钴基非晶磁芯巨磁阻抗效应电流传感器

Current sensor utilizing giant magneto-impedance effect in Co-based amorphous ribbon toroidal core

利用钴基非晶薄带环形磁芯的巨磁阻抗效应研制了新型非接触电流传感器。磁芯在2kA/m横向磁场作用下,用密度为25A/mm2短时矩形脉冲电流退火30s,通过CMOS多谐振荡电路产生的频率为900kHz窄脉冲电流激励,最大阻抗变化率为34%,磁场灵敏度约为45%/Oe。分析了传感器工作原理,设计了传感器电路,通过参数的优化和电流负反馈设计提高了传感器的分辨率、线性度、灵敏度和测量范围。设定测量范围为-2.5^+2.5A时,传感器测量精度为0.45%,灵敏度为0.67V/A。

The novel non-contact type current sensor based on giant magneto-impedance （GMI） effect in Co-based amorphous ribbon toroidal core was studied. The toroidal core was annealed with 25 A/mm^2 short time rectangular pulse current density under a transverse magnetic field of 2 kA/m for 30 s. When excited by 900 kHz short pulse current generated from a CMOS muhivibrator, the maximum GMI ratio is 34% and sensitivity is about 45%/Oe. The operation principle of the sensor was analyzed and the circuits were designed. The linearity, sensitivity, resolution and measurement range of the sensor are improved by optimizing the circuit design parameters and adopting current negative feedback. The measurement accuracy is 0.45%, sensitivity is 0.67 V/A, and measurement range is -2.5 - ＋2.5 A.