磁电系电压表测量交流电压和整流系电压表测量直流电压的结果分析

介绍磁电系电压表测量交流电压和整流系电压表测量直流电压的理论分析及实际测量结果,得到磁电系电压表不能测量交流电压,整流系电压表不能测量直流电压的结论。     

Characterizing voltage contrast in photoelectron emission microscopy

A non‐destructive technique for obtaining voltage contrast information with photoelectron emission microscopy is described. Samples consisting of electrically isolated metal lines were used to quantify voltage contrast in photoelectron emission microscopy. The voltage contrast behaviour is characterized by comparing measured voltage contrast with calculated voltage contrast from two electrostatic models. Measured voltage contrast was found to agree closely with the calculated voltage contrast, demonstrating that voltage contrast in photoelectron emission microscopy can be used to probe local voltage information in microelectronic devices in a non‐intrusive fashion.     

一种新的阻抗型电压跌落发生器设计

针对现有的阻抗型电压跌落发生器模拟电网电压跌落深度受限制的问题,提出一种基于串并联电阻、三相抽头变压器与限流电抗器等配合使用的电压跌落发生器拓扑结构。利用变压器副边不同抽头与电阻的组合模拟不同的电压跌落深度,设计的变压器限流电抗器在电压跌落和恢复期间投入,防止抽头电压等级切换而造成的电压冲击。基于50 kVA的电压跌落发生器样机实验结果表明,依据国家光伏太阳能及风能低电压测试标准,该设计可准确模拟不同等级的对称及不对称电压跌落,跌落暂态响应平稳无冲击,满足低电压穿越测试要求。     

一种改进的大功率逆变器脉宽控制电路设计

变频装置在电力系统中得到了广泛应用,特别是单元串联型高压大功率逆变器,其最高电压为功率单元的直流母线电压,能直接使用低压功率器件,不存在均压问题,但在电网电压的波动问题上,特别是当电网电压低于额定值时产生的抖动问题无法解决。针对此问题,本文提出了多单元串联的高压大功率、变频器脉宽控制。     

Establishment of Automated Multi-Range Multipliers Combined with TVC

An automated multi-range multipliers(range resistors)system is established for the AC voltage measurements by using a thermal voltage converter.It is performed automatically by selecting the appropriate multiplier whose voltage range contains the voltage to be measured without changing it manually through a new designed system.It consists of control part through a micro-controller controlled by specified prepared Lab-VIEW program and switching part through electronic relays in one circuit as clearly described in this work.It is used for measuring the ac voltage in the range from 1 V to 200 V.Also,it can be used for the voltage ranges up to 1 000 V by putting some factors into consideration.The AC-DC transfer differences for these multipliers combined with thermal voltage converter are determined automatically against another standard thermal voltage converter by using another Lab-VIEW program.     

基于单片机的无触点补偿式交流稳压器设计

本文设计了一种基于单片机的无触点自动补偿式交流稳压器.主电路采用交流斩波的方法进行电压补偿,通过过零点检测电路和单片机控制使补偿电压与输入电压同步来实现功率因数的提高,输出电压为严格的正弦波电压.该稳压器通过单片机实时地将电源输出电压幅值、电流幅值、功率及功率因数显示在液晶屏幕上.     

采用无线单片机的高压供电监测器设计

针对高电压供电监测中采用电压互感器和电流互感器体积大、绝缘要求高的缺点,设计了一套基于无线单片机的高压供电监测器电路。由于该电路采用无线单片机无线传输数据,高压与低压侧彻底分开,不但有效解决了高压绝缘问题,而且新的监测器体积更小,功能更强,相对于操作人员和监控值班员更加安全方便。     

基于DVR的电压跌落问题的研究

随着现代电力电子设备的广泛应用,电压跌落问题已成为影响电能质量的一个重要因素,提高动态电能质量,抑制系统电压跌落对敏感电力用户的干扰已成为急需解决的问题。随着高压大功率开关器件的出现,基于电力电子技术的动态电能质晕调节技术成为解决上述问题的有效手段。文章在介绍动态电压恢复器（DVR）的工作原理、系统框架及其数字控制系统的基础上,介绍了DVR解决电压跌落问题的应用效果。     

20kV中压配电的发展现状和趋势分析

介绍了国内外20kV中压配电的发展现状,列举了20kV中压配电比10kV中压配电的优势,指出了20kV中压配电推广的思路、原则和发展趋势,提出20kV中压配电的最终全面推广是一个漫长的过程。     

基于DS1267的精密数控电压源设计

该数控直流稳压电源采用单片机控制高精度的数字电位器DS1267,实现电压在1.25～13V之间可调输出,步进0.04V;且输出电压通过A/D MAX187采集反馈,实时闭环调整输出电压,保证了输出电压的精确度。系统输出电压采用LED数码管动态扫描显示。与传统稳压电源相比,具有操作方便、电压稳定度高、连续可调、精确等特点。适用于检修电路精确可变电压的提供或直流供电等场合,具有较高的实用价值。