基于组态技术的PLC系统开发

本文介绍了利用组态技术连接西门子PLC系统平台,提出使用组态王软件控制光伏配料系统,通过运行检验,可以满足实际的需要。     

S7-200PLC在太阳能跟踪控制系统中的应用

太阳能跟踪控制系统是光伏发电实训系统的重要组成部分,阐述了全太阳能跟踪控制系统的组成,以西门子S7-200PLC为核心配置了系统,以STEP 7 MicroWin为开发环境完成了光伏系统中的"逐日"用户程序的开发,并配有监控界面。结果表明,该系统能够实现光伏发电实训系统中太阳能的采集,提高太阳能发电系统的效率。     

建筑集成光伏系统的常见结构及其设计要素

太光伏发电技术是新能源发电技术的重要组成部分。建筑集成光伏(BI PV,Building Integrated Photovoltaic)技术作为光伏发电技术的一种应用形式,有其得天独厚的优势。BIPV系统在结构上可以分为独立光伏发电系统和并网光伏发电系统,系统设计过程中存在一些有别于一般光伏发电系统的设计要素。BIPV系统是未来光伏发电应用的主要发展方向之一,有很大的研究价值。     

光伏发电系统最大功率点激光定位系统

传统光伏发电系统最大功率点定位精度较差,导致光伏发电系统的功率增益较差,为此提出基于激光点跟踪定位的光伏发电系统最大功率点激光定位方法。构建光伏发电系统的电路阻抗参数分析模型,通过滤波电感和滤波电容联合参数估计的方法,进行光伏发电系统最大功率控制和潮流逆流点跟踪控制,根据控制器参数和功率变化量跟踪定位进行功率突变诱发的激光点,采用激光点扫描方法进行光伏发电系统的受控源参数分析,建立光伏发电系统的端电压分析等效模型,通过光伏并网逆变稳态控制对光伏发电系统最大功率点进行控制,通过激光点定位方法,实现光伏发电系统最大功率点激光定位系统的优化设计。仿真结果表明,采用该方法进行光伏发电系统最大功率点激光定位的精度可达99.96%,功率突变引发的电路过渡过程得到优化控制,提高了光伏发电系统的稳定性和输出增益。     

基于西门子LOGO!的智能太阳能跟踪系统

克服现有技术缺陷,提供一种电路简单、廉价、稳定性好的基于西门子LOGO!的光伏发电控制器,包括与该西门子LOGO!控制器连接的光线采集与转换模块、双组继电器互锁控制模块,以及与光线采集与转换模块连接的光照传感器模块、限位开关模块,还包括电压检测显示模块。本设计合理,电路结构简单,稳定性好,制作成本低,易于维护,适于推广。     

光伏智能汇流箱在光伏电站智能化中的应用探讨

随着新兴能源应用的不断发展,光伏发电系统的大量建设,光伏汇流箱得了到大量的使用。通过对光伏发电系统的光伏组件运行状况进行监控,使光伏发电系统的更加安全可靠地运行,且它所采集的光伏组件数据为光伏发电系统的整体发电效率的提升有着重要的研究意义。     

第二讲:太阳电池

2.1太阳电池的基本发电原理光伏发电系统中成本最高的部分当数太阳电池,也称为光伏电池。它是光伏发电系统中科技含量最高的部分,是光伏发电系统的核心,也是目前光伏发电系统普及和发展的瓶颈。太阳电池本体研究主要集中在物理学、材料学和微电子学等领域。     

独立光伏系统的储能技术研究

储能环节是独立光伏系统的重要组成部分,其优劣直接影响到光伏系统的好坏。文章简要介绍了独立光伏发电系统、储能技术的特殊要求,分析比较了各种储能技术的基本原理、技术特点、发展现状和储能技术在光伏系统中的适用性。     

光伏发电技术在变电站中的应用

光伏发电技术的特点，光伏发电技术在变电站中的应用，包括光伏发电与光伏蓄电系统、逆变器、光伏设备的参数设置、采光模式设计、光伏发电系统的线路设计。     

太阳能光伏照明系统概述

分别叙述了太阳能在荧光灯、HID灯、LED灯照明系统中的应用。为提高太阳能光伏照明系统的可靠性,介绍了太阳能光伏照明风光互补系统和太阳能光伏照明光电互补系统。并提出太阳能光伏照明系统中应注意的技术问题。     

The present status and future direction of technology development for photovoltaic power generation in Japan

In 2004 NEDO established the PV Roadmap Toward 2030 PV2030 as a long‐term strategy for PV R&D. In this Roadmap, PV is expected by 2030 to supply approximately 50% of residential electricity consumption (cumulative installed capacity in the range of 100 GW). In terms of economic efficiency, electricity costs are targeted to equal commercial use, approximately 14 Yen/kW h, by 2020 and industrial use, approximately 7 Yen/kW h, by 2030. For future PV systems, it is essential to improve the stand‐alone capabilities of PV system with electricity storage and to develop community‐based PV systems using multi‐function inverters. Advanced technological innovations beyond the existing levels are also essential. Therefore, NEDO is undertaking 2‐year projects for preliminary research to make clear the next R&D of solar cells and PV system technology. Copyright © 2005 John Wiley & Sons, Ltd.     

Technical and economic analysis of grid‐connected PV systems by means of simulation

Research on monitored grid‐connected PV systems can lead to an improved performance of PV systems. This view is based on monitoring results from PV systems in Western Europe which lag behind the expected values. However, current methods for analysing these systems do not allow to investigate the potential system efficiency improvement on the basis of field experience. Hence, we have developed a method for analysing monitored grid‐connected PV systems which meets this need. In this method the common technical approach to analysing PV systems is broadened with an economic assessment. First an energy loss analysis of the PV system is made using its monitored data. In our analysis the energy loss effects in the PV system are split up by simulation. This provides a profound insight into the actual performance of the system. Next, measures to enhance the performance of the system are identified. The costs involved to improve the performance are analysed. Finally, the cost‐effectiveness of the potential improvements is calculated. In this paper we will present our method TEAMS. Although we will not formulate strict rules, we will provide a well‐defined frame and structure for the application of the TEAMS method. It is shown that applying TEAMS contributes to improved transparency in the evaluation of monitored grid‐connected PV systems. Copyright © 1999 John Wiley & Sons, Ltd.     

铁路5G-R基站太阳能供电架构及应用

针对铁路5G专用移动通信(5G-R)系统基站布置密集、单体功耗高的特点,结合铁路无线通信的需求,研究采用太阳能(PV)为5G-R系统基站的射频拉远单元(RRU)设备供电的方案。对比分析5G-R系统RRU设备日用电规律及太阳能电池日发电规律,确定了采用太阳能结合储能与外电源的供电体系,通过比较几种太阳能电池与外电源组合供电架构的经济性与可靠性,推荐采用直流侧切换的供电架构,并进一步提出了采用直流侧智能配电的太阳能供电方案。本研究在保证5G-R系统运行安全可靠的同时,通过采用太阳能供电方式降低了铁路5G-R系统对外电源的需求。     

S7.300型PLC在全自动在链阳极钢爪校直机中应用

全自动在链阳极钢爪校直机是用于铝电解组装车间的新型自动化设备。通过对该设备的结构、工作原理、液压系统及其操作要求的分析,研制了基于S7-300型PLC和PV1000触摸屏的控制系统。该系统具备自动加热、校直运行、在线监视、离线故障检测和多台设备协同工作的功能。描述了该控制系统的软、硬件设计方法及其特点。     

Photovoltaic system simulation using a standard electronic circuit simulator

An approach to photovoltaic (PV) system simulation is presented based on the use of SPICE instead of using a specifically developed software package. SPICE models for PV cells, PV modules, lead-acid batteries and the rest of the main components of a PV system have been developed. A simulation example of a stand-alone PV system including measured irradiance data as an input is used to show some of the possibilities inherent in such an approach. Greater flexibility, quick access to all voltages and currents within the system and a simpler way of interfacing with standard electronic components are the main conclusions to be drawn from this work.     

A novel power benefit prediction approach for two‐axis sun‐tracking type photovoltaic systems based on semiconductor theory

Photovoltaic (PV) systems incorporated with sun‐tracking technology have been proposed and verified to effectively increase the power harvest. However, the actual power generated from a PV module has not been investigated and compared with that analyzed from theoretical models of the PV material. This study proposes a novel method for estimating the power benefit harvested by a two‐axis sun‐tracking type (STT) PV system. The method is based on semiconductor theory and the dynamic characteristics, including maximum power point tracking of PV modules that can be integrated with the database of annual solar incidences to predict the power harvested by any STT PV system. The increment of annual energy provided by an STT PV system installed at any arbitrary latitude, compared with that by a fixed‐type system, can be accurately estimated using the proposed method. To verify the feasibility and precision performance of this method, a fixed‐type and a two‐axis STT PV system were installed at 24.92° north latitude in northern Taiwan and tested through long‐term experiments. The experimental results show that the energy increments estimated by the theoretical model and actual measurement are 19.39% and 16.74%, respectively. The results demonstrate that the proposed method is capable of predicting the power benefit harvested by an STT PV system with high accuracy. Using our method, a PV system installer can evaluate beforehand the economic benefits of different types of PV systems while taking different construction locations into consideration, thereby obtaining a better installation strategy for PV systems. Copyright © 2012 John Wiley & Sons, Ltd.     

An analysis of reliability in the early stages of photovoltaic systems in Japan

In order to disseminate Photovoltaic (PV) technologies into the energy network, the cost down is not only important, but also improving the performance of the PV system is significant issues. Long‐term reliability is one of the most important issues in terms of PV system performance. Previous researches were mainly focused on the reliability of PV modules, but the PV system is composed of a power conditioner, wiring, junction box, and so on. To improve the reliability of PV systems, it is important to accumulate trouble cases focused on all components of PV system. In this paper, we aim at evaluation of the reliability for the PV system on the early stages of PV system's lifetime by using large number of Japanese PV systems' data from the field Test in Japan. New Energy and Industrial Technology Development Organization has been running the “Field test project in Japan” from 1992. In this project, PV system users have cooperated with the collection of monitoring data and reported on the information of maintenance and certain failures of PV systems for 4 years after installation of PV system. Using those reports each year of installation, we evaluated reliability of PV systems by means of parameters such as Mean Time Between Failure, Mean Time To Repair, and the suspension time of PV system. As a result, the main trouble of PV systems was related power conditioner, and a few trouble of PV module was caused by typhoon. Moreover, the trend of the failure rate before FY 2000 of installation was demonstrated as the trend of initial failure in “bathtub curve;” however, the trend of its after FY 2001 of installation was indicated as the accidental failure in “bathtub curve.” Further, the operator simply forgot to restart the power conditioner after maintenance or suspensions of PV system in many trouble cases, and the user did not notice that it had been suspended for a while. These trouble cases can be avoidable easily through the effective alarm such as error message of power conditioner systems with monitoring systems. Thereby, monitoring with the evaluation method of PV systems is one of the important technologies due to the long‐term reliability and stable operation. Copyright © 2010 John Wiley & Sons, Ltd.     

Development of an FPGA-based system for real-time simulation of photovoltaic modules

Photovoltaic (PV) simulators are indispensable for the operational evaluation of PV energy production system components (e.g. battery chargers, DC/AC inverters, etc.), in order to avoid the time-consuming and expensive field-testing process. In this paper, the development of a novel real-time PV simulator based on Field Programmable Gate Arrays (FPGAs), is presented. The proposed system consists of a Buck-type DC/DC power converter, which is controlled by an FPGA-based unit using the Pulse Width Modulation (PWM) principle. The system operator is able to define both the PV module type to be simulated and the environmental conditions under which the selected PV module operates. The proposed design method enhances the rapid system prototyping capability and enables the reduction of the power converter size and cost due to the high clock speed feature of the FPGA-based control unit. The experimental results indicate that, using the proposed method, the PV module current-voltage characteristics examined are reproduced with an average accuracy of 1.03%.     

Renewable Energy Systems With Photovoltaic Power Generators: Operation and Modeling

A substantial increase of photovoltaic (PV) power generators installations has taken place in recent years, due to the increasing efficiency of solar cells as well as the improvements of manufacturing technology of solar panels. These generators are both grid-connected and stand-alone applications. We present an overview of the essential research results. The paper concentrates on the operation and modeling of stand-alone power systems with PV power generators. Systems with PV array-inverter assemblies, operating in the slave-and-master modes, are discussed, and the simulation results obtained using a renewable energy power system modular simulator are presented. These results demonstrate that simulation is an essential step in the system development process and that PV power generators constitute a valuable energy source. They have the ability to balance the energy and supply good power quality. It is demonstrated that when PV array- inverters are operating in the master mode in stand-alone applications, they well perform the task of controlling the voltage and frequency of the power system. The mechanism of switching the master function between the diesel generator and the PV array-inverter assembly in a stand-alone power system is also proposed and analyzed. Finally, some experimental results on a practical system are compared to the simulation results and confirm the usefulness of the proposed approach to the development of renewable energy systems with PV power generators.     

Development of a Methodology for Improving Photovoltaic Inverter Reliability

In evaluating the energy-generation potential of a photovoltaic (PV) energy system, the system is usually assumed to work without interruptions over its entire life. PV energy systems are fairly reliable, but as any complex system, they may fail. In PV systems, the inverter is responsible for the majority of failures, and most inverter failures are blamed on the aluminum electrolytic capacitors typically used in the dc bus. This paper investigates the effects of common failure modes on the reliability of PV inverters and suggests a model framework for decomposing the inverter into subsystems for more detailed study. The challenges of statistical analysis based on small data sets are discussed, and simulations are performed to illustrate the proposed model using a simple decomposition into subsystems of the inverter used in the 342-kW PV system at the Georgia Tech Aquatic Center.