面向批料流测量的科氏质量流量计正交解调方法实现

为了提高科氏质量流量计在批料流工况下的测量精度,根据正交解调算法具有快速响应的特点,选取该算法作为批料流下的信号处理方法,并解决实现过程中的技术难点。利用正弦信号周期性的特点,实现解调信号单周期有限点数据循环调用;采用FIR陷波器和IIR低通滤波器级联完成对解调后信号的滤波,在保证滤波效果的同时降低了算法运算量;为了去除计算结果中的奇异点同时减小稳态波动,在相位差后期处理中加入两级平均;优化了算法实现过程中的资源分配。在此基础上,研制了科氏质量流量变送器,并进行了单相流和批料流标定实验,其测量误差小于0.1%,重复性小于0.05%。实验结果表明,正交解调算法在批料流下具有较好的测量精度,同时所研制的变送器具有较好的性能。

Realization of Quadrature Demodulation Method for Coriolis Mass Flowmeter under Batch Flow Measurement

In order to improve the measurement accuracy of the Coriolis mass flowmeter under batch flow conditions,the quadrature demodulation algorithm is selected as the signal processing method according to the characteristics of rapid response,it solves the difficulties in the implementation process. the demodulation signal with single period finite point data is realized by using the periodic characteristics of the sinusoidal signal;besides the demodulated signals are filtered by cascading the FIR notch filter and the IIR low-pass filter while guarantee accuracy and reduce algorithmic computation;a secondary average is added in the post-processing in order to reduce the steady-state fluctuations and remove the singular points in the calculation results,in addition,the resource configuration during algorithm implementation is optimized. On this basis,the Coriolis mass flow transmitter was developed,and the single-phase flow and batch flow calibration experiments were carried out. The measurement error was less than 0.1% and the repeatability was less than 0.05%. The experimental results show that the quadrature demodulation algorithm has better measurement accuracy under the batch flow,and the developed transmitter has better performance.