间谐波检测的快速自适应离散广义S变换方法

Inter-harmonics Detection Based on Fast Adaptive Discrete Generalized S-transform

采用传统广义S变换检测间谐波计算量大,不利于信号的实时检测。在此基础上,介绍了一种改进的快速自适应离散广义S变换方法来检测间谐波。首先,利用快速傅里叶变换估计信号间谐波频率;其次,应用折叠窗解决由于信号局部离散化引起的混叠,并通过自适应选择窗函数参数,达到缩小频域分析范围、大幅度节省分析计算时间、获得更加可靠的时频信号和提高时频能量集中度的目的。上述措施能有效抑制谐波、间谐波及噪声之间的相互干扰,提高信号间谐波参数及时间定位的估计精度。最后,对含稳态和动态谐波、间谐波的电气信号的分析结果验证了所提方法的有效性。

High computation and low precision constrains the application of traditional generalized S-transform （GST） in real-time estimating. In this paper, an improved fast adaptive discrete generalized S-transform is introduced to detect the inter-harmonics. First, the fast Fourier transform is used to estimate the inter-harmonics frequency. Secondly, the application of folded window can solve the local signal aliasing caused by discretization and select adaptive window function parameters. It is in order to narrow the range of frequency domain analysis, save calculation time, get the more reliable time-frequency signal and enhance the time-frequency energy concentration. These measures can effectively restrain harmonics, inter-harmonics and noise between mutual interference, amd improve the signal between the esti- ma-tion precision of the inter-harmonics parameters and time orientation. The validity of the proved method is verified by the simulation results of steady and dynamic power signals with harmonics and inter-harmonics.