Micro-grid harmonic and inter-harmonic analysis method based on cubic spline interpolation waveform reconstruction

A spline interpolation and waveform reconstruction technology, applied in the field of microgrid harmonic and interharmonic analysis, can solve problems such as fence effect, spectrum leakage, influence analysis accuracy, etc., and achieve the effect of simple implementation, improved accuracy and high accuracy

Inactive Publication Date: 2012-06-27
TIANJIN UNIV
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Problems solved by technology

The FFT algorithm can only decompose the harmonics of the integer order. Due to the existence of the intermediate harmonics of the microgrid and the change of the fundamental frequency, it is difficult for the traditional FFT algorithm to achieve synchronous sampling, which will lead to spectrum leakage and fence effects, thereby affecting the analysis accuracy.

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  • Micro-grid harmonic and inter-harmonic analysis method based on cubic spline interpolation waveform reconstruction
  • Micro-grid harmonic and inter-harmonic analysis method based on cubic spline interpolation waveform reconstruction
  • Micro-grid harmonic and inter-harmonic analysis method based on cubic spline interpolation waveform reconstruction

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Embodiment Construction

[0017] There are many power electronic devices and nonlinear loads in the microgrid, resulting in a large number of harmonics and inter-harmonics, and its fundamental frequency changes, which is difficult to analyze by FFT algorithm. The invention is suitable for the harmonic and interharmonic analysis of the micro-grid containing a large number of power electronic devices.

[0018] When the fundamental frequency of the microgrid changes, the fundamental frequency will shift by 50 Hz. Using a fixed sampling frequency and a limited analysis window width for harmonic and interharmonic analysis will inevitably produce spectrum leakage and fence effects. Let the fixed sampling frequency be

[0019] f s =N×f 0 (1)

[0020] In the formula: N is the number of sampling points in a fundamental wave cycle, f 0 is the fundamental frequency.

[0021] Due to the change of the fundamental frequency, it is generally difficult to determine the sampling frequency, an...

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Abstract

The invention belongs to the technical field of micro-grid signal processing, and relates to a micro-grid harmonic and inter-harmonic analysis method based on cubic spline interpolation waveform reconstruction. The method comprises the following steps of: sampling the original measuring signal at a given sampling frequency to acquire the original sampled signal; analyzing the original sampled signal to determine the actual fundamental frequency of a system by using a Hanning windowed double interpolation fast Fourier transform (FFT) algorithm; obtaining the corrected sampling frequency according to the actual fundamental frequency of the system; reconstructing a sampling waveform by using a cubic spline interpolation algorithm; processing the reconstructed signal sequence to determine fundamental waves and all harmonic components by using the Hanning windowed double interpolation FFT algorithm; subtracting the solved fundamental waves and each harmonic component from the original sampled signal; and determining each inter-harmonic component by using the Hanning windowed double interpolation FFT algorithm. By the method, spectrum leakage and a picket fence effect which are generated during harmonic analysis can be effectively reduced, and micro-grid harmonic and inter-harmonic analysis accuracy is improved.

Description

technical field [0001] The invention belongs to the technical field of microgrid signal processing, and relates to a microgrid harmonic and interharmonic analysis method. Background technique [0002] Among the many harmonic analysis methods, the fast Fourier transform (FFT) algorithm is most widely used. The FFT algorithm can only decompose the harmonics of the integer order. Due to the existence of the intermediate harmonics of the microgrid and the change of the fundamental frequency, it is difficult for the traditional FFT algorithm to achieve synchronous sampling, which will lead to spectrum leakage and fence effects, thereby affecting the analysis accuracy. Contents of the invention [0003] The purpose of the present invention is to overcome the above-mentioned deficiencies in the prior art, provide a microgrid that can effectively reduce the spectrum leakage and fence effect generated during harmonic and interharmonic analysis, and improve the accuracy of microgrid...

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Application Information

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IPC IPC(8): G01R23/16
Inventor 王继东杜旭浩
Owner TIANJIN UNIV
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