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High-frequency resolution harmonic and inter-harmonic Prony method and device

A resolution and harmonic technology, applied in frequency measurement devices, circuit devices, spectral analysis/Fourier analysis, etc., can solve the problem of high computational burden of subspace methods, and achieve the effect of reducing computational burden and improving accuracy

Active Publication Date: 2019-04-02
CHINA AGRI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, subspace methods require the construction and decomposition of autocorrelation matrices, which often involve high computational burden, and require prior estimation of the number of estimates

Method used

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  • High-frequency resolution harmonic and inter-harmonic Prony method and device
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  • High-frequency resolution harmonic and inter-harmonic Prony method and device

Examples

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example 1

[0129] Example 1: The model of the sample signal is as follows: x(t)=sin(2π50.1t). There is only one sine wave in the sampling signal, and the deviation of the fundamental frequency is 0.1Hz.

[0130] First, the number of estimates is correctly set to M=1, both the traditional Prony method and the improved Prony method provided by the embodiment of the present invention can give accurate analysis. However, if the number of estimations is not set correctly, for example, M=2, 3, ..., 31, the traditional Prony method will give a large error analysis, but the improved Prony method provided by the embodiment of the present invention can still be in a large Gives accurate analysis most of the time.

[0131] figure 2 The FPE schematic diagram of Example 1 provided for the embodiment of the present invention, wherein figure 2 (a) figure is the FPE schematic diagram of the improved Prony method that the embodiment of the present invention provides, M=30, figure 2 Figure (b) in t...

example 2

[0133] Example 2: The model of the sample signal is as follows:

[0134]

[0135] Here the fundamental frequency deviation is 0.1Hz, and there are 20% of the second, third and fourth harmonics in the signal.

[0136] There are four sinusoids in the sampled signal, experiments show that the traditional Prony method cannot give an accurate estimate even if the number of estimates is correctly set to M=4. However, when M≥4, the modified Prony method can give accurate estimates for all components.

[0137] image 3 The FPE schematic diagram of Example 2 provided for the embodiment of the present invention, wherein image 3 (a) figure is the FPE schematic diagram of the improved Prony method that the embodiment of the present invention provides, M=30, image 3 Figure (b) in the figure is the FPE schematic diagram of the traditional Prony method, M=21, such as image 3 As shown, it shows that for the traditional Prony method, the value of FPE is very large, and the minimum va...

example 3

[0138] Example 3: The model of the sampled signal is as follows:

[0139]x(t)=[1+0.1sin(2π1t)]sin(2π50t),

[0140] There is 1Hz amplitude modulation in the signal.

[0141] The sampled signal can be expressed as:

[0142] x(t)=sin(2π50t)-0.05cos(2π49t)+0.05cos(2π51t),

[0143] There are three sinusoidal components with close frequencies at 49Hz, 50Hz and 51Hz in the sampled signal, and it is difficult to separate these three components with a short data window of 40ms.

[0144] Calculate the value of FPE. For the modified Prony method, the minimum value of FPE is obtained at M=30, FPE=1.4e-17. For the traditional Prony method, the minimum value of FPE is obtained when M=1, FPE=1.3e-4.

[0145] Figure 4 The FPE schematic diagram of Example 3 provided for the embodiment of the present invention, wherein Figure 4 (a) figure is the FPE schematic diagram of the improved Prony method that the embodiment of the present invention provides, Figure 4 Figure (b) in (b) is a sc...

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Abstract

The embodiment of the invention provides a high-frequency resolution harmonic and inter-harmonic Prony method and device. The method comprises the steps that according to a sampled electric power system signal, an autocorrelation matrix is constructed, and characteristic decomposition is conducted on the autocorrelation matrix to obtain autocorrelation matrixes represented by corresponding featurevectors; a first Prony coefficient is obtained on the basis of a subspace method and the symmetry of the first Prony coefficient according to the feature vectors and the sine wave number in the electric power system signal; and the damping factor and the frequency of each component in the electric power system signal are obtained according to the first Prony coefficient. According to the high-frequency resolution harmonic and inter-harmonic Prony method and device, by utilizing the symmetry of the Prony coefficient and the advantages of the subspace method, the computing burden is greatly reduced, and the precision of high-frequency resolution harmonic and inter-harmonic analysis of an electric power system is improved.

Description

technical field [0001] The invention relates to the field of power electronics, in particular to a high-frequency resolution harmonic and interharmonic Prony method and device. Background technique [0002] The increasing use of time-varying nonlinear loads in power electronics systems and industry leads to severe harmonic and interharmonic distortion. Harmonic and interharmonic components in power systems can cause additional power loss, heating and damage to equipment. They can also interfere with communication circuits, causing resonances in the grid and abnormal operation of protection and control equipment. Accurate analysis of harmonics and interharmonics is critical to effectively preventing unwanted effects and gaining a complete understanding of power quality problems. [0003] Currently, many techniques have been proposed to analyze harmonics and interharmonics in power systems. Among these analysis methods, the Fast Fourier Transform (FFT) is a powerful tool. ...

Claims

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Application Information

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IPC IPC(8): G01R23/16G01R23/02H02J3/00
CPCG01R23/02G01R23/16H02J3/00
Inventor 薛蕙张铁涛林歆昊
Owner CHINA AGRI UNIV
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