The half-bridge (HB) submodule (SM) based MMC requires a large number of sensors to measure capacitor voltages. In this letter, a double half-bridge (DHB) SM-based MMC is proposed, where each SM consists of two HBs. But only one voltage sensor is equipped in each DHB-SM for the capacitor voltage estimation, which is connected between the positive poles of two capacitors in the DHB-SM. A capacitor voltage estimation method is also proposed, which can estimate capacitor voltages in the proposed MMC with only a half number of voltage sensors in comparison with HB-SM-based MMCs. A DHB-SM-based three-phase MMC is simulated with power systems computer aided design/electromagnetic transients including DC (PSCAD/EMTDC) and a DHB-SM-based single-phase MMC prototype is built in the laboratory. Both the simulation and experimental results confirm the effectiveness of the proposed method.

中文翻译：

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基于双半桥子模块的带降压传感器的模块化多电平转换器

基于半桥 (HB) 子模块 (SM) 的 MMC 需要大量传感器来测量电容器电压。在这封信中，提出了一种基于双半桥 (DHB) SM 的 MMC，其中每个 SM 由两个 HB 组成。但是每个DHB-SM中只配备了一个电压传感器用于电容电压的估计，它连接在DHB-SM中两个电容的正极之间。还提出了一种电容器电压估计方法，与基于 HB-SM 的 MMC 相比，该方法只需一半的电压传感器即可估计所提出的 MMC 中的电容器电压。基于 DHB-SM 的三相 MMC 使用电力系统计算机辅助设计/电磁瞬变（包括 DC (PSCAD/EMTDC)）进行仿真，并在实验室中构建了基于 DHB-SM 的单相 MMC 原型。