Research On Harmonic Analysis And Applications Based On ZFFT And Windowed Multispectral Interpolation Algorithm

With the use of nonlinear load and power electronic devices,the extent of the harmonic pollution is constantly increasing in the power grid.It is particularly important to accurately analyze harmonic and meter energy in order to reduce and eliminate the influence of harmonic.The precondition of harmonic problems is accurate detection and analysis of harmonic in the study.The accuracy of the harmonic parameters analysis is a scientific basis for the high accuracy measurement of the harmonic power.Fast Fourier transform(FFT)is the most common method in harmonic parameter analysis methods.Frequency spectrum leakage and fence effect have serious influence on harmonic parameters analysis,as a result,the accuracy of the harmonic parameter can be relatively lowered.Because of uncertainty,for example inter-harmonics in harmonic signal,the results of detection may be not accurate.A new harmonic analysis approach,based on Zoom-FFT(ZFFT)and windowed multispectral interpolation algorithm,can be put forward in the thesis.And then harmonic electric energy metering can also be calculated by Budeanu decomposition principle.Comparing with the traditional FFT harmonic analysis method,the simulation results indicate that the thesis has better effectiveness and superiority.The main contents are below:(1)The background and significance of the thesis can be analyzed.And then its developing situation can also be introduced.The reason of existing problems and phenomena can be analyzed by studying FFT theory.Some corresponding solutions can also be put forward.The elaboration and analysis lay the solid foundation for subsequent theoretical.(2)Typical window function and frequency domain features can be analyzed.The selection principles of window functions can also be discussed in the thesis.A new trapezoid self-convolution window function can be proposed by regulating the coefficient of typical window function and convoluting time domain function.And then a new harmonic analysis methord,based on 2-step trapezoid self-convolution window and four-peak spectral line interpolation algorithm,can be put forward in the thesis.The correction formula of harmonic parameters can also be deduced and established.Multiple modulation zoom spectrum analysis algorithm based on complex analytic band-pass filter can be established by analyzing the principle of traditional multiple modulation zoom spectrum analysis algorithm.(3)The basic theory of electric energy metering can be analyzed.The reason of error can also be studied on electric energy metering during existing harmonic.According to the Budeanu decomposition principle and ZFFT and 2-step trapezoid self-convolution window four-peak spectral line interpolation algorithm,the parameters of harmonic can be analyzed and harmonic electric energy metering can also be calculated.(4)The necessity and superiority of thesis can be analyzed.By comparing with FFT method,new trapezoid self-convolution window four-peak spectral line interpolation algorithm,2-step trapezoid self-convolution window four-peak spectral line interpolation algorithm and multiple modulation zoom spectrum analysis algorithm based on complex analytic band-pass filter,the simulation results show that the thesis can be more accurate and more feasible than other algorithms.