信号参数变化时系统频率准确测量方法

提出一种基于快速傅里叶变换FFT(Fast Fourier Transfom)准确测量系统频率的算法，并考虑了被测量系统频率的电压信号有效值的波动对系统频率测量准确度的影响。电压在其额定值附近变化对系统频率测量准确度影响较小，而偏离额定值越大对系统频率测量准确度影响较大。只要被测系统频率的电压有效值在170～260V范围内变化，所提出的算法可以使系统频率测量的准确度高于0．1％。给出的实例计算及仿真结果证明了这种算法的实用性、准确性和快速性。

Accurate estimation method of system frequency for signals with changeable parameters

A FFT(Fast Fourier Transform) based algorithm for frequency measurement of power system taking amplitude and phase fluctuation of signal into consideration. Frequency measurement is affected at a little degree if the amplitude fluctuates with smaller range around its rated value,and frequency measurement is affected at a great degree if the amplitude fluctuates with larger range around its rated value. The proposed algorithm guarantees a accuracy of 0.1 % for frequency mea-surement with a amplitude fluctuation range 170 ~260 V. Using Matlab software,the simulation results of the test example are satisfactory.