The granular multilevel converter (GMC) is a multilevel converter built by hybridizing a conventional two-level converter with an asymmetrical cascaded H-bridge converter. Addition of each additional H-bridge submodule doubles the number of the GMC output voltage steps. Thus, with a small number of power electronic switches and associated gate drive signals and circuits, a GMC can offer a high-quality ac voltage to meet the stringent requirements of high-performance drives and grid-tied converters in low and medium voltages. This paper proposes: 1) a generalized switching strategy to control the output voltage as well as capacitor voltages of H-bridge submodules for a GMC with an arbitrary number of submodules $n$ (this proposed strategy is scalable, which allows for easy modification of the voltage rating or the number of the voltage steps of the GMC) and 2) a systematic analysis for optimal sizing of the submodule capacitors to minimize the required total energy of the installed capacitors. Simulation and experimental case studies evaluate the performance of the proposed switching and capacitor sizing algorithms.

中文翻译：

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一种用于粒度多电平转换器的通用开关策略和电容器选型算法

颗粒多电平转换器 (GMC) 是通过将传统的两电平转换器与非对称级联 H 桥转换器混合而构建的多电平转换器。添加每个额外的 H 桥子模块会使 GMC 输出电压阶跃的数量增加一倍。因此，通过少量的电力电子开关和相关的栅极驱动信号和电路，GMC 可以提供高质量的交流电压，以满足高性能驱动器和中低压并网转换器的严格要求。本文提出：1) 一种通用开关策略，用于控制具有任意数量子模块 $n$ 的 GMC 的 H 桥子模块的输出电压和电容器电压（该建议的策略是可扩展的，这允许轻松修改 GMC 的额定电压或电压级数）和 2) 系统分析以优化子模块电容器的尺寸，以最大限度地减少安装电容器所需的总能量。仿真和实验案例研究评估了所提出的开关和电容器选型算法的性能。