A Novel Phase Difference Measurement Method for Coriolis Mass Flowmeter Based on Correlation Theory

Aiming at the poor precision problem in phase difference measurements with unknown frequencies in engineering practice, a new phase difference measurement method is proposed for Coriolis mass flowmeter based on correlation theories. Firstly, the signal frequency was estimated by using an adaptive notch filter, which was applied to filter the waves and determined the integer period of the sampling signals, and the non-integer period sampling signals needed to be extended. Then, the Hilbert transformation was conducted relative to the extended signals, and the correlation functions of these extended signals with the transformed signals can be computed. Finally, the formula of phase difference can be obtained by utilizing the sinusoidal function. Compared to traditional methods, such as the correlation method, the Hilbert transformation method, and sliding Goertzel algorithm, the proposed method is suitable for both integer period and non-integer period sampling signals, and its accuracy, real-time, and dynamic performance is superior. Simulation and experiment results validate the superiority and effectiveness of the proposed method.

Automated summary

A new phase difference measurement method for Coriolis mass flowmeter is proposed based on correlation theories, aiming to solve the poor precision problem in phase difference measurements in engineering practice. The method estimates the signal frequency using an adaptive notch filter, conducts Hilbert transformation on the extended signals, and computes the correlation functions. Compared to traditional methods, the proposed method is suitable for both integer period and non-integer period sampling signals, and demonstrates superior accuracy, real-time performance, and dynamic performance.