无轴承同步磁阻电机逆系统解耦控制仿真研究

研究无轴承同步磁阻电机稳定性控制问题,由于无轴承同步磁阻电机是一个强耦合的非线性系统,为实现负载条件下的稳定悬浮运行,需解除电机转矩和径向悬浮力等多变量之间的耦合关系。针对前馈补偿解耦的缺陷,给出了无轴承同步磁阻电机包含转矩控制和悬浮力控制的统一数学模型,证明电机逆系统存在,设计了一种通过非线性状态反馈的逆系统解耦控制方案,将复杂的无轴承同步磁阻电机系统解耦成两个转子径向位置二阶积分子系统和一个转速一阶积分子系统,并用PI和PID调节器分别对转子位置与转速进行综合设计。运用MATLAB软件对电机控制系统进行仿真。仿真结果证明,解耦控制方案的有效性,为电机系统优化设计提供了保证。     

基于最小二乘支持向量机的无轴承同步磁阻电机解耦控制

无轴承同步磁阻电机是一个复杂的多变量、强耦合非线性系统,实现其非线性动态解耦控制是无轴承同步磁阻电机稳定运行的前提.在推导其数学模型的基础上,采用最小二乘支持向量机的方法得到无轴承同步磁阻电机逆模型;根据逆系统基本原理,将复杂的原非线性多变量耦合系统解耦成伪线性系统;根据线性系统理论,设计了闭环控制器,并构建了系统仿真模型.仿真结果表明该方法实现了系统的动态解耦,并且具有良好的动、静态特性.     

永磁同步电动机的直接转矩控制方法

永磁同步电动机是一种强耦合的非线性系统。该文针对永磁同步电动机的特点,对其直接转矩控制方法和调速控制原理进行了深入的研究。文中首先介绍了永磁同步电动机的基本结构,并根据电机基本原理建立了三相永磁同步电动机在转子坐标系下的数学模型,分析了该型电动机直接转矩控制的基本理论,最后给出了永磁同步电动机直接转矩控制系统的原理。仿真结果表明,不但电机的转矩响应快速而平稳,而且在不同基准速度给定下系统均具有较好的适应性。     

基于神经网络多电机偏差耦合同步控制研究

针对多电机同步驱动系统,以四台电机为控制对象,基于智能控制技术,并结合多电机同步控制系统的非线性、时变、容易受负载扰动等特性,设计了神经网络PID控制器,提出了基于神经网络PID控制器与偏差耦合控制结构相结合的多电机同步控制策略;采用Matlab/Simulink构建系统仿真平台,对该控制策略进行仿真,结果表明:该控制算法稳定性能高,鲁棒性能好,收敛速度快,能有效的克服外部扰动和参数变化带来的同步误差,相对于传统的同步控制方案能够更好的实现多电机的同步控制.     

一类永磁电动机的混沌反控制研究

研究了永磁同步电动机系统在不改变电机结构参数条件下的混沌反控制问题.该方法借鉴非线性系统模型跟踪控制的思想,利用电机系统和混沌系统状态变量之间的关系来设计控制器.根据误差的变化,控制器随时做出响应,强迫被控系统的状态变量从非混沌状态转化为混沌状态.实现了永磁同步电动机系统比较精确跟踪混沌系统的过程.本文方法中控制器参数的选取范围比较宽,为控制器设计带来很大方便.仿真结果验证了本文控制方法的有效性.     

多电机变频调速同步系统的多模型预测控制

针对多电机同步系统具有强烈的非线性和耦合性,难以建立精确数学模型并施加有效控制的缺陷,提出一种多电机多模型动态矩阵预测控制算法．在辨识不同工况子模型的基础上,设计各自的子控制器,并利用加权和形式构造全局控制器,在有约束的条件下,通过滚动优化的策略获得合适的控制增量．控制过程中,无需进行磁链观测．仿真结果验证了该算法的有效性．     

基于自适应模糊反步法的永磁同步电机位置跟踪控制

研究具有参数不确定性的永磁同步屯动机位置跟踪控制问题.利用模糊逻辑系统逼近系统中非线性函数,采用反步设计方法实现永磁同步电动机的自适应模糊控制.所提出的自适应模糊控制器在电机参数不确定和负载扰动的情况下,实现了永磁同步电动机的高性能位置跟踪控制.仿真结果表明了所提出方法的有效性.     

基于非线性奇异子系统模型的同步发电机分散非线性控制

针对基于非线性奇异子系统模型的同步发电机,本文利用反推控制方法,研究了其非线性分散控制问题.同步发电机本质上是电力大系统中的一个非线性奇异子系统,与系统其余部分存存相互约束和影响.首先利用微分同胚变换和状态反馈,实现了同步发电机模型的等价转化.然后在等价系统的楚础上,在充分考虑系统其余部分对于同步发电机影响的前提下,利用反推控制方法设计了同步发电机组的非线性镇定控制器,使得闭环系统是渐近稳定的.最后的仿真结果农明了本文所提控制方法的有效性.     

交流感应电机矢量解耦控制系统仿真研究

为了考查实际系统中异步感应电机磁场会随着电机负载(转矩)变化而呈不同程度的饱和以致电机参数非线性的影响,文章从同步速d-q坐标系下异步感应电机动态模型和矢量解耦控制的基本原理出发,引入了内模控制方法,详细设计了基于转子磁链定向和内模控制的电流调节器,分析了电流内模控制器对这种非线性参数的鲁棒性.在此基础上建立整个异步感应电机矢量控制仿真系统,并分别对忽略磁路饱和和考虑磁路饱和两种情况下的系统进行了仿真和分析.仿真和分析结果表明了电流内模控制调节器在模型匹配和失配下均能提供良好的转矩动、静态解耦效果.     

超混沌系统同步非线性反馈控制

在将超混沌系统的控制、同步及反同步问题统一处理的基础上,给出了一种可实现超混沌系统同步的非线性状态反馈方法。该方法以非线性系统的线性化方法和极点配置理论为基础,把控制律分解为非线性和线性两部分之和,使超混沌系统得以控制、同步和反同步。对超混沌Newton-Leipnik系统的仿真实验表明了控制策略的有效性。     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.     

A pragmatic multi-method investigation of discrepant technological events: Coping,attributions, and ‘accidental’ learning

Discrepant technological events or situations that entail a problem, a misunderstanding or a difficulty with the Information Technology (IT) being employed, are common in the workplace, and can lead to frustration and avoidance behaviors. Little is known, however, about how individuals cope with these events. This paper examines these events by using a multi-method pragmatic approach informed by coping theory. The results of two studies – a critical incident study and an experiment – serve to build and test, respectively, a theoretical model that posits that individuals use a variety of strategies when dealing with these events: they experience negative emotions, make external attributions, and adopt engagement coping strategies directed at solving the event, eventually switching to a disengagement coping strategy when they feel they have no control over the situation. Furthermore, users’ efforts may result in ‘accidental’ learning as they try to overcome the discrepant IT events through engagement coping. The paper ends with a discussion of the results in light of existing literature, future opportunities for research, and implications for practice.     

The Distributed Time-Triggered Simulation Scheme: Core Principles and Supporting Execution Engine

Distributed real-time simulation is a young technology field but its practice is under increasing demands. In recent years the author and his collaborators have been establishing a new approach called the distributed time-triggered simulation (DTS) scheme which is conceptually simple and easy to use but widely applicable. The concept was initiated in the course of developing a new-generation object-oriented real-time programming scheme called the time-triggered message-triggered object (TMO) programming scheme. Some fundamental issues inherent in distributed real-time simulation that were learned during recent experimental studies are discussed along with some approaches for resolving the issues. An execution engine developed to support both the TMOs engaged in control computation and the TMOs engaged in DTS is also discussed along with its possible extensions that will enable significantly larger-scale DTSs.     

Software-Konfigurationsmanagement in großen Softwareprojekten

Zusammenfassung Mit zunehmender Größe der Softwaresysteme verschärfen sich die für die Software-Herstellung typischen Probleme: Beherrschen großer Objektmengen, Erhalten der Systemkonsistenz, Kontrolle der ständigen Änderungseinflüsse und Gewährleisten einer langen Lebensdauer. Die Disziplin Konfigurationsmanagement bildet den methodischen Ansatz, diese Probleme besser zu beherrschen. Software-Konfigurationsmanagement faßt die Herstellung von Softwaresystemen als eine Abfolge von kontrollierten Änderungen an gesicherten Zwischen- und Endergebnissen auf. Dargestellt werden die Objekte und Funktionen des Software-Konfigurationsmanagements sowie die hierfür in großen Software-Projekten benötigten Methoden, Instanzen und Hilfsmittel.     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and     

Editorial:Brain-machine interface(BMI) and cyborg intelligence

正Brain-machine interfaces(BMIs)aim at building a direct communication pathway between the brain and an external device,and represent an area of research where significant progress has been made during the past decade.Based on BMIs,mind information can be read out by neural signals to control     

Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate     

SCIENCE CHINA Information Sciences SUBJECT INDEX TO VOLUME 57(2014)

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Information for Authors

正http://www.zju.edu.cn/jzus http://www.springerlink.com Aim The Journals of Zhejiang University-SCIENCE(A/B/C)are edited by the international board of distinguished Chinese and foreign scientists,and are aimed to present the latest developments and achievements in scientific research in China and overseas to the world’s scientific circles,especially to stimulate