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为了克服单纯用Simulink元件库建立光伏阵列模型过程复杂的缺点,利用光伏阵列输出特性方程和MATLAB/Simulink建立了基于M函数的光伏阵列最大功率控制的通用仿真模型.将该通用模型用于单相光伏并网系统MPPT中,并在不同光照强度下,对单相并网系统进行仿真实验,仿真结果表明:该模型能快速找到新的工作点,并保持稳定,具有良好的动态特性和强鲁棒性. 相似文献
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本课题研究并设计了一种以太阳能为主要能源的户用光伏冷热电联供系统.主要是:1)在能源侧,研究并应用MPPT(Maximum Power Point Traeking)买现光伏发电的最大功率跟踪,提高太阳能利用率;2)基于太阳能的间歇性和不可控性,按照一定充放电规则,设计充电控制器,实现了实时对蓄电池的高效率充电;3)采用半导体制冷器模拟实现冷热联供;4)在负载侧,对系统进行实时智能检测,主要是光伏板下储水箱的水温和水位,冷热水供应箱水温、水位,实现系统余热回收,从而控制水循环系统,实现能源梯级利用;5)搭建实验模型,进行实验,得到了较好的结果. 相似文献
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随着计算机技术的发展,计算机仿真辅助教学受到了各高校的广泛关注。本文介绍了 MATLAB/SIMULINK仿真软件在电机控制教学环节中的运用,以直流调速系统和永磁同步电机系统为例,进行了仿真实验及结果的分析,结果表明,MATLAB/SIMULINK能够真实有效的进行动态系统建模、仿真和综合分析,辅助学生深入理解课程知识,培养学生分析问题和解决问题的能力。 相似文献
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本文针对兆瓦级的永磁直驱同步风电机组(D-PMSG)多运行于并网发电状态,在DIgSILENT/PowerFactory仿真软件中搭建了基于双PWM全功率变流器的D-PMSG并网仿真模型;阐述了系统的运行原理,对机侧和网侧的变流器的控制策略进行了详细的分析,该系统能够实现风能最大功率追踪以及并网控制,仿真结果验证了所建模型的正确性和控制策略的可行性. 相似文献
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本文介绍太阳能光伏发电系统的组成和分类,概述了光伏发电在我国的应用,总结了我国光伏发电产业存在的主要问题,并提出了如何解决这些问题的一些建议. 相似文献
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This study examined the effect of carbohydrate ingestion on metabolic and performance-related responses during and after a simulated 1h cycling time trial. Eight trained male cyclists (VO 2 peak = 66.5ml kg -1 min -1 ) rode their own bicycles mounted on a windload simulator to imitate real riding conditions. At a self-selected maximal pace, the cyclists performed two 1h rides (separated by 7 days) and were fed either an 8% carbohydrate or placebo solution. The beverages were administered 25 min before (4.5ml kg -1 ) and at the end (4.5ml kg -1 ) of the ride. With carbohydrate feeding, plasma glucose tended (P = 0.21) to rise before the time trial. Compared with rest, the plasma glucose concentration decreased significantly (P < 0.05) at the end of both rides, with no statistically significant difference being observed between treatments. Thereafter, plasma glucose increased significantly (P < 0.05) at 15 and 30 min into recovery, and was significantly higher at 30 min during the carbohydrate trial compared with the placebo trial. No significant changes in plasma free fatty acids were observed during the ride. However, a significant increase (P < 0.05) in free fatty acids was found at 15 and 30 min into recovery, with no difference between trials. Mean power output was significantly (P < 0.05) greater during the carbohydrate compared with the placebo trial (mean - S.E.: 277-3 and 269-3W, respectively). The greater distance covered in the carbohydrate compared with the placebo trial (41.5-1.06 and 41.0–1.06km, respectively; P < 0.05) was equivalent to a 44s improvement. We conclude that pre-exercise carbohydrate ingestion significantly increases endurance performance in trained cyclists during a 1h simulated time trial. Although the mechanism for this enhancement in performance with carbohydrate ingestion cannot be surmised from the present results, it could be related to a higher rate of carbohydrate oxidation, or to favourable effects of carbohydrate ingestion on the central component of fatigue. 相似文献
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Roy J. Shephard 《Journal of sports sciences》2013,31(7):603-620
The biology and medicine of rowing are briefly reviewed. Effort in a 2000 -m race is about 70% aerobic. Because the boat (and in some instances a cox) must be propelled, successful competitors are very tall, with a large lean mass and aerobic power. Large hearts may lead to erroneous diagnoses of a cardiomyopathy. Large respiratory minute volumes must be developed by chest muscles that are also involved in rowing. The vital capacity is typically large, and breathing becomes entrained. Expiration cannot be slowed relative to inspiration (as normally occurs at high rates of ventilation) and the limiting flow velocity may be reached, with the potential for airway collapse. Performance is strongly related to the power output at the ‘anaerobic threshold’, and lactate measures provide a guide to an appropriate intensity of endurance training. Peak blood lactate levels are higher in males (commonly 11–19 mmol·l -1 and occasionally as high as 25 mmol·l -1) than in females (9–11 mmol·l -1), probably because males have a greater muscle mass in relation to blood volume. The skeletal muscles are predominantly slow twitch in type, developing an unusual force and power at low contraction velocities. Many rowers have a suboptimal diet, eating excessive amounts of fat. Lightweight rowers also have problems of weight cycling. Aerobic power and muscle endurance often change by 10% over the season, but such fluctuations can be largely avoided by a well-designed winter training programme. Injuries include back and knee problems, tenosynovitis of the wrist and, since the introduction of large blades, fractures of the costae. 相似文献
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Alan M. Nevill Roger L. Holder Andrew Bardsley Helen Calvert Stephen Jones 《Journal of sports sciences》2013,31(4):437-443
A regression analysis of competitors' tournament results in relation to their world rankings was proposed to identify the effect of home advantage in international ‘grand-slam’ tennis and ‘major’ golf tournaments. The results provided little evidence of home advantage in either the grand-slam tennis or the golf tournaments held in 1993. The only possible evidence of home advantage was found in the Wimbledon tennis and the US Open golf championships. Even these findings can be explained, at least partially, by (1) the availability of information concerning the low world rankings of the British tennis players competing at Wimbledon, and (2) selective entry, allowing only the world's top-ranked foreign golfers into the US open golf tournament. In both cases, the lower ranking home competitors have a greater opportunity to perform above their anticipated world rankings. Therefore, provided entry into tennis and golf tournaments is truly ‘open’ to both the host nation's representatives and foreign competitors alike, home advantage does not appear to be a major factor influencing the competitors' performance in such competitions. These findings may be explained by the relatively objective nature of the scoring systems used in tennis and golf, unlike the subjective influence of refereeing decisions on the results of team-games such as soccer. 相似文献
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许良 《体育科技文献通报》2011,19(2):1-4
基于1985、1995和2005年全国学生体质调研数据,对各时期我国城乡学生形态、机能、体能发展水平进行系统地定量研究,动态分析20年全国城乡学生体质发展的特点与规律。主要研究结果：（1）近20年城乡学生生长发育持续提前,城市学生各项形态指标生长水平高于乡村,身高城乡差距缩小,体重、胸围城乡差距加大;（2）城市学生肺活量水平高于乡村,城乡学生肺活量20年持续下降,前10年乡村学生下降快、后10年城市学生下降快;（3）乡村学生800m、1000m跑水平高于城市,城市女生50m跑、仰卧起坐水平高于乡村,其他素质城乡学生水平波动较大;（4）城市女生50m跑20年持续下降,城乡学生800m和1000m跑、城市学生50m×8往返跑20年加速下降,其他素质20年间有增有降发展极不平稳。 相似文献
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采用测量、问卷调查、数理统计等方法,分析定向运动学习前后对大学生身心健康的影响.结果经T检验和x2检验且表明：定向运动不仅能增强学生体质健康水平,而且有助于学生的情绪调节,增强自信心与创新意识,培养勇敢顽强的意志品质,建立良好的人际关系,能有效地促进学生身心健康发展.为了全面提高大学生整体素质,积极实践,构建定向运动课内外一体化教学模式,进行定向运动课程模块化教学,以满足学生的多元化需求. 相似文献
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重新认识体育的社会关联 总被引：3，自引：1，他引：2
体育与政治之间存在一个悖论，体育的发展与经济实力之间没有直线相关，体育与教育部分重叠，体育与宗教最为近缘，体育可借用科学手段，体育的艺术禀性日益明显，体育与养生反映着两种人生观。 相似文献
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本文在专家访谈、问卷调查、数理统计和文献资料分析的基础上,探析了上海社区体育竞赛参与者的特点、参与者对社区体育赛事运作管理的看法等问题。在此基础上从引进社区体育赛事的志愿者、整合社区体育赛事的各种资源、开发社区体育竞赛的无形资产、组建非营利性的专业团队、规范社区体育赛事的服务管理等方面提出了进一步满足上海社区居民日益增长的体育竞赛参赛需求的对策与措施。 相似文献
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对全面把握游泳训练环节的探讨 总被引：4，自引：0，他引：4
从系统观点出发,结合训练实践,对全面把握游泳训练环节进行探讨。认为应强化非智力因素在运动员多年训练中的作用,在育材全过程中不断选材,从整体上把握动态训练的全过程,把培养高水平运动员的整个过程置于一个严格的科学控制之下。 相似文献