Abstract：It is important to accurately detect the ripple component of DC signal to evaluate the quality of DC power supply. In this paper, a combined algorithm based on the variational mode decomposition (VMD) and Hilbert transform (HT) is proposed to detect and analyze the characteristics of the ripple components of DC signals. Firstly, the optimal modal number of VMD algorithm is determined by means of permutation entropy mean method. By using VMD algorithm, DC signal can be accurately decomposed into a series of AM-FM functions. Then, the HT algorithm is applied to each AM-FM function to obtain the corresponding instantaneous amplitude and frequency, and determine the characteristics of DC signal. Finally, the feasibility and effectiveness of the proposed combined vmd-ht algorithm are verified by simulation and experiment. Compared with ensemble empirical modes decomposition (EEMD)-HT algorithm, VMD-HT algorithm has higher decomposition accuracy and more robust to noise for complicated signal. Moreover, VMD-HT algorithm has non-sensitive to sampling frequency. The proposed algorithm can be applied to DC ripple detection.
2020, Vol. 21 
