基于小波变换的循环流化床压力波动信号除噪分析

Study on reducing noise of pressure fluctuation signal in circulating fluidized bed

采用基于小波分析和分形理论的除噪方法对压力波动信号进行除噪,并将由此方法得到的信号与常用的Fourier滤波滤去20Hz、40Hz频率以上所得信号进行对比分析,结果表明,所提出的除噪方法能客观、有效地去除噪声,而Fourier滤波方法提取信号不能完全去除噪声的干扰。此外,循环流化床波动频率带随操作条件的不同而有所差异,所以在用压力波动信号对循环流化床混沌特性进行研究时,不能象Fourier滤波那样截去某个频率段。

A method was used to reduce noise based on wavelet transform and fractal theory. The pressure fluctuation signal in CFB was denoised with this method and Fourier transform (filtering>20 Hz and >40 Hz frequency) respectively. Results show that this method can reduce noise objectively and effectively. Fourier transform can not reduce the disturbance of low frequency. The frequency range in CFB changes with different operation conditions. Thus the true signal cannot be extracted simply by Fourier filter method.