基于超级电容器储能的时域激发极化法发射机研究

针对目前时域激发极化法发射机存在无电能存储、体积较大的问题,设计了一种基于超级电容器储能的时域激发极化法发射机。该发射机采用新的电路拓扑结构,在发射机空闲时由超级电容器存储发电机输出的能量,在发射机工作时超级电容器释放存储的能量,释放出的能量与发电机一起给负载提供功率,有效减小了发电机的体积;同时超级电容器在释放能量时与发电机电源是串联工作,不仅不需要升压电感而且能够实现升压作用,进一步优化了发射机的体积。仿真及实验结果表明,该发射机性能稳定、可靠。     

DIMOS — a software tool for optimizing display systems with LCDS

The Display Modelling System (DIMOS) is a software tool that was developed to evaluate the electro-elastic, electro-optic and colorimetric properties of display systems with liquid-crystal cells. DIMOS enables the user to perform a numerical analysis of the complex interdependencies between the numerous physical parameters of such display systems and the relevant output quantities. These must be known in order to optimize information content (multiplexability) and visibility of display systems with liquid-crystal cells. The structure and organisation of DIMOS is explained with special emphasis on the definition of dichroic dyes, polarizers and birefringence dispersion of LC materials. An overview is given of the numerical procedures used for the evaluation of the field-induced deformation and the optical properties of arbitrary chiral-nematic LC-configurations. The applicability of DIMOS to the optimization of supertwisted LCDs is shown in an example.     

基于单片机的比色光纤高温测量系统设计

比色光纤测温属于典型的非接触式测温技术,具有耐腐蚀、耐高温以及光路可弯曲等优点,适合高温铸造炉等特殊测温场合。但已有的光纤高温仪大多使用DSP处理器,编程复杂且成本高。本文以单片机处理器为核心设计高性价比的比色光纤高温仪。首先介绍比色光纤测温的原理与方法,然后论述基于51单片机的比色光纤高温仪的软硬件设计,重点论述跟单片机有关的温度发送、接收与显示等内容。实验结果表明,最大测温误差不超过8℃,满足一般高温铸造炉的测温要求。     

圆筒电容器静电场的数值分析

在 110kV电容分压式电压互感器设计的过程中 ,电容器本身的绝缘是很关键的。应用有限元法对圆筒电容器的电势分布进行了计算 ,为绝缘结构的设计奠定了理论基础     

The spherical capacitor: a vehicle to introduce numerical methods

Numerical methods are frequently introduced to the undergraduate Electrical and Computer Engineering student in the first course in electromagnetic theory. In this note, we demonstrate that a spherical capacitor can be first solved analytically and then compared with an easily obtained numerical solution.     

微网超级电容器储能系统的滑模控制策略研究

为改善微网运行不稳定的问题,针对与微网连接的超级电容器组储能装置的控制策略进行研究.储能装置由超级电容器组通过双向DC/DC变换器连接DC/AC变换器,通过滤波、升压后连入电网.通过对双向DC/DC转换器滑模控制的研究,使得任意操作条件均能正常工作,同时对运行中的稳定性进行了分析.最后,在Matlab中Simulink搭建储能系统仿真模型,验证了本文控制策略的可行性.     

数字化开关电容滤波技术应用

介绍了数字化开关电容滤波技术,并设计了可以通过改变开关时钟频率来自由调整中心频率的开关电容带阻滤波器,使中心频率具有很高的精度和稳定度。提出的抗混叠滤波技术能有效消除高频混叠和噪声干扰。在中心频率为200Hz,Q值为3的条件下,陷波深度可达到29dB。     

CAD modeling of coplanar waveguide interdigital capacitor

A lumped‐element circuit is proposed to model a coplanar waveguide (CPW) interdigital capacitor (IDC). Closed‐form expressions suitable for CAD purposes are given for each element in the circuit. The obtained results for the series capacitance are in good agreement with those available in the literature. In addition, the scattering parameters obtained from the circuit model are compared with those obtained using the full‐wave method of moments (MoM) and good agreement is obtained. Moreover, a multilayer feed‐forward artificial neural network (ANN) is developed to model the capacitance of the CPW IDC. It is shown that the developed ANN has successfully learned the required task of evaluating the capacitance of the IDC. © 2005 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2005.     

Stabilization of a synchronous generator with a controllable series capacitor via immersion and invariance

The immersion and invariance (I&I) technique (it IEEE Trans. Automat. Control 2003; 48 (4):590–606) is a recently proposed control methodology for stabilizing nonlinear systems. Here we apply this philosophy to stabilize a single machine infinite bus (SMIB) system using a controllable series capacitor (CSC). The synchronous generator is modeled using the second‐order swing equation and a first‐order model is used for the CSC. The control objective here is to immerse a desired second‐order dynamic model into the higher order system manifold and design an asymptotically stabilizing control law. Copyright © 2011 John Wiley & Sons, Ltd.     

基于单片机的液体点滴速度监控的研究

本文针对全国大学生电子设计大赛运动控制试题之一《液体点滴速度监控》的控制要求，提出了一种基于单片机和步进电机液滴自动监控的研究方法。考虑到控制的可靠性及精确性，在软件设计中使用TPID软件算法进行液滴速度的测算，形成一个闭环传递控制系统实现精确的控制。     

基于FPGA高速图像数据的存储及显示设计

设计了一种基于FPGA控制Nand Flash阵列实现高速流水线式存储的方案。设计利用FPGA作为主控制器,通过Camera Link输入通信接口将图像数据经过一/二级缓存写入Flash存储阵列中,并采用DMA传输技术将存储后的图像数据上传至计算机硬盘中作进一步处理;同时,利用SDRAM显存实时刷新数据,FPGA构造相应的VGA信号,最终实现100 MB/s图像数据的实时显示。     

电容器的火灾预防及群爆处理方法

电力电容器,具有改善电力系统的电压质量和提高输电线路的输电能力,是电力系统的重要设备。电容器在运行过程中,可能发生火灾,并联电容器单台保护熔断器会出现群爆现象,从而导致电容器无法正常工作。分析了电容器火灾产生原因及预防措施,电容器群爆的处理等。     

Symmetric coplanar waveguide sensor loaded with interdigital capacitor for permittivity characterization

This article presents the developing of interdigital capacitor (IDC) based symmetric coplanar waveguide (CPW) sensor to characterize the complex permittivity of unknown dielectric sheets. The symmetric structure is realized by using two identical 3 dB CPW dividers where each branch is loaded with an IDC unit. The proposed method is designed using three, five, and seven fingers of the IDC unit, and the measurement sensitivity is analyzed accordingly. The permittivity of tested samples is extracted by the genetic algorithm. To validate the robust sensing performance of the proposed method, simulation and experimental tests are performed and analyzed, and the accuracy is compared with published values. The proposed method gives the maximum error of 3.42%. With the feature of high‐sensitivity, the proposed sensor can be used as an excellent candidate for determining the permittivity of materials in microwave frequencies.     

High-performance MEMS shutter display with metal-oxide thin-film transistors and optimized MEMS element

Active matrix prestressed microelectromechanical shutter displays enable outstanding optical properties as well as robust operating performance. The microelectromechanical systems (MEMS) shutter elements have been optimized for higher light outcoupling efficiency with lower operation voltage and higher pixel density. The MEMS elements have been co-fabricated with self-aligned metal-oxide thin-film transistors (TFTs). Several optimizations were required to integrate MEMS process without hampering the performance of both elements. The optimized display process requires only seven photolithographic masks with ensuring proper compatibility between MEMS shutter and metal-oxide TFT process.     

网络存储系统的设计与实现

文章介绍了当前网络存储系统的几种流行模式，并着重描述了具有发展前景的SAN存储系统的管理、控制及实现的原理。结合实际应用阐述了设计构造SAN存储系统的有效方法及采用该技术的优越性。     

基于混合遗传算法的去耦电容网络设计

结合基于目标阻抗的设计方法,将混合遗传算法应用于PDN(电源分配网络)的去耦电容网络设计,对所需去耦电容器的种类和数目进行优化计算,同时与标准遗传算法和传统设计方法进行对比,借助Cadence电源完整性仿真工具验证设计结果的有效性和合理性。避免了传统设计需要借助EDA工具进行反复修改和验证的繁琐过程,同时减少了设计冗余,节省了PCB布局布线空间,为高频电路的PDN设计提供参考。     

基于AN051A的电容器组不平衡电压保护

现代电网广泛采用电力电容器组进行无功功率补偿。当某相电容器发生故障以后，由于熔断器熔断，将故障电容器切除，从而引起电容器组三相电容值不平衡而产生的电压不平衡来启动保护电路，动作于开关跳闸。基于电压检测器（AN051A）的并联补偿电容器组的不平衡电压保护电路，具有结构筒单、性能可靠、安装方便和保护灵敏度高等特点，经试用发现，能有效保护补偿电容器组，使电网正常运行。     

基于MOS电容衬底压阻的纳米梁检测研究

传统的纳米谐振器压阻检测在工艺上需解决制备结深浅、掺杂浓度高的薄层电阻的技术难题.基于MOS电容衬底压阻的谐振式纳米梁系统是一种新型的压阻检测方案,它通过将MOS电容耗尽层下的掺杂区用作力敏电阻,回避了制备浅结高浓度电阻的技术问题,也解决了MOS沟道压阻抗干扰性差的问题,在SoI硅片上制作了150 nm厚的梁结构.在检...     

Separating computation and storage with storage virtualization

Recent advances of hardware, software, and networks have made the management and security issues increasingly challenging in PC usage. Due to the tight coupling of hardware and software, each one of the hundreds or thousands of PCs connected in a networked environment has to be managed and administrated individually, leading to a high Total Cost of Ownership (TCO). We argue that a centralized storage of software and data, while distributed computation in clients, i.e., transparent computing, can address these challenges potentially and reduce the complexity with reduced software maintenance time, improved system availability, and enhanced security.This paper presents a novel approach, named StoreVirt, to realize transparent computing, which separates computation and storage from inside a single physical machine to different machines with a storage virtualization mechanism. With virtualization, all the OSes, applications, and data of clients are centered on the servers and scheduled on demand to run on different clients in a “block-streaming” way. Therefore, due to the central storage of OSes and applications, the installation, maintenance, and management are also centralized, leaving the clients light-weighted. Further, due to timely patching and upgrading, the system security can be improved. Experimental and real-world experiences demonstrate that this approach is efficient and feasible for real usages.     

基于差动电容的高精度倾角测量系统设计

介绍了一种新型的高精度倾角测量系统。采用差动电容式倾角传感器与温度特性好的精密电阻器构成阻容电桥,用文氏振荡电桥作为激励源,用差动放大电路组成阻抗变换和前置放大电路,采用低功耗18位A／D转换器MAX132对模拟电路调理后的直流模拟电压信号进行转换。提出通过在A／D转换器参考电压的电路中接入热敏电阻器的方法实现温度补偿。经过试验验证,该倾角测量系统达到了高分辨率、高稳定性和低功耗的设计要求。