方波激励的无铁芯多分段电感位移传感器

传统的差动变压器式电感位移传感器存在着铁芯惯量大、线性范围小、对正弦波激励电源的品质要求高、正弦波发生及传感信号提取电路复杂等问题。本文提出了一种具有多抽头螺管线圈和轻质滑环结构的电感位移传感器 ,取消了铁芯 ,采用方波激励 ,由简单的运放电路合成传感信号 ,并利用传感器自身提供的温度信号进行温度补偿 ,克服了传统差动变压器存在的问题。实验结果表明 ,这种传感器具有优良的综合性能     

差动式磁芯型电感测微仪系统工作原理的分析研究与应用

本文论述了差动式磁芯型电感测微仪系统的工作原理。对所采用的差动式磁芯型电感传感器的原理及转换电路作了理论性的分析 ,介绍了差动式磁芯型电感测微仪在检测缸体曲轴孔中的应用     

测量不同轴度的快速准确方法—推荐电感量仪的使用

工厂中对不同轴度有严格要求的制件较多,如车床主轴和台尾精度检查棒、铣车刀杆、床头箱体孔距检查棒、阶梯轴制件、锥度套等。对这些制件的不同轴度检查一般都是在顶针间或V型铁上用测微表进行,然后通过其高低点方向位置来确定其不同轴度偏差。这种方法既慢而又不直观,若碰上畸变情况如高低点的位置不在同方向或相对方向时更难下结论。运用瑞士TESA电感量仪或我国中原量仪厂的小型电感量仪可以准确方便地测出上述制件的不同轴度偏差值。瑞士TESA电感量仪是利用电感变换器将工件的微小位移变成电信号经放大后指示于刻度盘上的一种高精度的比较测量装置。仪器附带的轴向和杠杆(角度)测头可用于单独测测,也可用于两个(A和B)测头的差动组合     

一种五相Boost矩阵变换器研究

研究了矩阵变换器的控制方法,针对传统矩阵变换器"虚拟逆变部分"拓扑大多是推挽式、半桥式和全桥式结构,因而电压传输比较低的情况,提出了一种五相Boost矩阵变换器的结构。该结构整流侧采用传统的矩阵整流电路,其控制策略采用无零空间矢量调制,虚拟逆变部分则采用Boost逆变电路,该逆变电路具有升压特性,能提高矩阵变换器的电压传输比,其电压传输比可以达到1.0甚至更高。对该矩阵变换器的滑模变结构控制策略进行了研究,而且通过仿真和样机实验验证了其理论的正确性,为矩阵变换器的工业应用提供了一定的理论基础。     

软开关技术在开关电源中的应用

软开关PWM技术集谐振变换器与PWM控制的优点于一体,既能实现功率管的零电压开关,又能实现功率管的恒定频率控制,是电力电子技术的发展方向之一。与传统PWM硬开关变换器相比,元器件的电压、电流应力小,仅仅增加了一个谐振电感,成本和电路的复杂程度没有增加。移相控制零电压开关PWM变换器就是软开关PWM技术中的一种拓扑,它适用于中、大功率直流一直流变换场合。     

跑道型差动式涡流探头设计及其性能研究

针对传统差动式涡流探头几何尺寸大、缺陷检测灵敏度低的问题,在传统差动式涡流探头的基础上,设计了一种跑道型差动式涡流探头。它由激励线圈包裹2个尺寸相同、反向连接的感应线圈而构成。首先,利用COMSOL Multiphysics仿真软件建立了跑道型差动式涡流探头模型,比较了跑道型差动式涡流探头与传统差动式涡流探头涡流场分布的差异,并研究了在不同缺陷深度、不同扫查角度下2种差动式涡流探头的检测灵敏度。接着,制作了跑道型差动式涡流探头实物和碳钢板缺陷试件,利用试验测试的方法比较了跑道型和传统差动式涡流探头的检测灵敏度。试验结果表明,与传统差动式涡流探头相比,跑道型差动式涡流探头具有更紧凑的结构、更高的缺陷检测灵敏度。研究结果可为小尺寸、高精度差动式涡流探头的优化设计提供参考。     

一个高效的升压变换器设计

本文提出了一种新型的DC/DC升压变换器的电路。该电路有一个缓冲电路吸收的电感能量,实现开关管的零电压导通,减少开关管的开关损耗。同时减小二极管关断时反向恢复电流,减小二极管反向恢复的影响。通过Saber仿真和实验验证了所提出电路的可行性。结果表明,本文所提出的电路比传统的DC/DC升压变换器效率高。     

一种新型软开关BUCK变换器

本文提出一种新型软开关BUCK变换器。所提出的变换器具有如下的优点,零电压、零电流导通,零电压关断;不增加开关管的电压电流应力;输出电感电流工作在连续电流模式,其纹波很小;变换器可以工作在固定的频率,采用PWM控制。由于软开关的使用,变换器可以工作在很高的频率,同时其效率也很高。Pspice软件仿真验证了该电路的理论设计和分析。     

一种具有高电压传输比的新型Cuk矩阵变换器

对传统矩阵变换器存在电压传输比低的缺陷进行研究,提出一种新型的称为Cuk矩阵变换器的电路拓扑结构。介绍了该拓扑结构的基本构成及其工作原理,推导了其电压传输比与占空比之间函数关系的解析表达式,阐述了所采用的双闭环控制策略的基本设计方法,并通过仿真对其有效性和可行性进行了验证。结果表明：该拓扑结构能实现输出电压和频率的任意调节,其电压传输比可大于1,也可小于1,且直接输出标准的正弦波而无需滤波环节,有效地解决了传统矩阵变换器电压传输比低的难题,具有一定的应用价值。     

双差动快速结构光显微测量方法和系统

快速结构光显微测量技术具有高精度、高效率以及强适应性等特点,广泛应用于微纳检测领域。传统的快速结构光显微测量方法,利用轴向调制度响应曲线的线性区域,通过构建调制度值与实际高度之间的关系来实现三维形貌重建。但是,轴向调制度响应曲线的线性区域很短,传统方法的应用受限于其较窄的动态测量范围。为了克服这一缺陷,提出了一种双差动快速结构光显微测量技术。通过引入两条额外的探测支路构建双差动轴向调制度响应曲线,可以获得更宽的线性区域。在数值孔径为0.9,放大倍率为100倍的显微物镜条件下,其测量范围在仿真分析中可从380 nm提升到760 nm,在实验中可从300 nm提升到600 nm。仿真与实验结果均证明双差动快速结构光显微测量方法的动态测量范围相比传统方法的动态测量范围提升了一倍,有效地拓展了快速结构光显微测量技术的应用范围。     

一种电感式位移传感器的电路系统设计

介绍了一种电感式位移传感器的电路系统.该系统以一片AD698芯片为信号调整电路的核心,将位移量输出信号转换为相应的直流电压值,并结合其它一系列电路模块实现了测头位移量测量.通过对测头的标定试验证明该系统精度高、线性测量范围大.     

A Linear Variable Differential Capacitive Transducer for Sensing Planar Angles

A linear variable differential capacitive transducer for the measurement of planar angles (from 0deg to 360deg) is presented in this paper. The sensor part of the transducer is made of parallel plates of standard and easy-to-fabricate shapes, and the signal-conditioning electronics are realized, employing a couple of simple relaxation oscillators. The output of the transducer is only dictated by a pair of dc reference voltages, and hence, high accuracy and linearity over the entire range (from 0deg to 360deg) are easily obtained by the use of precision dc reference voltages. Detailed analysis indicates that the sensitivity of the transducer is minimal for variations in different parameters. Experimental results obtained on a prototype transducer that has been built and tested establish the efficacy of the proposed transducer. The worst-case error of the prototype transducer is found to be less than 0.1%.     

压电水声换能器宽带匹配特性研究

采用等效电路变换和多物理场有限元仿真计算进行压电水声换能器宽带匹配特性研究,得出不同匹配电路下的换能器电声性能的变化规律,合理选择电感电容值和串并联方式进行调谐匹配实现双峰谐振,一方面提高换能器的工作带宽,另一方面提高工作频率范围内的发送电压响应值并减小工作频带内响应值的起伏,依照仿真数据设计制作了一款球形换能器,采用串联电感进行调谐匹配,并测试调谐匹配前后的水中电声性能,对比匹配前后换能器性能的差异。结果表明,测试结果和仿真计算吻合,运用多物理场仿真计算手段对于预测分析水声换能器电声性能具有较好的指导意义。     

A self-compensated smart LVDT transducer

The authors present a novel technique of dual secondary coils for self-compensation of a linear variable differential transformer (LVDT) transducer for variations in excitation current and frequency and changes in ambient and coil temperatures. Experiments on compensated LVDT exhibited high sensitivity, good linearity, insensitivity to variations in excitation current and frequency, and self-compensation for changes in temperature. The transducer is suitable for both favorable and hostile environmental conditions for parameter acquisition and data handling     

Capacitive transducer for relative position error galvo mirrors

A transducer was designed to sense small angular displacements of servo-controlled galvo mirrors in rotary optical storage devices. The transducer is differential in nature, and operates on the principle of linear electrical capacitance variation with area overlap of uniquely shaped capacitor plates. These capacitive plates lie in planes normal to the axis of rotation, and consist of many electrically connected wedge-shaped projections aligned radially to the center of rotation. A prototype was fabricated and tested. For optical storage devices, experimentally determined characteristic curves show sufficient linearity and repeatability for relative position error (RPE) feedback applications, at plate spacings of 0.15 mm or less. A design change, for further extending the linear range of the characteristic curve of the transducer beyond RPE feedback requirements, is described. A circuit design to produce voltage variations proportional to differential capacitance changes in the transducer is discussed, and peak-to-peak signal-to-noise ratio is conservatively approximated at 2×10⁴ with 10 kHz bandwidth     

Long term operation of low noise DC-SQUID coupled to a very high Q gravitational radiation detector

We have coupled a very low noise dc-SQUID to the gravitational radiation detector of the Rome group at CERN laboratories. The SQUID used is a multiloop thin-film device with an input inductance of 1.6 μH, loop inductance of 5 pH and coupling coefficient of 0.5. The gravitational radiation detector is composed by a 2.3 tons Aluminum cylinder mechanically coupled to a resonant capacitive transducer; this is matched to the SQUID by means of a large superconducting transformer. The signal to be detected is essentially composed by the two mode frequencies at about 1 kHz and with quality factors of the order of 4×10⁶. To operate in a closed feedback loop mode we have used a particular setup in order not to degrade the performance of the system. The system operated for seven months with some interruptions due to refilling of liquid helium and various tests on the apparatus. The flux noise obtained was 1.5 to3times10^{-6} Phi_{o}/sqrt{Hz}at 1 kHz with a linearity over 6 orders of magnitude and a long term stability of1.5 times 10^{-8} Phi_{o}/hour.     

Vibration Damping Using CCII-Based Inductance Simulators

In this paper, we present an application of second- generation current-conveyor (CCII)-based active inductance simulators to mechanical vibration damping. The oscillation amplitude of a metallic beam, which is near some resonant frequencies, can be reduced by converting mechanical energy into electrical energy through a piezoelectric transducer that is bonded to the beam. An electric circuit, which is made up of the piezoelectric transducer, a resistance, and an inductance, accomplishes the task of dissipating the energy. To this end, the natural frequency of the circuit should be close to the natural frequency of interest of the mechanical system. The high value that is requested for the inductance (thousands of Henrys) can only be achieved through an inductance-simulator circuit. In the literature, the circuit implementations of the inductance simulators are typically based on operational amplifiers, such as the Antoniou circuit. In this paper, we make use of the CCIIs, which allow us to obtain both grounded and floating equivalent inductances that work within a regulated frequency range from three to four decades. The effectiveness of the traditional inductance simulators and CCII-based simulators is discussed, comparing the responses of an experimental mechanical-electrical system, with different circuit implementations, through experimental results. The use of series-resistance compensation, which is obtained through the use of a suitable topology based on the CCIIs, in the implementation of the equivalent inductance, allows one to obtain the best vibration damping, as confirmed by measurements, for all the natural mechanical frequencies of the realized system.     

Schematics of magnetically-elastic pressure transducers

Conclusions Experiments have shown that all three types of transducers with an appropriate selection of parameters have virtually linear output characteristics. Transducers with a variable inductance have a larger output power compared with the type of transducers made by the Swedish firm ASEA. The load resistances carry the difference of two voltages, the original biasing voltage and the voltage drop across a ballast lamp or the collector circuit of a transistor.The output power of a transistor with a variable inductance operating in a condition of free magnetization can be raised by measuring the magnetizing current increment and then amplifying it by means of the variable resistance which shunts the load and consists of a transistor or a magnetic amplifier with a negative current feedback through the transducer circuit.A suitable transducer circuit can be selected on the basis of specific conditions and requirements and by means of the comparison tests described in this work.N. P. Kunitskii and S. V. Krayushkin participated in the investigation of transducers with a variable inductance operating in a free or forced magnetization condition.     

力传感器的动态重复性,线性度与性能改进的研究

提出了传感器的动态重复性与动态线性度的计算方法，介绍了用有源模拟滤波器改善力传感器动态性能的方法，包括力传感器动态数学模型、动态补偿模拟滤波的设计方法、力传感器动态模拟器及其电路、滤波器的电路、动态性能改善的实验结果。     

Fully Automated Inductance Measuring System Using New Fabricated Inductance Box

Decade inductance boxes are widely used in electrical laboratories for calibration of instruments that measure inductance. The main aim of this paper is to construct a new inductance box providing a huge number of automated inductance steps, which are used in the laboratories to perform full automatic calibration of inductance meters. Therefore, a new inductance box has been introduced that mainly consists of three decades. The three inductance decades have the same design, but each has its four different internal inductive elements. Each decade can generate 15 different inductance values, so it is more economical and practical compared to the other ordinary decades, which produce only 10 values by using 10 internal inductive elements. 1666 different inductance values can be obtained from this inductance box, while 4096 inductance values can be obtained by the possible combinations of its three decades steps. Practical design, fabrication and specifications of this new inductance box are demonstrated in detail. It is designed to achieve relative accuracy in the range from 5 × 10^?4 to 5 × 10^?3. It could be used to perform full automatic inductance measurements at the National Institute of Standards, Egypt, for the first time. Comparison between an ordinary inductance box and the new introduced one has been made to validate its performance.