磁传感器阵列技术及其应用

磁测量技术被应用于越来越多领域的同时,单个磁传感器仅能测得被测磁场中某点处有限信息的局限性也逐渐显现出来。为了提高磁测量技术性能,扩大磁场测量的空间尺度和范围,并且实现对磁场信息更深层次、更多视角的利用,磁传感器阵列技术逐渐发展起来。文中基于对磁传感器阵列技术在几个领域应用实例的整理和归纳,总结出磁传感器阵列技术具有测量范围大、准确度高、可靠性好、可与时间和空间进行联合解算等优点,但同时也存在成本高、控制难度大、存在位置校准误差和噪声干扰等不可回避、必须解决的问题,进而展望了磁传感器阵列技术的发展前景。     

无轴承磁悬浮电机系统中的非接触传感器

文章介绍了适用于磁悬浮电机系统的非接触式转子位置传感器,对其原理、性能以及适用范围作了比较,系统地研究了涡流传感器的动、静态特性,分析了转子检测系统的误差来源及表现形式,提出了消除方法。给出了涡流传感器对一台无轴承磁悬浮电机系统转子位置检测的应用实例及其结果。结果说明涡流传感器结构简单,动态性能好,输出信号强,可以满足磁悬浮电机系统多自由度复杂控制的要求。     

非接触式距离测量系统

接近传感器可以在不与目标实物接触的情况下检测到靠近传感器的金属物体位移。该系统以C8051F310为主控制器,通过连接接近传感器,实现非接触式距离测量。接近传感器的模拟输出信号经过信号调理、ADC转换,变换为数字信号,传输给单片机。单片机根据传感器的输出信号和检出物体的距离关系,通过计算处理接近传感器的输出信号,获得检出物体的位移距离,并在显示屏实时显示检出物体的位移距离。本系统经过测试和实验,实现了非接触式距离测量,并设计了高精度显示和全量程显示2种界面。     

基于双轴各向异性磁阻传感器电流测量系统的研究

根据各向异性磁阻传感器(AMR)测量导线产生磁场强度的原理,利用两个双轴各向异性磁阻传感器建立虚拟等腰直角三角形结构的理论模型,并提出计算虚拟等腰直角三角形中任意位置的定位算法,实现对电流的非接触式测量。建立传感器单元和测试平台,设计Kaiser窗函数和卡尔曼滤波器处理外部磁场的影响。最后通过实验验证了提出结构、定位算法和信号处理的正确性。     

A new speed measurement system

Magnetic contactless speed measurement sensor targets steel industry. Controlling any production line requires the use of many sensors along the line. A basic measurement in steel lines is the determination of the exact linear speed of some portions of the process. This article comments on the complete speed measurement system for steel lines, with a cost lower than US$300, a range up to 800 m/min, and accuracy of about 0.4%. Accuracy is influenced by the position of the sensors.     

磁传感器阵列测量大电流的传感器拓扑问题研究

磁传感器阵列通常以非接触方式安放在多导体系统的周围空间用来测量电流。为研究磁传感器阵列拓扑而引起的理论误差,基于离散傅里叶变换（DFT）的电流测量算法,建立了以求解系数矩阵条件数最小值为目标函数的磁传感器阵列拓扑优化模型,并提出了若干优化约束条件。该数学模型可以同时适用于交流和直流的多母排平行导体系统测量大电流。最后,以三相电流测量系统磁传感器拓扑的优化问题为例给出了求解步骤,MATLAB仿真与实验结果验证了优化数学模型的有效性。     

基于GMI效应的磁传感器研究与发展现状

巨磁阻抗(GMI)效应的出现,使磁传感器在弱磁检测领域的小型化、高灵敏度、快速响应和低功耗方面成为可能,基于GMI效应的磁传感器具有广泛的应用发展前景,是近年来磁传感器领域的研究热点之一.本文从不同敏感材料类型的角度介绍了巨磁阻抗磁传感器的国内外研究现状,着重对传感器的敏感材料、结构形式、处理电路及性能做了介绍,并指出...     

车载天线稳定平台的光纤陀螺性能评估

"动中通"是现代移动指挥与通信系统的主要特点,通信天线的稳定与指向控制是动中通的重要组成部分,惯性传感器与系统敏感载体的三维姿态变化与位置变化,是实现天线指向控制的关键。光纤陀螺作为一种惯性敏感器,在惯性/组合导航系统应用不断扩展。面向指挥车天线稳定平台应用背景,分析了光纤陀螺的主要指标参数,构建了测试环境对某小型低成本光纤陀螺的性能进行试验评估,从评价结果判断,本陀螺可用于研制接近于导航级精度的指挥车天线稳定平台的惯性组合基准系统。     

基于气体扩散模型的气体源定位系统

为了快速准确地确定气体泄漏源的位置,利用无风连续泄漏点源浓度的扩散模型,提出了基于加权质心算法的气体源定位法。采用气敏传感器阵列对目标区域的气体浓度进行检测,并通过ZigBee无线传感器网络把收集的数据反馈给协调器,协调器把打包好的数据传递给主处理器,处理器依靠测量的结果计算出气体源位置,并可视化显示。在目标区域为4 m×4 m,以乙醇蒸汽为实验目标气体进行气体源定位实验。结果表明,平均定位结果相对误差不超过6%,验证了该方法的准确性。     

直流配电网隧道磁电阻传感器外磁场干扰模型及其抑制方法研究

隧道磁电阻传感器作为新一代磁传感器,具有温度特性好、灵敏度高等优点,在电能计量中得到大量研究和应用。外磁场干扰是影响磁传感器测量准确度的重要因素,文中针对直流配电网电流测量场景,建立了隧道磁电阻元件传感器阵列的外磁场干扰模型,继而基于自适应滤波(LMS)分析的算法,提出了磁传感器最优结构参数,并通过数值分析和有限元仿真验证了该模型的有效性。研究结果表明,当被测电流在±50 ~±300 A之间、阵列半径与母排间距比例为1:2.5时,外磁场影响最小,通过自适应滤波算法可将磁传感器测量误差降到1%以下。     

一种零磁通电流传感器适配装置的研制与应用

为了方便有源零磁通电流传感器的现场使用,研制了一种零磁通电流传感器适配装置,可作为电流传感器的配套产品,其内部集成的具有多种供电模式的电源模块可为现有的大部分主流传感器提供高稳定、低纹波的工作电源。采用电池供电可有效降低电流传感器的零点输出电流;同时通过专用的接口引出传感器的二次电流,并进行I-V变换、数字化等后续处理,在便于测量应用的同时,更拓展了电流传感器的有效测量范围。     

High-accuracy magnetic position encoder concept

Position sensors based on the detection of magnetic flux densities by Hall sensors or magnetoresistors are used in automotive applications for crankshaft and camshaft position sensing, which are needed for engine control. This paper identifies the limitations of traditional designs, which introduce an angular error between the position signal pulse and the actual location of the corresponding triggering feature on the sensor target wheel. It proposes a solution ensuring that the position signal pulse coincides with a point of symmetry in the triggering target wheel feature, thus eliminating the angular error. Two interesting implementations are described in this paper. One of them is analyzed in full detail, and a methodology for its design is provided. In particular, specific design rules are derived which link some of the design parameters to relevant dimensional specifications. These rules are established on the basis of a geometrical method developed for this particular type of problem which necessitates the calculation of flux densities in a few specific locations, namely, where the sensing elements are located. The overall approach, including these design rules, is validated by finite-element analysis, as well as by experimental data     

基于光学电流传感器的局部放电检测

局部放电检测可及早发现电气设备的绝缘缺陷,为状态检修提供依据。目前,各种检测方法仍难以解决抗电磁干扰能力差的问题。提出将基于Faraday磁光效应原理研制的双螺线管结构光学电流传感器应用于局部放电检测,丰富了局部放电检测的内容,突破了现有检测方法的局限性。建立了4种局部放电模型,利用马吕斯定律和安培定律研究了传感器光路损耗特性和抗电磁干扰性能,采用连续小波变换对光学电流传感器采集的局部放电信号进行了时频分析。与其他检测方法的比较结果表明,该传感器系统具有良好的使用特性,为今后光学方法在局部放电检测中的应用奠定了基础。     

基于Fluent的气井放喷时气液两相流流场仿真研究

In the last decade, significant progress has been made in applying passive capsule endoscopes (CE) to medical diagnostics. However, disadvantages still need to be overcome for better utilization. A major challenge is to actively control the movement of the CE and provide real-time location information. This paper proposes a magnetic tracking method for CE driven by an external magnetic field that is generated by four sets of electromagnetic coils around the CE. The tracking method is based on a magnetic sensor array. The magnetic actuation constitutes three steps. First, the driving current from each coil is obtained according to the control requirement for a certain position and orientation. Second, the magnetic field that is generated by the driving current in the tracking space is estimated according to the magnetic field model. It can also be measured by Hall-effect sensors embedded in the position system. Third, the magnetic field generated by the CE is subtracted from the total magnetic field measured by the sensors, and then the magnetic position algorithm is applied. In the experiments, the positioning error is found to be within 5.6 mm and the orientation error is under 8.5°. The proposed localization method would be used for closed-loop control of CE to achieve better and safer performance.     

智能传感器及其应用探讨

本文主要介绍了智能传感器技术在不同领域的基本组成结构、标准、应用和一些最新发展.与传感器相比,智能传感器可以与连接在传感网络中的专门用途计算设备相互通信.通过使用无线传感器网络,可以对关键设备进行监视和远程管理,从而产生更好的系统性能,获得更好的决策能力,进行更好的控制.在各个领域都有智能传感器的应用,例如供应链物流,...     

绕组分段永磁直线电机切换位置传感器故障诊断及容错控制

绕组分段永磁直线同步电机绕组切换过程中位置传感器信号的丢失,将导致电机速度剧烈波动,引起电机失步。针对以上问题,提出一种切换位置传感器故障诊断及容错控制方法。设计了绕组切换位置检测方法,研究了位置接近开关传感器的故障类型及信号特征,利用动子的运行速度及相邻的位置传感器信号进行传感器状态预测,并结合相邻传感器的边沿触发顺序及传感器状态预测值进行故障诊断。当检测到位置传感器故障时,隔离发生故障的传感器,采用估计值替代故障传感器输出驱动信号,可靠切换绕组分段永磁直线同步电机定子绕组,实现传感器容错控制。利用绕组分段永磁直线电机无绳提升系统进行了实验研究,研究结果表明,当增大传感器间隙,模拟传感器信号丢失故障时,电机定子绕组仍能可靠切换,电机速度运行平稳,该位置传感器故障诊断与容错控制方法可以满足绕组分段永磁直线电机切换控制实时性和可靠性要求,实验结果证明了其可行性和有效性。     

可穿戴的实时检测走姿矫正仪设计

在走姿矫正导航精度优化问题的研究中,针对当前姿态解算技术的精度不足,设计了一款在Linux环境下嵌入式走姿矫正设计方案,基于先验的位置磁矩迭代修正方程系数的方法,建立迭代误差指标函数及迭代公式,并进行了数值仿真实验。为实现姿态解算中姿态角实时检测,提出将传感器采集到的加速度、角速度以及磁场强度数据进行融合,利用三轴加速度传感器和磁力计的向量偏差来对姿态解算过程中积分累计误差进行修正。最后传感器将数据结果分别通过ZigBee和蓝牙协议将其传输到电脑端或手机APP客户端显示,以达到走姿检测和矫正的目的。实测结果表明,这种方案使得走姿矫正的精度准确度更高,实时检测性能更强。     

A current sensorless drive system of a synchronous motor with a low‐resolution position sensor

High‐performance drive of synchronous motors such as a permanent magnet synchronous motor and a synchronous reluctance motor can be achieved by current vector control. In such drive systems, the armature current is controlled as a sinusoidal waveform based on rotor position information from a high‐resolution position sensor, and the current vector (d‐ and q‐axis currents) is suitably controlled by current feedback control. This paper proposes a current sensorless drive system with a low‐resolution position sensor in order to simplify the SM drive system. High‐performance current control is achieved in the proposed drive system, where the current sensors are eliminated and the simulated currents are used for current control. The low‐resolution position sensor is used instead of a conventional high‐resolution position sensor, and the higher position information is estimated. The steady‐state and transient characteristics are examined in several experiments with respect to the synchronous reluctance motor and the interior permanent magnet synchronous motor. It is confirmed that sinusoidal current drive, high‐performance current vector control, and speed control can be achieved by the proposed drive system. © 2002 Wiley Periodicals, Inc. Electr Eng Jpn, 141(4): 34–43, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10072     

Characteristics of a two‐dimensional integrated magnetic sensor for position sensing and motor control

Two‐dimensional integrated magnetic sensors for position sensing were designed and fabricated with the standard 0.35‐µm CMOS process on silicon. One such type is the n‐type Hall sensor that uses an inversion layer under the gate oxide of the MOSFET. The Hall sensors were arrayed (64 × 64), and the control digital circuits and output amplifier were also integrated into the same chip. ‘One pixel’ was 50 × 50 µm, and the entire chip was 4.9 × 4.9 mm. The sensitivity of one of these sensors was 2.7 mV/(mA·kG). The two‐dimensional magnetic flux distribution was measured from the 5‐mm diameter Nd–Fe–B rare‐earth permanent magnet. About 42 s was required to measure one frame. The position of the magnet could be detected with the fabricated sensors. Magnetic sensors using an inversion layer in MOSFETs are useful for position sensing systems, but their noise characteristics, such as poor sensitivity, should be improved. © 2006 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

核安全级高容积传感器的研制

核安全级检测仪表是监测核电站安全状态以及事故工况的重要仪器.研制的核安全级高容积传感器是大型先进压水堆堆芯欠冷监测系统的关键设备之一.详细论述了高容积传感器遵循的标准和性能指标,重点分析了在高静压工况下的隔离、精度等技术难点以及解决的方案.研发成果获得了良好的推广应用,对于后续研发类似产品和行业拓展具有重要的参考意义.