非正弦状态下有功功率和功率因数测试

基于小波变换自适应分解层数门限去噪算法是去除数字信号中白噪声的有效方法,仿真结果表明,该方法具有较好的去噪效果,尤其适合于如电机测试这样的强噪声背景下弱信号的检测。采用三角窗加权算法并结合小波变换计算非正弦状态下三相异步电机有功功率、功率因数,其测量误差与相对频偏的平方成正比。该方法有实现简单,精度高,当相对频偏不大时,无须专门的同步措施可取得较高的测量精度。

Active Power and Power Factor Measurement Under Non-sinusoidal Waveform in Three-phase Circuit

Threshold de-noising based on wavelet transform which is proposed to determine the decomposition order adaptively is an efficient method to reduce the white noise in the digital signal.Simulation results show that the method proposed in this paper has good per- formance .It is especially suitable for the detection of faint signal under strong noise back- ground like motor testing.A weighted algorithm of Triangular window and wavelet transform are using to measure active power and power factor of three-phase asynchronous motor in the non-sinusoidal waveform.The error of active power and power factor is proportional to square of relative frequency deviation.The algorithm is characterized by easy implementa- tion,high precision.If the relative frequency deviation is not very large,a higher measuring precision still could be achieved even if the synchronous sampling technique was not uti- lized.