IR2110在IGBT驱动电路中的应用

针对IGBT的半桥或者全桥的驱动,利用具有双通道集成驱动的IR2110来驱动IGBT.对其自举工作原理进行了分析,同时增加了栅极电平箝位电路,克服了IR2110不能产生负偏压的缺点,并在2 kW、400 V汽车直流充电器中以此驱动IKW40N120T2电路的试验中验证了其理论分析的正确性.     

高频移相全桥变换器的数字驱动研究

基于经典全桥零电压零电流开关(ZVZCS)变换器拓扑,采用数字信号处理器(DSP)进行控制,提出了一种新型的移相PWM波形产生算法。结合IR公司最新推出的集成驱动芯片IR2304,通过对传统驱动电路增加两个无源元件,设计了带有负电压关断的硬件驱动电路,克服了IR系列不能产生关断负电压的缺点。实验验证了新型算法的正确性和驱动系统设计的可行性。     

一种IGBT负载回路滤波电路的设计

为了解决IGBT在关断过程中由于负载回路存在感性，IGBT集电极或发射极产生反向电动势导致IGBT被过压击穿的问题，本文提出使用RDC滤波电路进行电压尖峰有效滤除的设计理念。通过两路滤波电路对电压尖峰进行吸收并且不会影响IGBT原有的接通关断时间，可有效地保护IGBT不会在反向电动势所产生的电压尖峰下击穿。同时本设计也可以应用于其他功率器件的接通关断滤波电路中，提高了功率器件的安全性。     

基于PSpice的IGBT功耗分析与仿真

针对大功率感应加热电源功率开关器件IGBT功耗大的特点,给出了3种RCD缓冲电路结构及参数设计,在PSpice仿真软件下对3种缓冲电路中的IGBT和缓冲电阻的功率损耗进行了仿真分析,给出了相应的仿真结果。仿真结果表明,I型缓冲电路的电能损耗大,缓冲电阻发热严重;II型缓冲电路对关断瞬态电压抑制效果好,但不能有效地控制大功率级别IGBT的瞬变电压;III型缓冲电路具有寄生电感较小的优点,可有效地抑制振荡和控制瞬变电压,适用于大功率级别IGBT工作场合。     

直流电机的IR2110驱动控制设计及DSP实现

为了解决直流电机转向及速度控制问题,设计了一种H桥驱动电路。以IRF530为开关元件、IR2110为栅极驱动芯片,由DSP产生PWM信号,经过光耦隔离和逻辑电路后送至IR2110进行控制。给出了整体驱动控制电路、上下桥臂的栅源电压波形、上桥臂的浮动电压信号以及电机两端的运行电压信号。测试分析表明,该方案很好地实现了电机的正反转控制及电机速度调节,电机运行平稳,达到了设计要求,对直流电机控制应用具有较高的参考价值。     

一种基于多阈值保护的大功率IGBT驱动

通过分析VCE检测电路的传递函数,合理配置检测电路电气参数,根据IGBT发生短路时的特点,提出了一种基于多阈值过流保护和变电阻式软关断的大功率IGBT驱动保护策略,实现了驱动器对IGBT有效控制,并抑制开关过程中由于di/dt引起的电压尖峰.最后在Sabor中搭建了型号为FZ1500R33HE3的大功率IGBT的仿真模型,进行仿真分析,并搭建实物平台进行了短路保护实验.仿真和实验结果表明该驱动电路具有可行性.     

并联有源电力滤波器保护的关键技术研究

针对并联有源电力滤波器在运行过程中会多次出现IGBT爆炸的问题,经过实验分析了IGBT的过电压形成过程。鉴于IGBT的关断时间极短,连接导线上寄生的微小杂散电感在高频开关的作用下会产生尖峰过电压,并与原有电压叠加,从而对IGBT的安全构成威胁[1]。文中为设计的100kV·A并联有源电力滤波器所选择的IGBT模块设计了一种缓冲电路,从而解决了IGBT模块爆炸的问题,保证了并联有源电力滤波器的安全运行。     

一种新型PWM逆变器吸收电路

针对传统开关管吸收电路(RCD)存在自身消耗能量大,造成开关管温升加快,使用寿命降低等问题,提出了一种新型无源无损软开关吸收电路(Lossless Passive Soft-switching Snubber,LPSSS),解决了传统吸收电路自身的能量损耗,同时实现了能量回收。理论分析了逆变电路中IGBT关断过程中过电压产生的原因,以及RCD型吸收电路和新型LPSSS电路的工作原理。通过LPSSS吸收电路在逆变器中的分析可知LPSSS电路在IGBT关断过程中对浪涌电压dv/dt的有效抑制,同时最大程度地降低了吸收电路的能量损耗,实现了能量反馈,提高了能量转换效率。仿真分析表明,开关管的过电压降到了5.2%左右,验证了LPSSS电路的有效性和适用性。     

用于煤矿电缆绝缘参数在线测量的附加低频信号源设计

分析了附加低频信号源测量电缆绝缘参数的基本原理,详细介绍了该信号源中优化的SPWM驱动电路、输入和输出保护电路和RS232通信电路的设计,其中优化的SPWM驱动电路可输出-8～+12V的电压,保证了IGBT的可靠开通和关断。实验结果表明,该信号源输出电压幅值稳定、频率连续可调。     

一种IGBT集电极电压测量电路的设计

由于大功率IGBT开通和关断集-射电压具有跨度大的特点,现有的大功率IGBT驱动检测电路无法同时实现宽范围、高精度的测量.为此提出了一种新的IGBT集电极开通和关断电压集成的测量电路.该电路通过电阻分压网络实现IGBT关断电压的测量;利用驱动信号来控制电流源向高压隔离二极管注入微小电流使其导通,并对此二极管误差进行补偿,实现IGBT导通饱和压降的精确测量.仿真和试验验证了设计电路的正确性和有效性,可为高压大功率IGBT高性能驱动器的研制奠定基础.     

Only connect: teaching, technology and telesis

Abstract This paper describes an approach to the design of interactive multimedia materials being developed in a European Community project. The developmental process is seen as a dialogue between technologists and teachers. This dialogue is often problematic because of the differences in training, experience and culture between them. Conditions needed for fruitful dialogue are described and the generic model for learning design used in the project is explained.     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

Avoiding semantic and temporal gaps in developing software intensive systems

Development of software intensive systems (systems) in practice involves a series of self-contained phases for the lifecycle of a system. Semantic and temporal gaps, which occur among phases and among developer disciplines within and across phases, hinder the ongoing development of a system because of the interdependencies among phases and among disciplines. Such gaps are magnified among systems that are developed at different times by different development teams, which may limit reuse of artifacts of systems development and interoperability among the systems. This article discusses such gaps and a systems development process for avoiding them.     

Designing economic np control charts: A programmed simulation approach

This paper presents control charts models and the necessary simulation software for the location of economic values of the control parameters. The simulation program is written in FORTRAN, requires only 10K of main storage, and can run on most mini and micro computers. Two models are presented - one describes the process when it is operating at full capacity and the other when the process is operating under capacity. The models allow the product quality to deteriorate to a further level before an existing out-of-control state is detected, and they can also be used in situations where no prior knowledge exists of the out-of-control causes and the resulting proportion defectives.     

The development of robot art

Going through a few examples of robot artists who are recognized worldwide, we try to analyze the deepest meaning of what is called “robot art” and the related art field definition. We also try to highlight its well-marked borders, such as kinetic sculptures, kinetic art, cyber art, and cyberpunk. A brief excursion into the importance of the context, the message, and its semiotics is also provided, case by case, together with a few hints on the history of this discipline in the light of an artistic perspective. Therefore, the aim of this article is to try to summarize the main characteristics that might classify robot art as a unique and innovative discipline, and to track down some of the principles by which a robotic artifact can or cannot be considered an art piece in terms of social, cultural, and strictly artistic interest. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于QTE的蒙古文显示机制研究与实现

蒙古语言是中国蒙古族使用的通用语言,由于蒙古文区别于其他文字的书写方式和其自身变形机制等特点,在很多通用的文字处理引擎中都不被支持。在嵌入式产品开发与应用领域中Linux加QTE已经成为流行方式。该文给出了一种在QTE环境上实现基于标准Unicode的蒙古文点阵显示和变形算法, 并自定义了支持蒙古文的QTE组件,扩展了QTE功能,为在Linux加QTE方式的嵌入式体系结构中处理蒙古文提供了一种解决方法。     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。