共查询到19条相似文献,搜索用时 46 毫秒
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为研究局部阴影效应对光伏发电系统的影响,首先建立了光伏阵列工程数学模型,分析局部阴影条件下光伏阵列的输出特性。为了便于工程分析,该文利用PVSYST软件分析比较单晶硅、多晶硅和薄膜电池等3种不同材料光伏电池在局部阴影条件下的输出功率,为工程应用提供了良好的指导作用。最后提出了几种提高光伏阵列抗局部阴影能力的措施。 相似文献
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基于五参数光伏模型,在Matlab/Simulink平台中建立了该模型的计算模块,通过与制造商技术数据及一种四参数模型的对比实验表明,该模型具有极佳的准确度,整体最大功率偏差在1%以内,最大功率点电压偏差在0.5%以内。通过该五参数模型可准确得出光伏组件的特性曲线,为光伏系统研究提供了一个方便快速、准确度高又具有通用性的光伏模型。 相似文献
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针对传统BP神经网络在光伏阵列故障诊断时受初始权值阈值的影响,易导致全局搜索过程陷入局部最优这一问题,提出了一种基于改进麻雀搜索算法优化RBF神经网络(ISSA-RBF)的光伏故障诊断方法。首先,利用Matlab建立光伏阵列故障仿真模型,提取出故障诊断模型的特征参数;其次,融入Levy飞行和自适应权重φ对麻雀搜索算法进行改进,用优化后的算法建立ISSA-RBF故障诊断模型;最后,与传统BP和SSA-RBF模型进行对比验证,实验结果表明,ISSA-RBF模型在故障诊断精度上达到94.8%,可以有效诊断光伏阵列的故障类型。 相似文献
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基于MATLAB/Simulink中的S-Function Builder模块,所建立的光伏组件仿真模型利用C语言将简化的光伏组件数学模型编程,再与其他Simulink模块连接成电路以仿真电路性能。该仿真模型输出结果与户外实测光伏组件电流电压特性曲线比较结果显示出了良好的一致性,最大功率点处误差最大约为1.8%,可满足科研精度的要求。特别是该光伏组件仿真模型还可在Simulink中串联为光伏阵列,并对局部阴影下光伏阵列输出特性进行较好的仿真。 相似文献
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基于当前各种主流数字式光伏阵列模拟器的优缺点进行比较分析,提出一种新的拓扑结构:单相PWM整流器加电流可逆型斩波电路,整个模拟器的功率开关器件仅需一个IPM模块,结构紧凑。PWM整流器取代二极管整流电路,可降低电网的谐波污染;电流可逆型斩波电路取代Buck电路或桥式变流电路,可克服后者无法空载运行、结构复杂的缺点。对于电流可逆型斩波电路,在传统的电流环比例积分调节器基础上,提出一种基于负载电压前馈的电流环比例积分调节器,提高系统的快速性;对模拟器的数学模型和传递函数进行详细分析,定量给出调节器的参数整定方法。3kW光伏模拟器样机的实验结果验证了提出的主电路、控制算法的有效性和稳定性。 相似文献
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利用户用光伏发电系统开发偏远地区太阳能资源,可以有效解决该地区用电难问题,有必要建立户用光伏发电系统的仿真模型。在电力系统电磁暂态软件EMTP/ATP仿真环境下,建立了随机光照、温度、太阳能电池等仿真模型,同时结合Cuk斩波电路、蓄电池、PWM单向逆变器等,构建了简单的户用光伏发电系统,并对该系统在离网运行模式下的运行特性进行了研究,仿真结果验证了模型的有效性。 相似文献
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基于Matlab/Simulink软件建立了光伏发电系统的仿真模型,在此模型上分别模拟了电源侧扰动和电网侧扰动,通过分析扰动下光伏系统输出特性的变化情况,研究了暂态干扰下光伏发电系统的故障特性。 相似文献
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摘要: 针对局部阴影下光伏阵列出现多峰值输出的情况,提出一种优化粒子群算法与模糊控制扰动观察法相结合的最大功率点追踪方法。利用优化粒子群算法在全局范围内寻找极值点及最大功率点;通过设置语言变量、定义模糊子集及模糊控制推理,进行跟踪调节和稳定控制,实现光伏系统最大功率输出。提高了搜寻精度,缩短了搜寻时间,避免了在最大功率点处的震荡。仿真结果验证了所提算法的有效性和合理性。 相似文献
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Vasillaq Kacani 《能源与动力工程:英文版》2013,(8):1578-1585
During the start-up and shut-down phase of reciprocating compressors, the loads on all components of driven train system are very high. In this paper a method for calculating the forces on coupling, e-motor, crank shaft as well other components of the system will be described. The modelling of the electrical induction motor, coupling, crank shaft, damper as well as the compressor resistance torque are extremely important in simulating start-up and shut-down of reciprocating compressor. Furthermore the switching torque of the electrical motor and the instantaneous moment of inertia of the reciprocating compressor crank gear are important as well. The transient start-up and shut-down process under loaded and unloaded conditions is described using a non-linear differential equation for driven train system: E-motor--coupling--flywheel--reciprocating compressor--damper. Shaft torsional moments on the drive train and especially on the coupling, whether elastic or stiff, can then only be calculated using numerical simulation. This paper will describe some of the key elements in modelling, simulating and measurements of drive train start-up and shut-down carried out on already operational piston compressor units. 相似文献
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Experimental studies were performed to investigate the flow patterns of liquid films of R-134a on vertical arrays of horizontal tubes under adiabatic test conditions at room temperature and during condensation at a saturation temperature of 304 K. Three arrays with tube pitches of 25.5, 28.6, and 44.5 mm and up to ten tubes of four commercially available copper tubes with a nominal diameter of 19.05 mm and 544 mm in length were tested: a plain tube, a 26 fpi/1024 fpm low finned tube (Turbo-Chil), and two tubes with three-dimensional enhanced surface structures (Turbo-CSL and Gewa-C). Flow pattern observations and transitions were obtained and compared to existing flow pattern maps. The effect of the flow pattern on heat transfer was also investigated. The ideal flow modes (droplet, column, and sheet) could strictly be observed on the tubes with 3D enhanced surface structures. On the low-finned tube and the plain tube, the flow was very unstable, causing a part of liquid to leave the array sideways. For the 3D enhanced tubes, a difference in the formation of the sheets could be seen. The Gewa-C tube tended to form small sheets, while the Turbo-CSL formed large sheets at low film Reynolds numbers. A cyclic forward and backward motion of the sheet was observed that increased in amplitude with an increasing film Reynolds number. At high film Reynolds numbers, part of the liquid left the array of tubes sideways due to this oscillation, the effect of which on heat transfer was found to be more significant than the effect of the flow modes themselves. 相似文献
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针对某3缸增压小型化汽油机,基于一维和三维发动机循环仿真,分别研究了进气门早关(EIVC)和进气门晚关(LIVC)两种米勒循环形式对发动机油耗、爆震及燃烧特性的影响。结果表明:两种米勒循环形式均能有效降低全工况范围的燃油消耗率,平均降幅约为8%。与LIVC相比,低负荷时EIVC具有更大的节气门开度和进气压力,故泵气损失相对较小,具有更好的燃油经济性;而在高负荷区域,EIVC会显著降低缸内滚流和压缩终了时的湍动能,导致燃烧变慢,CA50相比LIVC滞后2.5°曲轴转角,燃油经济性和爆震抑制作用较差。 相似文献