基于Rife-Vincent窗的高准确度电力谐波相量计算方法

An Accurate Approach for Power Harmonic Phasor Calculation Based on Rife-Vincent Window

非同步采样时,快速傅里叶变换应用于谐波分析容易造成频谱泄露和栅栏效应,影响谐波相量计算的准确度。分析Rife-Vincent窗的旁瓣特性,提出一种基于5项Rife-Vincent(I)窗双谱线插值FFT的谐波相量计算方法。与传统窗函数相比,5项Rife-Vincent(I)窗具有更好的频谱泄漏抑制特性,而双谱线插值算法能够对栅栏效应进行有效修正。仿真实验结果表明,在非同步采样条件下,提出的方法适合于非线性电路谐波相量分析,22次复杂谐波电流信号的频率计算相对误差仅为5.7×10-11%,幅值计算相对误差≤5.3×10-7%,初相位计算相对误差≤3.1×10-6%。

When using the fast Fourier transform （FFT） for harmonic analysis in the non-coherent sampling, it suffers from two drawbacks： the spectral leakage and picket fence effect, and the harmonic phasor cannot be obtained accurately. The side-lobe characteristics of Rife-Vincent windows are analyzed and an approach for harmonic phasor calculation based on the five term Rife-Vincent（I） window interpolation FFT is proposed. Compared with the traditional window function, the five term Rife-Vincent（I） window with a better curb ability to the spectral leakage, and the picket fence effect can be modified by the double-spectrum-line interpolation algorithm. The simulation results show that, the approach presented in this paper is adapted for the harmonic phasor analysis in the nonlinear circuit, and by using the approach in the non-coherent sampling conditions, the errors of calculating frequency of 22 order harmonics is 5.7×10^-11%, as well as that of calculating amplitudes and phases are no more than 5.3×10^-7% and 3.1 ×10^-6%.