光伏阵列安装角度与安装节距的优化选择

光伏发电系统安装地点确定之后,其发电量主要受到光伏组件安装倾角和节距的影响。文章首先建立了光伏电池发电模型和斜面上的辐照度模型,以西安某公司的光伏发电系统为例,计算了不同倾角和节距下光伏阵列的年发电量。结果表明:在没有阴影遮挡的情况下,光伏组件在西安地区的最佳安装倾角为32°;在有阴影遮挡的情况下,节距越小,最佳倾角越小。光伏阵列的节距减小时,组件的发电量减少,利用效率降低。但是,由于组件安装量增多,单个组件占地面积减少,总安装容量增大,发电量增大。此计算方法可为光伏组件安装倾角和节距的选择提供参考。     

山地光伏电站的近场阴影模拟研究

结合复杂山地地形条件下光伏组件的布置方案，基于PVsyst软件和Helios 3D软件建立了山地光伏电站三维近场阴影仿真模型，以模拟计算近场阴影遮挡损失修正系数；另外根据项目建设区域内实际的光伏组件倾角和光伏方阵方位角，结合光伏电站朝向替代计算，得到近场阴影遮挡损失修正系数；最后对3种计算方案得到的近场阴影遮挡损失修正系数与该项目实际值进行对比。研究结果表明：由于山地光伏电站项目建设区域地形中的坡度、坡向变化对光伏组件倾角、光伏方阵方位角存在影响，导致山地场景下的近场阴影遮挡损失修正系数比平地场景下的更大。提出的Helios 3D模拟计算方案和公式计算方案同样适用于其他山地光伏电站，可以对特定地形条件下光伏发电系统的阴影情况进行模拟，以评估光伏组件倾角、光伏方阵方位角对近场阴影遮挡损失修正系数的影响，可为精细化评估山地光伏电站中光伏组件布置方案对近场阴影遮挡损失修正系数的影响程度提供合理的分析、研究方案。     

基于PVsyst的太阳能光伏电池电气特性的仿真研究

在不同辐照强度和光伏电池温度、有无旁路二极管条件下,利用光伏软件PVsyst对多晶硅光伏电池组件及其单体电池的反向特性进行了研究,对不同旁路二极管数量、局部电池不同阴影率条件下的光伏组件输出特性进行了仿真。基于辐照强度、电池温度、旁路二极管对光伏组件及其电池反向特性的影响,对旁路二极管和局部电池阴影率对光伏组件发电性能的影响进行了分析。研究结果表明:当光伏电池加反向恒定电压时,随辐照强度、电池温度升高,流过电池的电流逐渐升高;当无旁路二极管的光伏组件加反向电压时,随反向电压升高,电流升高缓慢,当带旁路二极管的光伏组件加反向电压时,旁路二极管导通,电流急剧升高;当光伏组件局部电池被遮挡时随旁路二极管数量增加,光伏组件功率损失逐渐减小,当光伏组件无旁路二极管时随光伏组件局部电池阴影率升高,光伏组件输出功率持续下降。     

阴影遮蔽条件下光伏发电效率的增大方法

受阴影遮蔽影响,光伏阵列输出功率下降,功率曲线呈现多峰值,使传统的最大功率点(MPPT)算法失效陷入局部极值点。基于光伏电池的等效电路模型,在正常和有阴影遮蔽情况下对光伏组件串并联输出特性进行仿真,分析功率曲线上局部极值点的产生原因及变化规律。针对阴影遮蔽对光伏发电效率的影响,提出建立微型光伏发电系统,采用光伏组件间解耦的方法,跟踪每个光伏组件的最大功率点,使光伏发电效率达到最优。试验结果验证了该方法的可行性,为今后光伏电站的建设提供了指导。     

吕梁市光伏发电系统效率提升研究

对影响光伏发电系统发电量的因素进行了研究,通过实验方法确定了倾角、方位角和局部阴影遮挡对吕梁市光伏组件发电量的影响.结果表明:在接近地理纬度的角度范围内,倾角对光伏组件发电功率的影响在12％左右;调整方位角对光伏组件功率的影响较大,在合理跟踪方位角的情况下,可使光伏组件发电功率增长1倍;遮挡对光伏组件的发电功率影响很大...     

考虑多点局部阴影的光伏阵列建模及复合型最大功率跟踪算法研究

构成光伏组件的每个光伏电池在运行中由于制造、遮挡等因素的影响,其输出会有差异。当若干个光伏电池受到不同程度阴影遮挡导致其输出与正常电池有较大差异的时候,组件输出的P-U曲线会出现多峰情况,针对单峰的传统最大功率点跟踪(Maximum Power Point Tracking,MPPT)策略很可能失效,从而陷入局部最优值。为解决该问题,推导了多点局部阴影下的光伏阵列数学模型,该模型能够理想描述任意阴影情况下的阵列输出特性曲线。基于此模型,提出了结合全局扫描法、电导增量法,以及快速逼近公式的复合型MPPT算法,并进行了仿真验证。仿真结果表明:相比于传统算法,算法在光伏组件受到遮挡时不会陷入局部最优;同时,相比于全局搜索法,该算法寻优效率更高。     

积灰对光伏组件发电性能影响的研究

提出了一种评估积灰对光伏组件发电性能影响的有效方法及其数学模型。该方法通过监测光伏发电效率和光伏组件连续积灰的灰尘密度值,建立了输出功率退化数学模型,从理论上说明光伏组件表面积灰对发电效率的影响,为定量研究灰尘影响发电效率提供了理论支撑。搭建了试验平台进行试验研究,验证了输出功率退化数学模型的精度。     

阴影遮挡下光伏组件横竖向放置对发电量的影响

为了提高阴影遮挡时光伏组件的发电量,针对横、竖向放置时光伏组件相互遮挡产生的功率损失,建立了光伏组件在阴影遮挡情况下的数学模型,考虑了光伏组件并联旁路二极管的影响,仿真模拟了阴影遮挡下横、竖向放置时光伏组件的输出特性,进而以某地100kW光伏阵列为例,计算了光伏组件在不同摆放方式、不同倾角与间距下的辐射量、年发电量、阴影损失及年平均效率,为光伏电站的初步设计提供了一定的参考价值。     

光伏电池最大功率点跟踪方法的研究

在光伏发电系统中,为了提高光伏电池的利用效率,需要对光伏电池的最大功率点进行跟踪。分析了在跟踪控制中常见的扰动跟踪法和功率数学模型法,比较了它们的优缺点,并基于这两种方法提出了一种改进的跟踪方法,利用MATLAB对该方法进行了仿真研究,仿真结果验证了该方法的有效性。     

基于新能源集控平台的光伏组件清洗分析系统的设计

灰尘是影响光伏电站发电效率的关键因素之一,其会大幅降低光伏电站的发电量。为降低积灰对光伏电站发电量损失影响的程度,电站需定期清洗光伏组件,因此,基于新能源集控平台设计了一款光伏组件清洗分析系统。该系统通过建立清洗计算模型,提出光伏组件无积灰理论发电量算法,量化了积灰损失发电量,推算光伏组件的最优清洗周期。结果显示：该系统能够为光伏组件清洗提供合理的决策依据。     

Efficiency study of different photovoltaic plant connection schemes under dynamic shading

An important growth in the power of the photovoltaic systems connected to a grid has recently been observed. In spite of the advances in module technology, the problems in the system design increased, especially regarding the surface of the earth they occupy. In this work we propose a complete model for plant simulation with different wiring diagrams and under dynamic shading. Results obtained from simulations showed that the configuration with the lowest performance was that of only one serial-parallel group, whereas the highest efficiency corresponded to a design of groups of modules in parallel connected then in series. In general, a higher efficiency was obtained diminishing the quantity of modules in series and increasing their number in parallel. The simulation model proposed allows exploring different alternatives of wiring modules and finding the most efficient configurations for photovoltaic plants of medium and high power.     

Reliable and efficient approach for mitigating the shading effect on photovoltaic module based on Modified Artificial Bee Colony algorithm

The operation and performance of a photovoltaic system (PV) are affected by some factors such as; solar radiation, ambient temperature, PV array configuration and shadow which may be either completely or partially. The partially shadow is caused by clouds, trees due to wind, neighboring buildings and utilities. The shadow effect causes the multiple local maximum power points in the PV module voltage-power characteristics and only one Global Maximum Power Point (GMPP); additionally the shadowing causes high power loss in the shaded cells and produces hot spot. In this paper a new optimization approach based on proposed Modified Artificial Bee Colony (MABC) algorithm is used to solve a proposed constrained objective function of PV module power loss and mitigate the shading effect. The proposed MABC is compared with GA, PSO and ABC. The obtained results proved that the MABC is the most efficient algorithm in solving the objective function that mitigating the power loss in the PV module under partially shading effect.     

光伏组件表面积灰对其发电性能的影响

利用计算机模拟的方法对有灰尘沉积的光伏组件输出性能进行研究,采用MATLAB／SIMULINK模拟灰尘沉积对光伏组件输出性能的影响,得到不同灰尘沉积情况下的光伏组件的输出特性曲线,由特性曲线可以看出,随着灰尘沉积的增多,最大功率点功率下降明显。在理论研究的基础上,搭建实验平台进行实验研究,结果证明仿真结果是有效可信的。     

局部阴影下光伏阵列的建模与仿真分析

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。     

Photovoltaic solar system connected to the electric power grid operating as active power generator and reactive power compensator

In the case of photovoltaic (PV) systems acting as distributed generation (DG) systems, the DC energy that is produced is fed to the grid through the power-conditioning unit (inverter). The majority of contemporary inverters used in DG systems are current source inverters (CSI) operating at unity power factor. If, however, we assume that voltage source inverters (VSI) can replace CSIs, we can generate reactive power proportionally to the remaining unused capacity at any given time. According to the theory of instantaneous power, the inverter reactive power can be regulated by changing the amplitude of its output voltage. In addition, the inverter active power can be adjusted by modifying the phase angle of its output voltage. Based on such theory, both the active power supply and the reactive power compensation (RPC) can be carried out simultaneously. When the insolation is weak or the PV modules are inoperative at night, the RPC feature of a PV system can still be used to improve the inverter utilisation factor. Some MATLAB simulation results are included here to show the feasibility of the method.     

基于并联光伏组件外特性的最大功率点跟踪方法

当阴影条件变化时,并联光伏组件的全局最大功率点(MPP)会随之改变.为了实现太阳能发电最大化,要求最大功率点跟踪(MPPT)方法始终能实时而准确地锁定住并联光伏组件的全局MPP.不同阴影条件下并联光伏组件会呈现不同的外特性特征,如多阶梯的电流电压特性以及多峰值的功率电压特性.基于此现象,该文提出一种基于并联光伏组件外特...     

自然降雨下光伏组件积灰预测方法研究

为了预测光伏组件上的积灰量,以相关气象因素为输入变量,基于最小二乘支持向量机(LSSVM)预测算法,并通过改进粒子群算法(PSO)中惯性因子的衰减方式提高预测算法寻优鲁棒性。在积灰预测模型中考虑当地时空因素,引入强相关的降雨量,并结合光伏组件发电功率衰减率,建立自然降雨清洗下的积灰预测模型。在杭州地区进行测量实验,通过实例计算表明此模型可快速预测统计周期内光伏组件积灰量以及积灰引起功率衰减率,为精准预测光伏发电功率和制定组件清洁频率提供依据。     

Analysis of spatial fixed PV arrays configurations to maximize energy harvesting in BIPV applications

This paper presents a new approach for efficient utilization of building integrated photovoltaic (BIPV) systems under partial shading conditions in urban areas. The aim of this study is to find out the best electrical configuration by analyzing annual energy generation of the same BIPV system, in terms of nominal power, without changing physical locations of the PV modules in the PV arrays. For this purpose, the spatial structure of the PV system including the PV modules and the surrounding obstacles is taken into account on the basis of virtual reality environment. In this study, chimneys which are located on the residential roof-top area are considered to create the effect of shading over the PV array. The locations of PV modules are kept stationary, which is the main point of this paper, while comparing the performances of the configurations with the same surrounding obstacles that causes partial shading conditions. The same spatial structure with twelve distinct PV array configurations is considered. The same settling conditions on the roof-top area allow fair comparisons between PV array configurations. The payback time analysis is also performed with considering local and global maximum power points (MPPs) of PV arrays by comparing the annual energy yield of the different configurations.     

Differentiation of multiple maximum power points of partially shaded photovoltaic power generators

Partial shading conditions have a major effect on the electrical characteristics of photovoltaic (PV) power generators. In this paper, the effects of partial shading on maximum power points (MPPs) of a PV power generator have been systematically studied by using Simulink simulation model of a PV power generator composed of 18 series-connected PV modules. It is shown that the local MPPs can be classified into MPPs at low and high voltages based on the MPP operating point of the PV generator. The results also show that based on the MPP current and voltage it is possible to directly know if the MPP at high voltages is a local or a global MPP. The differentiation between local and global MPPs at high voltages is based on the voltage difference between the actual MPP voltage at high voltages and the theoretical MPP voltage under corresponding uniform conditions. This differentiation method was also tested to work correctly by utilizing experimental measurements of the Tampere University of Technology Solar PV Power Station Research Plant. By using this method, it can be identified if the system is operating at a local or a global MPP. This method can further be utilized to develop global MPP tracking algorithms.     

中国馆世博中心主题馆太阳能应用技术

文章介绍了上海世博会永久场馆中国馆、世博中心、主题馆太阳能应用,包括光伏建筑一体化应用形式、光伏建筑一体化组件等。理论计算了中国馆、主题馆、世博中心光伏系统发电量及CO2减排。