谐波分析的加窗插值改进算法

加窗插值FFT是电力谐波分析的常用算法，文中在两方面对该算法进行了改进。提出了一类新的离散窗函数——矩形自卷积窗。m阶矩形自卷积窗由m个矩形窗通过卷积运算生成，其幅频特性在零点处的1-m-1阶导数均为0;谐波分析时，加这类窗可以最大限度地减小基波及各次谐波相互之间的频谱泄漏：另外，给出了适合新窗的插值算法，并对插值算法的一些常规做法进行了改进。基于新窗的改进算法易于实现，能显著提高谐波分析精度和减小计算量。仿真分析和实践验证了其可行性和有效性。

IMPROVED WINDOW AND INTERPOLATION ALGORITHM FOR ANALYSIS OF POWER SYSTEM HARMONICS

It is improved in two aspects to the traditional window and interpolation algorithm, which is now widely employed to estimate power harmonics parameters. Firstly, a new kind of windows, called as Rectangular Self-Convolution Windows (RSCW), is presented. The m-order RSCW is developed by convolving m rectangular sequences; and in the zero points of its amplitude-frequency characteristic, the value of m-1 order derivatives is zero. As a result of this character, the interferences between the harmonics due to spectrum leakage can be reduced furthest by applying RSCW, therefore, the precision of harmonics estimation is boosted. Secondly, an interpolation algorithm suitable for RSCW is given, and some novel measures are taken to reduce the computational load. At last, the feasibility and effectiveness of the improved algorithm based on RSCW is verified by the results of both simulations and practice.