电磁流量计矩形波励磁的信号模型研究

由于传统矩形波励磁模型未兼顾传感器磁路系统和励磁系统的影响，忽略了信号采样过程，因而无法建立符合实际的矩型波励磁流量信号模型。基于励磁电流的一般方程，提出了一种矩形波励磁模型，该模型建立了磁感应强度与磁路系统、励磁系统的数学关系，进而量化了微分干扰和同相干扰。在该励磁模型基础上，模拟电磁流量计对实际信号的采样过程，进一步提出了矩形波励磁的流量信号模型，并给出了模型参数的辨识方法。从流量信号仿真、模型基本参数辩识、零点漂移预测及基本误差估计4方面进行模型验证。仿真与实验结果表明，在DN50传感器上，其零点漂移预测的最大误差为1．48 mm／s，基本误差估计的最大偏差为0．270％。

Signal model with rectangular wave excitation for electromagnetic flowmeter

The traditional rectangular wave excitation model fails to take into account both the influence of the sensor magnetic circuit system and the excitation system simultaneously, and ignores the signal sampling process, thus, the signal model with rectangular wave excitation does not match the real conditions well. Based on the general equation of magnetic excitation current, a rectangular wave excitation model is proposed in this paper. This model demonstrates the mathematical relationship between the magnetic flux density and the relative parameters of magnetic circuit system and magnetic excitation system,and quantifies the differential interference and in-phase interference. On the basis of the proposed magnetic excitation model, a flow signal model with rectangular wave magnetic excitation is constructed via simulating the signal sampling process in electromagnetic flowmeter, and an identification method for the model parameters is also presented. A simulation experiment of flow signal and three practical experiments including model parameter identification, zero-point drift prediction and basic error estimation were carried out. The experimental results show that the maximum zero drift prediction error is 1.48 mm /s, and the maximum basic deviation is 0.270% .