This letter proposes a novel capacitor condition monitoring method for modular multilevel converters (MMCs) based on reference submodules (SMs). It significantly enhances the capacitor monitoring accuracy by making full use of the SM voltage sensor measurement range. Accuracy comparison between the existing method and the proposed method is conducted to quantify the improvement of accuracy. Moreover, its operation principle and practical implementation considerations are presented. Finally, a three-phase MMC platform is built to experimentally verify the effectiveness of the proposed method.

中文翻译：

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一种基于参考子模块的模块化多电平转换器电容器状态监测方法

这封信提出了一种基于参考子模块 (SM) 的模块化多电平转换器 (MMC) 的新型电容器状态监测方法。它充分利用了SM电压传感器的测量范围，显着提高了电容器监测精度。对现有方法和提出的方法进行精度比较，以量化精度的提高。此外，还介绍了其工作原理和实际实施注意事项。最后，搭建了一个三相MMC平台，通过实验验证了所提出方法的有效性。