Open-Circuit Fault Detection and Location in Modular Multilevel Converters Based on Principal Component Analysis

Modular multilevel converters (MMCs) are subject to various faults due to their complex structure and the large number of switches, which can cause malfunctions and severe damages to the load or grid. In this paper, a 10-level three-phase modular multilevel converter is investigated under permanent, transient, single, and multiple submodule open-circuit fault scenarios. The principal component analysis (PCA) is used to detect the fault and determine the failed switch(s) according to the capacitor voltages as the input variables. Fault detection and location procedures are performed based on the statistical analysis and contribution criterion, respectively. Simulation results in MATLAB environment confirm the accuracy and effectiveness of the proposed method. A comparative study is presented between the proposed method and other strategies presented in the literature.