基于霍尔元件的数字式霍尔电流传感器设计北大核心CSCD

为了进一步提高数字式电流传感器的测量量程,基于霍尔效应提出了一种数字式霍尔电流传感器的设计方案。利用有限元分析软件对磁芯的磁场分布情况进行仿真分析,得出不同电流激励下磁芯中磁场的分布情况。针对直流电流情况下磁芯气隙中磁场分布不均的问题提出楔形气隙结构的优化方法,仿真结果表明该结构可以有效改善气隙中磁场分布不均的问题。设计传感器样机,通过实验分析了所设计的电流传感器的有效量程及测量误差,实验结果与仿真结果相符。     

一种全新的直流电流检测方式

针对常规的直流电流检测方法存在的缺点,设计了一种全新的直流电流检测方式.在该方式中,以2个环形磁芯线圈作为传感器,将通有直流电流的被测导线穿过2个环形磁芯线圈,则该导线在磁芯中产生恒定的磁通,同时控制电路在2个环形磁芯中加入变化磁通,2部分磁通在每个磁芯中形成合成磁通,再将每个磁芯中的合成磁通所产生的磁场能经差动电桥电路进行差动运算,即可实现检测出导线通过的直流电流.实验结果证明了该检测方式的正确性和可行性.     

钴基非晶磁芯巨磁阻抗效应电流传感器

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／mm。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     

双轴磁通门传感器的仿真设计与制备

微型磁通门传感器是一种利用PCB(印刷电路版)技术制作的新型磁通门传感器,磁芯为十字交叉状双轴结构.介绍了传感器磁芯与线圈的组成结构,利用模拟软件Flux3D对传感器进行建模并仿真测试.最终制备的传感器尺寸为58.1mm×57.3mm,测磁范围±60μT,磁敏感度达到0.37mV/μT.仿真结果与试验结果基本相符合,证明了仿真设计与制备工作的可行性.     

电流传感器在直流测试平台的应用

随着传感器技术的进步与发展,电流传感器设备逐渐多元化,主要包括:分流式传感器、光纤电流传感器、闭环霍尔电流传感器、罗氏线圈和阵列霍尔传感器。在此背景下,介绍了等离子体物理研究所电气测试中心直流测试平台在不同运行模式下所采用的电流传感器。同时介绍了所使用电流传感器的基本工作原理和基本参数,并对不同运行模式下的电流传感器测量数据波形进行了分析。     

基于平面线圈线阵的直线时栅位移传感器

针对现有磁场式直线时栅位移传感器行波磁场产生过程中,齿槽的存在影响行波磁场的匀速性,提出基于平面线圈线阵的直线时栅位移传感器。无齿槽的结构形式提高了行波磁场的匀速性,可实现大极距下的高精度测量。传感器将施加正交信号的两相励磁线圈相间排列形成平面线圈线阵,产生的行波磁场通过磁场拾取线圈感应出电行波信号,处理后得到位移量。通过电磁场分析软件对传感器进行建模仿真,根据仿真结果得到测量误差;通过理论分析对测量误差进行分析溯源,并根据分析结果对传感器结构进行优化。基于分析和优化结果研制出传感器样机,并进行了精度实验。实验表明,传感器在240 mm内测量精度为±1μm,实现了精密测量。     

线性测微电感的精化

为提高测微电感传感器的测量精度,提出了基于赫姆霍兹线圈理论设计螺线管线圈的方法,改善了螺线管线圈内轴向上磁场的分布均匀性。首先,分析了螺线管线圈模型,建立了螺线管线圈参数与轴向磁场强度分布相互关系的广义函数模型。然后,通过线圈与磁芯的尺寸确定了系统轴向磁场强度分布函数模型,结合磁芯移动区间范围设置磁场均匀度最小误差目标函数,通过对目标函数寻优得到各螺线管线圈的各项参数。最后,搭建了测微电感传感器的测试系统,测试了传感器性能。实验结果表明:与传统线圈相比,改进型螺线管线圈在100μm测量范围内的线性度由0.46%提高到0.30%。实验显示通过对不同规格的螺线管线圈进行组合,可使得螺线管内轴向上磁场强度分布均匀,从而提高了测量精度。     

电流参数对基波正交磁通门传感器灵敏度的影响

为了研究激励电流参数对基波正交磁通门灵敏度的影响,利用钴基合金磁芯和单线圈构建基波正交磁通门。实验结果表明,增加激励电流振幅(Iac),会改善基波正交磁通门的灵敏度;然而,随着激励电流偏置(Idc)增加,基波正交磁通门灵敏度下降;激励频率对灵敏度影响相对复杂。随着频率的增加,灵敏度呈现先增加后降低的趋势,存在一个最佳频率。该频率大小近似等于基波正交磁通门线圈等效LC电路的谐振频率(fo)。基于旋转磁化理论和等效电路模型对上述实验结果进行了分析。该项研究对优化传感器灵敏度,提高正交磁通门信噪比具有指导作用。     

电流输出型磁通门传感器的灵敏度

研究了电流输出型磁通门传感器的灵敏度，一般磁通门的灵敏度随次级线圈匝数增加而增加，导致了灵敏度磁通门体积大，闭环工作时动态性能差，通过理论推导得出，忽略线圈的铜电阻和耦合电容的容抗时，电流型磁通门的灵敏度与次数线圈匝数成反比，因而可在小体积下获得高灵敏度和优越的动态性能。研制了6只次级线圈匝数不等双铁心电流输出型磁通门进行试验，用最小二乘法对实验数据进行了分析，结果表明理论推导与试验结果基本一致，分析还表明，若考虑次数线圈的铜电阻和耦合电容的容抗，用次数线圈匝数的倒数及其二次项表示电流输出型磁通门的灵敏度具有更高的精度。     

基于磁通门传感器的弱磁场检测方法

为了实现对弱磁场的检测,研究了磁通门传感器原理,建立了磁通门传感器数学模型;采用高磁导率材料钴基非晶合金VITROVAC 6025Z作为磁芯材料设计制作了磁通门传感器,结合DDS(直接频率合成器)激励电路和虚拟仪器构成磁通门磁强计.虚拟仪器上磁场调零功能可实现磁通门磁强计在不同磁场环境下的归零校准,对弱磁场的测量更加精确.经对比实验,选择激励信号频率为10 kHz,激励幅值为5V,此时该系统灵敏度较高.在稳定可控磁场中,利用特斯拉计对系统进行定标,实验结果表明,磁通门磁强计线性度较好,分辨力达μT级.     

Analysis and comparison of the performance of MEMS fluxgate sensors with permalloy magnetic cores of different structures

This paper presents four MEMS fluxgate sensors which were fabricated with same processes but with magnetic cores of different structures. Thick photoresist-based UV lithography and electroplating were adopted in the fabrication of the fluxgate sensors. Solenoid coils used as excitation and sensing elements were made of copper, whereas the magnetic core material was permalloy. Polyimide was used to support the structures of the sensors. An electronic testing system based on the second harmonic principle was established to characterize the fabricated devices. Each sensor was tested with the excitation coils being excited by a sine waveform current whose frequency was 100 kHz. From these experiments we can obtain some information about how the magnetic core structures affecting the magnetic field measuring performance of the fluxgate sensors, which might make some contribution to the performance improvement and miniaturization of fluxgate sensors.     

干涉式光纤电流传感器

高压输电线中的电流测量大都采用铁芯式电流互感器。由于铁芯的非线性特性，一次测电流过大或含有高次谐波分量时，会出现磁路饱和现象，使电流互感器二次测电流数值和波形发生失真，从而引起测量精度下降。文中，设计了一种干涉式光纤电流传感器，提出了使用Rogowski线圈进行电流-电压转换，利用压电晶体实现相位调制，用迈克尔逊干涉仪进行相位检测的方法，解决了在高压端无源情况下，由电流转换的电压小的问题，提高了传感器的精度、可靠性和测量范围。     

PCB型Rogowski线圈电流传感器检测电路设计

介绍了PCB型Rogowski线圈的工作原理及特点,详细分析并设计了该传感器的信号处理电路,对该线圈电流传感器进行了线性度和灵敏度测试,实验结果表明:该传感器测量时线性度好,准确度较高,能满足测量要求。     

用于冲击电流测量的自积分式Rogowski线圈的研究

文中介绍了一种自制的自积分式Rogowski线圈配合示波器所组成的冲击电流测量系统的基本原理,采用标准电阻对该Rogowski线圈的测量结果进行了实验校准,并对校准实验数据进行处理.从处理结果看,该Rogowski线圈具有较好的冲击电流测量精度.     

光纤电流互感器中Rogowski线圈的设计与分析

Rogowski线圈作为传感头是光纤电流互感器的关键部分,文章分析了Rogowski线圈的测量原理和等效电路,得出了测量关系,并根据分析设计了一个Rogowski线圈。实验表明该Rogowski线圈具有良好的线性度;频率特性分析显示该Rogowski线圈有非常充裕的带宽,进而为设计高精度的光纤电流互感器奠定了基础。     

Fabrication and characterization of a new MEMS fluxgate sensor with nanocrystalline magnetic core

This paper presents a new MEMS fluxgate sensor with a Fe-based nanocrystalline ribbon magnetic core and 3D micro-solenoid coils. The excitation coils were placed vertically to the sensing coil on the chip plane. Second harmonic operation principle was adopted in this fluxgate sensor. The total size of the fluxgate sensor was 6.25 mm × 4.85 mm × 120 μm. A simple testing system was established to characterize the fabricated devices. A band pass filter was used to pick up the second harmonic signals in the sensing coils. When excitation rms current of 120 mA and the operational frequency of 200 kHz were selected for the testing of the fabricated devices, the sensitivity of the developed fluxgate sensor was 1005 V/T in the linear range of −500 μT to +500 μT. Due to the combination of the 3D structure coils with the nanocrystalline core, relatively low sensor noise was achieved. The noise power density was 544 pT/Hz^0.5@1 Hz and the noise rms level was 9.68 nT in the frequency range of 25 mHz-10 Hz.     

时栅位移传感器在构造场中的耦合特性研究

为了进一步溯源时栅位移传感器磁场耦合过程引起的误差,对时栅位移传感器在构造场中的耦合特性进行研究,并研制了一种基于指数形平面线圈结构的新型直线时栅位移传感器。建立传感器工程构造磁场的数学模型,分析传感器耦合间隙对线圈耦合平面磁场分布的影响,研究不同形状平面线圈的耦合特性;根据传感器的耦合特性,构建了一种新型直线时栅位移传感器测量模型,对该模型进行了电磁场有限元仿真和仿真误差分析,得出该结构最佳感应间隙为0.4 mm;对传感器的结构误差进行了溯源分析,进一步优化传感器的结构;搭建实验平台,利用双层PCB绕线工艺加工传感器定尺和动尺,对优化前后的传感器样机开展对比实验。实验结果表明,设计的基于指数形平面线圈结构的新型直线时栅位移传感器可以有效抑制传感器的四次误差,新研制的传感器样机的原始测量精度在原有的基础上提高了45.8%。     

New Side-Looking Rogowski Coil Sensor for Measuring Large-Magnitude Fast Impulse Currents

This paper presents a new design of a side-looking “flat spiral” self-integrating Rogowski coil that is wound by twin coaxial cable with individual sheath. The coil is tested with different impulse current waveforms up to 7 kA peak value to improve its performance. The coil design is optimized to achieve bandwidth and sensitivity up to 7.854 MHz and 3.623 V/kA, respectively. The coil is calibrated versus two commercial impulse-current measurement devices at different coil-to-wire separations, coil inclination angles, and impulse current waveforms. Distortion of the coil output voltage waveform is examined by using the lumped-element model to optimize the connections of the four cable winding sheaths and the coil termination resistance. Finally, the coil frequency response is investigated to optimize the coil design parameters and achieve the desired bandwidth (large low-frequency time constant), high rate of rise, no overshoot, very small droop, high rate of fall, and no backswing.     

三分量磁通门梯度仪校准算法研究

针对三轴磁通门传感器非正交、灵敏度不一致、零偏以及构成梯度仪的两个磁通门传感器位置不一致引起的测量误差问题,建立了误差模型;基于地磁矢量模值短时不变原理,采用线性化最小二乘算法进行一个磁通门传感器参数的辨识;基于校准后三分量差值F范数最小原理,采用多元线性回归的方法进行另一个磁通门传感器参数以及两个磁通门传感器相对位置关系参数的辨识。实验结果表明,该方法能够将两个磁通门中最大总场误差从1 194.4 n T降低到30.0 n T,将三分量梯度仪最大输出误差从529.1 n T降低到13.4 n T,有效地改善了梯度仪性能。     

Detecting the position of the moving-iron solenoid by non-displacement sensor based on parameter identification of flux linkage characteristics

Currently, most researches use signals, such as the coil current or voltage of solenoid, to identify parameters; typically, parameter identification method based on variation rate of coil current is applied for position estimation. The problem exists in these researches that the detected signals are prone to interference and difficult to obtain. This paper proposes a new method for detecting the core position by using flux characteristic quantity, which adds a new group of secondary winding to the coil of the ordinary switching electromagnet. On the basis of electromagnetic coupling theory analysis and simulation research of the magnetic field regarding the primary and secondary winding coils, and in accordance with the fact that under PWM control mode varying core position and operating current of windings produce different characteristic of flux increment of the secondary winding. The flux increment of the electromagnet winding can be obtained by conducting time domain integration for the induced voltage signal of the extracted secondary winding, and the core position from the two-dimensional fitting curve of the operating winding current and flux-linkage characteristic quantity of solenoid are calculated. The detecting and testing system of solenoid core position is developed based on the theoretical research. The testing results show that the flux characteristic quantity of switching electromagnet magnetic circuit is able to effectively show the core position and thus to accomplish the non-displacement transducer detection of the said core position of the switching electromagnet. This paper proposes a new method for detecting the core position by using flux characteristic quantity, which provides a new theory and method for switch solenoid to control the proportional valve.