Base wave and harmonic detecting method based on Kaiser window double-line spectrum insert value FFT

Abstract

The invention discloses a fundamental wave based on Kaiser Window bispectrum line interpolation FFT (Fast Fourier Transform) and a harmonic wave detection method. The method comprises the following steps: analog-to-digital conversion and low-pass filtration treatment is conducted on the signal to be detected; the Kaiser Window with free proportion selection between the attenuation of a main lobe and side lobes, flexible design realization, low side lobe level and quick attenuation speed is adopted to conduct windowing FFT operation on the signal; and bispectrum line interpolation algorithm is used for detecting base wave and harmonic quantities of the detected signal. The following aspects are included: (1) analog-to-digital conversion and low-pass filtration; (2) the FFT operation based on the Kaiser Window; (3) base wave and harmonic wave parameters derived by bispectrum line interpolation and polynomial fitting.

Description

technical field [0001] The invention relates to a method for detecting fundamental wave and harmonic parameters in signals. Specifically, it is a fundamental wave and harmonic parameter detection method based on Kaiser window bispectral interpolation FFT (fast Fourier transform), which belongs to the technical field of signal processing and can also be used for spectrum analysis of other signals. Background technique [0002] Taking power signal detection as an example, with the development of power electronics technology, non-linear devices are widely used in power systems, and the harmonic problems brought by non-linear devices pose an increasingly serious threat to the safety, stability and economic operation of power systems. Accurate measurement of fundamental and harmonics can provide scientific basis for power grid energy metering, harmonic power flow calculation, equipment network detection, power system harmonic compensation and suppression, etc. [0003] Fundament...

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Problems solved by technology

The shortcomings of the existing technology are: the existing technology provides some electrical equipment design methods for fundamental wave and harmonic measurement, but due to the characteristics of diversity, randomness and polymorphism of harmonics, the frequency fluctuations caused by the fundamental wave Spectrum leakage and fence effects still exist, so real-time, high-precision fundamental and harmonic measurement analysis is difficult to achieve

In view of this feature, He Yihong and other scholars proposed to use the Kaiser window to sample the signal based on the real-time reactive power theory (He Yihong, Zhuo Fang, etc. Application of Kaiser window in harmonic current detection, Power Grid Technology, 2003, 27(1): 9-12); Wu Jun and other scholars proposed a frequency measurement method based on Kaiser window (Wu Jun, Wu Chonghao. Improved Fourier frequency measurement algorithm based on Kaiser window, Jiangsu Electrical Engineering, 2008, 27(4): 17-19), None of the above documents involve related processing methods based on Kaiser window interpolation FFT processing

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