考虑气象特征与波动过程关联的短期风电功率组合预测

为解决短期风电功率预测关键气象因素提取难、天气波动过程与功率波动过程匹配性差的问题,提出了一种考虑气象特征与波动过程关联的短期风电功率组合预测方法。首先,通过最大相关-最小冗余原则得到数值天气预报的气象特征因素来划分天气波动过程。其次,考虑天气波动过程与功率波动过程的关联关系,建立了以气象特征因素为输入、以风电功率为输出的波动过程关联的短期组合预测模型。最后,将不同天气波动过程下的风电功率预测值在时序上进行重新组合,以得到波动过程为输出的短期风电功率预测结果。实际算例表明,采用气象特征因素作为输入以及面向波动过程关联的组合预测方法能够明显地提高短期风电功率的预测精度。     

Kinetics of growth of calcium carbonate deposits in geothermal systems

Results from field investigations into the processes through which suspended particles are formed in geothermal water as a consequence of upset in carbonic acid equilibrium, as well as processes through which solid deposits of calcium carbonate are formed on the inner surfaces of geothermal equipment, are reported.     

Vapor phase anti-stiction coatings for MEMS

Due to their large surface-area-to-volume ratio, most micromechanical devices are susceptible to adhesion, friction, and wear. Conventional approaches to abate the deleterious effects of adhesion and friction rely on the deposition of organically based anti-stiction monolayers produced from liquid phase processes. It has become widely accepted that liquid phase monolayer processes are less desirable than vapor phase processes, especially for manufacturing purposes. Thus, current research is aimed at the development of vapor phase anti-stiction processes that yield comparable or better films than their corresponding liquid phase processes. To date, a variety of monolayer systems that have been well established via liquid phase deposition processes have been adapted to vapor processes. In this paper, current trends in anti-stiction technology and a discussion of available vapor phase anti-stiction methods are presented.     

1/f过程的小波合成

本文提出了1／f过程的小波合成方法。利用小波基函数的自相似特性和正交小波变换的去相关能力,分析了具有自相似性的1／f过程的小波变换系数的特点,并结合AR模型的相关函结构给出了1/f过程的小波模型。仿真结果表明,该模型有较好的逼近效果。     

两参数跳过程三点转移函数的连续与正则性

利用单参数跳过程已有结论，讨论了两参数跳过程三点转移函数的连续性，在坐标轴上的极限．     

A general procedure for investigation of electromagnetic processes of a valve engine under the full commutation

Features of physical processes in the electromechanical energy converter of a valve engine are described, and a general procedure of studying the electromagnetic processes in normal and emergency operational modes is developed that is based on them. As a result, the energy parameters and instantaneous values of output engine coordinates are obtained for these modes.     

晶闸管变压式电容无功补偿装置暂态特性仿真分析

笔者提出了晶闸管变压式电容无功补偿装置投入和换级过程的控制过程,建立了单相试验装置各过程的状态变量方程,采用数字积分对试验装置投入和换级过程的暂态电流及晶闸管断态电压进行了仿真分析,分析结果和试验结果基本吻合。分析结果表明,装置暂投入和换级过程暂态性能良好,也为换级控制提供了设计依据。     

电接触用精密异型复合触点带材制备工艺

介绍了各种精密异型复合触点带材的生产工艺及使用材料,指出了其优缺点,并对异型复合触点带材的开发前景及模式进行了展望。     

制备工艺对Cu/C滑动电接触材料组织与性能的影响

研究厂固相烧结、液相烧结、液相熔渗和热压烧结等四种工艺制备的Cu／C复合材料,并测试了其显微组织、密度、硬度和电导率,结果表明：四种工艺所制备材料的显微组织中,石墨均呈网状均匀分布于基体上。液相熔渗和热压工艺制备的Cu／C复合材料密度和硬度较高,而固相烧结的较差。几种工艺制备的材料其电性能差别不大。     

Mathematical simulation of working processes in the furnace of a circulating fluidized bed boiler

A software system developed for simulating and calculating boiler furnaces with circulating fluidized beds is described. The main principles on which the system is constructed are outlined, and the physical and mathematical models of processes in circulating fluidized bed furnaces are described together with the calculation algorithm. Results from a study of analyzing the effect the grinding fineness of initial fuel particles has on the processes in a circulating fluidized bed furnace are presented.     

Performance analysis of parameter estimation algorithms based on high-order moments

Recently, there has been a considerable interest in parametric estimation of non-Gaussian processes, based on high-order moments. Several researchers have proposed algorithms for estimating the parameters of AR, MA and ARMA processes, based on the third-order and fourth-order cumulants. These algorithms are capable of handling non-minimum phase processes, and some of them provide a good trade-off between computational complexity and statistical efficiency. This paper presents some results about the performance of algorithms based on high-order moments. A general lower bound is derived for the variance of estimates based on high-order sample moments. This bound, which is shown to be asymptotically tight, is neither the Cramer-Rao bound nor a trivial extension thereof. The performance of weighted least squares estimates of the type recently proposed in the literature is investigated. An expression for the variance of such estimates is derived and the existence of an optimal weight matrix is proven. The general formulae are specialized to MA and ARMA processes and used to analyse the performance of some algorithms in detail. The analytic results are verified by Monte Carlo simulations for some specific test cases. A by-product of this paper is the derivation of asymptotic formulae for the variances and covariances of the sample third-order moments of a certain class of processes.     

Processes for System Family Architecting, Design, and Integration

Today, many systems within government and industry are typically engineered, not as stand alone systems, but as part of an integrated system of systems, or a federation of systems, or systems family. A significant level of effort has been devoted in the past several years to the development, refinement, and ultimately, acceptance of processes for engineering systems or systems engineering processes. Today, we have four ldquostandardrdquo processes within present and past standards: EIA-632, IEEE 1220, ISO 15288, and MIL-STD-499C. We continue to use systems engineering processes espoused in our current set of standards, and are left to our devices to tailor these processes to one appropriate for a systems family context. This paper will examine the systems engineering processes in existence today and conclude with development of a process designed specifically for systems family applications.     

600 MW机组全程给水自动调节系统的最新控制策略

介绍了哈三电厂3号机组(600MW)全程给水自动调节状况,分析了原设计存在的问题,提出了解决问题的办法和实现全程给水控制系统新的控制策略,提供了全程给水控制系统投入运行后的相关调整参数和运行曲线。     

双电源快速切换事件过程仿真分析

使用ETAP仿真软件对某变电所进线三相短路故障进行了双电源快速切换分析。结果表明,在发生进线三相短路故障快速切换过程中,母联开关和电动机保护的冲击电流不大于电流保护整定值,快速切换装置切换成功,仿真和实际切换过程具有一致性。但是,快速切换成功的原因并不是满足快速切换的四个条件,而是由于三相短路故障母线残压衰减快满足母线残压切换条件,但又能达到快速切换的目的。     

声发射技术及其在机械加工特性研究中的应用

为提高机械加工的自动化程度 ,提高产品质量 ,对机械加工过程中在线监测技术的研究是十分必要的 .实验表明 ,机械加工过程中含有丰富的声发射信号 ,利用声发射信号对切、磨、钻等机械加工过程实行在线监测是可行的     

Self-oscillatory class-D power amplifiers with a hysteresis-free relay element

For a self-oscillatory class-D power amplifier, structural models and mathematical formulas are derived by the harmonic-balance method, in order to calculate the frequency and amplitude of self-oscillations and the mean processes occurring under the action of a slowly varying input signal. Formulas for the parameters of these models are determined. For the mean processes, the stability condition of the structural model is established. Transient processes in the amplifier are plotted in the case of constant and sinusoidal input signals, on the basis of a Matlab/Simulink model.     

带恒功率负载的DC/DC变换器阶跃响应过程分析

由于恒功率负载负阻抗输入特性,Buck直直变换器带恒功率负载与阻性负载阶跃负载响应过程不同,且带恒功率负载时不能保证系统性能不受影响。并基于平均大信号模型,借助相平面法,针对恒功率负载以及阻性负载,详细分析了平均电流控制Buck变换器两种情形下的阶跃响应动态过程。分析表明,变换器带恒功率负载阶跃响应过程存在2类4种类型。通过限制阶跃负载所导致的电压跌落的大小可以确保变换器级联后阶跃负载动态性能不受影响。具体可以通过增大源变换器电感电流限流值及提高其电流环带宽实现。实验结果验证了理论分析的正确性。     

Use of modern information technologies for making budgetary sectors of the economy more energy-efficient

A strategy of administrative management and technological control of heat consumption and energy conservation processes in budgetary sectors of the economy is described together with a system of integrated indicators for estimating the efficiency of these processes and the main results obtained from putting the strategy in use in the system of the Russian Federal Agency for Education are presented.     

Asynchronous motor drive based on self-excited current inverter with switched-off thyristors and provided with predicting relay and vector regulation of stator current

Methods for predicting relay and vector regulation of the stator current in a drive are presented based on an analysis of electromagnetic processes in an asynchronous motor drive based on a self-excited current inverter with switched-off thyristors. A system of automatic control of the drive speed using this type of regulation is developed, and electromechanical processes in the drive equipped with this system are also studied by methods of imitation modeling.     

Studying the decomposition of monoethanolamine in water using efficient oxidation processes

Results are presented for the first time from a study of processes through which monoethanolamine is decomposed in water by means of a photochemical reactor operating based on the principle of efficient oxidation processes with participation of OH radicals (OH*).