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太阳能光伏发电系统作为一个复杂系统,其中光伏阵列拓扑结构对整个系统的成本和效率有着重要的影响,它也关系着发电系统能否经济可靠地运行。对比分析了几种常见的光伏阵列拓扑结构,并对常见失配条件下阵列输出功率的仿真结果进行分析。分析研究表明阵列拓扑结构对光伏系统输出功率和成本有很大影响,这些研究为光伏阵列拓扑的设计提供了参考。 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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当光伏阵列受到不均匀光照时,输出的功率电压曲线含有多个局域峰值。针对此光照不均匀情况,建立光伏阵列多峰数学模型,并提出一种最大功率跟踪控制方法。采用连续函数构建光照不均匀情况下光伏阵列输出功率电压曲线;依次从该曲线的两侧或中部迭代搜索各局部最大功率点,确保在各种光照情况下均获得全局最大功率;通过Matlab仿真实例验证了所提多峰数学模型和最大功率跟踪控制方法的正确性。 相似文献
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以太阳电池尺寸为210 mm×105 mm、电路结构为并串结构的大尺寸光伏组件为例,首先分析单片太阳电池不同阴影遮挡比例时的情况,然后分析光伏组件6种不同阴影遮挡比例和18种典型阴影遮挡位置和形状对大尺寸光伏组件输出特性的影响。结果表明:随着单片太阳电池阴影遮挡比例不断增大,二极管始终未导通,但光伏组件的最大功率逐渐降低,最后降至初始功率的2/3;阴影遮挡比例对采用并串电路结构的大尺寸光伏组件的I-V特性的影响是非线性的。对于整块光伏组件而言,阴影遮挡比例越大,光伏组件的最大功率越小;在同一阴影遮挡比例下,集中阴影遮挡对光伏组件最大功率损失的影响更大。 相似文献
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该文通过数学建模研究雾霾相对湿度和质量浓度对辐照度的影响规律,并通过实验验证雾霾的相对湿度和质量浓度对辐照度和光伏组件输出功率的影响规律。实验结果表明:雾的相对湿度(RH)从23%上升至90%,辐照度下降52.17%,光伏组件输出功率下降46.5%,在相对湿度达到65%之后辐照度和功率下降幅度加快;霾质量浓度从18μg/m3增加至517μg/m3,RH=30%、50%、60%、75%、80%、90%时辐照度分别下降16.0%、25.0%、40.0%、74.4%、73.1%、68.6%,光伏组件输出功率分别下降21.8%、22.5%、35%、69.9%、70.1%、67.7%;RH从30%增加至90%,霾质量浓度为108、189、312、405、497μg/m3时辐照度分别下降60.0%、78.8%、800.%、85.1%、85.8%,光伏组件输出功率分别下降47.4%、73.3%、78.1%、82.5%、84.9%,随着RH的增大辐照度和输出功率的降幅在逐渐增大。关于雾的相对湿度和雾霾质量浓度对辐照度的影响进行数值模拟,... 相似文献
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A. Zegaoui M. Aillerie P. Petit J.P. Sawicki J.P. Charles A.W. Belarbi 《Solar Energy》2011,85(11):2953-2964
Maximum power point trackers (MPPTs) have a decisive role to extract power from the photovoltaic (PV) generators as they have to assume the maximum power output (MPP) whatever are the continuous changes of temperature and irradiation conditions. Therefore, they take a prior place in the global PV system efficiency. These trackers are driven by MPPT algorithms and lot of these MPPT algorithms are proposed in literature. The two most common implemented algorithms for power optimisation are the Perturb and Observe (P&O) and the Incremental of Conductance (IncCond) algorithms, which present a high simplicity of implementation within electronics programmable circuits. With an approach based on realistic parameters such as those found when the generator is integrated in a real photovoltaic installation, the two MPPT techniques are dynamically compared using testing procedures developed with Matlab/Simulink. The study leads us to conclude that both algorithms can be performed for PV exposures in unfavourable but realistic external conditions. 相似文献
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利用光伏电池数据手册提供的标准测试条件下的开路电压、短路电流、最大功率点电压和最大功率点电流,得到光伏电池的详细模型参数;提出一种光伏电池模型的等效并联电阻和串联电阻的估算新方法。利用数据手册中的光伏电池短路电流和开路电压温度系数,得到了任意光强和任意温度下的光伏电池模型。为降低求解隐函数模型方程的复杂性,采用近似方法求解隐函数超越方程,得到了光伏电池模型显函数表达式。通过与两种光伏电池在不同光强和温度下的测试数据及同类模型的比较,验证了所提出的模型及参数估算方法的正确性、有效性,具有较高的精度。 相似文献
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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。 相似文献
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Partial shading decreases the power output of PV arrays due to mismatch losses. These losses are dependent on the shading pattern and the relative positions of shaded modules in the array. Various static and dynamic reconfiguration techniques have earlier been proposed to mitigate these losses. In an earlier proposed static reconfiguration technique, the power generation is enhanced by altering the physical location of the PV panels using a random Sudoku configuration without modifying the TCT (Total-Cross-Tied) based electrical connections. However, this arrangement faces drawbacks due to ineffective dispersion of shade and significant increase in wiring required. In this work, an optimal Sudoku arrangement to overcome these drawbacks is formulated. Further analysis indicate that the global peak of the optimal Sudoku based PV array occurs as the right most peak in the curve for most shading conditions, thus evidently obviating the need for complex MPPT (Maximum-Power-Point-Tracking) algorithms. The proposed configuration is compared with various other existing reconfiguration schemes in terms of power output and the comparison is presented. In addition, a general formulation is proposed to expand this pattern to any generic array. A strategy is also proposed to make such an interconnection practicable for very large size PV arrays. 相似文献
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Partial shading is a common phenomenon in PV arrays. They drastically reduce the power output because of mismatch losses, which are reliant on the shape of the shade as well as the locations of shaded panels in the array. The power output can be improved by distributing the shade over various rows to maximize the current entering the node. A Su-Do-Ku configuration can be used to rearrange the physical locations of the PV modules in a total cross tied PV array with the electrical connections left unchanged. However, this arrangement increases the length of the wire required to interconnect the panels thus increasing the line losses. In this paper, an improved Su-Do-Ku arrangement that reduces the length of the wire required for the connection is proposed. The system is designed and simulated in a Matlab/Simulink environment for various shading patterns and the efficacies of various arrangements are compared. The results prove that the power output is higher in the proposed improved Su-Do-Ku reconfiguration technique compared to the earlier proposed Su-Do-Ku technique. 相似文献
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The pore structure of Xilingol lignite irradiated by microwave was investigated to determine drying time, microwave power level, and mineral composition. Pore structure was also determined using N2 adsorption/desorption as well as scanning electric microscopy. The results show that as microwave power increases from 400 W to 800 W, and irradiation time increases from 4 to 16 min, the specific surface area of lignite samples increases, average pore diameter and total pore volume decreases, and the percentage of mesopores increases. The pore volumes, average pore diameters, and special surface area in the center of the lignite sample were greater than those in the outer layers, while the percentage of mesopores decreased slightly. The cluster structure of the lignite samples is simpler and the surface neater, while flat and fibrous structures remain the same. Evolution mechanisms for pore structures during microwave drying were similar, and include structural collapse caused by shrinkage forces resulting from the removal of moisture, the opening and crosslinking of blind and closed pores, and the thermal decomposition of organic macromolecular structures under high temperatures. 相似文献
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Simulation is of primal importance in the prediction of the produced power and automatic fault detection in PV grid-connected systems (PVGCS). The accuracy of simulation results depends on the models used for main components of the PV system, especially for the PV module. The present paper compares two PV array models, the five-parameter model (5PM) and the Sandia Array Performance Model (SAPM). Five different algorithms are used for estimating the unknown parameters of both PV models in order to see how they affect the accuracy of simulations in reproducing the outdoor behavior of three PVGCS. The arrays of the PVGCS are of three different PV module technologies: Crystalline silicon (c-Si), amorphous silicon (a-Si:H) and micromorph silicon (a-Si:H/μc-Si:H).The accuracy of PV module models based on the five algorithms is evaluated by means of the Route Mean Square Error (RMSE) and the Normalized Mean Absolute Error (NMAE), calculated for different weather conditions (clear sky, semi-cloudy and cloudy days). For both models considered in this study, the best accuracy is obtained from simulations using the estimated values of unknown parameters delivered by the ABC algorithm. Where, the maximum error values of RMSE and NMAE stay below 6.61% and 2.66% respectively. 相似文献