磁感应传输钻杆耦合器设计及仿真研究

Design and Simulation of Drill Pipe Coupler with Magnetic Induction Transmission

磁感应耦合传输技术是一种高效的随钻数据传输技术。分析了感应耦合线圈的磁感应传输机理,以成熟的高频变压器电路模型为基础,建立了感应耦合器的电路模型。基于磁感应传输原理设计了耦合器,并选择锰锌铁氧体作为磁芯材料。利用COMSOL软件建立磁感耦合器的二维轴对称模型。该模型由铜导线圈、"U"型铁氧体和空气域组成。通过该模型研究了耦合器的磁场分布及频率特性,结果表明:"U"型铁氧体中的磁场强度远大于周围空气的磁场强度,原边线圈的"U"型铁氧体磁场强度最大,副边线圈的磁场强度次之;磁感应耦合器输出信号幅值随着两个耦合器间距的增大而减小;随着频率的增大,输出信号的幅值先增大后减小,频率为2.1MHz时幅值最大。实验所得耦合器频率特性曲线与仿真结果较为吻合,验证了磁感应电路模型的有效性,为该技术的进一步研究提供了理论支持。

Magnetic inductive coupling is an efficient technology for data transmission with drilling.The prin-ciple of magnetic induction transmission of inductive coupling coil was analyzed.Based on circuit model of mature high-frequency transformer,the circuit model of inductive coupler was designed.Based on the principle of magnetic induction transmission,a coupler was designed.Mn-Zn ferrite is the material of magnetic core.The circuit model of coupler was established based on high-frequency variable voltage model,which realizes contact-less transmission of signals among drill pipe.The magnetic field distribution and frequency characteristics of the coupler were researched with COMSOL software.The results show that magnetic field intensity of U fer-rite is far greater than that of the ambient air,the U ferrite magnetic field intensity of primary side coil is the maximum,and the magnetic field intensity of vice side coil is the second;The output signal amplitude of the magnetic inductive coupler decreases with the increase of the two couplers ＇ distance;The output signal amplitude increases first and then decreases with the increase of the frequency,and the output signal amplitude is the maximum when the frequency is 2.1MHz.The frequency characteristic curves of the coupler ob-tained by experiment are in good agreement with the simulation results,and the validity of the circuit model of magnetic induction is verified,which provides theoretical support for the further research.