基于高倍过采样与加窗插值FFT的电力谐波分析

为提高谐波分析精度，分析了信号加窗引起的信噪比损失以及AD转换产生的量化误差，阐述了过采样技术提高信噪比的原理。在此基础上，提出了基于高倍过采样和加窗插值快速傅里叶变换(fast Fourier transform, FFT)的谐波分析方法。该方法充分利用AD转换器的潜力，以尽量高的采样速率进行AD采样，同时通过均值滤波避免高倍过采样引起的采样数据量激增问题。详细研究了所提谐波分析方法对信号中谐波分量幅值和相位的影响，并给出了简洁实用的谐波幅值和相位校正方法。仿真表明，所提方法可在不增加系统成本的前提下改善加窗插值FFT的抗噪声能力，提高谐波分析精度。

Power harmonic analysis based on high-rate oversampling and windowed interpolation FFT

To improve the accuracy of harmonic analysis, the signal-to-noise ratio loss caused by signal windowing and the quantization error caused by AD conversion is analyzed, and the principle of improving signal-to-noise ratio by oversampling technology is expounded. A harmonic analysis method based on high-rate oversampling and windowed interpolation FFT is proposed. This method makes full use of the potential of an AD converter to take samples quickly, and at the same time, it avoids the surge of sampling data caused by high oversampling through mean filtering. The influence of the proposed method on the amplitude and phase of harmonic components in the signal is studied in detail, and a concise and practical correction method of harmonic amplitude and phase is given. Simulation results show that the proposed method can improve the anti-noise ability of windowed interpolation FFT and the accuracy of harmonic analysis without increasing system cost.