适用于频率偏移情况下谐波参数估计的改进算法  

Improved algorithm for harmonic parameters estimation under frequency offset

作　　者：马也驰[1] 陈隆道[1] 

机构地区：[1]浙江大学电气工程学院,浙江杭州310027

出　　处：《机电工程》2017年第9期1038-1043,共6页Journal of Mechanical & Electrical Engineering

摘　　要：针对电网信号基波频率偏移时传统相位差校正法测量结果存在较大误差,甚至可能产生测量失败的问题,提出了一种基于传统相位差的改进算法。将电网电压信号加入Blackman-Harris窗,通过分析加窗信号的频谱表达式,研究了电参量估计的误差来源,将频谱表达式进行了多项式变换从而加快了旁瓣衰减速度,进一步减轻频谱泄漏和各谱线之间的干扰,再依据传统相位差法的估计公式和多项式变换所得的新频谱表达式对电参量进行了重新估计。分别使用传统相位差法和经多项式变换的改进相位差法进行了数值仿真对比。研究结果表明:改进算法较传统相位差法相比各次谐波的测量精度提高了至少一个数量级,适用于频率偏移情况下电力系统谐波参数的高准确度估计;即使在噪声条件下,改进算法的优势也比较明显。Aiming at the problem that the traditional phase difference correction method has a large error in the measurement of the fundamental frequency offset of the power grid signal,it may even produce the problem of measurement failure. An improved algorithm based on the traditional phase difference was proposed. The voltage signal of the grid was added to the Blackman-Harris window. By analyzing the spectral expression of the windowed signal,the error source of the electrical parameter estimation was studied,and the spectral expression was polynomial transformed to accelerate the sidelobe decay rate,further reduce the spectral leakage and the spectrum Line,and then re-estimate the electrical parameters according to the new spectral expression obtained from the estimation formula of the traditional phase difference method and the polynomial transformation. Respectively,using the traditional phase difference method and the polynomial transformation of the improved phase difference method for numerical simulation comparison. The results indicate that the improved algorithm is improved by at least one order of magnitude compared with the traditional phase difference method,and it is suitable for the high accuracy estimation of the harmonic parameters of the power system under the frequency offset. Even under the noise condition,The advantages of the algorithm is also more obvious.

关 键 词：谐波分析 频率偏移 加窗傅里叶变换 相位差 多项式变换 

分 类 号：TM935.21[电气工程—电力电子与电力传动]