磁芯气隙中串联层叠非晶带GMI效应电流传感器

Novel current sensor based on GMI effect in serial laminated amorphous ribbons embedded in the air gap of a toroidal core

利用由CMOS多谐振荡桥及低通滤波器产生的正弦信号激励的钴基非晶带巨磁阻抗(GMI)效应设计出一种非接触型电流传感器。该非晶带经频率为2Hz,密度为35A/mm2,持续时间40s的脉冲电流退火。非晶带采用串联层叠方式嵌于带气隙的环形磁芯中,推出了气隙中的层叠非晶带受到的导线电流所产生的磁场公式。给出了传感器信号处理电路框图。当磁芯中引入强负反馈磁场时,实验结果表明,新型电流传感器的非线性误差小于0.5%FS,线性量程±7A。

Non-contact type current sensor was constructed using giant magneto-impedance （GMI） effect in an- nealed Co-based amorphous ribbons with an excitation signal produced by a CMOS multivibrator and a low-pass filter. The amorphous ribbons were annealed by pulse current with intensity of 35 A/mm2 and pulse frequency of 2 Hz for 40s. The sensitive elements are pieces of laminated amorphous ribbons connected in series and located in the air gap of a toroidal magnetic core. The calculation formula of the magnetic field for the amorphous ribbons inserted in the air gap is given. The block diagram of the signal processing circuit for the sensor is presented in the paper. When strong negative feedback field is introduced in the core, experimental results show that a novel DC current sensor with nonlinear error less than 0.5% FS, and a linear range up to ±7 A is obtained.