-
磁传感器因其优越的性能而被广泛地应用于地磁研究[1]、地质勘探[2]、空间磁场测量[3]、航空航海定位[4]、武器侦察[5]及材料无损探伤[6]等弱磁场[7]测量领域。而微型磁通门传感器,更是具有体积小、精度高、可以靠近或放置在被测样品的内部等优势,受到了近年来发展迅速的生物医学[8]领域的青睐,其对微型高精度磁传感器有了越来越大的需求。例如,它可通过心跳和头脑的磁场变化提供心脑磁图[9],从而代替原始电极得到的心脑电图,为医护人员提供更精准的诊疗依据。
磁通门传感器可以简单地看作为一种磁场放大器,它主要基于具有低矫顽力、高磁导率且易于饱和等特点的坡莫合金[10]材料的磁滞效应[11]工作。作为传感器,它的灵敏度主要与磁芯的几何结构、磁芯材料的磁导率、激励信号在磁芯上建立的磁场强度以及感应信号的匝数有关。
对于磁强计的设计与研发,英国的Bartington公司推出了三轴数字低噪声磁强计Mag679[12],具有1 kHz的带宽、±100 000 nT的测量范围、62.5 pT/bit的分辨率、10 pTrms/√Hz@1Hz的噪声以及10 mW的功耗水平;美国MEDA公司生产的FVM400[13]是一种价格低廉的微型手持设备,具有1 nT的分辨率、±100 000 nT的测量范围和±0.25%的精度。另外,瑞士科研人员发现非晶软磁合金的磁性能略优于坡莫合金,并利用集成电路工艺制作线圈和接口电路,使系统性能得到很大改善[14]。与之相比,国产的微型磁通门传感器在性能指标上略低于国际,但也取得了很大突破。上海交通大学微纳科学技术研究院设计的MEMS磁通门传感器[15]达到了31.07 V/T的灵敏度、±75 000 nT的测量范围;哈尔滨理工大学基于CMOS工艺制作的磁通门传感器则达到了30 800 V/T的灵敏度和0.62%的非线性度[16]。
为了更好地利用坡莫合金磁芯,本文从法拉第电磁感应定律出发对双铁芯磁芯建模,进一步研究磁芯材料磁导率对应的最佳激励电流和最佳激励频率,最后通过实验验证了所建立数值模型的有效性和准确性。以上的分析和建模为微型磁通门传感器的设计和优化提供了依据。
Simulation of the Excitation Module for Micro-Fluxgate Sensor
doi: 10.3969/j.issn.1001-0548.2017.05.024
- Received Date: 2015-12-09
- Rev Recd Date: 2017-04-01
- Publish Date: 2017-09-01
-
Key words:
- magnetic cores /
- magnetic flux /
- mathematical models /
- numerical simulation
Abstract: The micro-fluxgate sensor is widely used in the field of weak magnetic field measurement such as geophysical exploration, geomagnetic navigation, space environment monitoring, medical diagnosis and treatment and others because of its characteristics of low power consumption, high sensitivity, high resolution, simple structure and low cost. The excitation module directly determines the performance of the whole system and thus it is of significance to build an accuracy simulation model of the module. The mathematical model of the dual cores is built on the basis of the Faraday's law of electromagnetic induction, and the voltage waveforms and the magnetic value under the sinusoidal excitation are given. According to the structure parameters of the KDM-01 which is a fluxgate sensor designed by Institute of Geology and Geophysics, Chinese Academy of Sciences, a simulation model of the excitation module is built. The obtained simulation results are in good accordance to the test values. Then the model is applied to the designed magnetometer and the test data are similar enough to those of the standard magnetometer. It is proved that the built mathematical model for the excitation module is reasonable and accurate.
Citation: | ZHI Meng-hui, TANG Liang, MAO Sheng-rong, ZHAO Lin, JI Lei, JU Qing-yun, QIAO Dong-hai. Simulation of the Excitation Module for Micro-Fluxgate Sensor[J]. Journal of University of Electronic Science and Technology of China, 2017, 46(5): 795-799. doi: 10.3969/j.issn.1001-0548.2017.05.024 |