Harmonic/Inter-harmonic Detection Method Based on Variational Mode Decomposition and Hilbert Transform

In order to improve the detection accuracy of harmonics/inter-harmonics in power harmonic signals, a new harmonic detection method based on the combination of variational mode decomposition (VMD) and Hilbert transform (HT) is proposed. The intrinsic mode functions (IMF) are obtained by decomposing the harmonic signal using VMD, Then the characteristic parameters of each order IMF component, including instantaneous amplitude, instantaneous frequency and instantaneous energy, are obtained by combining HT transform. Simulations of four harmonic detection methods, such as VMD-HT, EEMD, HHT and FFT, are performed. The simulation results show that the VMD-HT method effectively overcomes the defects of HHT and FFT, which are sensitive to noise, in harmonic detection, and removes noise to a greater extent, which is conducive to improving the recognition accuracy and precision and better meets the practical application requirements.