基于改进加窗插值FFT的高精度谐波与间谐波检测算法  

Precise Algorithms for Harmonic and Inter-Harmonic Detection based on Improved Window-Interpolated FFT Method

作　　者：陈子珍[1] 夏冰冰[1] 阎威武[2] 

机构地区：[1]宁波职业技术学院海天学院,浙江宁波315800 [2]上海交通大学自动化系,上海200030

出　　处：《中国电力》2015年第9期73-79,共7页Electric Power

基　　金：浙江省自然科学基金资助项目(Y1100417);2013年度浙江省高职高专院校专业带头人专业领军资助项目(LJ2013032)~~

摘　　要：大量非线性元件的应用给电力系统带来了大量的整数次和非整数次谐波(称为间谐波),传统的谐波检测方法——快速傅里叶变换(fast Fourier transform,FFT)算法基于同步采样的方式,不适用于非整数次谐波的检测分析。频谱泄漏现象是由于有限长信号的傅里叶变换与理想傅里叶变换的不同而产生的。为了消除频谱泄漏,提出了基于余弦窗的插值FFT算法,给出了K项余弦窗插值的参数估计通式,并对矩形窗和汉宁窗的插值算法通过实例进行了验证。结果表明,基于汉宁窗的插值算法在基波频率偏离额定值或者大量间谐波存在的情况下,都能在非同步采样下准确地检测出谐波和间谐波的频率、幅值和相角。同时该算法也和其他非同步采样方法进行对比,结果表明,该算法较文献中方法具有精度高、计算复杂度降低的优点。The wide use of nonlinear components in power system produces integer and non-integer harmonics in the electrical power system. The conventional harmonic t algorithm-Fast Fourier Transform （FFT） is suitable for harmonic analysis under synchronized sampling condition, but is not capable to analyze non-integer harmonics due to its leakage effect. The leakage of FFT algorithm is caused by the different characters between the theoretic implementation of the Fourier Transform which deals with infinite signals and the practical implementation of Fourier Transform which deals with finite signals. The differences give rise to the measurement errors of inter-harmonics of FFT algorithm. In order to overcome the leakage effect of FFT algorithm, a new desynchronized signal processing technique is proposed, which is based on poly-item cosine window （CW） interpolation. The general expression of parameter estimation by K-item cosine window is obtained. Generally, extensive simulation results are provided to verify the validity and effectiveness of the proposed algorithm based on rectangular window and hanning window, which reveals that the frequencies, amplitudes and phase angles of the harmonics and the inter-harmonics are accurately calculated, even under significant fundamental frequency deviations in the input signal by adopting hanning window interpolation. Moreover, the proposed technique is found to have overwhelming advantages in terms of the improved estimation accuracy and the reduced computational burden compared to the existing unsynchronized sampling techniques in literature.

关 键 词：傅里叶变换 谐波与间谐波检测 栅栏效应 频率偏移偿相频特性 

分 类 号：TM935[电气工程—电力电子与电力传动]