大型水轮发电机组机械振动信号随机噪声控制

Random Noise Control of Mechanical Vibration Signals for Large Hydroelectric Generating Units

由于传统大型水轮机发电机组机械振动信号受到环境干扰,其稳定性较差,难以准确判断机组机械运行状态。因此,提出了一种基于变分模态分解-小波变换的振动信号随机噪声控制方法。采用交替方向乘子法和拉格朗日函数建立了振动信号模态分解寻优函数模型,并通过傅里叶变换和变分约束条件完成了振动信号的模态分解。使用能量差方式确定分层数,通过Stein无偏似然估计确定小波系数的阈值,得出随机噪声,并将剩余模态层信息重构,得出实际振动信号,实现了随机噪声控制。实验结果表明,该方法在振动信号随机噪声控制方面效果好且用时短。

Due to environmental interference on the mechanical vibration signals of traditional large water turbine generator units,their stability is poor and it is difficult to accurately determine the mechanical operation status of the units.Therefore,a random noise control method for vibration signals based on variational mode decomposition wavelet transform is proposed.A modal decomposition optimization function model for vibration signals was established using the alternating direction multiplier method and Lagrange function,and the modal decomposition of the vibration signals was completed through Fourier transform and variational constraints.The energy difference method is used to determine the number of layers,and the threshold of wavelet coefficients is determined through Stein unbiased likelihood estimation to obtain random noise.The remaining modal layer information is reconstructed to obtain the actual vibration signal,achieving random noise control.The experimental results show that this method has good performance and short time in controlling random noise in vibration signals.