Characterization of Contactor Degradation States Based on Improved Variational Modal Decomposition and Optimized Similarity Metrics With Combined Weights

Aiming at the problem that it is difficult to extract useful information from the contactor characteristic parameter data due to a large amount of noise interference and to determine the weight allocation of different characteristic parameters in the process of contactor degradation state characterization, this article proposes a contactor degradation state characterization method based on the improved variational modal decomposition (VMD) and the optimization of similarity metrics with combined weights. First, the CJX2-5011 model contactor is taken as the experimental object, and the full-life test is carried out to extract the contactor characteristic parameter data. Then, the sparrow search algorithm (SSA) is used to optimize the parameter settings of the VMD, and the optimal component selection and noise reduction are completed based on the correlation determination and wavelet threshold noise reduction, which effectively extracts the useful information of the feature parameters. Second, the combined weights of feature parameters are constructed by the analytic hierarchy process (AHP) and CRITIC weighting method, which solves the problem of weight allocation of feature parameters in the process of characterizing the degraded state of the contactor. Finally, the combination of weights is used to optimize the similarity measurement process and achieve a more accurate characterization of the contactor degradation state. In the multicharacteristic parameter noise reduction process, the noise rejection rate (NRR) and correlation (
$\rho)$
are at least improved by 0.0592 and 0.0006. In the degraded state characterization, the goodness of fit (R) is improved by at least 0.06723, and the root-mean-square error (RMSE) is reduced by at least 0.34689. Therefore, it can be seen that the method in this article is able to better complete the noise reduction of the contactor characteristic parameter data and to achieve a more accurate characterization of the degraded state of the contactor.