光伏系统最大功率点跟踪算法的研究与实现

发布时间：2018-02-01 18:54

本文关键词： 光伏发电系统最大功率点跟踪分数阶微分坐标变换扰动观察法跟踪效率　出处：《桂林电子科技大学》2014年硕士论文　论文类型：学位论文

【摘要】：在全球面临环境污染和能源危机的双重压力下，太阳能因其储量大、无污染、不受地域限制等优点正在成为世界能源组成中的重要部分。在太阳能光伏发电系统中，提高光伏阵列的转换效率是需要解决的核心问题之一，采用最大功率点跟踪（Maximum Power Point Tracking，MPPT)技术可以有效解决这一问题。在MPPT控制中存在两个相互矛盾的问题：响应速度和跟踪精度，目前的研究主要集中在如何调整步长平衡这两个问题。该论文针对以上问题，立足于现有研究成果和技术，主要从以下几个方面对光伏发电MPPT算法进行了研究：（1）提出基于分数阶微分补偿的扰动观察MPPT算法，在保证响应速度的前提下提高了跟踪精度。在扰动观察法微分判断条件的前提下，引入具有独有特性的分数阶微分，将其作为一阶纯微分的辅助新信息加入判断条件。提出一阶纯微分与分数阶微分结合的方法，利用分数阶微分的滤波特性，，有效地削弱功率振荡，克服跟踪精度与响应速度不能同时兼顾的缺点。同时给出所提出算法的直观理论分析。仿真结果表明，所提出的算法能有效地减小稳定运行时的固有振荡，减少跟踪过程中的功率损失，提高算法的跟踪效率。（2）提出基于坐标变换的变步长扰动观察MPPT算法，在保证跟踪精度的前提下提高了响应速度。以光伏阵列输出特性曲线的最大功率点电压为基准，分别对其两侧电压坐标进行自然对数变换。利用自然对数非线性递增的特性，对光伏阵列输出特性曲线进行不等比例地压缩，实现步长随实时电压调整的变步长跟踪。仿真结果表明，所提出的控制算法可以实现快速起动，并能快速准确地跟踪外界环境变化，提高了光伏阵列的利用率。（3）在光伏系统MPPT实验平台上对所提出的基于分数阶微分补偿的扰动观察MPPT算法进行实验验证，并与传统扰动观察法进行综合性能比较。实验分为室内模拟光伏阵列实验和室外普通光伏阵列实验，实验结果表明，在两种实验环境下所提出的基于分数阶微分补偿的扰动观察法比传统的扰动观察法在稳态性能上均有明显的提高。
[Abstract]:Under the double pressure of global environmental pollution and energy crisis, solar energy has no pollution due to its large reserves. In the solar photovoltaic power generation system, improving the conversion efficiency of photovoltaic arrays is one of the core problems to be solved. Maximum Power Point Tracking was used. MPPT can effectively solve this problem. There are two contradictory problems in MPPT control: response speed and tracking accuracy. The current research focuses on how to adjust the balance of step size. This paper aims at the above problems, based on the existing research results and technologies. The MPPT algorithm of photovoltaic power generation is studied from the following aspects: 1) A disturbance observation MPPT algorithm based on fractional differential compensation is proposed, which improves the tracking accuracy under the premise of ensuring the response speed. The fractional differential with unique characteristics is introduced and added to the judgment condition as the auxiliary new information of the first order pure differential. The method of combining the first order pure differential with the fractional differential is proposed, and the filtering characteristic of the fractional differential is used. It effectively weakens the power oscillation and overcomes the shortcoming that the tracking accuracy and the response speed can not be taken into account simultaneously. At the same time, the intuitive theoretical analysis of the proposed algorithm is given, and the simulation results show that. The proposed algorithm can effectively reduce the inherent oscillation while running stably, reduce the power loss in the tracking process, and improve the tracking efficiency of the algorithm. (2) A variable step-size observation MPPT algorithm based on coordinate transformation is proposed, which improves the response speed while ensuring the tracking accuracy. The maximum power point voltage of the output characteristic curve of photovoltaic array is taken as the reference. The natural logarithmic transformation of the voltage coordinates on both sides of the photovoltaic array is carried out, and the output characteristic curve of the photovoltaic array is compressed in varying proportions by using the natural logarithmic nonlinear increasing characteristic. The simulation results show that the proposed control algorithm can realize fast start and track the change of external environment quickly and accurately. The utilization ratio of photovoltaic array is improved. 3) the proposed perturbation observation MPPT algorithm based on fractional differential compensation is verified on the photovoltaic system MPPT experimental platform. The experiment is divided into indoor simulated photovoltaic array experiment and outdoor common photovoltaic array experiment. The experimental results show that. The perturbation observation method based on fractional differential compensation proposed in two experimental environments is better than the traditional perturbation observation method in steady-state performance.
【学位授予单位】：桂林电子科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM615

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