一种光伏发电系统效率优化策略的研究

研究优化光伏发电,提高发电效率问题,针对目前光伏发电系统效率低,南于发电受到外界光照强度和温度影响,发电功率不稳定,且最大功率点跟踪(MPPT)过程在不同时域分别对快速性和准确性具有不同要求,为了提高稳定性,提出一种带有调整因子的双模模糊控制策略,采用两种模糊控制相结合的组合模型,使PWM信号开关的占空比D总能根据外界条件的变化迅速调节至合适的值,从而在外界条件发生变化时将光伏阵列的输出功率迅速跟踪达到并稳定的最大值,解决了既要快速跟踪又要精确定位的问题,提高了光伏发电系统的效率.通过在MATLAB中建立模型,并进行仿真,结果表明双模模糊控制策略能够根据外部环境的变化,快速、准确地跟踪光伏阵列的最大功率点.适时地改变模糊规则,提高了控制精度,改善了控制效果.     

基于模糊PID控制的光伏最大功率点跟踪仿真研究

在分析光伏电池伏安特性的基础上,设计了一个模糊PID控制器,以提高光伏发电的性能。仿真结果表明,模糊PID控制能够快速、准确地跟踪最大功率点,避免最大功率点处的振荡,提高了系统稳定性和能量转换效率。     

小型风光互补发电系统最大功率控制的研究

独立运行的风电系统或光伏系统都有其自身的局限性,选择了结合风力发电和光伏发电优点的风光互补发电系统作为研究对象,建立了风光互补发电系统的仿真模型,对最大功率跟踪控制进行仿真研究。结果表明,最大功率跟踪控制可以实现风力发电子系统和光伏发电子系统的最大功率跟踪。仿真结果初步验证了系统集成控制策略的正确性和可行性。     

局部阴影遮蔽下光伏阵列MPPT算法的研究综述

光伏阵列作为太阳能光伏发电系统的基本发电单元,在局部阴影条件下,它的输出特性发生改变,相应的功率曲线含有多个局域峰值,使常规的最大功率点跟踪算法很难准确地跟踪到真正的最大功率点,在分析常规最大功率点跟踪方法(恒定电压法、扰动观测法、电导增量法)的基础上,对多峰值最大功率点跟踪方法做了比较全面的比较和分析(模糊免疫算法、粒子群优化算法PSO等),为实现光伏阵列在部分遮蔽下实现最大MPPT设计与实现提供参考。     

改进扰动观察法的光伏阵列最大功率点跟踪算法

为了更好地跟踪光伏阵列的最大功率点,分析单个光伏电池的物理特性,建立光伏阵列的Matlab仿真模型,分析光伏阵列随光照温度不同而变化的P-U、U-I特性.针对系统在工作工况发生变化时跟踪情况的不同,对传统的扰动观察法做了变步长的寻优算法,并结合调整策略搭建光伏系统最大功率点跟踪的仿真实验模型.结果表明该算法可以快速准确地跟踪最大功率点,稳态效果好,能够更好地提高光伏发电最大功率点跟踪系统的跟踪性能.     

基于Buck变换器的光伏发电系统MPPT 控制

介绍以Buck变换器为对象的太阳能光伏发电系统。用Buck变换器实现对光伏发电系统的最大功率跟踪,采用逐次逼近法的MPPT控制策略,通过调节Buck变换器的PWM占空比输出,使得负载的等效阻抗跟随光伏电池的输出阻抗,使光伏阵列在任何条件下获得最大功率输出,跟踪最大功率。仿真表明MPPT（最大功率跟踪）控制策略的可行性。     

模糊RBF太阳电池最大功率点跟踪算法

为了有效地利用太阳能,提高光伏发电系统的效率,通过分析太阳电池输出特性和最大功率点跟踪原理,结合模糊控制算法、神经网络与比例—积分—微分(PID)算法的优势,提出一种模糊径向基函数(RBF)神经网络的太阳电池最大功率点跟踪算法。利用模糊RBF神经网络对PID控制器的控制参数进行自适应整定,从而精确调节光伏电池变换器的功率开关占空比,达到太阳电池最大功率点跟踪控制。仿真与实测结果表明:算法能有效提高系统的响应速度、自适应能力。     

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。     

电导增量法在光伏系统MPPT中的研究

分析了光伏电池的工作特性和光伏系统的拓扑结构及原理,将电导增量法应用到光伏发电系统最大功率点跟踪控制中,使系统能够快速响应外界环境的变化,让光伏发电系统始终工作在最大功率点.最后在Matlab/Simulink环境下进行了仿真,并且对仿真结果进行了详细分析,验证了该方法的正确性.     

光伏发电系统中改进型MPPT控制技术研究

对光伏发电系统提出了一种新的最大功率点跟踪（MPPT）控制方法。对固定电压法、电导增量法以及所提的两者的结合方法分别进行仿真,结果表明,所提方法能够快速、准确地跟踪光伏阵列的最大功率点,减少了在最大功率点振荡的能量损失,提高了光伏发电系统的能量转换效率。     

Type-2 Fuzzy Adaptive Output Feedback Saturation Control for Photovoltaic Grid-connected Power Systems

The adaptive interval type-2 (IT2) fuzzy output feedback control problem is studied for a single-phase photovoltaic grid-connected power system. The equivalent resistors of the inductors in the system are unknown and the part states are not available. Interval type-2 fuzzy logic systems (IT2FLSs) are utilized to approximate the uncertain nonlinear dynamics, and an IT2 fuzzy state observer is designed to estimate the unavailable states. By introducing a command filter method and using a backstepping control design technique, an IT2 fuzzy output feedback control scheme is investigated, in which the constraint conditions of pulse width modulation are ensured via mean-value theorem. It is proved that all the variables of the closed-loop photovoltaic system are uniformly ultimately bounded. The simulation and comparison results demonstrate the validity of the proposed control scheme.

     

基于视觉伺服控制的光伏板清洗系统设计

光伏板上的鸟粪、枯叶等污渍若不及时清理会导致光伏板热斑现象的发生,严重影响光伏板的使用寿命和安全。现有光伏板清理方法存在清洗效果不好、浪费水资源、清洗效率低等问题,为此,及时清理维护光伏板成为光伏发电企业亟待解决的首要问题。基于以上问题,该文提出光伏板清洗视觉伺服控制系统和一种改进型模糊PID控制算法,利用从实时视频图像中提取的反馈信息控制机械臂对准污渍点,实现定点喷射清洗污渍点,达到节水高效的目的。实验结果表明,基于改进型模糊PID控制算法的光伏板清洗视觉伺服控制系统能够准确地定位到光伏板污渍位置并精准喷射清洗污渍,最大限度地节约水资源。     

在线扰动优化光伏MPPT模糊控制器

利用可在线优化的模糊控制器进行光伏最大功率点跟踪控制（MPPT）。利用模糊RBF网络根据专家经验建立初始模糊控制器,在模糊控制器输出的控制量上叠加正态分布的随机扰动,根据控制效果自适应地构造和调整模糊规则。根据控制效果记录器的结果决定是否叠加扰动,以削弱功率震荡现象。该方法可以减轻对模糊控制器相关参数进行离线调整的工作量。仿真结果表明该方法在光伏MPPT控制中的有效性。     

Adaptive fuzzy control systems with dynamic structure

This article proposes a novel fuzzy system, referred to as a dynamic structure fuzzy system, to address tracking control problems for unknown nonlinear dynamical systems. The fuzzy system is employed to reconstruct the unknown nonlinearities of dynamic systems. In the dynamic structure fuzzy system, the number of fuzzy rules can be either increased or decreased over time based on the required approximation accuracy. The advantage of the dynamic structure fuzzy system is that a suitable-sized fuzzy system can be found to avoid overfitting or underfitting data sets. By using Gaussian radial basis function (GRBF) as a membership function, adaptation laws are presented for tuning all parameters of the parameterized fuzzy system, including the output weights, the widths and the centers of the GRBF's. Global boundedness of the overall control scheme is guaranteed in the sense of Lyapunov. The tracking error converges to the required precision through the adaptive control scheme derived by the Lyapunov synthesis approach. Simulations performed on an underwater vehicle system demonstrate the effectiveness of our scheme.     

Fuzzy sliding mode control for a robot manipulator

This work presents the design of a robust control system using a sliding mode controller that incorporates a fuzzy control scheme. The presented control law superposes a sliding mode controller and a fuzzy logic controller. A fuzzy tuning scheme is employed to improve the performance of the control system. The proposed fuzzy sliding mode control (FSMC) scheme utilizes the complementary cooperation of the traditional sliding mode control (SMC) and the fuzzy logic control (FLC). In other words, the proposed control scheme has the advantages which it can guarantee the stability in the sense of Lyapunov function theory and can ameliorate the tracking errors, compared with the FLC and SMC, respectively. Simulation results for the trajectory tracking control of a two-link robot manipulator are presented to show the feasibility and robustness of the proposed control scheme. This work was presented in part at the 13th International Symposium on Artificial Life and Robotics, Oita, Japan, January 31–February 2, 2008     

Robust adaptive fuzzy control scheme for nonlinear system with uncertainty

In this paper, a robust adaptive fuzzy control scheme for a class of nonlinear system with uncertainty is proposed. First, using prior knowledge about the plant we obtain a fuzzy model, which is called the generalized fuzzy hyperbolic model (GFHM). Secondly, for the case that the states of the system are not available an observer is designed and a robust adaptive fuzzy output feedback control scheme is developed. The overall control system guarantees that the tracking error converges to a small neighborhood of origin and that all signals involved are uniformly bounded. The main advantages of the proposed control scheme are that the human knowledge about the plant under control can be used to design the controller and only one parameter in the adaptive mechanism needs to be on-line adjusted.     

板球系统的模糊控制方法研究

板球系统是一个典型的多变量、非线性控制系统，是杆球系统的扩展，用以检测各种控制方案。该文针对板球系统的定点稳定问题，首先提出了T—S模糊控制方案，仿真结果较好，但实物系统的试验却发现球在稳定点附件振荡、难以稳定、超调大；针对此缺点，在T—S模糊控制方案的基础上，提出变论域自适应模糊控制方案，仿真结果表明控制性能得到明显改善，且越是靠近稳定点效果越明显，体现了变论域自适应模糊控制方法具有精度高、无振荡、几乎无超调的特点。实物系统的试验结果也表明，变论域自适应模糊控制方案比T—S模糊控制方案的效果要好。     

Robust adaptive fuzzy control scheme for nonlinear system with uncertainty

In this paper, a robust adaptive fuzzy control scheme for a class of nonlinear system with uncertainty is proposed. First, using prior knowledge about the plant we obtain a fuzzy model, which is called the generalized fuzzy hyperbolic model （GFHM）. Secondly, for the case that the states of the system are not available an observer is designed and a robust adaptive fuzzy output feedback control scheme is developed. The overall control system guarantees that the tracking error converges to a small neighborhood of origin and that all signals involved are uniformly bounded. The main advantages of the proposed control scheme are that the human knowledge about the plant under control can be used to design the controller and only one parameter in the adaptive mechanism needs to be on-line adjusted.     

DSP控制的3kW非隔离型并网逆变器研究

提出了一种基于DSP控制的非隔离型并网逆变器的实现方案。介绍了该并网逆变器结构及原理,给出了基于DSP控制的硬件和软件的总体设计,实现了基于电压扰动观察与控制的最大功率点跟踪(MPPT)和无差拍控制的并网控制策略,并测试了其孤岛保护,完成了3 kW的实验样机及相关实验,对实验波形的分析证明了该控制策略和方案的有效性。