检测与转换技术网络化教学实验监测终端的设计

介绍了检测与转换技术网络化的教学实验监测终端系统,该终端硬件设计包括单片机基本应用系统、信号检测与转换电路、人机接口电路、CAN通讯电路等.其中微处理器负责数据的处理和控制信号的输出,信号采集电路负责模拟信号和波形的采集及其数字化转换,人机接口负责系统功能设定、信息录入与人机对话,CAN通讯电路实现数据的远程传输.软件设计采用C51语言编程,以模块化思想构建整个系统.借助仿真软件Multisim 10和Proteus 7.1对系统进行仿真分析,仿真结果表明设计可行,达到了预期目的.     

基于CAN总线煤炭安全监测无线传输系统的研究

针对目前的中小型煤矿安全系统中信号传输效率不高的问题,采用 CAN 总线技术解决的底层信号传输效率低的问题,实践证明该方案能够对提高煤矿安全生产系统的底层通信能力具有较好的效果.     

基于CAN总线和SD卡存储器的高速数据采集系统的设计

开发了一套基于CAN总线和SD卡的高速数据采集系统。硬件系统主要由信号调理模块、A/D转换模块、MEGA处理器模块、CAN通信模块组成。它能够实现信号的采集及前端处理,并能通过CAN总线与SD卡通信,实现对数据的存储、后端处理及显示重点阐述了系统原理及硬件、软件的设计。     

具有通信功能的风力发电并网实验平台设计

基于微网的特点和智能电网对网络通信技术的要求,在搭建风力发电并网实验平台的基础上设计了基于CAN总线和Modbus协议的通信系统并应用于该实验平台。介绍了实验平台的硬件组成和软件设计,详细地阐述了该实验平台的结构和工作原理。为了测试实验平台的功能及可靠性,以三相并网逆变器预测直接功率控制实验为例进行了验证。验证结果表明,以触摸屏为上位机的该实验平台可靠性较高,扩展性较好,可方便地实现多种功能。     

模块化三相三电平低压光伏逆变器实验平台设计

设计并搭建了一种模块化三相三电平低压光伏逆变器实验平台。实验平台包含断路器模块、直流母线电容模块、L滤波器模块、传感器模块、DSP控制板模块、三相逆变桥模块和隔离电源模块。光伏逆变器直流侧连接实验室建筑顶部的小型光伏阵列,交流电网通过变压器降压,能够保证实验过程的安全性。该实验平台能够完成电网电压锁相(PLL)、三电平空间电压矢量调制(SVPWM)、并网、最大功率跟踪(MPPT)等实验。     

基于间接电流控制方案的单／三相功率因数校正开关变流器研究

在大多数工业运用场合,三相整流电路由不可控二极管或相控晶闸管组成。这种变换器具有功率因数低、输入电流谐波成分高等缺点。利用功率因数校正（PFC）技术可以解决这些问题。论文对最常用的单、三相开关功率因数PFC进行了深入的研究。利用功率平衡和相量图,建立了三相电压型高功率因数整流器的静态数学模型,深入研究了系统参数与功率因数之间的稳态关系。在分析系统静态模型和稳态关系的基础上提出一种间接电流控制（PAC）方案,该方案与传统方案相比,并不检测输入电源电压,因而能减少硬件和降低成本。     

基于H桥的光伏并网逆变器不平衡功率控制

针对采用光伏组件独立供电的H桥光伏并网逆变器,提出了一种不平衡功率控制策略,该策略用于解决光伏板直流侧输出功率不均衡问题。该策略通过实时计算三相交流功率获得三相不平衡功率系数,并依据简化调制算法加入占空比修正量使得三相不平衡功率系数趋向期望值。最后,通过Matlab/Simulink仿真和实验验证了该控制策略的可行性和有效性。     

风光动能互补系统中电能质量监测评价方案研究

为了快速高效地监测和分析风光动能互补系统中的电能质量,建立了电能质量监测、评价方案。该系统由数据监测子系统、通信子系统、数据评估子系统组成,运用FFT提取系统中的电压、电流波形中的基波和各次谐波信号,进而计算频率偏差、三相不平衡度、谐波、闪变与电压波动5项电能质量指标和功率参数。用少部分硬件实现数据采集,用虚拟仪器技术实现数据分析、处理、上传等功能,成本大幅降低。     

基于LabVIEW的直流无刷电动机控制系统设计

给出了直流无刷电机控制系统设计方案,介绍了系统的硬件结构组成、功率电路的逆变模块的选择、开关器件的选型以及驱动电路的设计,并给出了上位机控制软件主要功能的编写程序,实验验证了该系统的可靠性和稳定性。     

最大功率传输定理实验设计与实现

将专业基础课"电路原理"中的最大功率传输定理与后续专业知识及实际应用相结合,提出了基于开关电路的最大功率传输定理的实验方案,并对该方案进行了设计和实现,搭建了实验平台,实验效果达到了预期目标。     

卡思卡特城堡

It is worthy of noting that, whilst Crookston Castle witnessed the earlier and happier portion of Mary's variegated life,     

不同的吃喝玩乐

一、吃和喝吃苹果 eat an apple, 吃药 take medicine,吃糖 have some sweets,吃饭 have one's meals,吃馆子 dine out,吃惊 be surprised/     

漏洞百出的教育

Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help?     

只要努力,不要后悔

There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love.     

浅谈移民问题

Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject.     

Sister Carrie, an Adherent of Desires

Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities.     

Improvement of one-cycle controller by use of proportional integral differential controller

1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec…     

库克斯顿城堡

城堡, 是欧洲典型的建筑之一, 每个城堡都有一个美丽的传说或是一段历史。从本期开始, 我们将推出“城堡之旅”, 带各位读者去浏览、观赏欧洲各地的城堡, 开始一段文化与历史的旅途!     

The Reader Response Approach to Teaching of English Literature

During interview with English majors, it was found that a majority of students expressed disappointment with their experience of English literature classes. Students' dislike of learning English literature appears to be the major problem of teaching English literature in China. Reader response approach is a good way to solve this problem. In this paper, I explain the rationale behind the reader response approach, such as its origin, definition, features, assumptions, and strategies. Then I illustrate how reader response approach works as a teaching strategy by presenting several teaching models. At last I evaluate its usefuiness for teachers and present the advantages of reader response approach in Chinese context.