基于Burg法AR模型谱估计的涡街流量计旋涡脱落频率提取

孙志强^{1, 2}，陈延平^{1, 2}

(1. 中南大学 能源科学与工程学院，湖南 长沙，410083；2. 中南大学 流程工业节能湖南省重点实验室，湖南 长沙，410083)

摘 要：为了从含噪信号中准确高效地提取出旋涡脱落频率，采用基于Burg算法的AR模型谱估计对测量介质为水、流量范围为3~35 m³/h的涡街流量计输出信号进行分析，讨论AR模型阶次对旋涡脱落频率估计性能的影响，建立频率相对误差小于3%的AR模型最小阶次与旋涡脱落频率的拟合关系式。结果表明，基于Burg算法的AR模型谱估计对涡街流量计旋涡脱落频率的提取精度较高；AR模型的阶次对Burg算法的谱估计精度和计算效率有重要影响，应选用匹配的AR模型阶次对涡街流量计输出信号进行估计；AR模型最小阶次随旋涡脱落频率的增大而减小。

关键词：涡街流量计；旋涡脱落频率；谱估计；AR模型；Burg算法

Extraction of vortex flowmeter frequency by Burg algorithm based AR model spectral estimation

SUN Zhiqiang^{1, 2}, CHEN Yanping^{1, 2}

(1. School of Energy Science and Engineering, Central South University, Changsha 410083, China;2. Hunan Key Laboratory of Energy Conservation in Process Industry, Central South University, Changsha 410083, China)

Abstract:The Burg algorithm based AR model spectral estimation was used to analyze the output signals of a vortex flowmeter within water flow rates from 3 to 35 m³/h, to extract the vortex shedding frequency from noisy signals accurately and effectively. The effect of the AR model’s order on the estimation of vortex shedding frequency was discussed. A fitting correlation was established between the minimum AR model’s order and the vortex shedding frequency with an error of 3%. The results show that the accuracy of the vortex shedding frequency extracted is high by the Burg algorithm based AR model spectral estimation. The AR model’s order has a marked influence on the spectral estimation accuracy and the computation efficiency of Burg algorithm, which suggests that an appropriate order be selected to estimate the vortex shedding frequency from vortex flowmeter output signals. The minimum AR model’s order decreases with the increase of vortex shedding frequency.

Key words:vortex flowmeter; vortex shedding frequency; spectral estimation; AR model; Burg algorithm