Three-phase inverters open-circuit faults diagnosis using an enhanced variational mode decomposition, wavelet packet analysis, and scalar indicators

It is critical to accurately detect IGBT (Insulated Gate Bipolar Transistor) switch faults in order to ensure the reliability and robustness of three-phase inverters. In this work, a new approach for the enhancement of the IGBTs open-circuit faults of a three-phase diagnosis inverter is proposed. This approach is based on an Enhanced version of the Variational Mode Decomposition algorithm (EVMD) combined with wavelet packet analysis (WPA) and scalar indicators such as the average and variance value. Firstly, the three-phase current signals are denoised using an improved version of the denoising technique based on a WPA. Secondly, the denoised current signals are decomposed by EVMD algorithm into Band Limited Intrinsic Mode Functions (BLIMFs). Thirdly, BLIMFs that have the highest correlation coefficients with current signals are selected as useful modes. Fourthly, the variance of the BLIMFs that have the highest correlation coefficient among those selected is calculated in order to detect the faulty phase and, consequently, the faulty arm. Finally, the average of the BLIMF that has the lowest correlation coefficient among those selected for the faulty phase is calculated to localize the fault position in either the upper or the lower IGBTs of the faulty arm. The proposed approach is applied to experimental signals and the results obtained show well the efficiency of the performance of the proposed approach in the diagnosis of open-circuit faults.