基于CPSOGSA算法的风-光-小水电微电网负荷频率 最优 鲁棒控制

在构建以新能源为主体的新型电力系统背景下,分布式光伏呈现高比例渗透趋势。光伏出力的波动性易引起配电网电压越限和三相不平衡问题,同时光伏逆变器的剩余容量又具有无功主动支撑作用,有利于改善电压质量。而且配电网阻感比大、电压与有功耦合明显,导致配电网电压受光伏有功无功的综合影响而更加复杂。从电压适应性角度研究配电网接纳三相和单相分布式光伏的承载能力。首先,按统计学原理分别建立最大值、期望值和众数值等反映电压质量的统计特征指标,并从光伏渗透率和接入分散程度两方面描述分布式光伏的接入特征。其次,基于历史天气数据构建典型日场景,考虑光伏主动参与无功支撑作用,运用随机模拟分析得出各节点电压质量统计指标。最后,采用AHP-CRITIC组合赋权法分别对电压偏差和不平衡指标进行一定的加权组合,综合反映电压适应性。应用OpenDSS软件进行算例分析,结果验证了所提方法的有效性。     

光伏快速充电站配电变压器端电能质量综合控制研究

针对光伏快速充电站将光伏发电与电动汽车快速充电站有机结合,在充分发挥清洁能源优势和大量提升充电效率的同时所带来的电能质量扰动类型复杂、变化快速等问题,提出了一种基于串并联组合配电网柔性交流输电(distribution flexible AC transmission system, DFACTS)的新型电能质量补偿器的电能质量综合控制方法。深入研究了新型电能质量补偿器主电路拓扑,建立起了动态工作模型。详细分析了新型电能质量补偿器线性自抗扰控制方法的工作原理,设计出线性自抗扰控制器。并针对各DFACTS控制器间的交互影响,提出多DFACTS控制器的协调控制策略。最后搭建仿真模型,进行仿真验证。仿真结果表明,所提出的新型电能质量补偿器采用线性自抗扰控制方法相比传统PI控制方法,提高了电能质量扰动快速变化时的综合补偿能力和动态响应能力。并且验证了该协调控制能有效提高系统电压稳定能力,具有良好的可行性和有效性。     

基于模糊故障树的光伏并网微型逆变器故障识别方法研究

为缩短光伏并网微型逆变器故障提取时间、提升采样精度和效率,基于模糊故障树研究光伏并网微型逆变器故障识别方法。首先利用模糊故障树方法对光伏并网微型逆变器进行故障映射,建立故障底事件与顶事件之间的联系,然后通过小波包变换提取光伏并网微型逆变器故障特征,最后通过构造SOFTMAX光伏并网微型逆变器故障多分类器,实现对光伏并网微型逆变器故障的识别。设计仿真实验,结果证明,在有功功率为3000W-12000W的范围内该方法的采样时间较短,且采样精度和采样效率较高,在光伏并网微型逆变器故障识别方面具有优越性能。     

带谐波补偿的T型三电平并网逆变器控制研究

为了提高光伏逆变器并网电流质量,鉴于有源滤波器的控制算法,提出了一种新型的带谐波补偿的T型三电平并网逆变器控制策略。首先,采用锁相环分析电网电压矢量相位角,并根据光伏阵列输出的功率计算光伏并网逆变器的基波输出电流。然后,通过自校正滤波器技术提取网侧负载谐波电流。最后,根据基波输出电流与负载谐波电流确定T型三电平光伏并网逆变器的开关导通序列。为验证该控制策略,搭建了基于Matlab/Simulink的仿真模型。仿真试验结果表明:该控制策略可有效改善网侧谐波电流,提高并网电流质量,在不增加设备的前提下实现光伏并网与有源滤波双重功能。该研究对于T型三电平逆变器在光伏并网及电能质量治理领域的推广应用具有重要价值。     

太阳能-空气光伏/光热一体化热泵热水系统实验特性

本文研究了一种新型光伏/光热一体化(PV/T)复合热源热泵热水系统,将多孔扁盒式PV/T集热板与空气源热泵相结合,根据不同控制方式组合成双热源并联、单太阳能和单空气能三种不同运行模式。在室外环境温度28.5℃下,将200 L 30℃热水加热到55℃,研究了加热时间、热水温度、COP等性能的变化规律,结果表明双热源并联运行模式下分别比单太阳能模式和单空气能模式的加热时间缩短了42%和54%,COP分别提高了32.78%和47.64%;同时实验研究了在夏季工况下将200 L水从9∶00循环加热到17∶00过程中系统热性能,探讨了太阳辐射强度、PV/T集热板温度对光电/光热效率的影响,通过实验对比可以得出在热电模式下系统的光电效率η_(pv)比单一光电模式平均高25.8%.     

Photoelectric properties of the photoconducting film composites based on ferrocenyl‐ and carbazolyl‐containing oligomer doped with polymethine dye

New photosensitive polymeric film composites based on oligomer containing ferrocenyl and carbazolyl fragments doped with symmetric polymethine dye are synthesized. Their photoelectric properties are investigated. Photovoltaic properties of these composites are detected. The mechanisms and peculiarities of the photovoltaic and photodielectric effects are discussed.     

Is floating photovoltaic better than conventional photovoltaic? Assessing environmental impacts

Photovoltaic (PV) solar energy installations are growing all over the world as a promising renewable alternative to generate electricity. However, many studies have highlighted some drawbacks associated with the installation and operation of conventional solar energy power plants. Thus, floating photovoltaic (FPV) systems have been emerging as a new concept in solar energy to lessen negative environmental impacts caused by allocation of conventional PV facilities. This paper is an overview of the potential negative and positive environmental impacts caused by photovoltaic systems with particular interest on large-scale conventional and floating photovoltaic. This study addresses and compares the impacts at all phases of project implementation, which covers planning, construction, and operation and decommissioning, focusing on ambient located in the tropics. The overall impacts associated with project allocation such as deforestation (for the project implementation and site accessing), bird mortality, erosion, runoff, and change in microclimate are expected to have higher magnitudes for the implementation of conventional PV facilities. The results highlight advantages of FPV over conventional PV during the operational and decommissioning phases as well. Though, further studies are required to assess both qualitative and quantitative aspects of installations in similar areas.     

Recent Advances in Rolling 2D TMDs Nanosheets into 1D TMDs Nanotubes/Nanoscrolls

Transition metal dichalcogenides (TMDs) van der Waals (vdW) 1D heterostructures are recently synthesized from 2D nanosheets, which open up new opportunities for potential applications in electronic and optoelectronic devices. The most recent and promising strategies in regards to forming 1D TMDs nanotubes (NTs) or nanoscrolls (NSs) in this review article as well as their heterostructures that are produced from 2D TMDs are summarized. In order to improve the functionality of ultrathin 1D TMDs that are coaxially combined with boron nitride nanotubes and single-walled carbon nanotubes. 1D heterostructured devices perform better than 2D TMD nanosheets when the two devices are compared. The photovoltaic effect in WS₂ or MoS₂ NTs without a junction may exceed the Shockley–Queisser limit for the above-band-gap photovoltage generation. Photoelectrochemical hydrogen evolution is accelerated when monolayer WS₂ or MoS₂ NSs are incorporated into a heterojunction. In addition, the photovoltaic performance of the WSe₂/MoS₂ NSs junction is superior to that of the performance of MoS₂ NSs. The summary of the current research about 1D TMDs can be used in a variety of ways, which assists in the development of new types of nanoscale optoelectronic devices. Finally, it also summarizes the current challenges and prospects.     

基于Matlab的光伏阵列数学模型的研究

通过对单体光伏电池的物理模型的研究,给出了易于求解、便于仿真的光伏阵列的数学模型,该模型可以计算在任一环境温度、太阳辐射强度下光伏电池的I-V特性;以该模型为基础,在工程误差允许的范围内,给出了可行的最大功率点的计算公式。Matlab仿真结果表明,光伏阵列的输出特性随温度和光强的变化而变化,并且光伏阵列I-V和P-V特性呈非线性;在不同光强和温度下,光伏阵列最大功率点不同,它能较好地反应光伏阵列的实际特性。     

三相光伏并网电流型PWM逆变器的研究

基于三相电流型PWM逆变器装置,将直接电流控制方法应用于该逆变器中,设计了一套1kW实验装置。通过仿真分析和实验验证表明,该方法不仅实现了逆变器网侧电流正弦化并与网侧电压同相位,而且实现了直流侧电压宽范围调节,提高了系统动态性能,更适合于光伏并网。