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.

Design of a Level-3 electric vehicle charging station using a 1-MW solar system via the distributed maximum power point tracking technique

Solar power is mostly influenced by solar irradiation,weather conditions,solar array mismatches and partial shading conditions.Therefore,before installing solar arrays,it is necessary to simulate and determine the possible power generated.Maximum power point tracking is needed in order to make sure that,at any time,the maximum power will be extracted from the photovoltaic system.However,maximum power point tracking is not a suitable solution for mismatches and partial shading conditions.To overcome the drawbacks of maximum power point tracking due to mismatches and shadows,distributed maximum power point tracking is util-ized in this paper.The solar farm can be distributed in different ways,including one DC-DC converter per group of modules or per module.In this paper,distributed maximum power point tracking per module is implemented,which has the highest efficiency.This technology is applied to electric vehicles(EVs)that can be charged with a Level 3 charging station in<1 hour.However,the problem is that charging an EV in<1 hour puts a lot of stress on the power grid,and there is not always enough peak power reserve in the existing power grid to charge EVs at that rate.Therefore,a Level 3(fast DC)EV charging station using a solar farm by implementing distributed maximum power point tracking is utilized to address this issue.Finally,the simulation result is reported using MATLAB®,LTSPICE and the System Advisor Model.Simulation results show that the proposed 1-MW solar system will provide 5 MWh of power each day,which is enough to fully charge~120 EVs each day.Additionally,the use of the proposed photovoltaic system benefits the environment by removing a huge amount of greenhouse gases and hazardous pollutants.For example,instead of supplying EVs with power from coal-fired power plants,1989 pounds of CO_(2) will be eliminated from the air per hour.

Control strategy of optimal deployment for spacecraft solar array system with initial state uncertainty

A control strategy combining feedforward control and feedback control is presented for the optimal deployment of a spacecraft solar array system with the initial state uncertainty. A dynamic equation of the spacecraft solar array system is established under the assumption that the initial linear momentum and angular momentum of the system are zero. In the design of feedforward control, the dissipation energy of each revolute joint is selected as the performance index of the system. A Legendre pseudospectral method(LPM) is used to transform the optimal control problem into a nonlinear programming problem. Then, a sequential quadratic programming algorithm is used to solve the nonlinear programming problem and offline generate the optimal reference trajectory of the system. In the design of feedback control, the dynamic equation is linearized along the reference trajectory in the presence of initial state errors. A trajectory tracking problem is converted to a two-point boundary value problem based on Pontryagin’s minimum principle. The LPM is used to discretize the two-point boundary value problem and transform it into a set of linear algebraic equations which can be easily calculated. Then, the closed-loop state feedback control law is designed based on the resulting optimal feedback control and achieves good performance in real time. Numerical simulations demonstrate the feasibility and effectiveness of the proposed control strategy.

Case Study of Solar Power Producing Efficiency from a Photovoltaic System

To study the efficiency increasing of electric energy generation in the Photovoltaic System is concentrated on this paper. There are four cases to improve the efficiency of power producing from the Photovoltaic System. This article not only describes the differences of facilities before and after the proposal, but also evaluates the electric energy generation efficiency and improved results for each proposal. Finally, the better efficiency of all improving ways is analyzed to get into conclusions in order to provide further improvement and reference for the industry in the future. Overall, these proposed methods can improve the efficiency of solar photovoltaic electric energy generation in about 30.18%.

Photovoltaic Sensor for the Solar Battery Guidance on the Sun Based on GeS:Sb Layered Crystals

Photovoltaic tracking sensor monitoring the position of the sun in the sky was developed on the basis of GeS:Sb layered crystals. The operating principle of this sensor is based on the phenomenon of photovoltaic effect in GeS:Sb crystals;the magnitude and sign of generated photo-emf depend on the position of the light probe relative to the ohmic contacts, deposited on (001) surface of the crystal.

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%。

太阳能电池板自动追光控制系统设计

以STC89C52单片机为核心设计出了太阳能电池板自动追光系统,给出了太阳能板自动追光系统总体设计方案。比较详细地设计出了太阳能板自动追光系统的硬件电路,包括两对光敏电阻组成的光照检测电路、风速检测电路、模数转换电路、舵机驱动等主要电路部分,并给出了自动追光控制系统软件流程。控制系统在实现自动追光的基础上,可以实现大风时放平太阳能板,以减小风阻,保证控制装置的安全。制作出了自动追光控制系统实物,验证了所设计的自动追光控制系统可行性。

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。

一种适用于监控系统中弱光条件的光伏逐日系统

太阳能是当前具有代表性的绿色能源之一,固定式光伏支架由于安装方向固定,光伏面板无法始终朝向太阳,而光伏逐日系统的监控系统对于跟踪其性能和确保高效运行至关重要。因此,该文提出一种基于监控系统中可适用于弱光条件下的光伏逐日系统,采用信捷XC3 PLC承担其主要程序控制任务,利用光敏传感器收集各个方向的光强差值,通过程序计算出最佳光照角度,进而驱动电机调整为最佳照射角度,将云量和天气预报数据集成到监测系统中,以预测阳光变化并相应地辅助逐日系统运行。大幅提高光电转化率。