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1.
利用扩张状态观测器将原来的非线性系统变换成线性系统,然后用状态PI控制器的设计思想设计了非线性状态PI控制器;并将其用于发电机励磁控制,以解决电力系统的强非线性和不确定性问题,避免了反馈线性化非线性励磁控制由于数学模型的误差而影响控制器性能的缺点。所得控制规律与系统运行点和网络结构完全无关,同时控制器结构简单。仿真计算表明,非线性状态PI励磁控制器对系统运行点和网络结构变化具有良好的适应能力,可以有效地改善系统的稳定性。 相似文献
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发现在进行非线性系统的非线性控制设计时,状态方程中输出函数的选取对线性化以后系统状态方程的形式有很大的影响,进而影响到所设计的控制器性能。在此研究结果的基础上,改进了电力系统非线性控制器的设计方法,可以在统一的非线性控制设计框架下同时对多个状态量的性能指标提出要求,兼顾受控系统多个状态量的响应特性,使系统的动态性能和静态性能能够很好地协调,实现高性能的非线性控制。将改进的设计方法应用于发电机组的励磁控制,采用逆系统非线性控制原理设计了一种具有综合性能指标的非线性励磁控制规律。将所设计的多指标非线性励磁控制律用于单机无穷大电力系统的同步发电机组中进行仿真实验,其结果表明所提出的控制器不仅能明显地提高发电机的动态稳定性,而且能准确地将发电机的端电压控制在其给定值上运行,不会因受扰而发生偏移。 相似文献
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针对电力系统区间低频振荡问题,提出了一种利用广域测量信号的电力系统阻尼控制器的设计方法。该方法采用广域测量系统(WAMS)提供的准实时测量数据,通过Prony传递函数辨识法和纯时滞环节Pade逼近法建立时滞电力系统模型;然后基于混合灵敏度 H ∞ 控制理论和极点配置方法设计阻尼控制器,使闭环系统在满足 H ∞ 性能指标的前提下极点分布于合适的区间,从而获得所需的系统动态性能。4机2区域电力系统和新英格兰测试系统仿真实例表明,采用广域测量反馈信号的阻尼控制器能够显著提高系统区间低频振荡的阻尼,并且具有时滞不敏感性。 相似文献
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同步发电机模糊PID励磁控制器仿真研究 总被引:4,自引:0,他引:4
随着电力系统的日益复杂,传统的水轮发电机励磁控制方式已不能满足其控制要求。文中在分析励磁控制系统控制算法的基础上提出了一种基于MATLAB中的S函数的可调因子的模糊PID励磁控制器,仿真研究表明该方法设计的控制器有很好的效果。 相似文献
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基于输电系统中同步电机的不精确励磁非线性模型,采用非线性控制 理论中的全局线性化方法和滑动模态控制方法,导出一个非线性切换控制律, 并用它设计出电力系统新型的非线性励磁控制器。针对单机无穷大系统进行数 字仿真实验,结果表明,该励磁控制器能良好地改善系统的动态响应特性,且 具有良好的鲁棒性。 相似文献
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提出了一种非线性自适应最优励磁控制器。新的控制设计方法基于同步发电机的三阶双轴数学模型,其仅由代数运算实现的分散非线性反馈补偿律保证了系统在各种运行方式下具有足够的稳态调节精度。控制算法内置一个简单的在线自适应变增益策略以达到在各种工况下动态最优化控制的目的,通过求解闭环特征值优化问题来选取权矩阵的方法改善了系统受扰后的暂态响应性能。仿真计算结果表明,与传统的线性最优控制器相比,新的励磁控制器具有多方面优点。 相似文献
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从发电机励磁、调速控制方式入手,在分析了传统综合控制器特点之后,给出了运用非线性逆系统方法实现发电机综合控制的方法,并进行了实验室仿真。仿真结果表明:与传统的常规单变量控制器相比,基于逆系统的综合控制方法不仅能够提高发电机在暂态情况下的系统稳定性,而且能提高电压控制精度。 相似文献
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将Lyapunov稳定性理论用于电力系统的非线性励磁控制,推 导了实用的发电机非线性最优励磁控制规律。通过理论分析、计算机仿真和动模实 验,证实了该控制方式具有较强的鲁棒性,在系统参数或运行状态变化时都具 有良好的控制效果。而且,励磁控制规律的获得不必经过繁杂的数学推导,易 为工程技术人员所掌握,具有明显的实用价值。为电力系统的励磁控制研究开 辟了一条新的途径。 相似文献
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提出将同步发电机及其励磁系统看做扭振励磁控制的执行元件,采用直接反馈线性化方法补偿其非线性因素,避免小偏差线性化模型的参数摄动问题,从而提高扭振励磁控制系统的鲁棒性。综合H∞扭振模态观测器、独立模态空间鲁棒控制器和非线性反馈补偿律,提出一种轴系扭振的鲁棒非线性控制策略,在大范围工况下具有一致的全局性能,并且3个组成部分可以分别独立设计;另外,可以方便地与常规非线性励磁控制律综合在一起,而不影响后者阻尼低频振荡的性能。以一台300 MW汽轮发电机组第1阶扭振模态的阻尼控制为例,通过仿真验证鲁棒非线性控制器的性能优于常规线性控制器。 相似文献
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从发电机励磁控制的发展过程介绍国内目前使用较为成熟的最优励磁控制技术———线性、非线性、自适应最优控制,并讲述了最优微机励磁控制器的主要功能。 相似文献
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根据冗各电站地下厂房开挖支护的施工顺序,以隐式杆单元模拟锚杆,以壳单元模拟混凝土喷层,采用三维非线性有限元技术,对洞室群的开挖支护动态过程进行了模拟计算。通过三维非线性有限元计算分析得到:洞室群动态开挖过程中围岩应力变形的分布规律,围岩塑性区的发展规律,锚杆受力变化情况。计算结果表明:整个开挖过程中,洞周围岩位移变化规律正常,量值较小,塑性区主要分布在洞室周边,围岩稳定性较好;但在洞室交叉口处围岩的变形较大,出现较大范围的塑性区,在此基础上提出了支护措施优化方案,并对优化方案的效果进行了评价。 相似文献
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The relocation of unionacean mussels is commonly used as a conservation and management tool in large rivers and streams. Relocation has been used to recolonize areas where mussel populations have been eliminated by prior pollution events, to remove mussels from construction zones and to re-establish populations of endangered species. More recently, relocation has been used to protect native freshwater mussels from colonization by the exotic zebra mussel Dreissena polymorpha. We conducted a literature review of mussel relocations and evaluated their relative success as a conservation and management strategy. We found that 43% of all relocations were conducted because of construction projects that were forced to comply with the Endangered Species Act 1973 and that only 16% were monitored for five or more consecutive years. Most (43%) relocation projects were conducted from July to September, presumably a period when reproductive stress is relatively low for most species and the metabolic rate is sufficient for reburrowing in the substrate. The mortality of relocated mussels was unreported in 27% of projects; reported mortality varied widely among projects and species and was difficult to assess. The mean mortality of relocated mussels was 49% based on an average recovery rate of 43%. There is little guidance on the methods for relocation or for monitoring the subsequent long-term status of relocated mussels. Based on this evaluation, research is needed to develop criteria for selecting a suitable relocation site and to establish appropriate methods and guidelines for conducting relocation projects. 相似文献
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Samples were taken year-round at eleven sites along the altitudinal profile (2900-1400 m a.s.l.) of the Gunnison River, a 329 km tributary of the Colorado River, to document the distribution of the Plecoptera and to evaluate responses to hypolimnial-release dams in the headwaters and middle reaches. Twenty-two species were present, with the greatest species richness occurring in an unregulated segment upstream of the middle reach dams; average nymphal biomass over the study period (175 organisms, 395 mg dry mass m?2) was also greatest in this segment. Only four species (58 organisms, 48 mg m?2) were present in the tailwaters of the headwater dam and values were greatly reduced (nine species; 35 organisms, 180 mg m?2) below the middle reach dams. The stonefly community recovered ca. 80 km downstream from the last dam (15 species; 244 organisms, 250 mg m?2), apparently in response to natural resetting of environmental conditions corresponding to those above the middle reach dams. At the most downstream site (11) only four species (four organisms, 16 mg m?2) were present. The observed distributional pattern is a classic serial discontinuity in response to hypolimnial stream regulation in a temperate latitude river. 相似文献
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In the lower River Murray, Australia, populations of gastropods have declined markedly over the past 40 years. Of the native fauna of about 18 species, only the ancylid Ferrissia petterdi remains common (but in patches), and another five species feature in sporadic local resurgences. Until recently the viviparid Notopala was thought to be extinct. The introduced physid Physa acuta is widespread, but in low numbers. The decline probably is associated with flow regulation, high turbidity and the introduction of common carp. Snail populations have persisted, however, in irrigation pipelines fed from the river, where they periodically cause blockages. This paper reports the discovery of the only known populaion of Notopala hanleyi in a pipeline where the inner wall accumulates microbial and other organic matter, providing high quality food for snails. In the Murray before regulation most of the periphytic biomass was probably microbial, as fluctuating water levels would have maintained littoral communities in a highly productive, early state of succession his postulated that, by stabilizing seasonal water levels, regulation has promoted the production of filamentous green algae, an inferior food source, and so displaced snail populations from the open aquatic environment. 相似文献
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V. K. Konovalov O. V. Yashkin V. V. Ermakov 《Power Technology and Engineering (formerly Hydrotechnical Construction)》2008,42(2):105-109
A system for removal and pneumatic transport of fly ash is examined, in which air pulses act on batches (pistons) of ash formed
in a duct. Studies are made of the effect of several physical parameters on the force required to displace a piston of ash
and these serve as a basis for choosing a system for removal and pneumatic transport of ash simultaneously from several hoppers
of an electric precipitator. This makes it possible to separate the ash particles according to size without introducing additional
components. Formulas are given for calculating the structural and dynamic parameters of this system and measurements of indirect
dynamic parameters are used to calculate the input-output characteristics of the system. In order to optimize the system,
configurations for summing several ducts into a single transport duct for pneumatic ash transport are proposed. Some variants
of dry ash utilization and the advantages of producing of size-separated particles are considered.
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Translated from élektricheskie Stantsii, No. 2, pp. 26–30 (2008). 相似文献
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Peter B. Bayley 《河流研究与利用》1991,6(2):75-86
The ‘flood pulse advantage’ is the amount by which fish yield per unit mean water area is increased by a natural, predictable flood pulse. Evidence for this increase is presented from tropical and temperate fisheries. It is argued that increasing multispecies fish yield by restoring the natural hydrological regime is consistent with increasing production of other trophic levels and with restoration from ecological and aesthetic viewpoints. When applied to a river-floodplain system, this restoration would provide a large, self-sustaining potential for recreation, commercial exploitation, and flood control. An interim ‘natural flood pulse’ restoration approach is proposed for systems modified for navigation. This approach approximates the natural hydrological regime in a river reach and is intended as a first step in the long process of restoring the watershed. 相似文献