基于单片机阈值数字可调电压比较器设计

以单片机、D/A转换器以及运算放大器为核心,设计了一种数字式阈值可调的比较电路,于报警系统、自动控制等领域,并分别对硬件电路和软件程序进行了设计与编写,运用Protues软件对设计的电路系统进行仿真分析.最终实现通过上位机电压数值输入确定电路输出电压值作为信号比较阈值的目的.     

一种高精度基准电压源的设计制作

对能引起电源的时间漂移及电源噪声的诸多因素进行了分析,采用了AD581集成三端器件和uA741运算放大器设计了恒温控制电路,并制作了恒温槽,设计制作高精度基准电压源。该基准源被应用于HHSV-1型高压高稳定性直流电源的基准电压,极大的提高了该直流电源的精度,使其高压高稳定性直流电源在输出电压为10000V,负载电流在2mA的工作情况下,输出电压和电流的稳定度、时漂、温漂均达到10—6量级,波纹系数达10—7。该电压源可以用作粒子加速器,质谱计,CT机等高精度医疗仪器的基准源。     

热敏电阻温度—电压线性变换电路

本文介绍了采用热敏电阴分压电路与比较放大器组成的温度—电压变换电路,来实现线性化的原理、性能及其电器参数的确定。     

基于差动电压放大器的占空比测量电路设计

介绍一种利用占空比与PWM电路补偿端电压之间的关系，设计的以差动电压放大器为核心构成的占空比测量电路；它能以数字显示形式直接给出脉冲电源输出电压的占空比。     

晶闸管变流装置控制电压与输出电压关系分析

晶闸管变流装置通过改变触发控制角α从而改变装置的输出电压ud,而α角与触发器电路的控制电压UK之间有着密切关系。正确分析与探索控制电压UK与输出电压ud的关系,从而为变流装置实现过流保护和闭环自动控制提供了一个平台。     

基于TA的电子式电压互感器

针对现有各类电压互感器存在的一些技术问题,提出了以电流互感器检测耦合电容器电流,再将电流信号传输至控制室转换为与一次电压成正比变化的二次电压信号的方法构成电子式电压互感器(EVT)的技术方案,详细阐述了新型EVT的传感原理及结构,在此基础上,与一般电压互感器进行了比较,并对所研制的110 kV EVT样机进行了高压试验,理论研究和试验结果表明:新型EVT具有结构简单、体小质轻、绝缘性能好、抗干扰能力强、测量准确度高等特点,具有很好的推广应用前景。     

一种带电压波动动态补偿的称重系统研究

为了消除称重传感器外部电源电压波动对称量不确定度造成的影响,对称重系统电压波动的检测和补偿方法进行了研究,分析了电阻应变片的应变效应和惠斯通电桥的测量原理,给出了称重传感器输出电压与外部电源电压之间的修正关系,提出了一种通过同步检测输出电压和外部电源电压信号动态补偿电压波动的方法,设计了基于数字信号处理器TMS320F28335以及模数转换芯片ADS1234的称重系统对所提出的方法进行了验证。研究结果表明,在外部电源电压的波动范围内,补偿后称量结果的相对误差始终小于1%,说明该方法能够用于有效提高称重系统的称量精度。     

一起500kV电压互感器二次电压异常的处理分析

针对一起500kV电压互感器运行中发生的电压异常情况，本文根据电压互感器的结构、红外测温、诊断性试验及解体检查情况，判断异常原因为中间变压器高压端静电屏安装工艺管控不到位，导致高压端静电屏与铁心间绝缘击穿所致。本文通过对该起异常事故的过程分析及解体试验介绍，对电压互感器的结构进行了详细的分析，对现场同类事故分析判断提供借鉴。     

基于AD620的微弱信号放大器设计

为了解决微弱信号放大电路中零点漂移、放大失真等缺陷,设计了一种基于AD620的高精度微弱信号放大器.该放大器是以仪表放大器AD620为核心,辅以电压跟随器和二阶低通滤波电路,来滤除电路中的噪声信号提高放大精度,利用零点漂移电路来调整电路输出零点,保证传感器未动作时,电路输出的放大电压为零.实际测试结果表明,该电压放大器...     

变电设备中的电子式电流/电压组合型传感器的研究

介绍了一种用于中高压电力设备中的新型电子式电流／电压互感器的结构和测量原理，用Rogowski线圈测量母线电压，用柱状分压电容测量母线电压，并从频域角度详细地分析了移相器的设计理论。给出了处理转换单元（PISA）结构框图，对输出信号采用光纤传输到二次低压控制保护杠进行处理分析和显示。整个测量系统通过了线性度实验测试，实验结果良好。     

有源静电悬浮系统的变预载控制

在基于静电悬浮轴承的惯性仪表中,为了保证系统的承载能力,需要选取很高的预载电压;而为了提高惯性仪表的精度,希望选取较低的预载电压以减小电场干扰力矩。为解决此问题提出了一种固定低预载与连续变预载相结合的控制方案,通过将被控对象精确反馈线性化和增益补偿后,能够保证系统性能基本不受预载电压变化的影响。实验表明,系统的预载电压降低了56.7%,高压放大器的功耗降低了45.3%。     

Time delay effects on performance and stability of a low cost electrostatic suspension system

To expand the potential industrial applications of electrostatic suspension systems, a low cost suspension system with high-voltage supplies instead of high-voltage amplifiers has already been implemented. In that system, the performance and stability are strongly affected by the time delay inherent in the system. It is therefore important to understand the sensitivity of stability and performance in relation to the time delay. In this paper a low cost electrostatic suspension system based on a delay controller is presented. The effect of time delay on the characteristics of the suspension system will be investigated. The critical time delay of the suspension system, defined as the maximum time delay that can be accepted by the system in order to ensure the system stability, will be derived in terms of bias voltage. The recoverable set whose domain depends on time delay will be found as well. The simulation and experimental results will show the effectiveness of the proposed method. In the experiments, a 3.5-inch aluminium disk was suspended without any mechanical contact at a reference gap length of about 300 μm in both atmospheric and vacuum environments.     

风电转盘轴承载荷谱的设计应用

建立了偏航、变桨轴承的空间力系及载荷方程,介绍了风电转盘轴承在各种设计要求下的静强度载荷谱和滚动接触疲劳载荷谱,并以此为基础对某型号风电转盘轴承进行了校核。     

考虑温度效应的两端固支微机电开关梁静力分析

建立考虑温度效应的二维两端固支微机电开关梁静力变形分析模型,利用该模型分析温度变化引起的失稳问题,并利用该模型对两端固支微开关梁受电场力和温度作用下的受力变形进行分析。分析过程分为三个阶段：梁受电场力和温度变化作用,而在梁中点不受任何约束的变形阶段;除受电场力和温度变化作用外,梁中点变形受约束,因而梁中点受支反力作用的变形阶段;梁受电场力、温度变化以及支反力作用,并且在梁的中间一段具有指定挠度和转角的变形阶段。第二阶段中支反力的大小以及第三阶段中支反力的大小和位置都同驱动电压和温度变化有关。在实例中,给出部分计算结果,包括：温度变化对不同阶段梁受力变形的影响、对吸合电压的影响、对微开关电容的影响,以及不同温度变化下梁长对吸合电压的影响和不同温度变化下梁高对吸合电压的影响等,从中可以看出温度变化的作用及考虑温度效应的必要性。     

一种微开关悬臂梁的静力变形分析模型及其应用

建立一种微开关悬臂梁的静力变形分析模型,该模型将微开关悬臂梁的受力变形分为三个阶段,受电场力作用的悬臂梁阶段,受电场力作用的一端固支、另一端铰支的单跨梁阶段以及受电场力和集中力联合作用而保持自由端有指定的位移和零转角阶段。第二阶段中铰支端支反力的大小以及第三阶段中集中力的大小和作用位置均与电场力的驱动电压有关;同时文中将求解微开关悬臂梁挠度的高阶微分方程问题转化为含有未知初始条件的一阶微分方程组问题。在实例中,设计一种求解未知初始条件的迭代方法,并给出部分计算结果,从中可得出一些有益的结论。     

Digitally gain controlled linear high voltage amplifier for laboratory applications

The design of a digitally gain controlled high-voltage non-inverting bipolar linear amplifier is presented. This cost efficient and relatively simple circuit has stable operation range from dc to 90 kHz under the load of 10 kΩ and 39 pF. The amplifier can swing up to 360 V(pp) under these conditions and it has 2.5 μs rise time. The gain can be changed by the aid of JFETs. The amplifiers have been realized using a combination of operational amplifiers and high-voltage discrete bipolar junction transistors. The circuit details and performance characteristics are discussed.     

力反馈微加速度计的准静态和阶跃响应模型

对于微机械电容式加速度计,为了检测微小电容变化,必须引入交直流电压驱动信号,然而该静电力的存在显著影响传感器的最大可靠工作范围。对准静态惯性信号和阶跃惯性信号,深入研究了力反馈加速度计的可靠工作范围,建立了不同偏压配置的驱动信号对引起吸合失效的临界加速度信号的影响模型。研究结果表明静电力对阶跃信号的影响要比准静态信号大,动态工作条件下所能承受的最大阶跃加速度信号比准静态信号要小一个数量因子。对于双边驱动的力反馈加速度计,正正偏压配置或正负偏压配置可以最大程度地减小驱动信号引起的传感器吸合失效,从而增大可靠工作范围;而负负偏压配置或负正偏压配置增大了驱动信号效应,从而大大减小了可靠工作范围。     

Load Distribution in Flexibly Supported Three-Row Roller Slew Bearings

In general, slew bearings are less firmly supported by their mounting structures than small bearings. Hence, the load distribution around the bearing may be vastly different than that predicted by classic bearing formulas. The finite element method has been employed to determine load distribution in a three-row roller slew bearing mounted between two flexible, ring shaped supporting structures composed of beam elements. A special bar element modeling the system of two opposite rollers in contact with its raceways has been elaborated. The influence of the nonlinear force displacement characteristics of each of the rollers, as well as the influence of gaps between the rollers and its raceways have been taken into account. The nonlinear contact problem has been solved utilizing the Newton-Raphson method with continually updated stiffness matrix due to both element nonlinearity and contact status. The effect of a number of design parameters on the load distribution has been investigated.     

A high-voltage power supply based on a distributed capacitive energy storage

For the corpuscular plasma heating in the MST plasma device (Madison, United States), an injector of hydrogen atoms with 25-keV energy, equivalent at omic current of >45 A, and 20-ms pulse duration was designed and put into operation at the Budker Institute of Nuclear Physics (Novosibirsk, Russia) in 2009. The pulse repetition rate is 5 min. The output current of the ion source in the atomic injector exceeds 50 A. A high-voltage source with a 1.5-MW power was design ed for the high-voltage powering of the atomic injector. The run duration of the power supply with rated characteristics is >20 ms. The power supply is based on a distributed capacitive energy storage, which allows the power consumption from the industrial network to be reduced down to 10 kW at a pulsed load power of 1.5 MW. The high-voltage power supply smoothly regulates the output voltage from 0 to 30 kV and is capable of being quickly deenergized if high-voltage breakdown of the load takes place. The diagram and structural components of the high-voltage power system of the atomic injector are described, and its test results are given.     

EFFECT OF ELECTROSTATIC RESISTANCE ON THE SHUTTLE OF MICRORESONATOR

To improve the performance and reliability of microelectromechanical system＇s devices, it is necessary to understand the effect of friction which exists in the majority of microelectromechanical systems （MEMS） with a large ratio of surface area to their volume. The model of electrostatic tangential force of the shuttle in laterally driven comb microresonator is established based on the rule of energy conservation. The effects of microscale, surface roughness, applied voltage, and micro asperities or dents or holes formed in fabrication are investigated, and the electrostatic resistance between two charged moving plates is analyzed. The analytic results are coincident well with those of ANSYS simulation. It is found that the electrostatic resistance becomes high as the increase of the ratio of the shuttle width to the gap between moving plates and the relative surface roughness or the increment of the applied voltage.