计及噪声的动态谐波准同步采样分析方法

Dynamic harmonic analysis method based on quasi-synchronous sampling algorithm considering noise

电网中非线性负荷投切等使谐波具有明显的动态特性,为此,提出一种基于准同步采样算法的动态谐波分析方法,从理论层面分析噪声对谐波频率测量的影响,建立谐波频率测量方差理论式。准同步采样算法通过复化梯形积分和迭代法计算信号局部频谱,通过适当增加采样周期和迭代次数减小同步偏差对测量准确度的影响。仿真和实验结果表明所提算法能准确测量谐波参数。

The harmonic has obvious dynamic characteristics caused by the switching of nonlinear load, for which, a dynamic harmonic analysis method based on QSSA （Quasi-Synchronous Sampling Algorithm） is proposed. The impact of noise on harmonic frequency measurement is analyzed theoretically, and the theoretical variance expression of harmonic frequency measurement is built. QSSA calculates local signal spectrum by composite trapezoidal integra- tion and iteration procedure, and reduces the impact of synchronous deviation on measurement accuracy by increasing sampling period and the number of iteration. Simulative and experimental results show that the proposed method can accurately measure the harmonic parameters.