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本文引入了一种新型的软开关PFC电路,文中首先分析了开关电源的发展历程,说明了谐波对公共电网的危害,接着给出了这种软开关PFC的电路拓扑并对其工作原理进行了分析,最后对其参数进行设置,用Matlab软件进行仿真,并得到了良好的电压-电流波形,而且减小了电路的损耗,提高了电路的效率,实现了小型化,绿色化的要求。 相似文献
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该文对新世纪初推出的新型高端电源元件——锂离子电容器进行了系统论述,扼要介绍了其发展历史,精辟分析了其组成结构和工作机理,定性定量探讨了其优异性能,案例化研究了其应用领域,逐项展现了其一系列新产品,辩证阐明了其发展前景,科学预测了其发展趋势。 相似文献
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基于角色访问控制在电力监控系统中的应用 总被引:3,自引:0,他引:3
针对电力监控系统对访问控制的要求,比较了几种常见的访问控制策略,提出了一种基于角色访问控制的电力监控系统访问控制策略.文中介绍了基于角色访问控制的基本概念及其特点和优势,分析了电力监控系统体系结构并建立了其资源模型,在此基础上设计了电力监控系统中的资源管理与访问控制,形成了完整的访问控制策略.该策略细化了资源的粒度,提高了资源管理的效率,简化了用户权限管理,提高了电力监控系统的安全性和可靠性. 相似文献
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在小学语文阅读教学领域引入信息技术后,丰富了课堂教学手段,学生在情感和行为上积极参与媒体活动,学习兴趣不断提高,多感官参与学习,课堂气氛活跃,缩短了教学时间,增加了教学密度,提高了课堂教学效率,极大地调动了学生的学习积极性;促进了学生全面发展,达到使学生“学会”和“会学”的转变,为小学语文全面落实课改精神提供了一个全新的思路。 相似文献
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把多媒体用于生物学科教育中,改变了教师传统的教学模式,转变了学生被动的学习模式,拓展了教学资源,提高了教学质量,收到了良好的效果。 相似文献
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温室气体排放权交易对发电公司最优报价策略的影响 总被引:10,自引:7,他引:3
CO_2排放权交易是温室气体减排的主要机制之一.一些发达国家和地区已经或即将实施CO_2排放权交易.在此背景下,根据排放权交易市场CO_2排放配额价格变化的特点,采用了类似于随机生产模拟的方法进行估计.在假设所研究的发电公司能够估计其竞争对手报价策略的概率分布的前提下,构造了发电公司最优报价策略的机会约束规划模型并给出了求解方法.以一个有6个发电公司参与的电力市场为例对所提出的模型和方法进行了验证,并与无CO_2排放权交易情况下的结果进行了对比. 相似文献
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In electricity industry with transmission constraints and limited number of producers, Generation Companies (GenCos) are facing an oligopoly market rather than a perfect competition one. Under oligopoly market environment, each GenCo may increase its own profit through a favorable bidding strategy. This paper investigates the problem of developing optimal bidding strategies of GenCos, considering bilateral contracts and transmission constraints. The problem is modeled with a bi-level optimization algorithm, where in the first level each GenCo maximizes its payoff and in the second level a system dispatch will be accomplished through an OPF problem in which transmission constraints are taken into account. It is assumed that each GenCo has information about initial bidding strategies of other competitors. Impacts of exercising market power due to transmission constraints as well as irrational biddings of the some generators are studied and the interactions of different bidding strategies on participants’ corresponding payoffs are presented. Furthermore, a risk management-based method to obtain GenCos’ optimal bilateral contracts is proposed and the impacts of these contracts on GenCos’ optimal biddings and obtained payoffs are investigated. At the end, IEEE 30-bus test system is used for the case study in order to demonstrate the simulation results and support the effectiveness of the proposed model. 相似文献
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在电力市场环境下,作为一项重要的辅助服务,自动发电控制(AGC)对维持系统频率稳定、联络线交易具有重要作用。文中建立了AGC容量预测和机组选择的动态统一模型。首先从概率学角度,利用机组历史发电数据,并考虑短 期负荷预测等因素,初步确定系统所需的AGC调节容量, 然后利用层次分析法对AGC机组的报价、机组性能进行综 基金项目:北京市自然科学基金项目(9062008)。 Project Supported by Natural Science Foundation of Beijing (9062008). 合评估排序;在一定AGC调节容量下,权衡AGC容量购 买费用和联络线处罚费率,最终建立兼顾系统运行安全性和 经济性的AGC容量预测和机组选择的动态统一模型;最后,通过算例验证了模型的有效性。 相似文献
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Yiqun Yixin Fushuan Felix F. 《International Journal of Electrical Power & Energy Systems》2004,26(10):797-804
In actual electricity market, which operates repeatedly on the basis of one hour or half hour, each firm might learn or estimate other competitors' strategic behaviors from available historical market operation data, and rationally aims at its maximum profit in the repeated biddings. A conjectural variation based learning method is proposed in this paper for generation firm to improve its strategic bidding performance. In the method, each firm learns and dynamically regulates its conjecture upon the reactions of its rivals to its bidding according to available information published in the electricity market, and then makes its optimal generation decision based on the updated conjectural variation of its rivals. Through such learning process, the equilibrium reached in the market is proven a Nash equilibrium. Motivation of generation firm to learn in the changing market environment and consequence of learning behavior in the market are also discussed through computer tests. 相似文献
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判断发电商市场势力的指标分析 总被引:3,自引:0,他引:3
以浙江省电力市场为例,分析判断发电商市场势力的三类度量指标,市场集中度指标、动态市场集中度指标、市场势力的直接度量指标(勒纳(Lerner)指数或PCM指数)。对市场的参与者在现货市场和合同市场中的市场份额及其竞价行为进行了分析,通过对市场集中度指标以及动态集中度指标的分析,得出浙江省电力市场的三个发电商拥有较高的潜在市场势力,具备了较强的通过各种手段控制市场成交价格的能力。为了促进电力市场的公平和有效竞争、减少发电商滥用市场势力所带来的负面影响,提出了加强输电网络的建设,合理配置电源分布,将目前还未参与发电市场的发电商引入发电市场竞争,签订长期合同和制定市场成交价格上限等一系列有针对性的平抑市场势力的措施。 相似文献