【作者】 李靖；

【导师】 谢华；

【作者基本信息】 电子科技大学 ， 检测技术与自动化装置， 2013， 硕士

【摘要】 传统化石能源短缺以及日益严重的环境污染问题使得新能源技术成为研究的热点。太阳能作为一种清洁、无污染的可再生能源已经成为当前最具发展潜力的新能源，而光伏发电作为利用太阳能最有效的方式受到了国际社会的广泛关注。在实际应用中，光伏阵列由于阴影遮挡常出现光照不均匀的情况，易导致热斑现象的发生和光伏电池的烧毁。为了解决热斑现象，常用作法是在光伏电池组件两端并联旁路二极管，但是旁路二极管的引入会改变光伏电池的电气特性，使得光伏阵列在阴影条件下其V-P特性出现多个峰值点，多峰情况下常规最大功率跟踪算法效率低下甚至完全失效。本文研究了光伏阵列在不均匀光照时其输出特性，并设计一种适合于阴影条件下的最大功率跟踪算法。首先借助光伏电池的等效数学模型，从原理上分析了旁路二极管造成V-I多膝和V-P多峰的原因，得出了光伏阵列在接受N种不同光照强度时，其V-I特性就会有N个膝形，V-P特性就会有N个峰值，并通过仿真进行了验证。其次，分析了阴影条件下光伏阵列局部峰值点的分布情况，推导出了某些峰值点位置的预测方程式，并通过仿真进行了验证。再次，分析了常见的单峰和多峰最大功率跟踪算法，通过分析粒子群算法和遗传算法这两种全局寻优算法，指出了其应用到光伏电池最大功率跟踪上的局限性，结合理论分析设计了双峰最大功率跟踪算法，并通过仿真验证了算法的可行性。最后，搭建了双峰最大功率跟踪的硬件试验平台，并在TI的DSP（TMS320F2812）上完成了软件设计与实现。本文设计的双峰最大功率跟踪算法的最大特点是具有预判功能和快速定位能力，且兼容单峰最大功率跟踪算法，解决了一般全局寻优算法在单峰情况时仍进行大范围搜索的问题。相关算法的仿真结果表明系统在光照强度均匀和不均匀情况下都能准确跟踪到全局最大功率点。在现有试验平台下，当光照强度均匀时同样能准确跟踪到最大功率点，光照强度不均匀情况下试验平台还有待完善。更多还原

【Abstract】 Shortage of traditional fossil energy and environmental issues are becoming moreand more seriously, in this case, the research about new energy technology becomes ahot topic. Solar energy, as a clean、non-polluting renewable energy, has become themost potential for development of new energy, Photovoltaic(PV) power generation, asthe most effective way to use solar energy, has been concerned widely in theinternational community.On the situation of uneven illumination, PV array will occur hot spot phenomena,even PV cell will be burned. To multiply bypass diode on both ends of PV module is thecommon solution, however, the bypass diode will change the electrical characteristics ofPV module, e.g., PV array’s V-P characteristic curve will appear multi-peak undershading conditions, in this case, the normal maximum power point tracking(MPPT)algorithm is inefficient and even complete failure.In this paper, output characteristics of PV array on the situation of unevenillumination are investigated, as well as, a suitable MPPT algorithm under shadingconditions is designed. Firstly, the reason that results in V-I multi-knee and V-Pmulti-peak by bypass diode is analyzed, with the help of equivalent mathematicalmodel of PV cell, the conclusion that V-I characteristic will have N knee shapes and V-Pcharacteristic will have N peaks is derived, and is verified by simulation. In the nextplace, the distribution of local peak point of PV array under shading conditions isanalyzed, the prediction equation of a certain peak point position is deduced andverified by simulation.Once more, some common unimodal and multimodal MPPTalgorithms are analyzed, focus on the analysis of particle swarm algorithm and geneticalgorithm what are both global optimization algorithms and point out the limitationsthat they apply to the MPPT of PV cell, the bimodal MPPT algorithm is designed bycombining theory analysis and the feasibility of the algorithm is verified through thesimulation. Finally, a test platform of MPPT is built and write a program based on TI’sDSP(TMS320F2812).The most outstanding characteristic of bimodal MPPT algorithm designed in this paper is anticipation function and capability of rapid positioning, the algorithm iscompatible with the unimodal MPPT algorithm and is different with general globaloptimization algorithm that will still search widely under unimodal condition. Thesimulation result shows the algorithm can track the global maximum power pointaccurately under the condition of uniform and uneven illumination intensity. In theexisting test platform, also can track the maximum power point accurately under theuniform illumination intensity condition, but the test platform remains to be perfectunder uneven illumination intensity condition.更多还原