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霍尔器件是漏磁检测中最常用的磁传感器,周期方波电流用作激励源可提高其灵敏度。试验表明,对于同样的外磁场,与直流激励相比,一定幅度的周期方波电流可使霍尔输出提高20dB。介绍方法的基本原理和信号处理方法,给出了方波电流幅度和霍尔输出的关系曲线,并从理论上进行了解释。考察了采用周期方波电流后霍尔输出和外部磁场之间的线性关系的变化,最后比较了同样条件下,用直流激励和方波激励时0.1mm深裂纹的检测结果。
Hall devices are the most commonly used magnetic flux leakage testing sensors, periodic square wave current used as excitation source can improve its sensitivity. Experiments show that, for the same external magnetic field, a certain period of square wave current can increase the Hall output by 20dB compared with DC excitation. Introduce the basic principle of the method and the signal processing method, give the curve of the square wave current amplitude and the Hall output, and explain it theoretically. The linear relationship between the Hall output and the external magnetic field after the periodic square wave current was investigated. Finally, the detection results of the 0.1 mm deep crack with DC excitation and square wave excitation under the same conditions were compared.