Analysis of terminal voltage waveform of AC exciting synchronous generators

Recently, adjustable speed hydroelectric power systems have been developed. In those power systems, ac exciting synchronous generators are used instead of the ordinary salient-pole-type synchronous machines. However, some higher harmonic sequences are included in the distribution of air-gap magnetic flux density and in the terminal voltage waveform of the ac exciting synchronous machines because these machines have open winding slots. To develop better machines without terminal voltage waveform distortions, an evaluation method of the terminal voltage harmonics has been needed. This paper describes the mechanism of higher harmonics generation qualitatively and proposes an analytical method of no-load terminal voltage waveforms on the basis of two-dimensional magnetic field analysis considering movement of the rotor for quantitative higher harmonics analysis. The analytical results of higher harmonics show good agreement with the experimental ones.     

Simple Signal Source based Micro Controller

Using micro controller, DAG and Multi-periods synthesis, we can buildup a very simple signal source with precise frequency, amplitude and waveform. Wave parameters can be programmed in advance. The circuit can satisfy some special requirements .     

按许用压力角确定直动推杆盘形凸轮机构最小尺寸的正确解法

本文论述了按许用压力角确定直动推杆盘形凸轮机构最小尺寸现有方法的局限性及欠妥之处,对其中的错误作了修正,给出了解决该问题简便实用的数值解法和图解法.     

350m^3高炉煤气净化单文氏管可调喉口理论计算及分析

通过单文氏管可调喉口的理论计算及分析，找出喉口最佳工作状态下的工艺参数及适合这种设备特性的煤气工作参数变化范围，以期能对实际操作过程及运行状态分析提供理论依据，提出单文氏可调喉口的更广泛意义上的设备、工艺参数选择、计算的方法。     

Explicit construction of quadratic lyapunov functions for the small gain,positivity, circle,and popov theorems and their application to robust stability. part II: Discrete-time theory

In a companion paper (‘Explicit construction of quadratic Lyapunov functions for the small gain, positivity, circle, and Popov theorems and their application to robust stability. Part I: Continuous-time theory’), Lyapunov functions were constructed in a unified framework to prove sufficiency in the small gain, positivity, circle, and Popov theorems. In this Part II, analogous results are developed for the discrete-time case. As in the continuous-time case, each result is based upon a suitable Riccati-like matrix equation that is used to explicitly construct a Lyapunov function that guarantees asymptotic stability of the feedback interconnection of a linear time-invariant system and a memoryless nonlinearity. Multivariable versions of the discrete-time circle and Popov criteria are obtained as extensions of known results. Each result is specialized to the linear uncertainty case and connections with robust stability for state-space systems is explored.     

双三点式逆变器控制系统的实现原理及特性分析

大功率的交流调速系统中都要求具有高动态和高品质的优良特性，ＤＳＣ控制技术在解决大功率的调速系统中具有特殊的效能。本文从双三点式主回路的基本原理出发，详细阐述了用ＤＣＳ控制技术的应用原理和实现方法，并根据动态调节的数学模型给出了仿真曲线，从而说明了双三点式逆变电路的实时控制策略。文中同时还对输出谐波进行了分析。     

涡轮叶片孔距测量系统设计

根据涡轮叶片上圆孔的特点，介绍一种快速检测涡轮叶片上圆孔距离的方案，该方案将采集的数字图像输入到计算机，根据事先给定的涡轮叶片上圆孔的模型，对图像进行匹配，然后对匹配区域进行二值化，经形态学处理，去除图像上小的噪声点，再检测出图像上的圆孔的大体位置，基于最小二乘原理确定圆孔的精确位置，由此得到圆孔间的距离和尺寸。此方法具有精确度高、速度快、抗干扰强的优点。     

基于仿射变换的图象定位方法

本文主要针对复杂地物背景下的一般图象目标,在应用本征空间方法进行鲁棒跟踪等方面做了大量研究工作.放弃了基于平移运动模型的传统相关算法,改用仿射变换运动模型,借助快速解法,在保持跟踪定位鲁棒性的基础上,实现了以实时的速度处理目标发生的旋转、平移、放缩等仿射变化.通过理论分析以及大量实验验证,配合以适当的模板更新策略,该方法可以构成一种替代传统互相关跟踪的新方法.     

A note on stability,least square estimation and inners

In this note the polynomial F_N(z) is considered as the inverse filter of an all-pole system. From the auto correlation function of the output of this system a matrix R_I is constructed. Using the theory of least-square estimation, it is shown that F_N(z) has all its zeros outside the unit circle if and only if matrix R_I is a positive innerwise (P.I.). Furthermore the number of zeros of F_N(z) inside the unit circle is equal to the number of negative ratios of inners determinants.