采用直流分量恢复法的直流系统谐波分析

直流系统中绝大多数谐波以叠加在直流分量上的形式存在,为了实现此类混合信号的精确分析,提出了一种直流分量恢复法用于谐波分析.根据加窗傅里叶变换的可加性原理,对混合信号进行加窗傅里叶变换不会影响到直流分量和谐波分量的各自分析结果,因此不需要对直流分量进行滤除就能同时实现直流分量和谐波分量的精确分析,保留了谐波信号分析的完整性.通过分析加窗傅里叶变换对直流分量幅值的影响,提出利用直流分量恢复系数对变换后的幅值进行恢复,针对谐波分量采用双峰谱线插值进行修正,进一步提高分析精度.仿真结果验证了方法的有效性且实现过程简单.

Harmonic Analysis of DC System Using DC Component Recovery Method

Most of the harmonics in the DC system exist in the form of superposition on the DC component. In order to achieve accurate analysis of such mixed signals, a harmonic analysis method using DC component recovery is proposed. According to the additivity principle of the windowed Fourier transform, the windowed Fourier transform of the mixed signal does not affect the respective analysis results of the DC component and the harmonic component, so that it is not necessary to filter the DC component at the same time. Accurate analysis of DC and harmonic components is achieved, retaining the integrity of harmonic signal analysis. By analyzing the influence of windowed Fourier transform on the amplitude of DC component, it is proposed to recover the transformed amplitude by DC component recovery coefficient, and the harmonic component is corrected by double-peak spectral line interpolation to further improve the analysis accuracy. The simulation results verify the effectiveness of the method and the implementation process is simple.