谐波分析用最大旁瓣衰落速度优化组合余弦窗函数的研究

非相干采样方式下直接用傅里叶变换做电网谐波分析存在频谱泄漏现象，利用组合余弦窗函数对采样数据加权是降低频谱泄漏的重要措施，其参数值决定了降低频谱泄漏的程度。针对这些情况，提出了组合余弦窗函数优化的通用原则，利用该原则导出最大旁瓣衰减速度优化组合余弦窗函数。在非相干采样方式下，这类优化组合余弦窗函数能使窗函数的旁瓣以最大速度来跌落，从而显著降低了频谱泄漏，有助于实现电网谐波的高精度分析。

Research on Improved Combined Cosine Window Functions with Maximum Side Lobe Decay for Harmonic Analysis

There exists spectral leakage when power grid harmonics are directly analyzed by Fourier transform in incoherent sampling mode. It’s a very important measure to weight the sampling data with combined cosine window functions to reduce spectral leakage, and their coefficients decide the grade of reducing spectral leakage. Aiming at these things, this paper puts forward general principles for improving combined cosine window functions, and deduces the improved combined cosine window functions with maximum side lobe decay. In incoherent sampling mode, these improved window functions can make side lobes decay with maximum speed, so they can obviously reduce spectral leakage and can help to realize high-precision power grid harmonics analysis.