基于模拟光纤传输的表面电流测试系统

Measurement System for Surface Current Based on Analogue Optic-fiber Transmission

为测试高强度辐射场环境中受试导体表面产生的感应电流,对该电流信号进行了研究,根据此信号的特点,提出了一套基于模拟光纤传输的表面电流测试系统设计方案。分析了表面电流信号检测的等效电路模型,并着重论述了测试系统的硬件电路设计及实现,包括内置电源电路设计、光发射与接收电路设计、印制电路板(PCB)设计及壳体设计等。使用点频法校准测试系统,并给出了该系统的传输阻抗校准曲线。由表面电流实测值和理论计算值的对比可知,两者能够较好吻合,证明了本文所提设计方案的可行性,表明该系统适用于强电磁场环境中受试导体表面感应电流的测试。该测试系统具有抗干扰能力强、测量精度高、幅值响应线性度好等特点,其可用工作带宽为70kHz～195MHz,该设计方案可为其他工作于类似强场强环境中的应用提供参考。

In order to measure induced current on the surface of conductor under test in high intensity radiated field（HIRF）,the surface current signal was studied.After analyzing the characteristic of the current signal,a system for measuring induced current flowing on the conductor surface was put forward based on analogue optic-fiber transmission.Equivalent circuit model of surface current signal detection system was given.Then hard circuits design and implementation of the measurement system were emphatically discussed.Certain parts of the hard design including schematic circuit of power supply,transmitter and AC coupled receiver circuit,printed circuit board（PCB） and current probe configuration design were described respectively.The measurement system was calibrated using point frequency method and the calibration curve of transfer impedance of the system was given.Subsequently,calculation and measurement values of surface current were compared.The comparison result shows that the calculation values have a good agreement with the measured ones.This demonstrates that the system put forward above is practicable,and can be used to measure induced current flowing on the surface of conductor under test in strong electromagnetic field.The measurement system has the characteristics of strong anti-interference ability,high accuracy of measurement,good linearity of amplitude response,and available operation bandwidth is from 70 kHz to 195 MHz.The design scheme presented above can provide reference for similar applications being in the environment of strong electromagnetic field.