基于改进TLS-ESPRIT与自卷积窗的谐波与间谐波检测算法

Harmonic and inter-harmonic detection algorithm based on improved TLS-ESPRIT and a self-convolution window

随着光伏发电系统大规模接入电网,不可避免地带来了严重的谐波污染问题。为了有效监测光伏并网系统输出电流的谐波、间谐波,提出了一种基于改进快速最小二乘法-旋转不变法(total least squares-estimation of signal parameters via rotational invariance technique,TLS-ESPRIT)与2阶Blackman-Harris自卷积窗相结合的检测方法。首先对待测信号进行三次采样并利用快速TLS-ESPRIT算法检测频率。随后对检测结果基于简化K-means聚类算法进行分析,提取出真实的谐波分量。最后结合2阶Blackman-Harris自卷积窗对信号进行加窗插值计算,准确估算出其幅值、相位信息,实现了谐波、间谐波的高精度检测。仿真算例和现场数据测试结果表明,所提方法相较于传统方法具有更高的谐波、间谐波检测精度,且抗干扰能力更强。

With the large-scale connection of PV power generation systems to the power grid,serious harmonic pollution is inevitable.In order to effectively monitor the output current's harmonics and inter-harmonics of a PV grid-connected system,this paper proposes a detection method based on the improved fast TLS-ESPRIT algorithm combined with the 2-order Blackman-Harris self-convolution window.First,the signal is sampled three times and the frequency is detected by the fast TLS-ESPRIT algorithm.Then the detection results are analyzed based on the simplified K-means clustering algorithm and the real harmonic components are extracted.Finally,the 2-order Blackman-Harris self-convolution window is used to interpolate the signal,and the amplitude and phase information of the signal are accurately estimated.The high-precision detection of harmonics and inter-harmonics is realized.Simulation and field data test results show that the proposed method has higher harmonic and inter-harmonic detection accuracy and stronger anti-interference ability than the traditional methods.