Harmonic analysis method based on Kaiser window double-spectral-line interpolation FFT

A technology of bispectral interpolation and harmonic analysis, applied in analytical instruments and automatic monitoring devices, analysis of grid voltage and current waveform distortion and automatic monitoring algorithms, can solve the problem of not being able to track the rapid change of signal frequency in time and the response of phase-locked loop Slow, unable to achieve synchronous sampling and other issues
CN103575984AInactive Publication Date: 2014-02-12西安钧能科技有限公司
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
西安钧能科技有限公司
Publication Date
2014-02-12
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention discloses a harmonic analysis method based on the Kaiser window function double-spectral-line interpolation FFT. The method is suitable for analysis and monitoring on voltages, currents and harmonic waves of a power network. The method comprises the steps of firstly, using linear frequency modulation Z conversion for extracting fundamental wave signal parameters (amplitudes, frequencies and phase positions) from electric power signals containing the harmonic waves in a high-precision mode, then adding a Kaiser window function into the analyzed electric power signals to cut off the electric power signals, using the FFT for calculating frequency spectra of remaining signals, and precisely calculating parameters of the electric power harmonic waves according to interpolations of the Kaiser window function by the harmonic frequencies in a frequency domain. The method can effectively overcome fluctuations of fundamental frequencies, and influences of white noise on the harmonic analysis, under the non-integer cycle cut-off condition, the relative error of the frequency calculation of the 21-time harmonic signals is 1.4*10%, the relative error of the amplitude calculation is smaller than or equal to 0.002%, and the relative error of the initial phase position calculation is smaller than or equal to 0.0001%.
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Description

technical field

[0001] The invention relates to an analysis and automatic monitoring algorithm of grid voltage and current waveform distortion, which can be used for analysis instruments and automatic monitoring devices of various grid voltage and current waveform distortions. The utility model belongs to the technical field of electric power measurement and automation. Background technique

[0002] With the wide application of various nonlinear loads, especially power electronic equipment in the power system, the harmonic pollution of the power grid is becoming more and more serious. FFT algorithm is the main algorithm of current harmonic analysis because of its simplicity and good practicability.

[0003] The FFT algorithm needs to be under the condition of completely synchronous sampling, when the measurement time of the signal is not equal to the integer multiple of the signal period, or when the signal contains non-integer harmonics, the frequency of each harmonic obta...

Claims

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