基于电压比较器的固态功率控制器驱动保护电路研究

研究了基于电压比较器的固态功率控制器驱动保护技术原理,设计了降栅压保护电路。通过设置降栅压保护电路的输出电压值和电压上升/下降的速度,实现了对MOSFET栅极电压的控制和对负载在过流或短路时的及时保护功能。解决了现有技术中使用稳压二极管判断过流门限电压,导致对MOSFET栅极电压的控制精度不高和受保护MOSFET在一个时延内反复开通/关断的问题。经过电路分析和仿真实验,结果表明降栅压保护电路可以在45μs内对短路负载进行关断保护。     

新颖的N沟道VMOSFET驱动电路

普通MOSFET的栅极、源极、漏极处于芯片水平方向的同一表面上．导通时的工作电流沿芯片表面按水平方向流动．称为水平式场效应管。VMOSFET的栅极做成V形．源极制馓在栅极的两边．栅极与半导体材料之间的S1O2层也做成V形。GS间施加电压后形成的反型层导电沟道呈V形．漏极电流垂直向源极流动．到达表面时沿V形导电沟道流到源极S．故称为VMOSFET。     

两线制压力变送器

阐述了两线制压力传感器的结构原理与两线制传递方式特点。分析了传感器结构原理及形式。文中还介绍了电压/电流功能模块AD693的工作原理、信号传输方式等。     

纳米级MOSFET亚阈值区电流特性模型

基于纳米级金属氧化物半导体场效应晶体管(MOSFET)器件结构,从基本的漂移扩散方程出发,分别建立了亚阈值区漏极电流模型和栅极电流模型。其中将频率与偏置依赖性的影响显式地体现在模型中。通过对比分析发现亚阈值区漏极电流模型具有等比例缩小的可行性,栅极电流具有跟随性和频率依赖性。同时将所建模型的仿真结果与实验结果进行了比较,验证了模型准确性。     

基于内压式点滴速度传感器的设计

点滴法在液体微流量检测与控制方面的应用普遍,液体微流量的检测一直是研究的难点.利用医用输液管储液瓶、压力传感器和仪表放大器设计一种点滴速度检测传感器,用压力传感器检测储液瓶内的压力并转换为电压输出,通过测量电压后换算为点滴速度.设计并制作了传感器硬件,并进行实验测试,获得传感器点滴速度关系表达式.     

基于PSD的微位移传感器

微弱电流的放大与处理是基于位置敏感探测器(PSD)的微位移传感器的关键技术。分析了电流—电压转换原理,指出转换误差主要来源于偏置电流及失调电压。应用屏蔽、Guard、避免自激等技术设计了前放电路,实现了微弱电流信号的提取。传感器工作距离为10 mm,测量范围为±0.5 mm,采用精度为±0.5μm的装置驱动钢板进行微位移测量,实验数据表明:传感器分辨力为±0.5μm,检测精度为±2%。     

基于李萨如分析法的微型传感器系统

针对变压器成套的电压电流传感器测量输出值均较大、不便测量的缺陷,使用应用于三相智能电表中微型电压传感器与微型电流传感器构建李萨茹图分析法的工频信号传感器微系统,可实现将PT与CT测量值精确转换为适于处理的较小值.此微型系统测量精度高,额定工作频率、电压和电流可与变压器成套PT和CT相配合,便于采集卡对数据进行采集.     

聚酰亚胺MOSFET湿度传感器研究

将聚酰亚胺(PI)薄膜制作在金属氧化物半导体场效应管(MOSFET)的栅极上,当环境湿度发生变化时,将引起PI吸湿量的变化,电容量改变,据此可制成湿度传感器件,测试结果显示:该湿度传感器具有明显的湿度敏感特性.     

闭环霍儿电流传感器在开关稳压电源中的应用

本文主要介绍了闭环霍儿电流传感器的工作原理,推导了传感器输出电压与测试电流、导线位置、导线类型以及导线分布的关系,并实际测试了各种不同情况下电流传感器的输出电压值、对理论分析进行了验证。     

基于Simulink的零磁通微电流传感器的仿真与实验

根据零磁通补偿原理,基于Simulink平台建立了带有零磁通补偿的微电流传感器模型.为了快速准确地补偿微电流传感器的误差,提高微电流传感器的测量精度.该模型中的补偿单元采用有源与无源相结合的方法对对输出电流进行相位和幅值补偿.通过对仿真结果的分析,证明了该模型的正确性和有效性.并根据模型研制出了一种零磁通微电流传感器,对其误差进行测量.结果表明利用该补偿方法时电流传感器在测量微安级到毫安级的工频电流时准确度可达到0.2级,且补偿方式方便快捷.     

可植入眼压微传感器

对眼压进行长期、连续和实时的监测对于提高青光眼的诊治水平具有重要的意义.可植入眼压微传感器能够实现对眼压的长期连续监测.总结了国内外的可植入眼压微传感器技术;归纳了不同种类的可植入眼压微传感器的工作原理,并对不同的可植入眼压微传感器技术进行分类和比较;讨论了可植入眼压微传感器的各技术模块.     

微传感器和执行器的计算机模拟技术

介绍了计算机模拟技术在微传感器和微执行器设计中的应用 ,通过对多晶硅压力传感器和微泵膜片的计算机模拟分析 ,优化了器件的结构设计。研究工作表明计算机模拟是微传感器和微执行器设计的有效工具     

Design and modeling of a novel microsensor to detect magnetic fields in two orthogonal directions

In this paper, we present the design and modeling of the electrical–mechanical behavior of a novel microsensor to detect magnetic fields in two orthogonal directions (2D). This microsensor uses a simple silicon resonant structure and a Wheatstone bridge with small p-type piezoresistors (10 × 4 × 1 μm) to improve the microsensor resolution. The resonant structure has two double-clamped silicon beams (1000 × 28 × 5 μm) and an aluminum loop (1 μm thickness). The microsensor design allows important advantages such as small size, compact structure, easy operation and signal processing, and high resolution. In addition, the microsensor design is suitable to fabricate using silicon on insulator (SOI) wafers in a standard bulk micromachining process. An analytical model is developed to predict the first bending resonant frequency of the microsensor structure using Macaulay and Rayleigh methods, as well as the Euler–Bernoulli beam theory. Air and intrinsic damping sources of the microsensor structure are considered for its electrical–mechanical response. The mechanical behavior of the microsensor is studied using finite element models (FEMs). For 10 mA of root mean square (RMS) excitation current and 10 Pa air pressure, this microsensor has a linear electrical response, a fundamental bending resonant frequency of 52,163 Hz, and a high theoretical resolution of 160 pT.     

基于小挠度假设的电容式微型压力传感器模型

在小挠度变形假设的基础上对接触型电容式微型压力传感器进行分析。通过对压力传感器敏感元件硅膜片的弹性分析给出了传感器的模型。传感器的接口电路由ＭＯＳ电流镜和模拟开关构成,该电路具有线性度好和测量增益高的特点,并能有效地消除电路中的寄生电容对测量的影响,大大降低测量噪声。     

硅谐振式压力微传感器模型与开环特性测试

基于谐振式硅微结构压力传感器幅、相频率特性的分析,利用北京航空航天大学微传感器实验室研制的谐振式硅微结构传感器开环测试系统的测试实验结果和Matlab实验数据处理与拟和分析计算,建立了微传感器的二阶模型.该模型排除了未知相位延迟的影响,从幅值和相位混合的测试数据中精确计算出谐振频率、品质因数以及相位特性,为闭环测试系统的研制提供了依据.     

新型硅基MOS力敏传感器的设计与制作

随着汽车、航天、生物等领域对力敏传感器的越来越巨大的市场需求,力敏传感器再次成为研究的热点.压阻式力敏传感器由于其性能稳定、制作工艺简单、稳定性好且价格低成为商家的首选.研究表明,在应力作用下,MC6晶体管的源漏电流的大小会随着沟道区所受应力大小而变化,具有类似压敏电阻的力敏效应.基于MC6晶体管的这种力敏效应,采用晶体管和电阻构成压敏电桥,提出了一种新型的硅基MOS力敏传感器.该器件在与传统的压阻式力敏传感器相比,一方面继承了其制作工艺简单、稳定性和线性度好等优点,另一方面大幅提高了传感器灵敏度并降低了功耗,使得器件性能得到整体提高.     

Performance evaluation of wireless sensor network protocols for industrial applications

Recently, distributed wireless microsensor systems have provided more flexible leverage to emerging industrial applications. The tiny distributed wireless microsensor network systems, however, should be designed to overcome various constraints such as limited energy, bandwidth limit, and unexpected failure of communication under disturbances. In addition, their network topologies need to be managed with designated communication protocols. Thus, design of microsensor network protocols still needs to be application-specific. It should be also evaluated through designated tools at each level of networking characteristics. This research describes essential factors that affect the performance of sensor network systems in the design of wireless microsensor network protocols, and presents effective time-based network protocol and performance evaluation tool which are applicable for various protocols in industrial applications. The developed network evaluation tool, called TIE/MEMS, also includes functional comparison with recent protocols proposed for wireless microsensor networks, and provides design guidelines for multi-sensor network systems needed for emerging industrial applications.     

A sensitive nitric oxide microsensor based on PBPB composite film-modified carbon fiber microelectrode

In this work, a sensitive electrochemical microsensor of nitric oxide (NO) was reported. The microsensor was constructed by coating PBPB composite on carbon fiber microelectrodes (CFME). The NO microsensor displayed excellent electrochemical activity toward the oxidation of NO and have the virtue of good stability, reproducibility and high sensitivity. Under optimal working conditions, the oxidation current of NO at this microsensor exhibited a good linear relationship with NO concentration in the range of 3.6 × 10⁻⁸ to 8.9 × 10⁻⁵ mol/L with a low detection limit of 3.6 × 10⁻⁹ mol/L (S/N = 3). The microsensor was successfully applied to the direct and real-time detection of NO release from biological samples, foreseeing the promising applications of this microsensor in fields like biology and medicine.     

Mechanical design and characterization of a resonant magnetic field microsensor with linear response and high resolution

A resonant magnetic field microsensor based on Microelectromechanical Systems (MEMS) technology including a piezoresistive detection system has been designed, fabricated, and characterized. The mechanical design for the microsensor includes a symmetrical resonant structure integrated into a seesaw rectangular loop (700 μm × 450 μm) of 5 μm thick silicon beams. An analytical model for estimating the first resonant frequency and deflections of the resonant structure by means of Rayleigh and Macaulay's methods is developed. The microsensor exploits the Lorentz force and presents a linear response in the weak magnetic field range (40–2000 μT). It has a resonant frequency of 22.99 kHz, a sensitivity of 1.94 V T^?1, a quality factor of 96.6 at atmospheric pressure, and a resolution close to 43 nT for a frequency difference of 1 Hz. In addition, the microsensor has a compact structure, requires simple signal processing, has low power consumption (16 mW), as well as an uncomplicated fabrication process. This microsensor could be useful in applications such as the automotive sector, the telecommunications industry, in consumer electronic products, and in some medical applications.     

汽车仪表板注射成形浇注系统方案及翘曲分析

针对汽车设计中的轻量化需求,分析不同浇口模型下汽车仪表板的注射成形过程.分析3种浇注模型下模具型腔的充填情况,发现熔接痕的数量不仅与浇注系统的布局有关,还受产品结构影响;分析3种浇注模型下的充填压力,发现浇口数量越多,充填压力损失越小,但浇口数量的增加会导致熔接痕数量增多;4浇口模型与5浇口模型对应的制品收缩率分布基本一致,3浇口模型的收缩率略高;采用高性能有限体积法（High Performance Finite Volume Method,HPFVM）分析3种浇注模型下制品的翘曲情况,发现3浇口模型的总翘曲变形量分布最宽,5浇口模型的总翘曲变形量分布最窄.