光伏电池组件工作状态监测研究

由于新能源光伏发电在当今电网中愈加重要,因此通过物联网技术实时监测光伏组件的健康状况对于保障光伏发电系统的高效运行意义重大。光伏系统无法对光伏电池最大功率点的输出进行实时监测,针对现有最大功率点跟踪算法MPPT只跟踪不监测的特点,提出以太阳能电池基本电路方程为基础,构建不依赖于变换器及MPPT算法的光伏电池功率输出曲线模型,结合电压-功率输出特性曲线的特点,采用最小二乘法拟合曲线,精准得到最大功率点附近的二次曲线数学模型,进而得到实时最大功率点。通过Matlab对光伏发电系统进行建模与仿真,系统仿真结果显示,算法准确有效,可以迅速稳定地响应环境变化,适用于各种条件下MPPT的快速、精准获取。     

分布式光伏发电并网数字化建模与仿真北大核心

为了改善光伏发电性能,需要对分布式光伏发电并网控制技术进行研究。提出基于MPPT控制的分布式光伏发电并网建模方法,建立光伏电池模型,在所建模型的基础上研究光伏发电系统输出功率受光照强度变化的影响。并利用MPPT控制方法跟踪分布式光伏系统的最大功率点,提高分布式光伏系统在运行过程中的输出功率。通过滑膜控制对光伏并网逆变器进行控制,保持电网电压与光伏发电系统输出电流的同步性,实现分布式光伏系统并网发电。通过仿真,验证了所提方法可有效地实现光伏阵列最大输出功率的跟踪,满足分布式光伏发电并网系统的运行要求。     

基于滑模控制的独立光伏发电系统控制策略

针对独立运行的光伏发电系统,提出了基于滑模控制的最大功率跟踪(MPPT)策略;针对光伏微源输出功率随机性引起的逆变器输入侧直流母线电压波动,通过储能控制实现电压稳定;针对负载变化引起的系统输出电压波动,设计了系统输出电压电流双闭环控制器。通过MatLab/Simulink对提出控制策略进行了仿真验证。分析结果表明,所提出滑模控制策略可实现光伏电池的MPPT;储能控制策略可有效抑制光伏微源输出功率波动引起的直流母线电压波动;输出电压控制策略能稳定系统电压,确保安全可靠运行。     

独立光伏系统中超级电容充电控制策略研究

针对应用在独立光伏系统中的超级电容模组,提出采用Buck变换器对其进行充电,在充电过程中,进行过压保护,未达到额定电压时采用扰动观察法对光伏阵列进行最大功率点跟踪（MPPT）控制,仿真结果表明了充电过程中能跟踪光伏阵列的最大功率点,且具有过压保护功能。     

基于Boost变换器光伏发电MPPT控制方法

在基于Boost变换器的光伏发电系统中,以MCU TMS320F2812为主要控制芯片,采用检测发电系统Boost变换部分输出电流的控制策略,并调节变换器PWM的占空比输出,实现最大功率点更好地跟踪,并通过Mat-lab/simulink验证该策略的可行性。     

基于交错Buck变换器的光伏系统MPPT控制

具有最大功率点跟踪(MPPT)功能的控制器常采用单相Buck变换器,输出功率稳定性差;鉴于此,提出将交错并联技术应用于Buck变换器,并以两相交错并联Buck变换器为例进行研究,减小输出电压、电流纹波,提高了输出功率稳定性,有利于实现MPPT控制;然后针对固定步长扰动观察法跟踪速度与精度之间的矛盾,研究了一种自适应变步长的算法,MATLAB仿真结果表明,改进算法具有较好的跟踪速度和稳态性能。     

光伏并网逆变系统的MATLAB仿真研究

光伏并网发电系统是光伏发电系统发展的趋势。单极式光伏并网逆变系统具有拓扑结构简单，成本较低的有点。这种系统中只存在一个能量变换环节，太阳能最大功率点跟踪（MPPT），电网电压同步等控制目标需要考虑。本文介绍了单极式光伏系统的拓扑结构和实现最大功率的工作原理．阐述了电导增量法实现MPPT的基本思想。根据光伏系统并网发电拓扑结构，设计了一套新型的实现最大功率跟踪的单极式光伏并网逆变器，逆变器控制部分由DSP实现最大功率跟踪和输出电流跟踪控制，实现了逆变输出电流与电网同步，且高功率因数运行。仿真和实验结果表明，单极式光伏并网逆变系统能准确跟踪太阳能电池最大功率点，并具有较好的稳定性。     

基于分组粒子群的光伏最大功率点跟踪方法

针对光伏发电系统在复杂遮阴条件下,光伏输出P-V特性曲线呈现高度非线性,采用基于分组粒子群算法（particle swarm optimization, PSO）和优化的扰动观察法(perturb and observe, P&O)相结合的MPPT（maximum power point tracking）算法进行光伏发电系统输出功率的提升。提出的最大功率点算法分为两个阶段,首先通过将混合蛙跳算法(shuffled frog leaping algorithm, SFLA)的分组思想引入到传统粒子群算法,并采用改进后算法实现近似全局最大功率点的快速搜索,以加快最大功率点跟踪的收敛速度和稳定性。然后,采用优化的扰动观察法实现最大功率点附近的动态精确跟踪,同时减少后续最大功率点跟踪过程中的计算量。通过在不同阶段发挥两种MPPT算法的各自优点来提高光伏最大功率点跟踪控制的效率。最后进行光伏系统遮阴条件变化的仿真实验,与传统粒子群算法相比,提出MPPT方法具有较快的跟踪速度和稳定的功率输出。     

小功率光伏发电逆变器的设计

设计以TMS320LF2407型DSP为核心的小功率光伏发电逆变器。主电路采用全桥式逆变器,针对传统PI控制的不足,采用了PI控制和重复控制相结合的控制策略,以实现输出电流与电网电压可靠同步。采用了电导增量法实现了最大输出功率（MPPT）的快速、稳定跟踪。实验结果表明所设计的逆变器运行稳定可靠,可用于小型光伏发电系统。     

基于极值搜索的光伏电池最大功率点跟踪仿真

针对光伏发电系统中最大功率点跟踪问题,在太阳能电池的数学模型的基础上建立了PV模块的Matlab仿真模型;考虑到了太阳能的波动性和随机性对太阳电池阵列的影响,利用一种基于极值搜索方法的实时MPPT控制原理,控制Buck DC/DC变换电路,结合S函数在Matlab/Simulink环境下建立其动态仿真模型,实现了光伏电池输出的最大功率跟踪;仿真结果表明,该算法具有较好的动态特性和稳态特性,具有一定的实用价值。     

Output feedback control of sensorless photovoltaic systems,with maximum power point tracking

This paper presents an output feedback control of sensorless photovoltaic systems with maximum power point tracking (MPPT). The system consists of a Photovoltaic Generator (PVG) which supplies a DC centrifugal pump, via a DC/DC boost converter. This later being connected to the PVG by a long PV cable. Generally, PV systems are established near the control unit of the converter. The MPPT methods and control laws are based on the PVG voltage and current measurements. However, PV arrays must be located in a site that guarantees good solar radiation. In most cases, such a site is at great distance from the control unit. Thus, on the one hand, the PVG voltage and current measurements become difficult and, on the other hand, the PV cable parameters could significantly effect the MPPT control accuracy if only voltage and current measurements in the cable converter side are used. To overcome these issues, a state estimation for PV systems is considered in this paper. A high gain observer is designed on the basis of a PV system model that accounts for PV cable parameters. It provides estimates of PVG output voltage and current using only current and voltage measurements in the converter side of the cable. A backstepping controller is then synthesized with the view of ensuring the MPPT objective. The output feedback control convergence is formally analyzed and its performances are illustrated by simulation.     

采用自适应扰动观察法的光伏并网系统最大功率点跟踪

提出了一种自适应扰动观察（P＆O）算法,用于在不同天气条件下太阳能光伏（PV）并网系统的最大功率点跟踪（MPPT）控制策略。该策略对于从太阳能光伏电池板中,获取最大的功率输出是十分重要的。利用一种依赖于功率变化的可变的扰动步长,提出了改进的自适应扰动观察算法。最后将通过仿真所得到的数据与传统的扰动观察算法进行了比较,结果表明所提出MPPT算法的收敛值和速度得到了改善,稳定时间缩短25%,稳态值提高20%以上,在太阳能光伏并网系统的最大功率点跟踪时是有效而实用的。     

基于PI调节占空比的自适应MPPT方法

最大功率点跟踪(MPPT)技术是提高光伏发电效率的重要途径之一;扰动观测法是MPPT控制中最常用的方法,针对其无法兼顾跟踪速度与最大功率点跟踪过程的震荡问题,提出了一种基于PI调节占空比的自适应MPPT方法,该方法针对占空比采用基于PI调节的自适应策略;通过Simulink建模仿真,与其他方法进行对比分析,结果显示了该方法可显著地提高了最大功率点跟踪的速度与精度。     

A novel fuzzy logic control technique tuned by particle swarm optimization for maximum power point tracking for a photovoltaic system using a current-mode boost converter with bifurcation control

This paper presents a novel fuzzy logic control technique tuned by particle swarm optimization (PSO-FLC) for maximum power point tracking (MPPT) for a photovoltaic (PV) system. The proposed PV system composes of a current-mode boost converter (CMBC) with bifurcation control. An optimal slope compensation technique is used in the CMBC to keep the system adequately remote from the first bifurcation point in spite of nonlinear characteristics and instabilities of this converter. The proposed PSO technique allows easy and more accurate tuning of FLC compared with the trial-and-error based tuning. Consequently, the proposed PSO-FLC method provides faster tracking of maximum power point (MPP) under varying light intensities and temperature conditions. The proposed MPPT technique is simple and particularly suitable for PV system equipped with CMBC. Experimental results are shown to confirm superiority of the proposed technique comparing with the conventional PVVC technique and the trial-and-error based tuning FLC.     

Bond graph modelling of a photovoltaic system feeding an induction motor-pump

Water pumping using induction motors has become one of the most feasible photovoltaic (PV) applications. A bond graph model to enable testing the PV system performance by computer simulation was developed. The PV-powered water pumping system investigated in this paper consists mainly of a PV generator, DC–DC and DC–AC converters, and induction motor-pump. The DC–DC converter control strategy is based on pulse width modulation (PWM). However, the oriented field control is used for the induction machine control. Computer simulations were carried out for maximum power point tracking (MPPT).     

Maximum power tracking of a generic photovoltaic system via a fuzzy controller and a two-stage DC–DC converter

This study presents a new two-stage DC–DC converter for maximum power point tracking (MPPT) and a voltage boost of a generic photovoltaic (PV) system. An intelligent MPPT of PV system based on fuzzy logic control (FLC) is presented to adaptively design the proposed fuzzy controlled MPPT controller (FC-MPPTC) while a voltage boost controller (VBC) is used to fix the output voltage to a voltage level that is higher than the required operating voltage to the back-end grid impedance. Modeling and simulation on the PV system and the DC–DC converter circuit are achieved by state-space and the software Powersim. The PV string considered has the rated power around 600?VA under varied partial shadings. The FC-MPPTC and VBC are designed and realized by a DSP module (TMS320F2812) to adjust the duty cycle in the two-stage DC–DC converter. A special FLC algorithm is forged to render an MPPT faster and more accurate than conventional MPPT technique, perturb and observe (P&O). The simulations are intended to validate the performance of the proposed FC-MPPTC. Experiments are conducted and results show that MPPT can be achieved in a fast pace and the efficiency reaches over 90?%, even up to 96?%. It is also found that the optimized tracking speed of the proposed FC-MPPTC is in fact more stable and faster than the general P&O method with the boost voltage capable of offering a stable DC output.