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介绍一种由乌克兰“汉姆斯”引进的高压同步电动机的变频起动装置。该装置采用磁场定向的矢量控制原理,对高压同频电动机实现变频起动,可大幅度降低电机起动电流和功率,减小网上容量,降低机械冲击。使起动过程平滑,起动时间可调。在几个大型钢厂使用效果很好。 相似文献
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1 升速与起动 1.1 升速过程中要解决的主要问题 (1) 工频起动与变频起动 ① 工频起动 以4极电动机为例,在接通电源瞬间,同步转速高达1500r/min,转子绕组与旋转磁场的相对速度很高,故转子电动势和电流、定子电流都很大,可达额定电流的4~7倍,如图1中(a)和(c)所示。从机械特性上看,整个起动过程中,动态转矩很大,如图1(b)所示,故起动时间很短。 ② 变频起动 采用变频调速后,可通过降低起动时的频率来减小起动电流。仍以4极电动机为例,假设在接通电源瞬间,将起动频率降至5Hz,则同步转速只有150r/min,转子绕组与旋转磁场的相对速度只有工频… 相似文献
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文永红 《电子制作.电脑维护与应用》2012,(8)
在石油化工企业,常使用一些几千伏甚至几万伏的高压同步或异步大电动机来驱动风机、压缩机或挤压机等.但是在其电动机起动过程中电流高达电动机额定电流的5-10倍,对电动机及所拖动的设备造成电气和机械损伤,而且引起电网电压下降,本文就讨论一下交流高压大电动机的起动问题. 相似文献
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现代交流提升机拖动系统比较 总被引:1,自引:1,他引:0
《工矿自动化》2009,35(10)
现代交流提升机拖动系统主要包括高压交流电动机和高压大功率交流变频调速系统。文章分析比较了异步电动机拖动系统和同步电动机拖动系统的特点,介绍了交-交变频调速系统和交-直-交变频调速系统的原理和结构,比较了二者的优缺点,重点介绍了3种交-直-交变频调速系统的变频调速技术:定子侧高压变频调速技术、转子双馈三电平变频调速技术和定子侧短封转子变频调速技术,并对该3种变频调速技术进行了两两比较,最后得出结论:在大功率现代交流提升机拖动系统中,定子侧高压变频调速技术适用于所有驱动电动机,定子侧短封转子变频调速技术的运行特性稍差,转子双馈三电平变频调速技术能满足调速要求,且能够提高系统的功率因数。 相似文献
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《电子制作.电脑维护与应用》2020,(16)
本文分析了永磁同步电动机与传统电机在结构、调速、过载能力以及效率上的优点,介绍了现代工业中应用的前景,研究永磁同步电动机变频速率调整系统的设计方案。该论题分析阶段内,通过总结变频调速控制原理,了解永磁同步电动机运行状态、开展数学模型建立分析以及调速系统的设计操作,最终为永磁同步电动机变频调速提供了理论依据。阐述了永磁同步电动机在变频控制中的运行与维护。 相似文献
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为减小大功率开关电源启动电流对整流桥和滤波电容的冲击,设计了辅助电源启动电路。此电路采用基于DSP控制系统的两路开出信号来实现开关电源的软启动。实践证实该方法无冲击电流、成本低、体积小且简单实用。 相似文献
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大数据的应用越来越广泛,将大数据思维应用到管理中已是大势所趋。电力大数据是指各种数据采集渠道收集到的海量业务数据的集合,具有数据量大、时效性强、使用价值高等特点。国网、南网等电网企业早已嗅到了大数据的价值,采取了很多措施,及时作出了必要的战略部署。目前,基层供电企业的业务部门开明人士和运监人员正开始数据管理尝试,还处在起步阶段,面临诸多问题需要解决。本文列出的几个数据管理分析案例,是基层供电企业在大数据管理方面的“星星之火”,提出面对大数据潮流基层供电企业可主动作为的几点建议,以在未来的大数据管理潮流中占据主动地位,并展望大数据管理在基层供电企业应用的场景。 相似文献
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We study the computing power of a class of numerical P systems introduced in the framework of autonomous robot control, namely enzymatic numerical P systems. Three ways of using the evolution programs are investigated: sequential, all-parallel and one-parallel (with the same variable used in all programs or in only one, respectively); moreover, both deterministic and non-deterministic systems are considered. The Turing universality of some of the obtained classes of numerical P systems is proved (for polynomials with the smallest possible degree, one, also introducing a new proof technique in this area, namely starting the universality proof from the characterization of computable sets of numbers by means of register machines). The power of many other classes remains to be investigated. 相似文献
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基于"物联网+"的人工智能算法使制造业发生了翻天覆地的变化。采用由设备层、任务层和辅助生产层三层结构构建的能耗结构,详细描述了离散制造系统层的数学模型,通过对模型的分析,发现设备层为耗能主体,且其关键参数无法直接获取,基于此,从设备层能耗模型切入,通过测量设备总功率与主轴实时功率,采用基于变遗忘因子算法来估计设备加工时的附加载荷损数系数,结合能耗集成化模型和预测出的附加载荷损耗系数用于能耗量化分析。 相似文献
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Malcolm Bersohn 《Computational Intelligence》1986,2(1):191-195
The input to the described program, in learning mode, consists of examples of starting graph and result graph pairs. The starting graph is transformable into the result graph by adding or deleting certain edges and vertices. The essential common features of the starting graphs are stored together with specifications of the edges and vertices to be deleted or added. This latter information is obtained by mapping each starting graph onto the corresponding result graph. On subsequent input of similar starting graphs without a result graph, the program, in performance mode, recognizes the characterizing set of features in the starting graph and can perform the proper transformation on the starting graph to obtain the corresponding result graph. The program also adds the production to its source code so that after recompilation it is permanently endowed with the new production. If any feature which lacks the property "ordinary" is discovered in the starting graph and only one example has been given, then there is feedback to the user including a request for more examples to ascertain whether the extraordinary property is a necessary part of the situation. 相似文献
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Rule-based ethical theories like Kant's appear to be promising for machine ethics because of the computational structure of their judgments. Kant's categorical imperative is a procedure for mapping action plans (maxims) onto traditional deontic categories--forbidden, permissible, obligatory--by a simple consistency test on the maxim. This test alone, however, would be trivial. We might enhance it by adding a declarative set of "buttressing" rules. The ethical judgment is then an outcome of the consistency test, in light of the supplied rules. While this kind of test can generate nontrivial results, it might do no more than reflect the prejudices of the builder of the declarative set; the machine will "reason" straightforwardly, but not intelligently. A more promising (though speculative) option would be to build a machine with the power of nonmonotonic inference. But this option too faces formal challenges. The author discusses these challenges to a rule-based machine ethics, starting from a Kantian framework. This article is part of a special issue on Machine Ethics. 相似文献