基于高低压电源切换的双环恒流控制电磁流量计励磁控制系统

High/Low Voltage Power Switching Based on Dual-Loop Constant Current Control for Electromagnetic Flowmeter Excitation Control System

为了提高电磁流量计高频方波励磁性能，基于励磁恒流控制仿真分析，采用外环高低压电源切换和内环电流微调的双环励磁恒流控制方式，以保证电磁流量计高频方波励磁时一次仪表输出信号零点稳定、电源利用效率高。设计方波励磁控制系统，以实现高频方波精确励磁。仿真结果表明，高压源电压越高越有利于拓宽励磁频率范围。实验结果表明，系统在高频方波励磁时，励磁电流响应速度快且电磁流量计传感器输出信号零点稳定。

Based on the simulation analysis of constant excitation current control, a novel method of dual-loop control for constant excitation current control is proposed in order to improve high-frequency square wave excitation performance of the electromagnetic flowmeter. This method includes an outer loop for high/low voltage power switching and an inner loop for current fine-tuning, which can ensure zero satiability of the sensor output signal and high power efficiency of the excitation system when electromagnetic flowmeter is excited by high-frequency square wave. A square wave excitation control system is designed to realize to excite the coil by high frequency precisely. The simulation results show that the higher the high voltage power, the more widely the excitation frequency can be expanded. The experimental results show that the speed of constant excitation current control is fast and the sensor output signal of the electromagnetic flowmeter has steady zero when the excitation system is excited by high-frequency square wave.