Fast fixed-point frequency offset measurement method

Abstract

The invention discloses a fast fixed point frequency deviation measurement method, comprising: sampling the frequency of a power frequency alternating current signal, and at least collecting the frequency data of power frequency alternating current signals of two periods; respectively performing discrete Fourier transform on the frequency data collected within a previous period and the frequency data of collected within a subsequent period to obtain a first complex number and a second complex number respectively; selecting a group of identification parameters according to the data characteristics of the first complex number and the second complex number; obtaining a first radian value of the first complex number according to the first complex number and a first reciprocal mark, and obtaining a second radian value of the second complex number according to the second complex number and a second reciprocal mark; searching for a coefficient mapping table according to in-group values of theidentification parameters to obtain a first coefficient value, a second coefficient value and a third coefficient value; and calculating the frequency deviation of the power frequency alternating current signal according to the algorithm disclosed by the invention. The fast fixed point frequency deviation measurement method has the advantages of high measurement efficiency and less occupation ofhardware resources.

Description

technical field [0001] The invention relates to the field of power detection, in particular to a fast fixed-point frequency deviation measurement method. Background technique [0002] Electricity is a basic industry for social public use, and an important energy source indispensable for social and economic development and people's lives. The electricity market is a big market involving the production and life of thousands of households. The quality of the market order is directly related to the vital interests of the people. Therefore, the research on anti-stealing technology is very meaningful. [0003] For electricity theft prevention, it is often necessary to restore the real electricity consumption data under incomplete or limited data conditions. Frequency measurement technology is the most basic and important technology for measuring various electrical parameters in power system AC signals. That is to say, if the frequency measurement is inaccurate, then other electr...

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Problems solved by technology

[0005] In the process of realizing the present invention, the inventor found that for the traditional zero-crossing detection technology, its anti-interference and anti-harmonic disturbance ability is relatively poor; especially in the field of anti-theft electricity, there is no voltage signal but only the current signal, and this current signal is actually the superposition of the current of all terminal electrical equipment

Due to the different working methods of each terminal equipment, various harmonics will be generated, that is to say, it is a very common phenomenon that the waveform distortion rate exceeds 50% for current signals, so the zero-crossing detection method has completely lost its value. use value

Another method using DFT to calculate the period of the signal under test, the conventional method is to use floating-point calculations, a large number of floating-point operations and logic comparisons, and angle correction, which requires high hardware resources and low floating-point calculation efficiency , A large number of segmented judgments lead to poor real-time performance

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