关键词: 振动与波, 非稳态信号, 小波包变换, 信号分析, 燃料电池汽车

Abstract: Based on wavelet package transform technology, this paper proposes a method for analyzing the frequency characteristics of nonsteadystate signals in an energyratio and frequencyband coordinate system. Result of this method is compared with that of common frequency spectrum method. The correctness and feasibility of this method is verified. Meanwhile, taking the fan's noise signal of a fuel cell vehicle as an example with a lowfrequency sinusoidal interference signal chosen as the representation of periodic signals, the periodic signals hidden in the nonsteadystate signals are identified. Finally, the fan's noise signals are analyzed. The noise due to low and medium frequency vibration and the noise due to high frequency vibration in the signals are separated. Their information is extracted in timedomain. The measures for further noise reduction are proposed.

Key words: vibration and wave, nonsteadystate noise signal, wavelet package transform, signal analysis, fuel cell vehicle