一种抗干扰涡流检测激励信号源的设计

Design of an Excitation Signal Source for Eddy Current Testing with Anti-interference Ability

为提高涡流检测中激励信号源的精度,介绍了一种应用线性控制理论设计涡流检测激励信号源的方法。首先,构建了多输入单输出(MISO)反馈控制系统,实现对涡流传感器的恒流驱动;其次,设计了模块电路,分析了MISO反馈控制系统的稳定性和系统干扰的来源与抑制方法;最后,建立该系统的数学模型,对系统的稳定性及带宽进行了仿真实验,并应用PCB铜箔测厚仪对所设计的信号源进行了负载效应及温度试验。仿真及实验结果皆表明,相比于传统的开环恒压驱动激励信号源,该信号源不仅具有较稳定的激励电流和较强的抗干扰能力,还具有较小的温漂及较强的负载稳定性,从而保证了基于该信号源的测厚仪具有更高的测量精度。

In order to enhance the precision of excitation signal source for eddy current testing,this paper presents a method of using linear control theory to design this kind of source.Firstly,a multiple-input single-output（MISO）feedback control system is established to excite the current of eddy current sensor;secondly,the module circuit is designed to analyze the stability of the control system as well as the source and the suppression of the system interference;finally,by establishing the mathematical model of the system,simulations on the stability and bandwidth are performed,furthermore,by using the PCB copper foil thickness gauge,the temperature experiment and load experiment on the signals are also performed.Both simulations and experimental results indicate that compared with the traditional open loop constant voltage drive signal source,this signal source has the characteristics of more stable output,stronger anti-interference ability,and smaller temperature drift.Therefore,the foil thickness gauge based on this system has higher accuracy of measurement.