基于遗传算法的模糊神经网络在动态系统辨识中的应用

复杂不规则系统的语言建模构成了许多控制／决策系统的核心问题,模糊逻辑是进行语言建模最有效的方法之一。本文介绍了一种基于模糊逻辑、神经网络和遗传算法的语言建模方法,并给出了新型的混合学习算法,即：首先由自组织算法确定出模糊神经网络的初始隶属度函数;其次由最大匹配因子学习算法完成模糊规则确定;最后提出了一种改进的遗传算法用来优化调节已经获得的隶属度函数。通过具体的仿真实例说明了所提出的建模方法在动态系     

大型发电机射频监测装置的应用

介绍了藉接收发电机中性点处高频电流传感器的射频信息 ,监视 3 0 0 MW汽轮发电机局部放电的射频监测装置的功能 ,统计分析了装置运行 4年多来的报警情况。使用该套装置 ,排除了发电机定压线圈断股、发电机线圈表面受潮和接地碳刷接触不良和其他导流部位接触不良可能引发的故障     

改进遗传算法在发电机励磁系统参数辨识中的应用

提出了一种基于改进遗传算法的将发电机励磁系统原模型转换为仿真软件下标准模型的参数辨识方法,以原模型和标准模型的输出误差最小作为辨识目标,利用改进遗传算法不断优化调整标准模型中的参数,最终得到满足要求的励磁系统标准模型参数。与传统的励磁系统参数辨识方法相比较,该方法很好地解决了励磁系统非线性环节难以有效辨识的问题,方便可靠,精度高。实际发电机励磁系统参数辨识结果表明,该方法具有很好的效果。     

改进遗传算法在发电机励磁系统参数辨识中的应用

提出了一种基于改进遗传算法的将发电机励磁系统原模型转换为仿真软件下标准模型的参数辨识方法,以原模型和标准模型的输出误差最小作为辨识目标,利用改进遗传算法不断优化调整标准模型中的参数,最终得到满足要求的励磁系统标准模型参数.与传统的励磁系统参数辨识方法相比较,该方法很好地解决了励磁系统非线性环节难以有效辨识的问题,方便可靠,精度高.实际发电机励磁系统参数辨识结果表明,该方法具有很好的效果.     

超大截面煤矿用移动金属屏蔽软电缆的研制

本文主要阐述了超大截面煤矿用移动金属屏蔽软电缆的结构设计和生产制造工艺。     

射频电容液位计在海上溢油液位检测中的应用

简单介绍了射频电容液位计进行油水双液位检测的基本原理,阐述了海上溢油回收检测装置的基本构造及其工作过程。针对海上特殊应用环境的测量需求,提出分别按油、按水标定的液位检测方案。油水混合状态下,对2组实验测试数据进行误差和线性度的数值计算,通过曲线拟合对比分析,最终确定了海上溢油回收集油箱油位检测的最优化方案—按油标定检测。实验证明,该方案可以满足现场实际测量环境的要求,液位计的测量精度高、线性度好。     

Blind identification of sparse Volterra systems

This paper is concerned with blind identification for single‐input single‐output Volterra systems with finite order and memory with the second‐order and the third‐order statistics. For the full‐sized Volterra system (i.e. all its kernels are nonzero) excited by unknown independently and identically distributed stationary random sequences, it is shown that blind identifiability does not hold in the second‐order moment (SOM) and the third‐order moment (TOM) domain. However, under some sufficient conditions, a class of truncated sparse Volterra systems, where some kernels are restricted to being zero, can be identified blindly and more Volterra parameters can be estimated in TOM than in SOM. Numerical examples illustrate the effectiveness of the proposed methods. Copyright © 2007 John Wiley & Sons, Ltd.     

On bounded-error identification of feedback systems

This paper studies identification of linear feedback systems from closed loop time series. Unfalsified approximate bounded error identification is shown to result in a control-relevant identification methodology for robustness optimization under BIBO-stable coprime factor uncertainty. Furthermore, well-posedness (continuity) of the robustness optimization method for controller synthesis is established.     

LED在汽车照明系统中的应用

汽车车灯是汽车行驶必不可少的安全部件。据统计，车辆总行驶里程的25％是在夜晚或自然光线不足的情况下行驶的，1986年Nissan公司在300ZX型汽车上使用了72只Ф5mm的LED作为中央高位刹车灯，标志着LED开始进入了汽车领域中的应用。     

Application of catastrophe theory to power systems

In recent publications dealing with nonlinear systems, nonlinearities existing in the systems under study have drawn much attention. Studies on the effects of nonlinearities in power systems are becoming an increasingly important part of the research on system stability. It is probable that heretofore undiscovered phenomena caused by the nonlinearities involved in load flow equations, generator swing equations and characteristics of control equipments and loads, etc., may be found. This paper presents a new Catastrophe Theory application to nonlinear power systems. Making use of the concept of Duffing's equation, it is shown that a Catastrophe Theory analogy can be used to interpret unstable phenomena caused by system nonlinearities from the viewpoint of oscillations. When considering system nonlinearities due to poor combinations of system parameters and periodic disturbances, there may exist the characteristic “jumps” in system ates that correspond to slow (quasi-dynamic) changes of the frequencies of periodic disturbances. With this Catastrophe Theory approach, a system bifurcation set can be identified to assess the unstable phenomena of power systems.     

DC conductivity of metal/DLC/Si/metal heterostructures

Electrical conduction of metal/DLC/silicon/metal heterostructures has been investigated, Both DLC/p-Si and DLC/n-Si systems shows rectifying properties. The current-voltage (I-V) characteristics of the heterostructures can be described well by the simplified diode equation with the ideality factor between 21.2 and 3.25, decreasing with increasing temperature. The directive tendency of I-V characteristics is independent of the type of silicon substrate. A simple qualitative band model of DLC/Si junction is proposed     

基于图像处理技术的绝缘子覆冰自动识别

绝缘子覆冰是高压输电线路中经常出现并产生较大危害的异常运行状况.通过对绝缘子覆冰特征的分析,结合现场拍摄画面研究了基于图像处理技术对绝缘子覆冰的情况和图形特征量进行自动分析和识别的方法.主要基于图像平滑处理、阈值变换和轮廓跟踪等算法实现了基于现场图像的绝缘子覆冰及覆冰厚度等特征参数的自动识别.     

Application of genetic algorithms to service restoration in distribution systems

Service restoration in distribution systems can be formulated as a combinatorial optimization problem to determine power sources for each load considering radial network constraints and power source limits. Until now, the problem has been considered using conventional methods, e.g., the branch-and-bounds method, expert system, neural networks, and fuzzy reasoning. Recently, Genetic Algorithms (GA) have been recognized as one of the efficient methods for solving large combinatorial optimization problems. The method can perform parallel search, and can more easily search optimal solutions. This paper presents an application of GA to service restoration in distribution systems. The feasibility of the proposed method is demonstrated on a typical distribution system model. The result shows that the method can solve the problem efficiently, and this tendency becomes dominant by increasing problem dimensions.     

小波变换在电力系统谐波检测方面的应用

针对傅里叶变换的谐波检测方法无法同时实现时-频变域分析这一缺点,提出了小波变换这一新方法对谐波进行分析。通过小波变换对电力系统中的谐波电流进行分解,得到信号的基波分量和高次谐波分量。针对电力系统中的突变信号,提出了基于小波变换的模极大值的奇异性检测方法,通过小波变换模的极值点在多尺度上的综合表现,来表示信号的突变特征,并通过仿真实例验证该算法的有效性。     

Application of dynamic braking to mine hoisting systems

Accidents occurred on counterweighted mine hoisting systems when the mechanical brake failed while the cage was empty. This allowed the counterweight to fall to the bottom of the shaft, causing the cage to overspeed and crash into the headframe. Direct-current hoist motors have the potential for preventing this type of accident by incorporating a passive electrical braking system known as dynamic braking. Installation of dynamic braking requires minimal control system modifications and modest expense. The various circuit designs that can be configured to implement dynamic braking on a DC mine hoisting system are discussed. Selection of the load resistance for the desired dynamic braking system performance is addressed. Data from tests of a mine hoisting system that was modified in the field to incorporate dynamic braking are analyzed, to provide technical credibility to the dynamic braking concept     

网络时间同步在电力系统的应用

简单介绍了电力系统时间同步技术发展的现状,详细阐述了网络时间同步协议的类型和概念,以案例的方式具体分析网络时间同步的结构模式,最后就现阶段两种传输技术进行了分析比较.     

复杂网络理论在电力网络中的应用与研究

从结构模型的层次简述了复杂网络的相关研究,并根据文献中的研究成果,分析说明了电力网络所具有的符合复杂网络共性的性质,即小世界性和无标度性.概述了复杂网络理论在电力系统中的应用,重点说明了利用复杂网络分析大停电事故的方法和意义,以及如何从复杂网络的角度来分析和研究电力网络的动态特性.总结了目前复杂网络研究尚需解决的问题并预测了复杂网络在今后的电力网络研究中的作用及其发展趋势.     

DSP控制器在电力变换系统中的应用研究

论述一个基于DSP控制器的电力变换系统及进行仿真与实验的过程。介绍其主电路电气结构和控制、保护电路,阐述控制软件结构及为实现实时控制而采用的设计方法,最后进行了仿真与实验。实验研究表明设计的DSP控制器完全满足变压变频系统的要求。     

电力线在现代通信系统中的应用

介绍用电力线作为网络的基础设施,开发电力线接入网技术.阐述了电力线通信的2种解决方案和网络体系结构,分析了电力线通信中特殊的技术问题,以及现代电力线通信的应用现状与发展前景.