基于加窗插值FFT和动态频率的谐波检测算法

快速傅立叶变换在非同步采样的情况下存在较大的误差，因而无法在电能计量过程中获取准确的谐波能量。为了减小非同步采样对快速傅立叶变换的影响，提高电能计量的精确度，通常采用加窗的方法。本文详细分析和推导了加窗插值算法。在此基础上，采用Hanning窗，对插值算法进行改进，最后通过仿真试验，分析结果进一步验证了，改进后的谐波分析的结果与实际情况更为接近。

A harmonic measuring approach based on windows and interpolated FFT and dymamic frequency

The FFT has a higher error when used with a sample sequence which is not synchronized with the signal, which makes that the electric harmonic energy can not be gotten accurately. To reduce the influence of an unsynchronized sample on FFT and improve the precision of the harmonics in electric energy metering, the windows and interpolation methods is usually used. This paper analyzes the interpolation algorithm in detail. After that, we make a fitter change to the interpolation formula on Harming window. An example of simulation is given and validates that the improved algorithm hold a very high precision.