This paper presents a new DC to AC Modular Multilevel Converter (MMC) topology. The proposed topology requires less number of arms than the traditional MMC to generate equal magnitude and excellent quality of output AC voltage. The positive arm of the proposed converter is having submodules similar to traditional MMC. In contrast, passive tuned LC filters are present in the place of the negative arms in the proposed MMC topology. This helps to generate an equal magnitude of output AC voltage as traditional MMC with half of the input DC bus voltage magnitude. Additionally, traditional MMC requires large number of submodules to generate many voltage levels and hence create small steps in the output voltage matching close to a sine wave. The passive tuned LC filters in the proposed circuit topology are designed to absorb the switching harmonics generated from the positive arms. This makes the output AC voltage very close to a pure sine wave, with highly reduced higher order switching harmonics. This paper explains the operational principle along with the pre-charging of the submodule capacitors at start-up of the new converter. Simulation and experimental studies confirm the operation of the new converter topology.

本文介绍了一种新的直流到交流模块化多电平转换器 (MMC) 拓扑。与传统 MMC 相比，所提出的拓扑结构需要更少的臂数来产生相同幅度和出色质量的输出交流电压。所提出的转换器的正臂具有类似于传统 MMC 的子模块。相比之下，无源调谐LC滤波器代替了所提出的 MMC 拓扑中的负臂。这有助于产生与传统 MMC 相同幅度的输出交流电压，输入直流总线电压幅度的一半。此外，传统的 MMC 需要大量子模块来生成许多电压电平，因此在输出电压匹配中产生接近正弦波的小步长。被动调谐LC所提出的电路拓扑中的滤波器旨在吸收正臂产生的开关谐波。这使得输出交流电压非常接近纯正弦波，高阶开关谐波大大降低。本文解释了工作原理以及在新转换器启动时对子模块电容器进行预充电。仿真和实验研究证实了新转换器拓扑的运行。