Symmetry-analysis-based diagnosis method with correlation coefficients for open-circuit fault in inverter

A current-based, real-time and fast symmetry-analysis-based diagnosis method with a correlation coefficient for an open-circuit fault in a voltage-source inverter is proposed. The proposed method includes three steps: data reconstruction, features extraction, fault detection and isolation. To achieve fair robustness, real-time and fast performance, sliding windows with length of a period current samples are designed for data reconstruction. Correlation coefficients of each of the two phase currents are designed to describe the symmetry of the inverter both in a healthy and a faulty condition, and mean values of current samples during a period are used to accurately isolate the faulty switch or switches. The proposed method is current-based sharing the current sensors that are used for the current regulators, hence it is low-cost. The high effectiveness and merit of the proposed method are validated by experiments.