电磁流量计干扰信号识别及处理方法研究  

Research on Interference Signal Identification and Processing Method of the Electromagnetic Flowmeter

作　　者：徐志敏 辛会翠 李晋[3] 王磊[3] 王大平 XU Zhimin;XIN Huicui;LI Jin;WANG Lei;WANG Daping(Hebei University of Petroleum Technology,Chengde 067000,China;Instrumentation Engineering Technology Research Center of Hebei Province,Chengde 067000,China;Hunan Normal University,Changsha 410000,China;Chengde Central Power Electronic Co.,Ltd.,Chengde 067000,China)

机构地区：[1]河北石油职业技术大学,河北承德067000 [2]河北省仪器仪表工程技术研究中心,河北承德067000 [3]湖南师范大学,湖南长沙410000 [4]承德市中威电子有限公司,河北承德067000

出　　处：《仪表技术》2022年第2期55-58,共4页Instrumentation Technology

基　　金：承德市科技计划(202001B009);中央引导地方科技发展资金资助项目(206Z1705G)。

摘　　要：针对电磁流量计在液体测量时因受气泡干扰而造成测量信号波动剧烈、测量精度降低的问题,提出了基于自适应噪声识别和形态滤波的去噪处理方法。计算3点采样值方差,统计10点采样值方差总和、最大方差与方差总和之比,以及连续采样点间波动大于5 mV的个数等参数,作为判别是否存在噪声的依据。通过对方差总和进行等级划分,确定滤波阈值,实现自适应噪声识别。采用形态滤波进行噪声抑制,通过计算10点采样值噪声特征,包括尖峰噪声个数、尖峰噪声宽度,自适应选择不同尺度的结构元素进行形态滤波处理。依据正常流量信号具有的低频信号特征,判别是否存在滤波失效的情况及作进一步处理。实验结果表明,此方法在气泡干扰下可以实现干扰信号的有效识别及流量信号的平稳输出,信号处理效果达到国内领先水平。In view of the fact that the electromagnetic flowmeter is interfered with the bubbles in the liquid measurement which causes the fluctuation of the measurement signal and the measurement accuracy is greatly reduced,a method based on adaptive noise recognition and mathematical morphology filtering is proposed.By calculating the variance of 3 sampling points,and counting the sum of variance of 10 sampling points,the ratio of the maximum variance to the sum of variance and the number of continuous sampling points whose fluctuation is more than 5 mV,the noise can be judged.The filtering threshold can be determined by grading the sum of variance to realize adaptive noise recognition.The mathematical morphology filtering algorithm is used to suppress the noise.By calculating the noise characteristics of the 10 point sampled values,including the number of spike noise and the peak noise width,the morphological elements of different scales can be adaptively selected for mathematical morphological filtering.According to the characteristics of the low frequency signal,the normal flow signal is used to judge whether there is filtering failure.Through experimental tests,it is verified that the method can effectively identify disturbance signals and smooth output of flow signals under bubble interference,and the signal processing effect reaches the leading level in China.

关 键 词：电磁流量计 低频励磁 噪声识别 数学形态学 信号处理 

分 类 号：TH852[机械工程—仪器科学与技术]