Novel P-Hausdorff distance-based fault diagnosis scheme for submodules in hybrid MMCs

In the operational context of the hybrid modular multilevel converters (MMC), the submodule stands out as a pivotal and vulnerable element, susceptible to various faults (Zheng et al. in IEEE Access 7:34946–34953, 2019; Xue et al. in IEEE Trans Power Deliv 33:1448–1458, 2017; Lee et al. Reactive power control operation scheme of LCC-HVDC for maximizing shunt capacitor size in AC systems. IEEE PES Asia-Pacific Power and Energy Engineering Conference (APPEEC). pp 1–5, 2015; Lin et al. in IEEE Trans Power Deliv 31:1342–1350, 2015; Debnath et al. in IEEE Trans Power Electron 30:37–53, 2014), including insulated gate bipolar transistors (IGBT) open-circuit, short-circuit, capacitor faults, etc. Therefore, accurate and rapid diagnosis of submodule faults is crucial to maintaining the reliability of both the hybrid MMC and its associated DC system (Xu et al. in IEEE Trans Power Electron 31:2720–2729, 2015; Wang et al. in IEEE Trans Power Deliv 32:1535–1544, 2016; Guo et al. in IEEE Trans Power Deliv 32:666–677, 2016; Zeng et al. in IEEE Trans Power Deliv 30:1298–1306, 2014). To enhance the reliability of the hybrid MMC, a comprehensive study on fault analysis and a diagnosis scheme based on waveform similarity for the submodules in hybrid the MMC are proposed. The devised scheme leverages a sliding window approach to capture essential feature data and employs partial Hausdorff (P-Hausdorff) distance for the diagnosis of open-circuit faults within the submodules. Finally, the proposed diagnosis scheme is implemented in MATLAB and the effectiveness and validity of the scheme are verified.