逆系统方法在电力系统控制中的应用

本文指出：逆系统方法和微分几何方法本质上是等价的，而逆系统方法的物理意义直观，不局限于仿射型系统，使用时仅需求导运算和代数运算，求解控制律过程比较简捷，便于工程应用。     

Root loci design using Dickson's technique

Traditional techniques for determining the root loci were developed by Evans. Given the characteristic equation {1+G(s)H(s)=0}, Evans root locus method requires the magnitude of G(s)H(s) to be equal to minus one and is well established for determining the pole locations as the system gains are changed. In this paper, nontraditional techniques for developing the root loci of control systems are introduced. Illustrations are developed by using a method for plotting the root loci that involves setting the real and the imaginary portions of the characteristic equation equal to zero. Setting the real and imaginary parts of the characteristic equation equal to zero arises from work in the theory of equations by Dickson. Application of this technique allows adjustment of the gain, to establish the system requirements, and introduces collateral equations subject to unique geometric interpretation     

Geometric links among classical controls tools

This paper develops a geometric perspective that ties together a number of graphically based techniques from classical control theory. In particular, in the frequency domain, a connection between the Nyquist diagram and the Bode plots is unfolded via a sequence of three-dimensional representations. A parallel development in the “gain-domain” begins with the Evans root locus plot and leads to a set of gain plots that portray eigenvalue behavior as an explicit function of forward gain. The gain plots extend the standard root locus plot by depicting explicitly the influence of gain (or any system parameter) on the closed-loop system eigenvalues. This is similar to the way the Bode plots embellish the information of the Nyquist diagram by exposing frequency explicitly. The gain plots enable direct determination of gain values for which the closed-loop system is stable or unstable. By exposing the correspondence of gain values to specific eigenvalues, the plots serve as a pole-placement tool for identifying closed-loop designs meeting performance specifications. Furthermore, the gain plots reveal by inspection information about the closed-loop root sensitivity. The authors have found the gain plots as well as the underlying geometric development in both the frequency and gain domains invaluable in undergraduate and graduate controls education     

大型水轮发电机组水门开度控制零动态设计方法

针对一类非线性非最小相位系统,利用微分几何控制理论,首先通过引入动态反馈对其扩维以获得稳定的零动态,然后采用标准的线性系统方法设计非线性控制器;进一步利用哈密顿 — 雅可比 — 贝尔曼方程和中心流形理论分别证明所设计控制律的最优性以及闭环系统的稳定性。结合水轮机调速系统模型,求得大型水轮发电机组水门开度非线性最优控制律。对川渝—华中电网的仿真结果表明,与常规控制器相比,所设计的调速系统控制律能够显著提高电力系统的暂态稳定性。     

线性系统的核空间、象空间、不变子空间的直观诠释

"线性系统的几何理论"是将线性系统的动态分析转化为状态空间中相应的几何问题。这种几何方法的特点是简洁明了,避免了状态空间中大量繁杂的矩阵推演计算。拟从核空间、象空间、不变子空间入手,给予它以直观的诠释。目前,几何理论已广泛应用于系统分析与综合中,特别是Robust调节器设计有关定理证明,自始至终都使用了核空间、象空间的概念与计算方法。     

A new aerodynamic decoupled frequential FDIR methodology for satellite actuator faults

This paper presents new results regarding the development of a supervision scheme for a nonlinear satellite model. The main issue concerns the handling of frequency faults affecting the reaction wheels of a spacecraft attitude control system, that is, how to detect and isolate faults, how to determine the different frequencies characterising these faults through spectral analysis and lastly, how to prevent propagation into failures with potential mission abortion as a consequence. Thus, this work investigates the design of a scheme for fault detection, isolation and control reconfiguration applied to the reaction wheels of a spacecraft attitude control, based on the satellite model. This scheme is classifiable as active fault tolerant control. As the study focuses on a general satellite nonlinear model, where aerodynamic and gravitational disturbances, as well as measurement errors, are present, the robustness of the suggested strategy is achieved by exploiting an explicit disturbance decoupling method via a nonlinear geometric approach. To achieve accurate fault diagnosis, aerodynamic disturbance decoupling represents the key point because the aerodynamic model is often uncertain. Moreover, an improvement of the nonlinear geometric approach is presented, to realise both aerodynamic and manoeuvre decoupled fault diagnosis. To the best authors’ knowledge, this is the first works presenting a methodology for frequency fault diagnosis, which is based on the nonlinear geometric approach for fault and disturbance decoupling. The obtained results demonstrate that the proposed methodology can achieve better performances with respect to traditional fault detection and isolation schemes. Copyright © 2013 John Wiley & Sons, Ltd.     

混流式水轮机叶片的几何造型

本根据几何造型学的一般原理,介绍了混流式水轮机水轮机叶片几可造型方法、造型中的一些实际问题以及提高造型的精度。     

Manipulation of structural and optical behaviors in zincblende and wurtzite mercuric sulfide (HgS) nanocrystals: atomistic tight-binding theory

To obtain comprehensive information regarding the effect of size and geometric structure on the associated atomistic properties of mercuric sulfide (HgS) nanocrystals, the structural and optical properties of HgS semiconductor nanocrystals were explored numerically using atomistic tight-binding theory. The optical bandgap, charge density, density of states, electron–hole Coulomb energy, and optical spectrum were evaluated for different sizes and geometric structures. Size-dependent computations were realized by changing the diameter of the HgS nanocrystals. In addition, HgS nanocrystals with wurtzite and zincblende geometric structures were compared numerically. The theoretical results highlight that control of the electronic structure and optical properties of HgS nanocrystals can be achieved by changing their size and geometric structure. The dependence of the optical bandgap on the dimension of the HgS nanocrystals is mainly determined by quantum confinement. Finally, the optical properties of zincblende HgS nanocrystals are more promising than those of wurtzite HgS nanocrystals.     

改善机端电压的非线性励磁控制

为了提高发电机励磁控制器的控制效果,提出了一种将基于机端电压偏差的比例积分控制和基于微分几何理论的非线性励磁控制相结合的改善机端电压的非线性励磁控制器设计方法。为验证方法的有效性,用MATLAB进行仿真试验。仿真结果表明,所设计的非线性励磁控制器在小扰动和大扰动情况下不仅能较好地保证发电机角速度、功角的稳定,而且能改善机端电压的精度和稳定度。     

图形分析器--生成控制系统方框图拓扑结构的软件工具

图形分析器通过对控制系统方框图的几何结构进行跟踪探索和结构分析,生成相应的拓扑结构。研究了算法的程序实现问题,给出了应用图算法解决这一问题的具体技术方案并阐述了其中在的特殊问题的处理方法。实践表明,良好的拓扑关系存储方法将为整个系统的设计及功能实现奠定基础。     

电流型PWM整流器的非线性控制

电流型PWM整流器在同步坐标系下的数学模型呈现非线性、强耦合的特性，使其控制器的设计较为困难。该文首先基于非线性微分几何理论，分析了三相电流型PWM整流器实现输入/输出精确线性化的条件，指出线性化后的系统存在一阶零动态，然后提出了三相电流型PWM整流器的非线性控制策略，实现了交流电流d轴分量和q轴分量的解耦控制。最后该文分析了非线性系统一阶零动态的稳定性，并设计了状态反馈控制器以改善其动态响应特性。仿真和试验结果验证了所提出方法的有效性。     

New stability method applied to the stabilization of fuzzy control systems

This paper addresses stability analysis and stabilization for Takagi-Sugeno fuzzy systems via a new stability method previously developed and presented by the authors. The new stability method is here extended to fuzzy systems. In essence, the authors consider the stabilization of a fuzzy control system with parallel distributed compensation. This problem has been considered in detail previously by different authors using fuzzy Lyapunov function theory. However, in this paper the authors show that their new stability method presents a viable alternative to Lyapunov?s method for such control systems. This statement is confirmed by a demonstration that the new stability method always provides necessary and sufficient conditions, the satisfaction of which guarantees that the system in question will be asymptotically stable.     

ASVG非线性控制方式的研究及其对暂态稳定性的改善

基于微分几何控制理论中的零动态设计方法，首次提出了新型静止无功发生器(ASVG)非 线性控制的设计方法和相应的控制规律。计算机仿真结果表明，该控制规律可以有效地改善 电力系统的有功稳定性和动态品质。     

非线性系统自适应控制及其在电力系统中的应用

电力系统中存在众多不确定的参数，所面临的运行条件和外界扰动复杂多变，有必要引入自适应控制理论来处理这些不确定因素。非线性系统的自适应控制与线性系统相比，在研究方法等方面都有着很大的不同，目前处在继续发展的阶段。文章首先对近十几年来非线性系统的参数自适应控制、鲁棒自适应以及智能化自适应控制做了简明的归纳，然后介绍了其中一些研究成果在电力系统稳定与控制研究中的应用，最后对全文做了总结和展望。     

Robust failure detection for linear distributed parameter systems

This paper discusses the robust failure detection methods in general separable Hilbert space using an operator approximation approach. It is simple and provides an intuitive geometric interpretation. The computational procedure required is the Schmit expansion of an operator. An example arising from the sensor failure detection design for space structures is given to illustrate the methodology suggested. This paper was recommended for publication by editor A. Benveniste     

水轮机调节系统非线性扰动解耦控制

该文针对水轮机调节系统非线性、时变、非最小相位的特点，采用微分几何非线性控制理论中的扰动解耦控制方法，设计了水轮机调节系统的非线性扰动解耦控制策略。在新控制策略中，除了机组转速偏差外，接力器行程偏差和有压引水系统水压力的变化也是控制信号的一部分。仿真结果表明该控制策略能有效的改善水轮机调节系统的动态性能，增强其鲁棒性和抗强干扰的能力。     

股票价格服从几何布朗运动的证明

通过由一般的离散过程逼近连续随机过程的方法，给予证券价格按有漂移率的几何布朗运动变化的一个严格的证明，并指出了股票价格过程的一般模型．     

发电机励磁及SVC非线性最优协调控制

发电机励磁和静止无功补偿器(static var compensator,SVC)对远距离输电的稳定性有很大影响。为了提高系统在大扰动情况下的暂态稳定性,提出一种发电机励磁系统与SVC协调非线性最优控制方法。通过建立发电机励磁与SVC系统的综合模型,将微分几何反馈线性化理论与线性最优控制理论相结合,设计了发电机励磁与SVC系统的非线性最优协调控制规律。控制信号实现了本地化,避免了远距离的信号传输。仿真结果证明,该控制方法能同时改善系统的功角稳定性和电压稳定性。     

基于结构奇异值的网络化水电机组鲁棒控制

考虑到网络化控制系统中的通信延迟会影响被控系统的稳定性，本文依据鲁棒控制理论将传感器、执行器以及控制器之间的不确定延迟采用乘摄动模型来表示，使得控制器可以用鲁棒控制理论来求解。由于m 综合理论能兼顾稳定鲁棒性和性能鲁棒性，因此控制器采用m 综合理论来求解。最后采用本文方法利用SIMULINK对一个实际的水电机组进行了仿真分析，结果表明该方法可以有效抑制延迟对系统稳定性的影响。     

13吨燃油锅炉燃烧自寻最优控制

作者在一台13吨燃油锅炉的燃烧系统中采用自寻最优控制技术,取得了比较满意的控制效果,本文介绍了此项技术的基本理论和实施结果,并给出了用正平衡方法计算锅炉瞬时热效率的一种近似算法.