基于通用可调(p, q)阶Rife-Vincent自乘-卷积窗的改进四谱线插值高精度谐波分析算法

The windowed fast Fourier transform(WIFFT) is one of the most important harmonic parameter estimation methods. However, the inherent fence effect of FFT and the spectrum leakage caused by asynchronous sampling seriously affect the estimation accuracy of harmonic parameters. Therefore, a universal tunable (p, q) order Rife-Vincent self-multiplication-convolution window(RVSMC p-q) was proposed by using class I Rife-Vincent window with maximum decay as the parent window. The mainlobe width, sidelobe peak value and sidelobe attenuation speed of RVSMC p-q window can be flexibly controlled by changing the multiplication order and the convolution order. On this basis, a high-precision harmonic parameter estimation method based on four spectral line interpolation by using RVSMC p-q window was proposed. The low complexity polynomial estimation formulas corresponding to the amplitude, frequency and phase of harmonic signals were given via the least square fitting. Experimental simulations were conducted to evaluate the performance of the proposed harmonic parameter estimation method based on the four spectral line interpolation by using RVSMC p-q window in the case of complex harmonics, interharmonics and fundamental wave frequency fluctuations. The results show that the proposed algorithm can achieve better estimation accuracy than the classical WIFFT algorithms based on self-multiplication or self-convolution window even under the condition of low orders of multiplication and convolution, and the algorithm complexity of the new algorithm is relatively low.