磁翻柱液位计中容栅传感器电容极板的优化设计

Optimum Design of the Polar of Capacitance Sensing Electrode Array in Magnetic Level Meter

设计了一种新型容栅传感器,使磁翻柱液位计在更广泛的工况条件下,仍能准确地测量液位值并实现电信号远传．采用Hybrid-Trefftz有限元方法建立传感器中电场的数学模型,并精确地计算出磁翻柱翻转所引起的电容相对变化量．以此电容相对变化量为目标函数,分别对4种不同形状的电容极板和同形状不同结构参数的极板进行定量研究．从电容相对变化量随电容极板结构的变化曲线中,可知形状2且极板间距为5 mm为极板的最优形状．以此结构的样机进行实验,结果表明,此传感器极板结构的优化与实验相吻合,其仿真值与实验值的相对误差仅为3．3％．

To enable magnetic level meter to measure the level accurately and transmit the electric signal under wider working conditions, a new type of capacitance array sensor is designed. Using Hybrid-Trefftz finite element method, the change of electrostatic field that happens between the electrodes of the sensor is analyzed, its mathematical model is established, and the relative variation of capacitance caused by the magnetic pole turning around can also be counted. Taken the relative variation of capacitance as an object function, there are four different types of electrodes that will cause different relative variation of capacitance. It is seen from the curves between the relative variation of capacitance and the structure of capacitance electrode that the second type of electrode with 5 mm space between electrodes is the optimum structure. The relative error between the simulation results and experimental values is only 3.3%, proving that the optimum design accords with the experiment.