含确定性分量和随机噪声分量的宽频带信号分解方法

可再生能源发电、储能、电动汽车等基于电力电子变流器的并网设备快速增加导致配电网信号日趋复杂。将电力系统宽频带信号分为确定性分量和随机噪声分量,建立了电力系统宽频带信号模型,并基于此模型提出了一种宽频带信号分解方案。首先,应用鲁棒局部回归平滑滤波方法提取并过滤随机噪声分量;提出了基于均值和标准差估计的自适应阈值确定方法,用于分解随机噪声分量。然后,提出了基于间谐波子群频谱的自适应阈值确定方法,用于提取间谐波分量。最后,用无限脉冲响应滤波器组将确定性分量分解为独立的子信号,并基于泰勒傅里叶变换估计确定性分量的频率和相量,实现确定性信号的分解。仿真验证了所提方案能在低信噪比、系统频率动态变化等情况下实现间谐波分量的自适应捕获和宽频带信号的高精度分解并应用所提分解方案分析了实测电压信号。

Decomposition Scheme for Wideband Signals Containing Deterministic Components and Stochastic Noise Components

With rapid increase of the grid-connected equipment based on power electronic converters(such as renewable energy generation, energy storages and electric vehicles), the electrical signals of distribution networks are becoming more and more complex. A wideband signal model of power systems is established, which is composed of deterministic components and stochastic noise components. Based on this signal model, a decomposition scheme for wideband signals is proposed. Firstly, the robust local regression smoothing method is used to extract and filter the stochastic noise components. A determination method for the adaptive threshold based on the estimation of mean and standard deviation is proposed, which is used to decompose the stochastic noise components. Then an adaptive threshold based on the spectrum of interharmonic sub-groups is built to detect the interharmonics. Finally, the Taylor-Fourier transform algorithm is used to estimate the parameters of deterministic components based on the independent sub-signals decomposed by the infinite impulse response filter bank. Simulation results show that the proposed scheme can achieve time-varying interharmonics detection and precise decomposition of wideband signals under the conditions of low signal to noise ratio and frequency dynamics, and the field voltage measurement is decomposed by using the proposed decomposition method.