到广泛采用，在中压电机驱动和直流电网应用中具有巨大的应用潜力。受 MMC 结构的启发，文献中开发了许多扩展转换器拓扑。除了传统的并联多相连接之外，这些还包括各种串联拓扑。扩展MMC集成了MMC的级联SM的模块化特性，但具有不同的拓扑结构，导致显着不同的操作原理。鉴于此类拓扑的数量不断增加，本文对 MMC 派生拓扑进行了严格审查，并总结了各个拓扑的优点和缺点。分析了这些不同拓扑的控制方案和应用领域。本综述有助于对扩展 MMC 进行分类和理解，并为基于 MMC 的新拓扑和应用开发通用框架提供必要的框架。