Flicker value calculation method based on improved FFT and inverter

Abstract

The invention relates to a flicker value calculation method based on improved FFT and an inverter. In order to solve the technical problems, the flicker value calculation method based on the improved FFT and the inverter are provided, and high-precision flicker value calculation is achieved. According to the technical scheme, the method includes the steps that (1), all phases of voltage signals are sampled to obtain a voltage sampled sequence; (2), a voltage root-mean-square value is calculated according to sampling length per semi-circle wave, so that a voltage root-mean-square value sequence is obtained; (3), the average value of the voltage root-mean-square value sequence is calculated, and the average value is subtracted from each voltage root-mean-square value, so that a new voltage root-mean-square value sequence is obtained; the new voltage root-mean-square value sequence is windowed, FFT is performed, and amplitude frequency is corrected through double spectrum line interpolation operation; (5), curve fitting is performed on voltage fluctuation and fluctuation frequency discrete points; (6), please see the formula in the specification, a transient flicker value P is calculated; (7), the steps from one to six are repeated, all transient flicker values P within ten minutes are calculated, and according to the formula in the specification, a short-time flicker value Pst is calculated. The flicker value calculation method and inverter are used for the field of electric power technologies.

Description

technical field [0001] The invention relates to the technical field of signal processing, in particular to an improved FFT-based flicker value calculation method and an inverter, which are mainly applicable to the electric power technical field. Background technique [0002] With the increase of nonlinear and impact loads in the power grid, voltage fluctuations are becoming more and more serious, which has seriously affected industrial production and social life. Voltage fluctuation is a series of relatively rapid or continuous changes in the root mean square value of voltage. Voltage flicker is an evaluation index to measure the degree of harm caused by voltage fluctuations. It is a harmful result caused by voltage fluctuations and is a sensitive response of the human eye to fluctuations in the illuminance of incandescent lamps. Therefore, real-time monitoring of voltage fluctuations and flicker, that is, accurate measurement of voltage flicker indicators - instantaneous f...

AI Technical Summary

Problems solved by technology

[0004] The technical problem to be solved by the present invention is to provide a flicker value calculation method based on improved FFT and an inverter for the above-mentioned existing problems, so as to overcome the problems of large flicker calculations and the inability to accurately obtain voltage flicker signals in the prior art Spectral components and fluctuation amplitude issues, as well as the inability to achieve high-precision flicker measurement and analysis

Images