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.     

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。     

基于PVsyst的山地光伏系统设计与优化

针对山地光伏电站建设的技术难点进行分析,在提高山地光伏电站的效率、降低成本、保证系统运行安全的情况下,对徐州鼓楼区九里山南山坡太阳能光伏电站的系统进行设计与建设,对组件的排布方式、阵列间距、组件的支架与基础设计、系统设备的选型、方阵阴影分析、电站发电量与节能减排进行优化设计与计算。     

Implementation of photovoltaic array MPPT through fixed step predictive control technique

This paper proposes the implementation of Photovoltaic (PV) array Maximum Power Point Tracker (MPPT) through Fixed Step-Model Predictive Controller (FS MPC). The proposed controller scheme is based on the modified INcremental Conductance (INC) algorithm combined with the two-step horizon FS MPC. The current based INC algorithm is subject to major modifications in order to be capable of real time interaction between the MPPT and the controller obtaining sufficient information in one sampling time. The developed technique has been incorporated into a model for the overall simulation of the performance of a PV array for solar energy exploitation and is compared to the conventional approach under solar radiation variation improving PV system utilization efficiency and enabling to optimize system performance. This study also illustrates the effectiveness of the proposed controller scheme under various sky conditions with a simulation model employing real solar radiation data.     

Maximum photovoltaic power tracking for the PV array using the fractional-order incremental conductance method

This paper proposes maximum photovoltaic power tracking (MPPT) for the photovoltaic (PV) array using the fractional-order incremental conductance method (FOICM). Since the PV array has low conversion efficiency, and the output power of PV array depends on the operation environments, such as various solar radiation, environment temperature, and weather conditions. Maximum charging power can be increased to a battery using a MPPT algorithm. The energy conversion of the absorbed solar light and cell temperature is directly transferred to the semiconductor, but electricity conduction has anomalous diffusion phenomena in inhomogeneous material. FOICM can provide a dynamic mathematical model to describe non-linear characteristics. The fractional-order incremental change as dynamic variable is used to adjust the PV array voltage toward the maximum power point. For a small-scale PV conversion system, the proposed method is validated by simulation with different operation environments. Compared with traditional methods, experimental results demonstrate the short tracking time and the practicality in MPPT of PV array.     

SolarPV 3D在光电建筑中光伏发电系统设计时的应用研究

自主开发了一款基于SketchUp软件的三维数字化设计插件SolarPV 3D,并对该插件的主要算法进行了介绍,算法包括光伏阵列自动化布置算法和逐时阴影遮挡计算方法,解决了光伏发电系统数字化设计过程中的关键技术难题,并提高了其设计效率.以河海大学常州校区英才楼的屋面光伏发电系统布置为例,结合无人机拍照三维成像技术及So...     

光伏电站太阳能电池阵列间距的计算

用两种方法探讨了太阳能光伏电站设计中的太阳电池阵列间距的计算方式。分析表明,当阵列高度一定时,后排电池阵列上不出现前排电池阵列的阴影的最小距离与太阳高度角密切相关。最后,导出了可供光伏电站设计参考的理论计算式。     

跟踪式光伏发电系统研究

根据某地实测的太阳辐射数据,仿真比较了配备有单轴跟踪和双轴跟踪等4种跟踪控制的光伏发电系统与固定式光伏发电系统的太阳辐射利用率。并在此基础上对4种跟踪系统的跟踪角控制规律及跟踪控制方式进行了详细的分析,得出倾纬度角单轴跟踪系统控制规律最为简单,算法实施更为实用的结论。同时,也在理论上证明了采用步进式控制方式的跟踪系统能够在保持较高太阳辐射利用率情况下简化控制系统设计,有利于工程设计及应用。     

光伏电站中可调支架系统经济技术分析

通过建立太阳能辐射数据库,优化可调光伏支架的接收角度,以提高光伏系统发电效率,改善传统的固定倾角支架和自动跟踪支架模式。文章以沈阳地区10 MW并网电站为例,比较了每年以不同次数手动调节支架与固定倾角支架的发电量。经济技术分析显示,每年调整支架倾角12次的年发电量最多,每年调整倾角4次的经济效益最好。     

双面组件光伏电站最优容配比的研究

通过对采用双面光伏组件的光伏电站(以下简称"双面组件光伏电站")系统效率损失进行分析,发现在光伏组件-逆变器容配比(下文简称"容配比")变化的情况下,逆变器过载损失对此类光伏电站发电量的影响最大.提出了双面组件光伏电站容配比的优化方法,并以太阳能资源Ⅰ、Ⅱ、Ⅲ类地区的典型城市为例,进行了不同容配比和背景反射率下双面组件...     

基于BIM的光伏电站自动化布置及发电量评估

对光伏电站自动化布置的区域填充算法以及进行阴影分析的射线检测算法进行研究,进而以BIM技术为基础在Sketchup平台上实现光伏组件自动参数化布置及逐时阴影遮挡分析功能,并和实际电站的性能进行比较。研究结果表明：自动化布置算法和阴影分析算法符合电站实际应用情况,相对于传统的光伏电站性能模拟方法可视化性能有明显提升,此外基于实测气象数据模拟电站全年发电量和实测发电量的差异约为1.5%,具有一定精度。     

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。     

On the investigation of photovoltaic output power reduction due to dust accumulation and weather conditions

Certain environmental conditions such as accumulation of dust and change in weather conditions affect the amount of solar radiation received by photovoltaic (PV) panel surfaces and thus have a significant effect on panel efficiency. This study conducted an experimental investigation in Surabaya, Indonesia, on the effect of these factors on output PV power reduction from the surface of a PV module. The module was exposed to outside weather conditions and connected to a measurement system developed using a rule-based model to identify different environmental conditions. The rule-based model, a clear sky solar irradiance model that included solar position, and a PV temperature model were then used to estimate the PV output power, and tests were also conducted using an ARM Cortex-M4 microcontroller STM32F407 as a standalone digital controller equipped with voltage, current, temperature, and humidity sensors to measure real time PV output power. In this system, humidity was monitored to identify dusty, cloudy, and rainy conditions. Validated test results demonstrate that the prediction error of PV power output based on the model is 3.6% compared to field measurements under clean surface conditions. The effects of dust accumulation and weather conditions on PV panel power output were then analyzed after one to four weeks of exposure. Results revealed that two weeks of dust accumulation caused a PV power output reduction of 10.8% in an average relative humidity of 52.24%. Results of the experiment under rainy conditions revealed a decrease in PV output power of more than 40% in average relative humidity of 76.32%, and a decrease in output power during cloudy conditions of more than 45% in an average relative humidity of 60.45% was observed. This study reveals that local environmental conditions, i.e., dust, rain, and partial cloud, significantly reduce PV power output.     

并网型分布式光伏电站待机运行状态下的降损优化策略

光伏发电的输出功率存在明显的间歇性和波动性,其不参与电力平衡调节,只提供电量价值,不提供容量价值。因此针对分布式光伏电站的研究主要集中在提升系统发电量和发电效率等方面,而对于分布式光伏电站在夜间不发电的待机运行状态,即处于并网状态但无发电功率输出情况下的电站模型未形成完整的分析论证。选取典型的已并网分布式光伏电站,对其待机运行状态下各类负荷进行分类,通过理论建模计算,并结合电站实际运行数据做对比性验证,分析其理论损耗电量与实际损耗电量的偏差及损耗电量占总发电量的构成比例,据此推导出降低损耗的路径。经实测,在满足分布式光伏电站安全运行的条件下,通过改变原有系统运行方式、降低设备空载运行时间等策略,可达到降低待机损耗电量的效果,电站整体发电量提升约1%,获得了更好的财务收益率。     

Time dependent model of a complex PV water pumping system

A complex time-dependent solar water pumping system is analysed in this paper. Several existing models (e.g. for the PV cell, the battery and the assembly electric motor—centrifugal pump) are used. New models are proposed for PV array and water storage tank operation. The system has two main operating modes, which depend on the level of the incident solar global irradiance. The mathematical model consists of systems of eight or five ordinary differential equations, as a function of the operating mode. Using a water storage tank improves the stability of PV pumping system operation. The mechanical power stored in the water tank is rather constant during the year. The fraction of collected solar energy that is stored in the water’s gravitational energy is higher during the winter months, during the cloudy days and around sunrise and sunset. It is smaller during the summer months, during the clear sky days and in the middle of the day. The fraction of the power supplied by the battery that is stored in the gravitational energy of water is almost constant during the year.     

A note on diffuse solar radiation on a tilted surface

We are presenting a note on comparative study of diffuse component of solar radiation on tilted surface with different angle of inclination. The monthly mean daily diffuse radiation have been calculated on inclined surfaces from the data of horizontal surface using the Circumsolar and Isotropic model and the anisotropic model of Klucher and Hay at Lucknow (Latitude 26.75°, Longitude 80.85°), Uttar Pradesh, India. These calculated results are compared with our measured value. The comparison shows that Klucher model who considered the effect of cloudy sky conditions gives comparatively good estimations particularly at low inclination angles.     

New maximum power point tracker for PV arrays using fuzzy controller in close cooperation with fuzzy cognitive networks

The studies on the photovoltaic (PV) generation are extensively increasing, since it is considered as an essentially inexhaustible and broadly available energy resource. However, the output power induced in the photovoltaic modules depends on solar radiation and temperature of the solar cells. Therefore, to maximize the efficiency of the renewable energy system, it is necessary to track the maximum power point of the PV array. In this paper, a maximum power point tracker using fuzzy set theory is presented to improve energy conversion efficiency. A new method is proposed, by using a fuzzy cognitive network, which is in close cooperation with the presented fuzzy controller. The new method gives a very good maximum power operation of any PV array under different conditions such as changing insolation and temperature. The simulation studies show the effectiveness of the proposed algorithm.     

抛罩-展开期间航天器太阳电池阵温度场的数值模拟

将太阳电池板中发生的辐射-传导复合传热过程等效为一个无内热源的三维瞬态热传导问题。根据实测数据得出太阳电池板的三维等效导热系数。针对任意两相邻电池板表面间的热辐射交换规律，构造适用于这两个表面内节点温度的离散方程系数。研究折叠状太阳电池阵边界节点的热特点时，仔细考虑了地球红外辐照、太阳辐射加热、航天器舱体几何遮挡、深冷环境散热、飞行轨道高度及航天器在太阳-地球系中不同位置等造成的影响。采用SIP算法，对离散方程进行了求解。比较了考虑和不考虑地球红外辐射电池阵温度分布的影响。该文的分析对折叠状太阳电池阵展开时刻的认定有重要 的参考价值。     

光伏电源接入500 kV变电站站用电对保护的影响分析

针对光伏电源接入500 kV变电站站用电后对系统保护的影响进行了研究。首先,介绍500 kV变电站站用电的一般接线方式和光伏电源基本模型;然后,根据500 kV变电站工程特点以及光伏布置,分析了光伏电源的发电功率、光伏电源的接入方案。最后,基于实际500 kV变电站站用电参数,搭建了光伏电源接入站用电的Matlab仿真模型。通过在该仿真模型上进行了短路故障仿真计算,分析了光伏电源接入对站用电保护系统的影响,并提出了改进的措施。     

CVT光伏泵水系统瞬态工作点特性分析

采用定电压跟踪器（CVT）的光伏水泵系统在不同地区已成功地投入实际应用。实地运行数据表明，CVT不能适应太阳电池阵列伏安特性的变化，使系统瞬态工作点偏离阵列输出最大功率点，导致系统功率损失。该文报道了2.5kWp，光伏水泵系统的基本构成和典型实地运行数据，并对系统瞬态工作点特性进行了分析讨论。