大功率光伏电池阵列模拟器研究

为满足实验室中光伏逆变器综合性能测试的需要,提出一种新型的大功率光伏电池阵列模拟器.分析了输出的I-V特性曲线指令信号的运算方法,利用三相电压型高频PWM整流电路实现指令信号的功率放大,介绍了光伏电池阵列模拟器的控制方案.仿真结果表明该光伏电池阵列模拟器具有很好的稳态与动态性能.     

局部阴影条件下光伏阵列输出特性仿真分析

就局部阴影条件对太阳能光伏电池阵列输出特性的影响规律与程度,建立了局部阴影条件下光伏组件、光伏阵列的数学模型,采用Matlab/Simulink模块做了不同阴影条件下的对比仿真分析。结果表明,局部阴影对光伏阵列输出特性的影响因阴影的数量、分布及光照强度的不同而有所差异。     

基于扩展频域时域反射法的在线光伏阵列故障检测信号特性研究

基于扩展频域时域反射法（Spread Spectral Time Domain Reflectometry, SSTDR）的光伏阵列故障诊断方法存在检测盲区和衰减特性,有必要研究检测信号的性质以提高故障检测性能。首先,对检测信号在光伏阵列中的传输行为进行研究,探究不同信号参数对检测范围和精度的影响;其次,根据光伏电池的动态模型和排布规律,搭建光伏阵列故障检测仿真平台,通过断路故障仿真实验对结果进行验证,结果表明,改善信号能有效增强相关峰辨识能力,使光伏组件检测数量增加4块;最后,综合考虑检测盲区和衰减特性对检测性能的影响,提出基于SSTDR的光伏阵列故障检测信号选择策略,用以确定测距范围和最优信号参数。     

微气候对单晶硅光伏阵列特性曲线的影响

采用数值计算方法分析了微气候对单晶硅光伏阵列特性曲线的影响。同时考虑三大微气候变量建立了光伏电池-组件-阵列的数学模型,并采用分段迭代方法求解,所得到的特性曲线与试验数值相吻合。当环境温度为15～35℃,随着温度的升高,在低电压区间的I-U曲线保持不变;在高电压区间,以STC下的I-U曲线为基准均匀地向左偏移;在太阳辐照量为200～1 000 W/m2时,随着辐照量的增加,I-U曲线均匀向上偏移;在风速为2～6 m/s时,随着风速的增加,I-U曲线在低电压区间保持不变,在高电压区间向右偏移,逐渐靠近STC下的I-U曲线,且偏移速率逐渐变小。     

3种斜面月平均总辐射模型评估及光伏阵列最佳倾角研究

为分析倾角变化对斜面辐射和光伏发电量(或效率)的影响,对武汉地区正南朝向斜面月平均总辐射计算方法和光伏阵列最佳倾角问题进行理论研究和探讨,并通过湖北省气象局多倾角光伏组件观测试验系统进行试验验证,结果表明:1)Hay模型最适合散射辐射较多的武汉地区斜面辐射计算;2)武汉地区固定式光伏阵列年最佳倾角理论值和实测值均为20°,该倾角年总辐射量相比水平面增加4.0%,而年发电量增加14.9%,最佳倾角安装下系统效率为86.1%,装机年发电量约1.02 k Wh/Wp;3)分冬/夏半年调整一次安装倾角,可使斜面年总辐射量增幅较大,冬/夏半年的最佳倾角理论值均小于实测值(45°/10°),该方式下年总辐射量相比于水平面增加7.5%,而年发电量增幅高达18.1%。     

基于四参数模型的光伏阵列Matlab/Simulink仿真模型

继承了传统四参数模型结构简单、计算快速的特点,克服了传统四参数模型准确度低的问题,提出了一个快速、准确、具有通用性的光伏模型。基于此新型四参数光伏模型,在Matlab/Simulink平台中建立了此模型的计算模块。通过对比试验表明,该模型具有极佳的准确度,整体最大功率偏差在2%以下,光伏阵列长期运行环境条件下的最大功率偏差在1%以下。     

光伏阵列幂函数模型及其模拟装置

以目前应用最为广泛的光伏阵列工程数学模型为基础,推导出一种新型工程数学模型——光伏阵列幂函数模型,并将其应用于光伏阵列模拟器的设计。模拟器控制环节利用IPC完成系统的数据分析处理以及实时控制,实现了模拟光伏阵列在光强、温度动态变化中的对外输出,并可以实时显示光伏阵列I-U特性曲线。测试结果表明,该模拟器可以根据负载等效阻抗的变化快速调节输出,使负载工作点迅速稳定在光伏阵列I-U特性曲线上,动态响应良好。     

正常光照条件下全工况光伏阵列通用Matlab/Simulink仿真模型

基于五参数光伏模型,在Matlab/Simulink平台中建立了该模型的计算模块,通过与制造商技术数据及一种四参数模型的对比实验表明,该模型具有极佳的准确度,整体最大功率偏差在1%以内,最大功率点电压偏差在0.5%以内。通过该五参数模型可准确得出光伏组件的特性曲线,为光伏系统研究提供了一个方便快速、准确度高又具有通用性的光伏模型。     

局部阴影下光伏阵列的建模与仿真分析

为研究局部阴影效应对光伏发电系统的影响,首先建立了光伏阵列工程数学模型,分析局部阴影条件下光伏阵列的输出特性。为了便于工程分析,该文利用PVSYST软件分析比较单晶硅、多晶硅和薄膜电池等3种不同材料光伏电池在局部阴影条件下的输出功率,为工程应用提供了良好的指导作用。最后提出了几种提高光伏阵列抗局部阴影能力的措施。     

基于Bezier函数光伏阵列建模对比仿真研究

针对光伏阵列建模存在所需参数较多和计算较繁琐的弊端,基于一种新型的Bezier函数光伏阵列建模方法,利用厂商给定参数对BN20-M进行建模,并与传统迭代法的计算结果进行对比,利用已有的实测数据进行验证,结果表明,Bezier函数计算精度虽略低于迭代法,但具有参数获取方便和计算简单的特点,并能够有效地缩短仿真时间,提高计算效率,证明了Bezier函数在光伏阵列建模中的适用性和有效性。     

Analytical model for predicting the performance of photovoltaic array coupled with a wind turbine in a stand-alone renewable energy system based on hydrogen

We present the results of an analysis of the performance of a photovoltaic array that complement the power output of a wind turbine generator in a stand-alone renewable energy system based on hydrogen production for long-term energy storage. The procedure for estimating hourly solar radiation, for a clear sunny day, from the daily average solar insolation is also given. The photovoltaic array power output and its effective contribution to the load as well as to the energy storage have been determined by using the solar radiation usability concept. The excess and deficit of electrical energy produced from the renewable energy sources, with respect to the load, govern the effective energy management of the system and dictate the operation of an electrolyser and a fuel cell generator. This performance analysis is necessary to determine the effective contribution from the photovoltaic array and the wind turbine generator and their contribution to the load as well as for energy storage.     

光伏网阵与水泵性能匹配机理初探

从理论上论述了光伏网阵与水泵性能匹配的机理,以及影响提高系统匹配性能的因素,给出了通过实践得出的提高独立光伏水泵系统性能匹配的方法,并已在内蒙古进行了示范点建设,总出水量可达5m^3／d和2m^3／t。     

分布式光伏发电系统最大功率点跟踪技术比较研究

基于当前光伏阵列最大功率点跟踪技术的研究现状,介绍了适用于分布式光伏发电系统最大功率点跟踪的各种常用控制方法,阐述了每一种控制方法的技术原理,分析和比较了这些常用控制方法的特点,总结了各自的优点和缺点,最后对分布式光伏发电系统最大功率点跟踪方法的选择问题进行了探讨,并指出了具体选择方法时应综合考虑的各种因素。     

A new method for estimating the longevity and degradation of photovoltaic systems considering weather states

The power output of solar photovoltaic (PV) systems is affected by solar radiation and ambient temperature. The commonly used evaluation techniques usually overlook the four weather states which are clear, cloudy, foggy, and rainy. In this paper, an ovel analytical model of the four weather conditions based on the Markov chain is proposed. The Markov method is well suited to estimate the reliability and availability of systems based on a continuous stochastic process. The proposed method is generic enough to be applied to reliability evaluation of PV systems and even other applications. Further aspects investigated include the new degradation model for reliability predication of PV modules. The results indicate that the PV module degradation over years, failures, and solar radiation must be considered in choosing an efficient PV system with an optimal design to achieve the maximum benefit of the PV system. For each aspect, a method is proposed, and the complete focusing methodology is expounded and validated using simulated point targets. The results also demonstrate the feasibility and applicability of the proposed method for effective modeling of the chronological aspects and stochastic characteristics of solar cells as well as the optimal configuration and sizing of large PV plants in terms of cost and reliability.     

Identifying the parameters of different configurations of photovoltaic models based on recent artificial ecosystem-based optimization approach

Identifying accurate and precise photovoltaic models' parameters is the primary gate in providing a proper PV system design simulate its real behavior. Therefore, this article proposed a new approach based on a recent meta-heuristic algorithm of artificial ecosystem-based optimization (AEO) to identify the optimal parameters of PV cell and module models. Various PV models are considered in this work as single diode (SD), double diode (DD), and triple diode (TD)-based circuits. The analysis is performed on which are R.T.C. France silicon solar cell, FSM-25 PV module, and Canadian-Solar-(CS6P-240P) multi-crystalline solar panel with the aid of experimental data under different operating conditions. Moreover, Lambert form is employed to validate the constructed model. Furthermore, comparative analysis with Harris hawks optimizer (HHO), gray wolf optimizer (GWO), and salp swarm algorithm (SSA) is performed. Additionally, statistical analysis using the Wilcoxon signed rank test is implemented across the three series of experiments for all employed optimizers. The obtained results confirmed the competence of the proposed approach in identifying the PV cell and modules equivalent circuits' parameters.     

Assessment of a fuzzy logic based MRAS observer used in a photovoltaic array supplied AC drive

In this paper a fuzzy logic (FL) based model reference adaptive system (MRAS) speed observer for high performance AC drives is proposed. The error vector computation is made based on the rotor-flux derived from the reference and the adaptive model of the induction motor. The error signal is processed in the proposed fuzzy logic controller (FLC) for speed adaptation. The drive employs an indirect vector control scheme for achieving a good closed loop speed control. For powering the drive system, a standalone photovoltaic (PV) energy source is used. To extract the maximum power from the PV source, a constant voltage controller (CVC) is also proposed. The complete drive system is modeled in MATLAB/Simulink and the performance is analyzed for different operating conditions.     

The impact of array inclination and orientation on the performance of a grid-connected photovoltaic system

The impact of PV surface orientation and inclination on grid-connected photovoltaic system performance under maritime climates was investigated using validated TRNSYS simulations. Insolation, PV output, PV efficiency, inverter efficiency, system efficiency, performance ratio (PR) and PV savings were estimated annually, seasonally and on monthly bases for various surface inclinations and orientations. Incident insolation and PV output were maximum for a surface with inclination 30° facing due south and minimum for a vertical surface with orientation 90° east or west from south. The monthly optimum collection angle maximising incident insolation varied from 10° to 70°. For the particular location and system studied, the maximum annual PV efficiency, the inverter efficiency, the PR and the system efficiency were for a south-facing surface with an inclination of 20°. For a horizontal surface, the monthly variation of system parameters was significant over a year. For time-dependent tariff rates, the annual PV savings were higher for a system oriented with same orientation towards the west than east from south while for constants tariff rates, the PV savings was the same for east or west orientation from south.     

Performance evaluation of Chinese photovoltaic companies with the input-oriented dynamic SBM model

In Chinese photovoltaic (PV) industry, business groups and overseas listing with respect to specialized operation and domestic listing became two prevalent management practices. The previous studies mainly focus on the impact of business groups and overseas listing on the performance of the firms. However, they neglect the performance comparison of different business models or listing markets. In this paper, we formulate an input-orientated dynamic SBM model, which emphasizes the excesses in input and carry-over resources and enhances the accuracy of the evaluation, to measure the operational efficiency of Chinese PV producers and further explore the impact of business models as well as listing markets on the performance of PV companies. Some managerial findings are concluded in the end and can be referred to by the existing and future PV investors.     

Research on the influence of PV cell to thermal characteristics of photovoltaic/thermal solar system

In the paper, we analyzed internal thermal transmission characteristics of water‐heating photovoltaic/thermal (PV/T) solar collector covered by photovoltaic (PV) cell, established photothermal conversion model of PV/T solar system, and analyzed the influence of PV cell coverage to photothermal characteristics of PV/T solar system. Results show that the thermal efficiency of PV/T solar system by optimizing PV cells coverage can reach 68%. In addition, by designing four water‐heating PV/T solar system prototypes with PV cell coverage of 0.4, 0.56, 0.7, and 0.82, respectively, we conducted experimental researches for the four prototypes and found that the four prototypes can achieve thermal efficiencies of 58%, 51%, 64%, and 67%, respectively, in heating 250 L of water to 50°C. The experiment results are consistent with theoretical analysis results, indicating that it is feasible to improve thermal characteristics of PV/T solar system by optimizing PV cell coverage. Copyright © 2017 John Wiley & Sons, Ltd.     

Explicit model of photovoltaic panels to determine voltages and currents at the maximum power point

A simple explicit photovoltaic formulation for characterizing and dimensioning cell-arrays is presented. The method permits the short-circuit current, the open-circuit voltage, the maximum cell power and the optimum cell-operation conditions to be determined. Further, the model also allows quantifying the effects of panel temperature and solar irradiance on key cell parameters. Based on several datasheets, the methodology is validated by covering a wide range of operation conditions. The proposed approach can thus, be very useful for design engineers to quickly and easily determine the performance of any photovoltaic array without performing tedious numerical calculations.