Phase difference estimation method for Coriolis mass flowmeter based on correlation and Hilbert transform

The phase difference estimation methods for Coriolis Mass Flowmeter are unsuitable for many high precision flow measurement areas, due to high computational load, high calculation complexity, low real-time performance, and poor accuracy. To solve these issues, a new phase difference estimation method for Coriolis mass flowmeter is proposed based on correlation and Hilbert Transform. Firstly, the signal frequency is estimated by FFT, which is used to determine the integrer period of the sampling signal, and the non-integer period sampling signals need to be extended. Then, the same frequency reference signal can be generated by using auto-correlation of original signal. Then, the Hilbert Transform is conducted to these three signals, and the correlation functions of these three signals with the transformed three signals can be computed. Finally, the formula of phase difference can be obtained by utilizing the sine functions. Compared with traditional methods, 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. Simulations and experiment results verify the effectiveness and superiority of the proposed method. © 2017, Science Press. All right reserved.