【摘要】 小波变换可以在非同步交流采样情况下,提取畸变信号中的基波分量,但检测结果存在少许误差。三点法可通过任意三个等间隔检测点提取正弦信号频率,但检测点误差会严重影响测频精度。对三点法误差的数学机理进行分析发现,合理的选择检测点之间的间隔可以使结果误差最小。极值分析和牛顿迭代法可被用来近似计算最优检测点间隔。通过误差的抑制和个别较大误差结果的剔除,小波变换能与三点法结合对电网中畸变信号的基波频率进行高精度检测。仿真算例证明本文算法精度要优于小波变换与过零法或极值法结合的算法精度。更多还原

【Abstract】 Fundamental component can be extracted from distorted signal by wavelet transform under asynchronous sampling.But there are a few errors in the results.The three-point algorithm can be used to detect sinusoidal signal frequency by any three equal interval detection points.But the errors of detection point might seriously affect detection precision.The analysis on mathematics mechanism of three-point algorithm errors proved that the errors can be reduced to the greatest degree by choosing points number between detection points reasonably.The extreme value analysis and Newton Iteration Method can be used to solve optimal points number between detection points approximately.The wavelet transform and three-point algorithm can detect fundament frequency high precisely by reducing results and rejecting minority results which have gross errors.The instance simulation shows the precision of proposed algorithm is higher than precision of algorithm combined of wavelet transform and zero crossing or peak value detecting.更多还原