光伏发电的双轴自动跟踪控制系统

如果光伏电池板能自动跟踪太阳,保证太阳光始终垂直于光伏电池板平面,使光伏电池板接受的光通量最大,能大大提高发电量。本文研究了一种基于PLC的光伏电池板自动跟踪系统,通过东西南北4个光线传感器来检测太阳光的方位,将得到的模拟量电压信号转化为数字量信号,使用PLC控制偏转机构中的直流电机正转或反转,带动光伏电池板转动,使光伏电池组件正对太阳光源,从而实现实时跟踪的目的。试验结果表明,该控制系统能准确跟踪光源,光伏发电效率增加30%以上,并且工作性能稳定。     

基于新型拟合算法的光伏阵列模拟器的设计与实现

随着生物能源日益枯竭,越来越多的国家开始重视可再生能源,其中利用太阳能的光伏发电技术受到世界各国的广泛青睐。但是太阳能电池板的昂贵造价,给实验研发带来了一定的经济困难,成为目前光伏产品开发的瓶颈。为减小实验成本,该文设计一种能够满足太阳能电池板输出特性的特殊电源,称为太阳能电池模拟器。分析光伏阵列模拟器的工作原理,并设计该模拟器的算法,同时利用Matlab对其进行仿真验证。最后用实验证实了理论分析的正确性。     

太阳能电池按经纬和时间自跟踪控制器设计

为使太阳能电池板保持与太阳光线垂直,以便提高太阳能电池的光电转换效率,设计了基于经纬和时间控制的太阳能电池板自动跟踪控制系统。采用2级控制方式,即利用高度/方位角全跟踪方式进行粗调、利用光照传感器进行细调。由PC计算出当前太阳位置,并将控制信息通过无线装置发送到现场,现场装置以PC计算的数据作为参考,控制步进电机改变电池板的方向,再通过光照传感器对电池板进行进一步的校正,使太阳能电池板始终保持与太阳光线垂直。通过实验分析,这种自动跟踪式电池板比固定式电池板对太阳能的吸收率可提高49.10%,有助于进一步提高能源的利用率。     

基于双环控制的光伏制氢变流器设计与测试

利用 MATLAB/Simulink建立光伏制氢设备变流器仿真模型,包括太阳能电池板、光伏制氢变流器、蓄电 池、制氢负载组成的完整系统.根据实际现场需求设计仿真模型参数,在光伏制氢变流器的控制部分采用了双环控制,使得太阳能电池板和蓄电池组成的供电系统与制氢负载出现瞬时功率不匹配时,光伏制氢变流器可快速调节太阳能电池板的输出功率以满足制氢负载功率上的匹配.最后搭建硬件平台进行试验验证,进而证明光伏制氢变流器的设计与测试方案的可行性.     

太阳能电源热源一体化系统的设计与开发

从外观结构、能量流向及控制电路等方面设计了太阳能电源热源一体化系统。本系统具有可移动性,配备了滚轮且模拟光源可拆卸,可以在室外工作,在没有任何外接电源的情况下进行太阳能的相关应用。本系统结合了太阳能发电和太阳能发热两方面的技术,其中太阳能电源部分用于为自身供电并可对外输出电能,太阳能热源部分用于产生热能。通过实验测试结果可知,本系统每年可产生691kWh的电能和3047.8kWh的热能。本系统由于可移动且不需外接电源等特点,可满足偏远地区或孤岛等无电网地区的日常生活对热水与电力的需求,也可用于太阳能方面的实验测试。     

太阳发电自动光源跟踪系统

由于不可抗的自然规律,人们不能全天候24小时持续使用太阳能。为了最大程度地利用太阳能,高效能的太阳能电池和先进的太阳发电自动光源跟踪系统必不可少。太阳发电自动光源跟踪系统通过判断不同方向的阳光强度,不断调整至最佳方位,以便太阳能电池面向最强的阳光。太阳发电自动光源跟踪系统凭借多轴运动控制系统,不断调整太阳能电池板,达到最佳的角度和位置,获得最强烈的阳光。     

太阳能电池板充放电测试仪的设计与实现

为了更合理的利用太阳能,设计了太阳能电池板充放电测试仪。通过分压电路采集太能电池板及蓄电池的端电压,采用霍尔电流传感器采集太阳能电池的输出电流及蓄电池的充放电电流;经过模拟多路转换开关CD4052实现对不同电压等级的电池板和蓄电池的电压采集与切换;最终将电流与电压信号经过16位数据采集卡USB5953传输到PC机,并通过LABVIEW平台显示电压电流变化曲线,计算出太阳能电池板的充放电效率。给出了实验测试数据,实现了对48 V、36 V、24 V、12 V太阳能电池板充放电的实时监测。     

白光LED汽车前照灯的光学设计探讨

基于近年来白光LED的发展 ,应用LED光源来设计汽车前照灯已成为可能。虽然LED的输出光通量在逐步提高 ,但它仍不能完全满足汽车前照灯的特殊要求。本文主要讨论了汽车前照灯的光学特性、光学设计原则、光强分布和集中性的要求 ,以及驾驶安全和客户需求 ,同时通过与传统的卤钨灯泡的比较 ,分析了在汽车前照灯中应用LED光源时的一些特殊问题 ,尤其是光学径角性 (Etendue)的定义 ,最后提出了汽车前照灯应用LED光源的一些准则。     

基于TracePro软件的组合反光镜设计与分析

为了提高光源的利用率以及提升光学系统的成像质量,该文设计了一种椭球、球面组合反光镜系统。利用TracePro光学软件建立了组合反光镜模型,并对其进行模拟仿真。仿真结果表明:与传统的椭球反光镜相比,光学组合反光镜能够较大程度地提高光源的利用率。同时还对氙灯光源与组合反光镜系统的应用进行了分析。     

2006年将推出可输出交流电太阳能电池板

日前获悉，光学滤镜和太阳能电池板等产品厂商一日本Fujipream公司成功开发出一种配备了输出转换电路(可将输出电源由直流转换成交流电)的太阳能电池板“hybridsolarpandel(混合太阳能电池板)”。每枚电池板的最大功率为120W，将电池板上伸出的电源线接到家电插头上即可直接使用。经过实地试验后，将于2006年6月建立月产5000枚的量产体制。计划通过互联网和家电商场进行销售。     

影响太阳模拟器测试精度的主要因素

在太阳模拟器使用中参数设置不当或模拟器精度低都会影响测试结果的准确性,得到的组件输出伏安特性曲线往往不能准确反应组件在标准条件下的实际输出特性,影响了组件的测试结果。本文总结了影响太阳模拟器测试的主要因素有太阳模拟器的温度系数值、太阳模拟器的光强值、标准组件的标定值、太阳模拟器的级别等,针对这些主要因素,找到提高测试精度的对策。文章在分析温度系数设置值对测试精度影响的实验中,重点介绍了太阳模拟器温度系数值的设置不当且测试温度偏离25℃时,太阳模拟器测试结果误差变大的问题。研究测试得出了温度系数正确的设定值,使模拟器在15℃～35℃范围内的测试结果误差小于1%。     

Numerical modeling of loss mechanisms resulting from non‐uniform illumination in multijunction concentrator solar cells

Quasi‐3D distributed emitter models utilizing a unit cell‐based methodology have been successfully applied to the analysis of lateral current flow in solar cell emitter layers. However, the analysis of the specific loss mechanisms resulting from this flow has not been given adequate attention. In this work, a quasi‐3D model for the simulation of effects related to the lateral flow of current in a solar cell emitter layer, particularly under non‐uniform illumination, is developed. The model is applied to a specific case in which a GaInP/GaAs‐like two‐terminal solar cell is illuminated with a Lorentzian irradiance pattern, which is the expected pattern for parabolic trough concentrator. It is shown that bias‐point loss, which results from the variation in the local operating condition of the cell, is significant under highly non‐uniform illumination at low–moderate optical concentration. Understanding this loss mechanism is useful in considering trade‐offs related to the design of the optical concentrator system, as well as, the design of a grid electrode pattern for maximum power output. Copyright © 2013 John Wiley & Sons, Ltd.     

Towards the establishment of maximum PV generation limits due to power quality constraints

The solar irradiance dependent level of harmonic distortion due to PV generation is investigated through a combination of experimental and simulation studies. The expected growth of connection densities of PV systems in distribution networks coupled to the environmental conditions and in particular the fluctuations in solar irradiance can lead to undesirable variations of power and supply quality. In order to be able to predict the harmonic pollution due to PV generation, measurements of power quality indices were carried out at the output of a PV system for a period of 2 weeks. Then, a typical distribution system was modeled using the statistically obtained outcome of the measurements from the PV system. From the simulation of the chosen distribution system we obtained results for voltage distortion and categorized them based on solar irradiance levels. The procedure was then validated using the EN50160 analysis approach. The most extreme case, the high solar irradiance condition, was subsequently used for the simulation of different concentration scenarios, in order to assess the concentration limits set by power quality indices and the results are presented.     

Forecasting of solar irradiance with just‐in‐time modeling

PV power output mainly depends on solar irradiance, which is affected by various meteorological factors. Thus, it is required to predict solar irradiance in the future for the efficient operation of PV systems. In this paper we develop a novel approach for solar irradiance forecasting, in which we combine the black–box model (JIT modeling) with the physical model (GPV data). We investigate the predictive accuracy of solar irradiance over a wide controlled area of each electric power company by utilizing measured data from 44 observation points throughout Japan provided by JMA and 64 points around Kanto provided by NEDO. Finally, we propose an applied forecasting method of solar irradiance to deal with difficulties in compiling databases. We also consider the influence of different GPV default times on solar irradiance prediction. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 182(4): 19–28, 2013; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.22338     

Optomechanical Monte Carlo Tolerancing Study of a Packaged Free-Space Intra-MCM Optical Interconnect System

We report on the performance of an intra-multichip-module free-space optical interconnect that integrates microlenses and a deflection prism above a dense optoelectronic chip, under various fabrication and assembly errors. This paper describes the results of a combination of mechanical Monte Carlo analysis and optical simulations. Both the technological requirements to ensure a high process yield, and the specifications of the technology we use at our laboratories to fabricate the microoptical and micromechanical components, deep lithography with protons (DLP), are discussed. Therefore, we first conduct a sensitivity analysis that is subsequently used to set the variances of the random perturbations of the Monte Carlo simulation. By scaling these variances, we are able to investigate the effect of a technology accuracy enhancement on the fabrication and assembly yield. We estimate that 40% of the systems fabricated with DLP will show an optical transmission efficiency above$-4.32$dB, which is$-3.02$dB below the theoretical obtainable value. In this paper, we also discuss our efforts to implement an optomechanical Monte Carlo simulator. It allows us to deal with specific issues not directly related with the microoptical or DLP components, such as the influence of gluing layers and structures that allow for self-alignment, by combining mechanical tolerancing algorithms with optical simulation software. In particular, we determine that DLP provides ample accuracy to meet the requirements of a high manufacturing yield (around 91% meet an optical transmission that is$-0.75$dB below the theoretical maximum). The adhesive bonding of optoelectronic devices in their package, however, is subject to further improvement to enhance the tilt accuracy of the devices with respect to the optical interconnect modules.     

模拟器辐照不均匀度对组件性能测试的影响

总结了脉冲太阳模拟器辐照不均匀度对太阳电池组件电性能测试的影响.通过测试脉冲太阳模拟器有效辐照面内的辐照不均匀度分布情况.然后选取辐照不均匀度最好与最差位置对不同规格组件测试其电性能,进行结果比较、分析、探讨辐照不均匀度变化对各个电性能参数测量误差产生的影响,摸索出减小辐照不均匀度对组件电性能测试误差的有效可行的测试方法.     

太阳能-煤炭互补的发电系统与互补方式

多能源综合互补利用系统是近年来能源系统的发展方向之一。该文进行了太阳能与煤炭互补的发电系统与互补方式研究。分析了太阳能热量用于不同容量燃煤机组不同受热面的热经济性,得出在大容量机组上利用太阳能满足水的汽化潜热吸热热经济性要优越于其他方式;利用技术成熟的抛物面槽式集热器收集太阳能热量,和国产300 MW机组进行互补发电系统的拟定;分析了在这种互补发电方式太阳能场的设计中,影响设计辐射强度选取的主要因素,并以3个地区的辐射资源为例进行研究,得出太阳能辐射资源与最佳设计太阳能辐射强度的关系。     

Integration of a Photovoltaic Panel with an Electric City Car

Abstract—Autonomy of light electric vehicles with limited mobility can be improved by assisting onboard energy sources, such as battery and ultra-capacitors, by solar energy. This article discusses the integration of a photovoltaic panel with an electric city car. The Photovoltaic Geographical Information Systems of Joint Research Center, Europe, is used for estimating the solar irradiance. Based on the estimations, a DC-to-DC boost converter topology is considered to interface the panel with the DC bus of the electric car. Experimental evaluation of the performance is carried out under a real climatic situation. An analytical loss model is used to comment on the associated losses and to explain the measured changes in gain and efficiency under varying irradiance. Acceptable extension in the autonomy of the electric city car is predicted from the results.     

基于光伏MPPT采样电流的自适应变步长INC算法

针对传统电导增量INC（incremental conductance）算法在跟踪最大功率点的过程中无法兼顾跟踪速度与稳态精度的问题,以及传统变步长算法在光照变化时容易发生误判的问题,提出了一种新型的自适应变步长INC算法。光照强度变化较大时,利用负载曲线与I-V特性曲线的工作原理,在暂稳态和非稳态下都可以根据最大功率点跟踪MPPT（maximum power point tracking）采样电流的变化,自适应调节跟踪速度;光照强度变化较小时,能够根据输出电压与功率的变化自适应减小步长,提高稳态精度。追踪速度是传统算法的9.3倍,是现有变步长算法的4.2倍,有效减少了光照强度变化带来的功率损失。     

适用于电网规划的光伏发电概率模型及其应用

提出了一种兼顾短时波动性和中长时间尺度变化规律的光伏电源出力概率模型。采用气象模型基于少量参数即可建立太阳辐照度小时均值在一年内变化的离散概率时间序列模型。采用Beta连续概率分布描述每小时内太阳辐照度相对于均值的随机波动性。所提模型所需统计参数少,能有效反映光伏电源出力时间特性的规律性和随机波动性。将算例结果与实际光伏电站辐照度检测数据进行对比,验证了所提模型的有效性。结合分布式光伏电源接入配电馈线的选址定容规划实例说明了所提模型的应用场景。