Harmonic analysis method based on Kaiser self-convolution window dual-spectrum line interpolation FFT (Fast Fourier Transform) and device thereof

Abstract

The invention discloses a harmonic analysis method based on Kaiser self-convolution window dual-spectrum line interpolation FFT (Fast Fourier Transform) and a device thereof. The method comprises the following steps of sampling a signal: sampling a time-domain continuous signal, and discretizing to obtain an infinitely long discrete sequence; windowing a four-order Kaiser self-convolution window function: performing four-order Kaiser self-convolution window operation on the infinitely long discrete sequence; performing N-point FFT on a windowed and truncated signal to obtain the discrete spectrum of the signal; determining the peak parameter of the discrete spectrum: searching the local spectrum peak of each integer harmonic frequency around the integer harmonic frequency; and calculating a harmonic parameter: solving a coefficient alpha by adopting a discrete spectrum interpolation correction formula based on an LSM (Least Square Method), and calculating parameters such as a harmonic frequency, an amplitude, an initial phase angle and the like. Due to the adoption of the method, the fundamental and harmonic components of a tested signal can be detected rapidly and accurately, and accurate frequency measurement is realized; and the method is convenient for implementing an embedded system, and the tested signal can be detected continuously for a long time.

Description

technical field [0001] The invention belongs to the field of signal processing and technology, and relates to a harmonic analysis method and a device thereof, in particular to a Kaiser self-convolution window bispectral interpolation FFT harmonic analysis method and a device thereof. Background technique [0002] With the development of power electronics technology, nonlinear devices are widely used in power systems, and the harmonic problems brought by nonlinear devices pose an increasingly serious threat to the safety, stability and economic operation of power systems. Accurate measurement of harmonic parameters can provide scientific basis for grid harmonic energy metering, harmonic power flow calculation, equipment network detection, power system harmonic compensation and suppression, etc. [0003] Fast Fourier transform (fast Fouier transform, FFT) has high computational efficiency and is easy to implement in embedded systems such as DSP. It is currently the most widely...

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Problems solved by technology

[0008] The purpose of the present invention is to overcome the disadvantages such as the higher the order of the windowing function, the greater the computational complexity, the computational accuracy is not high enough, and the power system detection device with high real-time requirements is extremely unfavorable, and provides a self-convolution based on Kaiser Window bispectral interpolation FFT harmonic analysis method and its device, through which the frequency, amplitude and phase of the fundamental and harmonics of the power system can be calculated more accurately, the method is relatively simple and the calculation complexity is low

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