基于准同步DFT的非整数谐波分析算法

在准同步DFT谐波分析算法的基础上,提出了一种基于非整数波概念的谐波分析算法。该算法的核心思想是:信号频率漂移导致频谱峰值出现的位置与理想位置不一致是短范围泄漏产生的根本原因,而信号频率的漂移可以通过测量相邻点基波相角差来获得,那么应用该漂移值对基波和高次谐波的波次值进行非整数修正就可以准确测量各次谐波的幅值和相角。仿真实验和工程实例证明,该算法能够有效抑制频谱的长范围泄漏和短范围泄漏,提高基波与高次谐波的幅值与相位测量准确度。

Non-integral harmonic analysis algorithm based on quasi-synchronous DFT

Based on the quasi-synchronous DFT harmonic analysis algorithm,a non-integer harmonic analysis algorithm is proposed.The core of the algorithm is that the original source of short-range leakage is frequency drift,which causes the real location of the spectral peak discrepant with the ideal one.The frequency deviation between the real signal and ideal signal can be obtained through measuring the fundamental phase angle difference between adjacent sample points,then the amplitudes and phases of the fundamental and high harmonics can be calculated with high-precision through modifying the number of the harmonics to a non-integer value based on the frequency deviation.Simulation and engineering examples show that this algorithm can effectively suppress long-range spectrum leakage and short-range leakage,and improve the amplitude and phase measurement accuracy.