基于PWM控制的电磁流量计脉冲励磁系统分析与研制

Analysis and Development of Electromagnetic Flowmeter Pulse Excitation System Based on PWM Control

为了提高励磁频率和减少发热,使电磁流量计能够更好地用于浆液流量测量和灌装流量测量,并长期稳定、可靠地工作,研究了基于PWM控制的脉冲励磁方案,分析其工作原理,计算各种参数,研制实际系统,进行测试和实验。结果表明,该系统能实现更高的励磁频率,产生稳定的励磁电流,极大地减小了励磁系统的功耗,能去除微分干扰对流量信号测量的影响,水流量检定准确度优于0.5级。

In order to improve the excitation frequency and reduce heat generation, making electromagnetic flowmeter （EMF） be able to measure slurry flow and fill better, and also work in a stable way, the pulse excitation scheme based on PWM control method was studied, its operational principle was analyzed, its various parameters were calculated, the actual system was developed, and tests and experiments were conducted. Results showed that the system can realize the higher frequency excitation with stable excitation current, which greatly reduced power consumption of excitation circuit. It can also prevented the differential interference from influencing the flow signal and its verification accuracy was better than 0.5% on water flow calibration.