基于AR模型的间谐波检测算法的研究

间谐波是频率介于两个谐波之间的信号。电力系统中间谐波问题日益突出,准确检测间谐波参数具有重要意义。由于传统的FFT算法在检测间谐波方面有一定的局限性,针对该局限性,提出了适合间谐波检测的基于AR模型的现代谱估计方法。介绍了AR模型谱估计的两种递推算法,Burg算法和改进协方差算法,并研究讨论了模型阶数选取、算法谱分辨率及谱抗噪声能力等问题,最后通过一系列仿真,证明该方法能够在较短的采样时间里准确检测出间谐波分量,在同样的采样频率和采样长度下,比FFT算法具有更高的精确度和频率分辨率,而且具有一定的抗噪声能力,在谐波检测方面有着很好的应用前景。

Interharmonics measuring algorithm based on AR model spectral estimation

Interharmonics are defined as the signal that have frequencies between two harmonics.As the problem of interharmonics in electric power system is increasingly serious,it becomes more and more important to measure interharmonics exactly.To overcome the limitations of FFT based algorithms in interharmonics measurement,a new algorithm based on AR model spectral estimation and suitable for measuring interharmonics is presented in this paper.The two algorithms of AR model spectral estimation,the Burg method and the modified covariance method,are detailed.Some essential issues,such as choice of model order,the spectral distinguishing ability and the antinoising ability of the algorithm,are investigated.The simulation results show that the algorithm is more effective than FFT on both antinoising ability and measuring accuracy in interharmonics measurement,so its application in interharmonics measurement has a good future.