采用加窗插值FFT与逐幅谐波消去法的电机谐波算法

对电机的实测信号进行谐波分析时,由于难以保证信号同步采样和存在测量噪声,采用快速傅立叶变换(FFT)方法进行谐波分析会出现栅栏效应和频谱泄漏现象,不能获得信号准确的谐波参数.作者采用加窗插值FFT,并提出逐幅谐波消去法,以便能精确地分析高次谐波.以基于Blackman-Harris窗的加窗插值FFT算法推导出关于频率偏差的9次方程.实例计算表明,采用加窗插值FFT和逐幅谐波消去法可有效地减少泄漏,降低噪声的干扰,从而可精确地获得各次谐波的幅值和相位.

Harmonic analysis in the electric machine based on windows and interpolated FFT and harmonic expurgation according to amplitude

Due to non-synchronous sampling and noise in electric machine harmonic measurement,the picket-fence and leakage effect is introduced by fast Fourier transform,so that the accurate electric harmonic parameters can't be achieved.So,the windows and interpolated FFT is developed,and the harmonic expurgation according to amplitude is put forward for high order harmonic parameters analysis in this paper.The 9th order equation of the frequency offset based on Blackman-Harris window and interpolated FFT is derived.Through the analysis of an example,it is proved that the methods can effectively reduce the leakage error and the noise interference.Thus the high accurate electric harmonic parameters can be achieved by the methods.