【作者】 雷蕾；

【导师】 张从力； 段其昌；

【作者基本信息】 重庆大学 ， 控制科学与工程， 2011， 硕士

【摘要】 光伏发电是太阳能的一个重要应用,是当前最有发展前景的新能源和可再生能源技术。提高光伏发电的技术水平对改善能源结构,构建能源安全体系具有重大意义。在不均匀光照情况下,光伏阵列由于局部温度过高,会出现热斑现象。解决热斑效应的常用方法是给光伏电池组件并联旁路二极管,这种方法虽然可以防止部分遮光的光伏电池热击穿,但使得光伏系统的发电效率降低,并且二极管不具有可控性。光伏阵列受到不均匀的光照时,输出的伏安特性曲线呈阶梯状,其功率伏特曲线含有多个局部峰值。在外界环境突变时,传统的光伏电池数学模型和单峰最大功率点跟踪方法都不再适用。所以,建立一种新的光伏系统拓扑结构,研究新的控制算法,从而快速的找出不均匀光照情况下光伏系统的最大功率点,实时调整最大功率输出,有利于提高光伏发电效率。本文在查阅了国内外大量的相关文献的基础上,针对目前光伏发电技术的研究现状,设计了一种新的集成转换器的光伏系统拓扑结构,采用改进的粒子群算法,对不均匀光照下光伏发电系统的控制技术进行了深入的研究。分析了光伏电池在不均匀光照下的电气特性和最大功率点跟踪(Maximum Power Point Tracking,简称MPPT)的原理和基本算法。研究了集成转换器的拓扑结构和工作原理,并对多个模块组成的光伏阵列的集成转换器控制策略进行了详细探讨,使每个电池模块都工作在各自的最大功率点。提出了带扩展记忆的粒子群算法(PSO with Extended Memory,简称PSOEM),与标准粒子群算法的性能进行了仿真比较试验,针对不均匀光照下光伏阵列输出特性曲线存在多个局部峰值,根据PSOEM在多峰函数的全局寻优、多变量寻优方面的良好性能,将其应用到不均匀光照下光伏阵列的最大功率跟踪控制中,解决了局部遮阴下多峰寻优的问题。根据建立的数学模型和系统的控制策略,在Matlab/Simulink中对两个模块组成的系统在各种不同遮光情况下进行仿真试验,通过试验来验证该控制策略的整体性能。试验结果表明,相对于并联旁路二极管的方法而言,本文提出的方法在提高光伏阵列的输出功率方面具有优势,从而验证了所提方法的可行性和有效性。更多还原

【Abstract】 Photovoltaic Power Generation is a very important kind of applications of solar energy, it is acknowledged to be the most development prospects of all the kinds of the new energy and renewable energy sources. It has great significance both for improving the engineering level of Photovoltaic Power Generation and constructing security structure of the energy sources.On the situation of uneven illumination, if photovoltaic array has overtopped temperature, there would be the phenomena named hot spot effect. The usual solution of this problem is multiplying bypass diode. This solution can prevent the photovoltaic battery to be breakdown, but it would lower the efficiency of generating electricity in a photovoltaic system, and diode can’t be controlled. During the situation of uneven illumination, the output current-voltage curve of the PV system will appear echelonment, and there would be many local peaks in its P-V curve. When the external environments changed, the traditional mathematical model and tracing method of the unimodal maximum power point would fail. So, it’s necessary to construct a new kind topological structure of photovoltaic power system and develop a new kind of control arithmetic to find the maximum power point, adjust the peak power output and improve the generating efficiency of the photovoltaic power system.Based on the studying of domestic and foreign literature, this thesis present a new kind of topological structure which with integrated converter and a kind of improved Particle Swarm Optimization (PSO) was used to research control technology of photovoltaic power system under the situation of uneven illumination. In this paper, the electrical characteristic and the maximum power point tracing of photovoltaic cells were analysis, and deeply study on the topological structure and operating principle of the integrated converter, and particularly analysis control method of the integrated converter constituted by multi- modules to make every photovoltaic cell work in their maximum power point. A kind of method named PSO with Extended Memory (PSOEM) is proposed. Compared with the standard PSO, PSOEM has better performances in global optimization and multivariable optimization in the situation of multi-modal function. It is used in the photovoltaic array maximum power tracing control under the situation of uneven illumination, and solve the problem of multi-peak optimization in partial shading. On the basis of the mathematical model and control strategy, Using Matlab/Simulink to do simulation experiments of the system constituted by two modules under different shading conditions. The overall performance of this control strategy is checked by this simulation experiments. Test results shows that compared with the solution by multiplying bypass diode, this method has superiority in improving output power of photovoltaic array , the feasibility and effectiveness of this proposed method is proved.更多还原