基于EWT的离心压气机出口动态压力样本熵分析

以800 kW离心压气机从稳定状态经过过渡过程进入喘振状态时段的出口动态压力为研究对象，采用经验小波变换并结合样本熵特征，分析了系统在不同工况下的复杂特性。首先，在分析系统动态压力波形特征的基础上，采用经验小波变换并结合皮尔逊相关系数进行信号的提取。其次，研究了提取信号的样本熵与系统工作状态变化的关联关系，并讨论了经验小波的分解层数和样本熵的维数对分析结果的影响。最后，通过将白噪声加入原始信号以验证该方法的抗干扰性能。研究结果显示：当系统由稳态进入喘振状态时，系统出口动态压力的样本熵表现出明显的突变特性，其值由0突变至0.7左右。从系统参数的选择角度，样本熵维数的变化对系统特征的分析影响较小。并且，采用该方法抗干扰性能较好。

Sample entropy characteristics of dynamic pressure at outlet of centrifugal compressor based on EWT

Taking the dynamic outlet pressure of the 800 kW centrifugal compressor during the period of transition from steady state to surge state as the research object, the empirical wavelet transform combined with sample entropy characteristics was used to analyze the complex characteristics of the system under different working conditions. First, on the basis of analyzing the characteristics of the dynamic pressure waveform of the system, the empirical wavelet transform combined with the Pearson correlation coefficient was used to extract the signal. Second, the relationship between the sample entropy of the extracted signal and the change of the system working state was analyzed to discuss the influence of the decomposition layer of the empirical wavelet and the dimension of the sample entropy on the analysis result. Finally, white noise was added to the original signal to verify the anti-interference performance of the method. The research results showed that when the system entered the surge state from the steady state, the sample entropy of the system outlet dynamic pressure showed an obviously sudden change characteristics, and its value changed from 0 to about 0.7. From the perspective of the selection of system parameters, the change of sample entropy dimension had little effect on the analysis of system characteristics. In addition, this method had better anti-interference performance.