摘要: With the power electronic devices densely connected to the power grid, it is easy to make the inter-harmonics which are closed to the harmonics appear in the power system signals. When the frequency of inter-harmonics is adjacent to that of harmonics, the spectrum of inter-harmonics will leak to the harmonic spectral lines, and generate serious main lobe interference with the spectrum of harmonics, which will make the performance of current detection methods based on discrete Fourier transform or fast Fourier transform (DFT/FFT) algorithm deteriorated or even completely invalid. Based on the specified signal processing recommendations by IEC61000-4-7, this paper proposes a ratio correction method based on the inter-harmonic leakage estimation to detect adjacent inter-harmonics and harmonics. Firstly, the characteristics of spectral interference between the harmonics and the inter-harmonics under fundamental frequency synchronous sampling are analyzed in this paper. According to the characteristics of the inter-harmonic leakage on each spectral line, the spectral values of inter-harmonics on the harmonic spectral lines can be estimated by solving the spectral line equations, which are constructed by using the inter-harmonic spectral lines around the harmonic spectral lines. And the frequency correction components of inter-harmonics will be obtained by using the ratio correction algorithm. Secondly, considering the influence of the inter-harmonic spectral leakage on amplitude and phase detection, according to the estimated frequencies, the amplitude and phase parameters of each component can be corrected by using the incidence matrix inversion algorithm ,which is constructed by the windowe spectral funtion. Finally, the theoretical simulation example and the practical simulation example analysis of the proposed method are carried out on the MATLAB simulation platform. The results show that the method proposed in this paper can effectively suppress the influence of the inter-harmonic spectral leakage, and it can rapidly and accurately detect the parameters of adjacent harmonics and inter-harmonics based on a limited data length of samples.