科氏质量流量计相位差的一种高精度估计方法

High-precision method of phase difference estimation in Coriolis mass flowmeter

科氏质量流量计是一种用于直接测量质量流量的流量计,其测量精度易受环境噪声的影响。为提高其精度,提出了一种高斯噪声背景下的科氏质量流量计相位差估计新方法。当传感器信号频率在较小范围内缓慢波动时,通过锁相环实现整周期采样。采用离散傅里叶变换计算两路传感器信号的相位差,并实现了219点离散傅里叶变换,以获得精确的相位估计值。与快速傅里叶变换相比,所提出方法具有计算量小、计算速度快等优点,大大降低了数据处理容量。仿真结果表明:当信噪比高于0dB时,该方法的相位估计误差小于0.12°。

Coriolis mass flowmeter,a type of flowmeter for mass flow measurement,is sensitive to environmental noise.A novel method of phase difference estimation under Gaussian noise is proposed to improve the precision of Coriolis mass flowmeter.As the sensor’s sinusoid frequency fluctuates slowly in a limited scope,a phase-locked loop is used to realize synchronous sampling.The phase difference of signals from two sensors is calculated by DFT and 2^(19)-point DFT is fulfilled to get accurate estimating phases,in which RAM for sampled data storage and DFT algorithm is much less than that for algorithm of FFT.Simulation results show that phase estimating error is less than 0.12 when signal-to-noise ratio is higher than 0dB.