共查询到20条相似文献，搜索用时 109 毫秒
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针对高校实验室电源或线路容量较小的工况,构建了基于双变流器的电力电子课程创新实验平台,介绍了平台的主电路结构和主要环节的设计原理,并对平台的整流、逆变、能量回馈、无功生成及补偿等多项实验教学功能进行了实验验证。结果表明,该实验平台不仅克服了电源或线路容量有限的缺点,而且丰富了电力电子课程探究性实验的教学内容,可显著提升电力电子课程的实验教学质量。 相似文献
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针对电力电子实验室设备管理中鲜有对设备进行全面介绍和对其使用情况进行量化建模分析的现状,提出并实践了一种电力电子实验室设备的量化管理方法。根据电力电子实验的需求对电力电子实验室常用设备的种类和特点依次进行介绍,然后通过分析电力电子实验设备功能不同,需要有针对性的购置、管理的特点,剖析了目前电力电子实验室设备管理存在责任意识淡薄、设备使用不当和盲目购置设备的主要问题,进而从评估电力电子实验室设备供需平衡的角度,提出了一种基于功效系数法的量化管理法。实践证明,该方法能客观地评估实验设备的供需匹配关系,避免设备的盲目购置,有力提高科研资金的使用效益,为电力电子实验室设备的购置和科研经费的使用提供了针对性的建议。 相似文献
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针对电力电子技术课程传统教学过程中强调主电路而忽视控制电路分析的情况,提出在电力电子技术课程教学中引入系统级电力电子仿真软件PLECS进行辅助教学的新方法,通过在降压斩波电路的应用,说明该方法能灵活应用于仿真教学,加深学生对电力电子控制技术知识的理解. 相似文献
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介绍了目前国内外电力电子变压器的研究概况,对电力电子变压器发展过程中出现的斩控式电力电子变压器、交-交-交型电力电子变压器、反激型电力电子变压器、双PWM变换型电力电子变压器几种典型的设计构想进行了梳理,并且给出了相应的主电路拓扑。通过分析电力电子技术在电力电子变压器研究领域的相关理论及其应用,阐述各种拓扑的优缺点,并给出了主要的研究方向和发展趋势。 相似文献
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设计了一种DSP28335作为控制器的硬件在环(DSP-HIL)教学实验平台。针对电力电子与电力传动方向的HIL系统,设计了专用的DSP28335控制器,接口设计简洁方便,测量点丰富;采用MATLAB/Simulink自动代码生成技术,对DSP控制算法代码进行快速自动生成;采用Starsim软件搭建运行在FPGA卡上的电力电子主电路,电路参数修改灵活,电气量及控制变量能够实时示波观察。该DSP-HIL平台功能完善,使用简便,可快速实现先进控制算法在电力电子与电力传动领域应用的教学实践。 相似文献
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蒋敏 《宁波职业技术学院学报》2005,9(2):14-16
Pspice软件在电力电子领域由于器件的特殊性和非线性状态下，仿真使用起来不太容易，介绍的二种方法使其能够方便地应用在三相可控整流电路和直流斩波电路中。 相似文献
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晶闸管的开通和关断条件、触发电路以及实际应用中高低压侧的隔离方案是电力电子课程的重要知识点,以涵盖上述知识点的晶闸管典型工程应用案例有载调压变压器为例,构建了基于晶闸管的有载调压实验系统,并对其升降压的调压效果进行了实验验证。该实验系统有助于开展电力电子课程的探究性实验教学。 相似文献
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结合电力电子和DSP的发展情况,简述CCS在电力电子以及DSP平台上的发展概括和应用研究,并结合自己的看法进行简单的评述。 相似文献
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罗艳萍 《读与写:教育教学刊》2008,5(6)
The communication of people partially is the communication of cultures. Culture has a direct effect on international commercial activities in all aspects. Different conceptions about time, space, equality, law and the like, lead people to deal with things in different ways. So to know cultures of the counterpart is to facil-itate our enterprises so as to have a smooth and successful communication in commercial activity. 相似文献
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Richard Denner 《海外英语》2007,(4):14-15
Rosco and I wait for the fishermen to return.I sit at a wooden bench near the store at Mt.Baker Resort and watch the clouds change shape. Rosco has my belt around his neck and an eight foot tow chain hooked to a tree. Dogs must be on a leash. Ducks and rabbits are loose. 相似文献
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Given a graph G,a subgraph C is called a clique of G if C is a complete subgraph of G maximal under inclusion and |C|≥2. A clique-transversal set S of G is a set of vertices of G such that S meets all cliques of G. The clique-transversal number, denoted as TC (G), is the minimum cardinality of a clique-transversal set in G. The clique-graph of G, denoted as K (G), is the graph obtained by taking the cliques of G as vertices, and two vertices are adjacent if and only if the corresponding cliques in G have nonempty intersection. Let F be a class of graphs G such that F={G|K(G) is a tree}. In this paper the graphs in F having independent clique-transversal sets are shown and thus TC (G)/|G|≤1/2 for all G ∈ F. 相似文献
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《海外英语》2007,(5):10-11
Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help? 相似文献
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陈美曦 《山东教育学院学报》2008,23(2):103-107
Different nations have different social cultures, and the social culture of every nation is developing with the development of the nation, language is greatly influenced by social culture, which enables language to possess national and historical characteristics. Word is the smallest, independent, meaningful linguistic unit of language. It can well reflect the national and historical characteristics. From synchronic aspect, the social and cultural influence on word meaning is mainly embodied in conceptual and associative meanings of word. The incorrespondence of word meaning is a phenomenon that exists in both conceptual and associative meanings of word among different languages. From diachronic aspect, the development of social culture causes some changes of word meaning to some extent. Therefore, social culture plays a key role in vocabulary learning and mastery of a language. 相似文献
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邱崇丙 《唐山师范学院学报》2014,(1):21-23
汉字的六书,《说文》对“转注”一类,语焉不详。后世学者提及转注,也仅限于许慎所举出的例字。《汉字例说》一文,作者从转注的角度综合考虑,对部分现代常用字作了分析,跟传统的解释有所不同。希望能抛砖引玉,互相切磋,以推进学术研究。 相似文献
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《海外英语》2007,(4):36
There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love. 相似文献
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Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject. 相似文献