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基于拓展禁区判据的光伏接入牵引供电系统低频稳定性分析 被引量:1
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作者 赵霞 谢子昀 +3 位作者 王英 陈小强 辛月阳 母秀清 《高电压技术》 EI CAS CSCD 北大核心 2023年第5期1997-2007,共11页
在“双碳”愿景下,光伏通过铁路功率调节器接入牵引供电系统具有良好的发展前景,但光伏接入会对系统的低频稳定性产生影响。针对这一问题,首先建立了光伏-车-网耦合系统小信号阻抗模型,得到了该系统的回比矩阵;然后针对禁区判据进行拓展... 在“双碳”愿景下,光伏通过铁路功率调节器接入牵引供电系统具有良好的发展前景,但光伏接入会对系统的低频稳定性产生影响。针对这一问题,首先建立了光伏-车-网耦合系统小信号阻抗模型,得到了该系统的回比矩阵;然后针对禁区判据进行拓展,提出了拓展禁区判据并给出了判据形式;最后利用拓展禁区判据分析了铁路功率调节器控制器参数等系统参数对低频稳定性的影响,并搭建MATLAB/Simulink测试模型和StarSim半实物实验平台进行了验证。结果表明,与禁区判据相比,拓展禁区判据能更准确地判断光伏-车-网耦合系统低频稳定状态,降低了一定的保守性。 展开更多
关键词 光伏-车-网耦合系统 铁路功率调节器 光伏并网 拓展禁区判据 低频稳定性 StarSim
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High-order field theory and a weak Euler–Lagrange–Barut equation for classical relativistic particle-field systems
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作者 范培锋 陈强 +1 位作者 肖建元 于治 《Plasma Science and Technology》 SCIE EI CAS CSCD 2023年第11期42-54,共13页
In both quantum and classical field systems,conservation laws such as the conservation of energy and momentum are widely regarded as fundamental properties.A broadly accepted approach to deriving conservation laws is ... In both quantum and classical field systems,conservation laws such as the conservation of energy and momentum are widely regarded as fundamental properties.A broadly accepted approach to deriving conservation laws is built using Noether's method.However,this procedure is still unclear for relativistic particle-field systems where particles are regarded as classical world lines.In the present study,we establish a general manifestly covariant or geometric field theory for classical relativistic particle-field systems.In contrast to quantum systems,where particles are viewed as quantum fields,classical relativistic particle-field systems present specific challenges.These challenges arise from two sides.The first comes from the mass-shell constraint.To deal with the mass-shell constraint,the Euler–Lagrange–Barut(ELB)equation is used to determine the particle's world lines in the four-dimensional(4D)Minkowski space.Besides,the infinitesimal criterion,which is a differential equation in formal field theory,is reconstructed by an integro-differential form.The other difficulty is that fields and particles depend on heterogeneous manifolds.To overcome this challenge,we propose using a weak version of the ELB equation that allows us to connect local conservation laws and continuous symmetries in classical relativistic particle-field systems.By applying a weak ELB equation to classical relativistic particle-field systems,we can systematically derive local conservation laws by examining the underlying symmetries of the system.Our proposed approach provides a new perspective on understanding conservation laws in classical relativistic particle-field systems. 展开更多
关键词 high-order field theory weak Euler-Lagrange-Barut equation infinitesimal criterion of symmetric condition Noether's theorem geometric conservation laws
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基于性能曲面特性的干湿球温度允差等级划分 被引量:3
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作者 张忠斌 杜垲 +1 位作者 黄虎 张若楠 《化工学报》 EI CAS CSCD 北大核心 2014年第9期3676-3679,共4页
在试验结果的基础上,分析制冷量和能效比随干湿球温度的变化特性。用赤池信息量准则(Akaike information criterion,AIC)选取制冷量和能效比最优拟合三维曲面方程,求解制冷量和能效比随干湿球温度变化的梯度极值区间,以两者梯度极值区... 在试验结果的基础上,分析制冷量和能效比随干湿球温度的变化特性。用赤池信息量准则(Akaike information criterion,AIC)选取制冷量和能效比最优拟合三维曲面方程,求解制冷量和能效比随干湿球温度变化的梯度极值区间,以两者梯度极值区间内干湿球温度允差范围的并集为A级、现行干湿球温度允差为C级,以各级最大(最小)能效比变化率相等原则,对允差进行三级非线性划分。实例表明随着允差等级的升高,能效比最大变化率由5.19%缩减至1.04%,分级允差能够更加准确地判别房间空调器的能效等级,并给国家标准的修订提供参考。 展开更多
关键词 允差 干湿球温度 房间空调器 性能试验 赤池信息量准则
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夏热冬冷地区居住建筑节能设计初探 被引量:3
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作者 姚大江 邱文航 《华中建筑》 2006年第4期205-208,共4页
能源供应日益紧张、社会对绿色环保节能建筑的呼声不断高涨。由于目前可供选择的节能保温材料不多,能采用的保温节能方式有限,所以该领域的发展前景还十分广阔。现在国家倡导产品自主创新,如果材料、科研与设计能携手合作,该领域必将大... 能源供应日益紧张、社会对绿色环保节能建筑的呼声不断高涨。由于目前可供选择的节能保温材料不多,能采用的保温节能方式有限,所以该领域的发展前景还十分广阔。现在国家倡导产品自主创新,如果材料、科研与设计能携手合作,该领域必将大有可为。 展开更多
关键词 节能建筑 采暖空调年耗电量 规范限值 体系系数 窗墙比 外墙平均传热系教
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Convergence of iterations of Euler family under weak condition 被引量:5
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作者 王兴华 《Science China Mathematics》 SCIE 2000年第9期958-962,共5页
The iteration maps of Euler family for finding zeros of an operatorf in Banach spaces is defined as the partial sum of Taylor expansion of the local inversef z -1 off atz. The unified convergence theorem is establishe... The iteration maps of Euler family for finding zeros of an operatorf in Banach spaces is defined as the partial sum of Taylor expansion of the local inversef z -1 off atz. The unified convergence theorem is established for the iterations of Euler family under the assumption that $\alpha \leqslant 3 - 2\sqrt 2 $ , while the strong condition thatf is analytic in Smale’s criterion α is replaced by the weak condition thatf is of finite order derivative. 展开更多
关键词 Banach space zero of operator iterations of Euler family criterion α under weak condition universal constant unified convergence theorem
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