Method for calculating amplitude and phase of alternating-voltage signal based on iteration Fourier transform

An iterative Fourier, AC voltage technique, applied in the phase angle between voltage and current, measuring current/voltage, measuring electrical variables, etc.

Active Publication Date: 2012-11-28
WISDRI ENG & RES INC LTD
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Problems solved by technology

When applying dynamic reactive power compensation technology, it is necessary to detect the fundamental wave amplitude and phase of the bus voltage, while the traditional me

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  • Method for calculating amplitude and phase of alternating-voltage signal based on iteration Fourier transform
  • Method for calculating amplitude and phase of alternating-voltage signal based on iteration Fourier transform
  • Method for calculating amplitude and phase of alternating-voltage signal based on iteration Fourier transform

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Embodiment

[0064] There is a load system connected to the 6.5kV bus in a steel factory, and the following is obtained through actual measurement figure 2 The A-phase voltage curve shown, at this time the sampling frequency f s =10000Hz, sampling period T s =0.0001s. If it is necessary to obtain the amplitude and phase of the fundamental voltage (that is, n=1) from the detected voltage data, the frequency of the fundamental voltage signal to be extracted in this embodiment is f 1 =50Hz, the angular frequency is w 1 =2πf 1 =314.15rad / s, the number of sampling points in one cycle N = f s f n = 10000 50 = 200 .

[0065] When N≥k>0, calculate the sine function sin(w 1 kT s ) and the cosine function cos(w 1 kT s ) value, the specific numerical curve is as image 3 shown.

[0066] Judging ...

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Abstract

The invention discloses a method for calculating the amplitude and phase of an alternating-voltage signal based on an iteration Fourier transform and belongs to the technical field of electric power supply. The method comprises the following steps of: determining a sampling frequency and initializing parameters; determining an alternating voltage frequency to be extracted; calculating a sine function and a cosine function; sampling an alternating voltage value; judging a sampling sequence and calculating an alternating voltage sub-harmonic cosine amplitude and a cosine amplitude; and obtaining an alternating voltage sub-harmonic voltage amplitude and the phase. The method disclosed by the invention utilizes sampling data of each time to carry out primary addition and subtraction calculation to obtain accurate fundamental wave voltage amplitude and phase; and compared with the traditional Fourier transform, a lot of calculation processes are reduced; and the requirements of the rapidness and the accuracy of signal detection of an electric power system are met.

Description

technical field [0001] The invention belongs to the technical field of electric power supply and relates to the design of a dynamic reactive power compensation device in a power supply system, in particular to a method for calculating the amplitude and phase of an AC voltage signal based on iterative Fourier transform. Background technique [0002] Impulse loads such as rolling mills and electric arc furnaces in the iron and steel metallurgical industry cause flicker to the grid voltage, so it is necessary to use dynamic reactive power compensation technology for real-time control to stabilize the bus voltage. When applying dynamic reactive power compensation technology, it is necessary to detect the fundamental wave amplitude and phase of the bus voltage, while the traditional method based on Fourier transform to obtain the fundamental wave amplitude and phase requires a large number of calculations at each sampling point to obtain precise results. Contents of the inventi...

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Application Information

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IPC IPC(8): G01R19/00G01R23/16G01R25/00
Inventor 张华军陈方元褚学征尉强
Owner WISDRI ENG & RES INC LTD
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