应用插值FFT算法精确估计电网谐波参数

High-accuracy estimation of electrical harmonic parameters by using the interpolated FFT algorithm

深入研究了插值快速傅里叶变换(FFT)算法在电网谐波参数估计中的应用.加窗宽度和窗函数的类型是影响插值FFT算法分析精度的主要因素.通过对常用窗函数的特性分析,得出了加窗宽度关于分析精度的估计公式.电网信号的基波幅值远大于各次谐波幅值,分析表明,Hanning窗比较适合分析电网信号,同时给出了基于Hanning窗的电网谐波幅值、频率和相位的显式计算公式.仿真结果证明,应用上述分析结果,电网谐波幅度、频率和相位的估计达到了预期的分析精度.

A thorough research on the high-accuracy estimation for the electrical harmonic parameters by using the interpolated FFT algorithm was conducted. The window size and the window type are the main factors influencing the analysis precision. Based on the features of the commonly used windows, a formula for the analysis precision in relation to the window size is given. Studies show that according to the power signal's characteristic that the fundamental amplitude is much higher than that of the harmonics, Hanning Window is more suitable for the analysis of electrical signals and the computing formula for the harmonic parameter estimation are given. Simulation result demonstrates that by using the above results, the estimation of harmonic frequencies, amplitudes and phases reaches the expected precision.