基于改进复调制细化法和加窗插值快速傅里叶变换的电力系统谐波分析

Power System Harmonic Analysis Method Based on Modified Multiple Modulation Zoom Analysis and Windowed Interpolation FFT

当遇到含有频率接近成份的谐波信号时,加窗插值傅里叶变换(fast Fourie transform,FFT)等传统的谐波分析方法不能准确地进行分析。文章采用基于复解析带通滤波器的复调制细化法对频率接近的谐波成份进行细化分析,然后再用加窗插值FFT分析其他频率成份。与直接使用加窗插值FFT法对比的仿真分析表明,该方法能够以较高的频率分辨率分析出频率较接近的谐波成份。

Along with the utilization of lots of power electronics equipments, more and more harmonics and inter-harmonics occur in power system, however when the analyzed signal contains components with frequencies close to each other, precise analysis couldn＇t be made by traditional harmonics analysis methods such as windowed interpolation FFT method. A new method, namely multiple modulation zoom analysis based on complex analytic band-pass filter, is adopted to make accurate analysis to this kind of components, and then the remaining components are also analyzed by windowed interpolation FFT. Simulation results of the proposed method show that comparing with the results from directly using windowed interpolation FFT, the harmonic contents with frequencies close to each other can be the proposed method can recognized with higher frequency resolution.