Theoretical and Experimental Quantification of Solar Radiation through a Tracking System

This work deals with the estimation of solar radiation through a solar tracker aimed at evaluating the effect of solar tracking on the solar deposit in Burkina Faso. Using a two-axis solar tracking system, we experimentally measured solar radiation at our Joseph KI-ZERBO University site and compared it with that obtained by a numerical simulation run using Fortran programming software based on a mathematical model by Brichambaut. The results obtained from the mathematical and experimental studies show that, with a solar tracker, on a clear-sky day, solar irradiation is between 800 W·m−2 and 1000 W·m−2 between about 8 a.m. and 4 p.m., i.e. a duration of 8 hours of insolation. Analysis of the numerical and experimental results shows very good quantitative and qualitative agreement, with an average relative error of 18%.

Theoretical Comparative Energy Efficiency Analysis of Dual Axis Solar Tracking Systems

This paper developed a theoretical model substantially based on the principle that only the normal component of solar radiation is actually converted into electrical energy. This theoretical model helped to predict minimum and maximum daily energy gain (compared to static PV system tilted with certain angle) when using dual axis PV solar tracking systems, at any given location on earth without prior experimental data. Based on equations derived from model, minimum and maximum energy gain is computed and summarized in tables of minimum and maximum. Furthermore, the model equations could be used to set up future experimental studies related to the matter.

A Sun Tracking System Design for a Large Dish Solar Concentrator

Energy crisis promotes the development of renewable energy, especially the solar energy. Sun tracking system proposed in this paper is such a device for efficiency improvement. This closed loop tracking system with two axis sun tracking method is controlled by a programmable logic controller (PLC) and is used for a large dish solar collector. A combination tracking mode combined active and passive tracking methods used in the design make the tracker efficient whatever the circumstances. Two stepper motors and two reduction boxes move the device towards the sun with chain transmission. Besides sun tracking, the system also has functions of overheat monitoring, wind speed monitoring and measurement of illumination.

Comparative assessment of maximum power point tracking procedures for photovoltaic systems

The fast growing demands and increasing awareness for the environment, PV systems are being rapidly installed for numerous applications.However, one of the important challenges in utilizing a PV source is the maximum power harnessing using various maximum power point tracking techniques available. With the large number of MPPT techniques, each having some merits and demerits, confusion is always there for their proper selection. Discussion on various proposed procedures for maximum power point tracking of photovoltaic array has been done. Based on different parameters analysis of MPPT techniques is carried out. This assessment will serve as a suitable reference for selection, understanding different ways and means of MPPT.

Three-degree-of-freedom Parallel Manipulator to Track the Sun for Concentrated Solar Power Systems

In concentrated solar power（CSP） generating stations, incident solar energy is reflected from a large number of mirrors or heliostats to a faraway receiver. In typical CSP installations, the mirror needs to be moved about two axes independently using two actuators in series with the mirror effectively mounted at a single point. A three degree-of-freedom parallel manipulator, namely the 3-RPS parallel manipulator, is proposed to track the sun. The proposed 3-RPS parallel manipulator supports the load of the mirror, structure and wind loading at three points resulting in less deflection, and thus a much larger mirror can be moved with the required tracking accuracy and without increasing the weight of the support structure. The kinematics equations to determine motion of the actuated prismatic joints in the 3-RPS parallel manipulator such that the sun＇s rays are reflected on to a stationary receiver are developed. Using finite element analysis, it is shown that for same sized mirror, wind loading and maximum deflection requirement, the weight of the support structure is between 15% and 60% less with the 3-RPS parallel manipulator when compared to azimuth-elevation or the target-aligned configurations.

A Novel Roll Compensation Method for Two-Axis Transportable Satellite Antennas

Two-axis transportable satellite antennas(TATSAs) have been widely adopted owing to its simple structure and low cost. However, by searching in a wide range, it will take a very long searching time. Under extreme conditions, it will even fail to work. In this paper, we propose a novel roll compensation(RC) method for the low-cost TATSAs to achieve faster tracking even if when the antenna has no azimuth sensor. By analyzing the influence of roll axis on the system performance, details of the compensation method are derived. Simulation and measurement results indicate that the proposed RC method can effectively reduce the initial searching time for satellite communication. In addition, tracking along with the ellipse path with the RC method provides the highest tracking efficiency.

New Linkage with Linear Actuator for Tracking PV Systems with Large Angular Stroke

This paper focuses on the development of an optimized photovoltaic tracking system involving low-cost, relative simple mechanisms, with linear actuators able to insure strokes comparable with those resulted when using gear rotary actuators. Starting with a rhombus linkage, with a linear actuator on the diagonal used for the elevation motion till 90°, a new performance solution is generated. This new linkage allows large angular strokes by using an asymmetric rhombus and an eccentrically positioned linear actuator. The paper can be divided in three main parts. Firstly the kinematical modeling of the new linkage is addressed, which permits the establishing of the linkage dimensions according to two adjustable parameters （k2, k5）. Using the resulted correlations, in the second part the linkage synthesis algorithm is developed; the steps followed in this algorithm are presented in a numerical application considering a tracked PV platform, where the azimuthal vertical movement is obtained with the new proposed rhomboidal linkage. In the last part of the paper an analysis is done with the aim of determining the PV platform tracking efficiency （which represents the ratio between the received and the available beam solar energy） using the new linkage, in the meteorological conditions of Brasov, Romania implementation site.

Complete Solution of Sun Tracking for Heliostat

A general solution of sun tracking for an arbitrarily oriented heliostat towards an arbitrarily located target on the earth is published. With the most general form of solar tracking formulae, it is seen that the used azimuthelevation, spinning-elevation tracking formulae etc. are the special cases of it. The possibilities of utilizing the general solution and its significance in solar energy engineering are discussed.

Performance Evaluation of New Two Axes Tracking PV-Thermal Concentrator

The overall problem with PV （photovoltaic） systems is the high cost for the photovoltaic modules. This makes it interesting to concentrate irradiation on the PV-module, thereby reducing the PV area necessary for obtaining the same amount of output power. The tracking capability of two-axes tracking unit driving a new concentrating paraboloid for electric and heat production have been evaluated. The reflecting optics consisting of flat mirrors provides uniform illumination on the absorber which is a good indication for optimised electrical production due to series connection of solar cells. The calculated optical efficiency of the system indicates that about 80% of the incident beam radiation is transferred to the absorber. Simulations of generated electrical and thermal energy from the evaluated photovoltaic thermal （PV/T） collector show the potential of obtaining high total energy efficiency.

A new two-axis solar tracker based on the online optimization method:Experimental investigation and neural network modeling

This article presents a new two-axis solar tracker based on an online optimization algorithm so as to track the position of the sun without using its movement model.In this research,four well-known optimization algorithms are employed to find the two unknown parameters named azimuth and zenith angles,which determine the position of the sun.The magnitude of the sunray is considered as the cost function of all algorithms.Then,several experiments are carried out to find the best optimization algorithm with optimal population size,number of iterations,and also the best initialization method.Uniform initialization leads to faster convergence compared to random initialization.The results clearly show that the particle swarm optimization algorithm with a population size of 15 and 7 iterations using uniform initialization method has better performance than the other algorithms,with a convergence time of less than 40 s.The average fitness value or voltage received by the tracker is 2.4 Volts in this method,which is higher than other methods.TLBO also performs well with a population size of 15 and 7 iterations.Afterward,the artificial neural network with one hidden layer and 20 neurons is employed to predict these two parameters in each day and moment in a year in Shiraz city according to the experimental data extracted from PSO.Number of the day from January and the time are inputs and zenith and azimuth angles are considered the output of neural network modeling.The performance of the proposed ANN model is evaluated using regression plots,demonstrating a strong correlation between predicted and target outputs.Finally,the outcomes reveal the feasibility of using online optimization algorithms and neural network modeling in an effort to bypass the complex mathematical model of mechatronic systems and predict the movement of the sun automatically.

Ka频段车载遥感站天线伺服控制系统设计

针对Ka频段7.3 m车载遥感站天线高精度标校、窄波束跟踪等应用需求,提出一种多数据源融合的跟踪控制方法。该方法采用双GPS/北斗定北和太阳标校相结合的角度校准方法,提高了天线捕获概率,解决了车载站天线难捕获以及车载站转场后伺服高精度角度标校的问题;综合利用天线系统中的接收机跟踪误差数据、程序跟踪点位数据、外部引导角度数据和天线实时角度测量数据,通过自适应加权最小二乘方法进行数据融合跟踪,提高了车载站天线伺服控制系统跟踪精度和跟踪性能。测试结果表明,组合标校方法实现天线外场角度标校精度优于0.02°;多源融合跟踪与单一数据源跟踪相比,伺服控制系统跟踪误差减小了30%以上,跟踪精度优于1/15个波束宽度。验证了组合标校和多源融合跟踪方法的有效性,可用于指导大口径高频段遥感接收天线伺服控制系统设计。

入射偏角对非跟踪复合抛物面聚光器性能影响

为了降低复合抛物面聚光器对跟踪精度的要求,提高其在集热过程中的光热转化能力,探究入射偏角对新型复合抛物面聚光器非跟踪工况时光热性能的影响机制。理论分析该聚光器在集热过程中的能量转化关系,并利用光学仿真软件TracePro研究入射偏角对聚光器光学性能的影响规律;在此基础上搭建非跟踪复合抛物面聚光器性能测试试验台,在实际天气条件下测试分析聚光器光热性能随径向入射偏角的变化规律。结果表明:当光线正入射时,聚光器的光线接收率与聚光效率分别为100%和83.42%;当径向入射偏角α为16°时,该聚光器的光线接收率与聚光效率分别为53.00%和44.82%;当轴向入射偏角β为30°时,光线接收率与聚光效率分别为88.74%和74.42%;在空气流速为3.7 m/s时,聚光器的最高出口温度与瞬时集热量分别为31.3℃和782.8 W,分别比聚光器接收上偏10°和下偏10°入射辐射时提高了3.7、6.1℃和131.0、217.9 W;该聚光器接收正入射辐射时的平均光热转化效率为77.45%,比接收上偏10°和下偏10°入射辐射的平均光热转化效率高42.14%和52.97%。

基于4级放坡光电传感器的太阳跟踪系统设计

为提高太阳能利用装置的采光效率,设计了一种4级放坡四棱台光电传感器,分析了其跟踪范围和跟踪精度,并以此为基础设计了太阳跟踪系统的硬件部分和软件部分。试验结果表明:光电传感器粗跟踪装置的跟踪范围远远超过了一年当中方位角、高度角变化范围最大的夏季,能够满足对太阳在高度角和方位角大范围跟踪的需要。通过对软件流程的设计,采用5 min修正一次角度的循环方式,能够满足精跟踪装置跟踪精度的需求。通过光照强度对比试验,验证了太阳跟踪系统在粗、精两级跟踪模式下,太阳能利用装置的采光效率相比休眠模式采光效率提高了57.02%。该设计为太阳跟踪系统光电传感器跟踪范围的扩大和跟踪精度的提高提供了参考。

基于物联网远程监控的太阳能定向跟踪系统设计

设计了一种基于物联网远程监控的太阳能定向跟踪系统,分别对太阳能定向跟踪系统本体和远程监控系统进行了设计与开发,采用离线和实时控制两种方式,通过监控数据计算当前的太阳高度角和方位角,调整光伏板的倾角,从而提高太阳能光伏板的发电率。对该装置设备层的太阳能定向跟踪系统本体采用框架式结构设计,并通过模糊PID算法对跟踪装置电机进行调控;对应用层的远程监控系统采用B/S架构设计,使用MQTT协议与云平台进行数据交互,用户可直接通过浏览器访问监控系统,实现太阳能定向跟踪系统的远程状态检测、实时控制、数据管理等功能。经测试,用户能通过该监控系统控制和监控太阳能定向跟踪系统的运行,满足太阳能定向跟踪系统远程监控的要求,系统具有较高的实用性。

多模式风光火储系统多目标优化调度

风光发电具有波动性和随机性,大规模并入电网影响电力系统的稳定性、安全性。建立考虑火电机组深度调峰和电储能寿命折损成本的风光火储能源系统模型,提出负荷跟踪、功率平滑两种出力模式。以风光火储各子系统出力为决策变量,建立了一种以风光火储能源系统运行成本最低、新能源消纳最多、环保性最好为目标的优化调度模型。通过NSGA-Ⅱ算法分别求解两种模式的调度模型,得到帕累托解集,最后基于AHP决策方法确定最优调度方案,实现能源系统出力跟踪负荷、能源系统功率平滑的功能,降低风光发电并入电网带来的冲击。仿真计算结果表明两种模式下的调度策略可以提高风光火储能源系统的经济性,增强新能源消纳能力,减少污染性气体排放,验证了优化调度模型的有效性。

考虑风光出力不确定性的风光储微电网系统智能协调控制策略

对风光储互补的微电网发电系统进行研究,针对风光发电与负载功率不匹配问题,提出了一种基于新型变步长电导增量法的最大功率点追踪控制方法,利用基于Ziegler-Nichols法的改进自适应PID算法实现负载功率蓄电池充放电控制的协同控制策略。通过在MATLAB/Simulink中搭建仿真模型并进行验证,证明了所述方案的准确性以及可行性。

基于STM32F103C8T6光电跟踪的多功能太阳能光伏花

为充分利用新能源并解决景区照明能耗高、观赏性低、光源固定等问题,设计一种基于STM32F103C8T6光电跟踪的多功能太阳能光伏花。采用光电跟踪法收集尽可能多的太阳能并将其转换为电能储存在锂蓄电池中,以为装饰灯和其他模块供电。同时,设计了L298N电机驱动模块,控制受光模块与小车以反方向转向运动,解决由小车方向导致太阳能电池板同向运动的问题。用户可通过蓝牙控制光伏花的开花、闭花和移动。在相同环境下分别测试了视日轨迹跟踪和光电跟踪对太阳能的吸收效率,结果表明光电跟踪法在成本控制和对太阳能的吸收效率上表现更优。利用光电跟踪法可充分利用太阳能,不易受突发天气影响。

光伏跟踪电机的分数阶自抗扰控制方法

针对光伏跟踪系统运行时负载端产生高频振荡以及在运行过程中遇到的极端天气等不可控因素导致的系统失调、鲁棒性降低等问题,根据光伏跟踪系统中负载反馈模型实现速度控制,设计了一种改进型分数阶自抗扰控制器。该控制器采用函数优化后的分数阶跟踪微分器和线性组合的分数阶扩张状态观测器来抑制高频振荡,加快负载端速度响应并提高系统抗干扰能力。实验结果表明,改进后的分数阶自抗扰控制器使得抑制了负载端39.60%的高频振荡,系统稳态时间缩短了20.83%,转速波动减少了36.97%,有效改善了系统控制性能,提高了系统鲁棒性。

基于Fourier拟合的光伏跟踪系统设计

[目的]为提高光伏支架的发电效率,以基于Fourier拟合算法的视日运动轨迹光伏跟踪器为研究设计对象。[方法]借助MATLAB分析了传统视日运动轨迹算法的跟踪精度情况,更进一步地在此基础上提出了精度更优的8阶傅里叶拟合视日运动轨迹跟踪算法,并结合GNSS定位技术,得出太阳实时运行轨迹。系统设计以STM32单片机作为微处理器,采用6轴加速度传感器,通过重力矢量在其轴上的投影确定光伏跟踪支架的实时倾斜度,以此二者建立跟踪支架三维运行模型,通过分析太阳光线在支架上的余弦效应即可得到电机需要运行的动作角。同时为解决晨昏时刻光伏组件间的阴影遮挡问题,系统增加逆跟踪算法。并考虑到大规模机组的应用,提出主从电机同步控制策略。[结果]傅-2里叶拟合算法拥有更高的跟踪精度,精度可达到10数量级,高于传统算法一个数量级。同时采用逆跟踪技术可节约24.3%光伏阵列用地面积,大幅提高了土地利用率。[结论]本研究采用更为精准的视日运动轨迹跟踪模型,较好地解决了太阳辐射利用的余弦效应,提升了电站的发电效率,实现了安全高效绿色能源体系的建设,促进了我国“双碳”目标的推进与达成。

基于工程实践的一种太阳能无碳小车设计

为设计一款具有方向控制功能的太阳能无碳小车,首先通过SolidWorks软件对小车进行了整体三维建模,然后设计了小车的关键机构,包括传动机构、微调转向机构和凸轮的设计,并选择适合的电机。在满足无碳小车尺寸要求的前提下,借助MATLAB软件对小车的运行长征轨迹进行了凸轮仿真和轨迹优化。最后,通过Motion运动仿真成功验证了小车设计方案的合理性,实现了太阳能驱动和固定点打卡的功能要求。设计出的小车结构简单、性能良好、运行效率高,为今后将太阳能技术应用于无碳小车设计提供了一种新的方法和思路。