过零检测和曲线拟合的电力系统频率算法

Power System Frequency Algorithm Based on Zero Crossing Detection and Curve Fitting

提出了一种基于带通滤波、过零检测和最小二乘非线性曲线拟合的新型离散傅里叶变换DFT(discreteFourier transform)频率算法。首先将原始信号经过带通滤波器滤波后,用过零检测算法计算其频率并将此值作为最小二乘非线性曲线拟合参考频率;之后对拟合后的正弦曲线进行重采样得到重采样数据;再对重采样数据运用DFT算法计算频率。仿真实验结果表明,所提算法能抑制或消除噪声以及频率波动对频率同步测量的影响,提高了频率测量精度。

In this paper, a new discrete Fourier transform （DFT）frequency algorithm is proposed based on band pass fil- tering, zero crossing detection and least square nonlinear curve fitting. First, the original signal is filtered by a band pass filter, and zero crossing detection is used to calculate the frequency value of filtered signal, which is adopted as the reference frequency of least square nonlinear curve fitting. Second, the fitted sine curve is resampled, and DFT algorithm is used to calculate the frequency of resampled data. The simulation results show that the proposed algorithm can restrain or eliminate the effect of noise and frequency fluctuation on the frequency synchronization measurement, which improves the accuracy of frequency measurement.