基于超大电容器储能的独立光伏系统的建模研究

Eestor电容功率密度大、能量密度高且使用安全无污染,是理想的储能器件。设计了一种基于Eestor电容储能的独立光伏系统的系统模型,建立其小信号模型,用Simulink仿真对其运行特性进行了分析,结果表明,系统在光伏输入功率大幅波动以及负载突变时具有很好的稳定性,为其进一步应用于可再生能源发电系统提供了参考。     

一种变结构控制系统设计方法

为了进一步优化传统变结构控制系统的设计过程和综合性能,利用一组相交的直线簇,提出一种直线簇趋近理论。基于此理论,针对等效干扰作用下的单输入线性时不变系统设计了直线簇趋近模态控制方案,包括基本切换控制方案和改进平滑控制方案,并分别给出了其设计准则。根据Lyapunov稳定性理论,给出了切换控制方案下状态变量渐近收敛性和平滑控制方案下状态变量有界性的数学证明。利用直流电机伺服系统,依据给出的设计准则,完成了两种控制方案的构造。计算机仿真结果表明,所提出的控制方案可以使伺服电机在持续等效干扰的影响下能够快速、精确地跟踪指令。仿真结果验证了控制方案的鲁棒性和综合性能。     

电能量采集管理自动化系统的分析探讨

结合榆林供电公司电能量采集管理自动化系统(电量系统)运行现状,分析了电量系统在管理中存在的问题,探讨了目前采用的重新划分管理职责和固定表地址的解决措施,最后提出了电量系统在管理中各工作环节的职责,对今后系统内规范电量系统的管理有借鉴意义.     

基于相位叠加原理的有源滤波器谐波指令新算法及控制

具有移相变压器的交交变频器运行中功率因数较低且产生丰富的谐波,采用多套并联型有源滤波器分别在变压器各套移相副边进行有源滤波和无功补偿.在瞬时无功功率算法的基础上利用移相变压器副边谐波在原边可以叠加的特点,提出将变压器各副边谐波指令叠加的算法推算原边需要补偿的谐波指令,剔除掉在变压器原边通过反相位叠加而抵消的副边某些谐波分量,不必再在副边用有源电力滤波器补偿它们,从而减小了补偿容量.同时,在逆变器出线串联电容以降低有源滤波器直流侧电容工作电压.PSCAD/EMTDC软件仿真结果证实了新算法和降压控制的正确性.     

亚临界600MW双缸双排汽直接空冷汽轮机综述

介绍了宁夏大唐大坝发电公司亚临界600MW双缸双排汽直接空冷汽轮机的特点,及34″空冷末级叶片和双排汽空冷低压的性能特点。从而说明该600MW空冷汽轮机结构合理、技术先进、性能优越、安全可靠。     

抽水蓄能发电电动机电磁设计若干系数计算

本文在深入研究抽水蓄能发电电动机电磁设计若干系数计算原理基础上,建立了数值模型并对ALQUEVA水轮发电机,白莲河、宝泉和广州抽水蓄能发电电动机的相关系数进行了计算,为电机的准确设计提供了条件。文中还提出了在电机主要结构保持不变的情况下,通过调整阻尼条在极靴表面的分布来改善电压波形的方法,从而有效地拓宽了电机的可选槽数。此方法已应用于哈电发电电动机以及常规水轮发电机的设计中。     

Evaluation of measurement uncertainty based on grey system theory for small samples from an unknown distribution

To evaluate measurement uncertainty for small sample size and measurement data from an unknown distribution, we propose a grey evaluation method of measurement uncertainty based on the grey relation coefficient. The uncertainty of measurement is analyzed using grey system theory, and the defects of the grey evaluation model of measurement uncertainty (GEMU) are studied. We then establish an improved grey evaluation model of measurement uncertainty (IGEMU). Simulations show that the precision of IGEMU is greater than that of GEMU, and that sample size has only a small effect on the precision of IGEVU. In particular, IGEMU is applied to evaluating measurement uncertainty for small sample size and measurement data from an unknown distribution. The measurement uncertainty of total profile deviation, which is measured by the CNC gear measuring center, can be evaluated by a combination of IGEMU and the Monte Carlo method.     

Simulation of X-ray pulsar signals with multiphysical properties

In view of the few and discontinuous X-ray pulsar data, based on the physical properties of the X-ray pulsar real data from the Rossi X-ray Timing Explorer (RXTE) spacecraft, this paper adopts the fast iterative method and the 10 μs time transformation model, simulates the X-ray pulsar signals which have the periodic property, spectral property, and the background noise property as well as a variety of delay effects. We design and implement simulation software which can simulate the X-ray pulsar signals with multi-physical properties. The results of comparing the real data and simulation data in the same situation show that the simulation noises and the actual noises have the same distribution, that the period stability of the simulated X-ray pulsar data agrees with the real data, with the error of only 0.43％, in different energy levels, that the simulated data's integrated profile and the real data's standard profile are highly correlated with the Pearson correlation coefficient of 0.99, and that under the 10μs time transformation model, the time conversion accuracy of the simulation data can reach 10^-7s, the error between the simulation and the real data being just only 10^-7s, which meets the time transformation accuracy. Therefore, the proposed method can realize the high-fidelity simulations and generate the continuous pulsar signal with many physical properties.     

影响小型泵站效率的因素浅析

我国的泵站尤其是小型泵站数量大，分布广，但小型泵站的效率普遍较低。分析了影响小型泵站效率的若干因素，以引起同行们的重视。     

R(Fe0.95Mn0.05)x合金的显微结构与磁致伸缩的研究(R=Dy0.6Tb0.3Pr0.1,1.7≤x≤2.0)

采用金相、X射线衍射、电子探针显微分析和标准应变测试技术研究了电弧浇铸的R(Fe0.95Mn0.05)x(R=Dy0.6Tb0.3Pr0.1,1.7≤x≤2.0)合金的显微结构与磁致伸缩.结果表明,合金的基体为MgCu2型立方结构的(Dy,Tb,Pr)(Fe,Mn)2相, 当x≤1.8时,第二相为富稀土相,当x>1.85时,变为(Dy,Tb,Pr)(Fe,Mn)3相.合金的磁致伸缩测量表明,当x≤1.80时,磁致伸缩随x的增加而增加,当x>1.85时,磁致伸缩随x的增加而降低.对于采用提拉技术制备的R(Fe0.95Mn0.05)x取向样品,当x=1.85时磁致伸缩呈现出一个峰值.相对于电弧浇铸的样品,取向样品的磁致伸缩特性得到改善.