基于GMR传感器的无损探测系统的设计

Design of Nondestructive Detection System Based on GMR Sensor

为了减少常规涡流检测系统的人工干预程度,便于实现自动化检测,文中采用高灵敏度的巨磁电阻(GMR)芯片作为敏感元件,设计了一款新型的无损探测系统。该系统基于涡流检测的基本原理,采用AD9850直接频率合成器和TDA2030A功率放大芯片搭建交变电流信号发生电路,利用GMR磁传感器来提取被测金属有缺陷时引起的涡流磁场变化量。文中利用Ansfot Maxwell软件进行了验证,当线圈通以200 m A交变电流时,缺陷处磁场变化量为0.3 m T,通过GMR传感器可以灵敏地探测到该磁场的变化量,因此可以根据传感器输出的电压信号直观地检测到被测金属的缺陷情况。

In order to reduce the degree of human intervention and realize automatic detection,the paper designed a new type of nondestructive detection system using the sensitive giant magneto resistance （GMR） chip as the sensitive element. The system based on the basic principle of eddy current testing, adopted direct frequency synthesizer AD9850 and power amplifier chip TDA2030A to compose the alternating current signal generating module, using the GMR magnetic sensors to extract the changes of the magnetic signals caused by the changes of the eddy current. The principle of the system was verified by Ansoft Maxwell. soft- ware. When the coil was with 200mA alternating current, the magnetic field variation was 0.3 mT. The GMR sensor is sensitive to the changes of the magnetic field, so the defects of the measured metal can be detected directly by the voltage sensor output.