五项最大旁瓣衰减窗插值电力谐波分析

Power Harmonic Analysis Based on 5-term Maximum-sidelobe-decay Window Interpolation

提出一种简单的加窗插值快速傅里叶变换方法,用于非同步采样下的电力谐波分析。首先,分析了五项最大旁瓣衰减窗的时域、频域特性;然后,给出基于五项最大旁瓣衰减窗的插值方法,并推导了谐波幅值、初始相位和频率的计算公式;最后,分别用仿真分析、实验测试对所述方法的有效性进行验证。研究表明,五项最大旁瓣衰减窗具有较好的旁瓣特性,能够充分抑制频谱泄漏;基于五项最大旁瓣衰减窗的插值算法,插值公式简单、有解析解、谐波分析精度高、计算量小,易于在嵌入式系统中实现。

A simple windowed interpolation fast Fourier transform (FFT) algorithm is proposed for power harmonic analysis under asynchronous sampling.The time and frequency domain characteristics of 5-term maximum-sidelobe-decay (MSD) window are analyzed first.Then an interpolation approach based on 5-term MSD window FFT is given and the formula of harmonics amplitude,initial phase and frequency are deduced.The approach presented is finally verified by simulations and experimental testing.Results show that the 5-term MSD window has satisfactory sidelobe characteristics for fully suppressing spectral leakage and the 5-term MSD window based interpolation method is easy to realize in embedded systems for its simple interpolated correction formula,closed form expression,highly accurate power harmonic analysis,and low computational burden.