基于时频自适应最优核分布理论的谐波检测方法

Harmonics Detection Based on Time-Frequency-Adaptive Optimal-Kernel

针对电能质量分析的现状,采用一种高分辨率的时频分析方法对谐波进行分析。该方法通过对时频平面内每一点计算模糊函数,获得时频最优核函数,并以此来抑制同时间点多分量信号引起的交叉项干扰,从而获得较高的时频分辨率。仿真结果表明,将该方法结合快速傅里叶变换检测谐波幅值,能够准确地检测出谐波各频率分量的时频分布特性和幅值大小。

According to the present status of power quality analysis, a novel time-frequency analysis method with high resolution, called time-frequency-adaptive optimal-kernel, is proposed in this paper for investigating the detection of harmonics. This method obtains time-frequency optimal-kernel function by computing ambiguity function of each point in time- frequency plane to suppress cross-term interference caused by multi-component signal under same time, so that high time- frequency resolution is obtained. The method is applied to the analysis of harmonics, and the harmonics amplitude is detected by combining with fast Fourier transform. The test results show that the method describes the frequency and amplitude characteristics of the harmonic components accurately, and harmonics are detected and identified accurately.