规模光伏阵列高效运行电池板管理关键问题研究

In order to improve the efficiency of photovoltaic (PV) system, the main object of this project is how to realize the fault diagnosis,fault location and and multi-local maximum power points tracking (MPPT) in scale PV array system. The key issues are as follows:.①In order to make the PV system run uninterruptedly and fault diagnosis cost low, a mathematic model of PV array under fault conditions is established, which is based on the physical character of PV array and PV cell mathematic model. Accordingly, the inner laws of healthy and unhealthy PV string under fault conditions are got. It provides a new method for fault diagnosis with divisional current and voltage sensor. .②In order to optimize the number of sensor, a method of combining the assembled power union and optimized sensor placement without redundant information is proposed. It overcomes the conflict between the number of sensor and PV array scale and achieves the fault location in huge PV array..③In allusion to multi-local maximum power points (MPP) problem under PV array fault condition, the healthy and unhealthy sections are divided using the fault diagnosis information, so that the sections of single MPP and multi-local MPP can be divided. It provides a new method for MPPT..With the implement of this project, PV system running efficiently and reliably will be guaranteed and the PV industry will also be promoted greatly.

为从源头上提高光伏系统效率，本项目重点研究在规模光伏阵列中如何实现故障诊断、故障点定位以及利用故障诊断信息实现多极值最大功率点跟踪，其研究内容有：.①为实现光伏系统的不间断运行与故障诊断之间能够低成本有机结合，基于电池数学模型与阵列物理特性，建立故障下光伏阵列输出模型，揭示故障状态下健康支路与故障支路电特性的内在规律，开辟基于电压电流分区域故障诊断的新途径。 .②为优化故障诊断中传感器数量，提出以组合功率单元和无冗余信息的最优传感器配置相结合的方法，从而解决传感器数量与阵列规模之间的矛盾，实现规模阵列中故障电池板定位。 .③针对阵列故障时存在多个局部最大功率点问题，利用故障诊断信息，将阵列划分为无故障和故障区域，实现单极值点与多极值点区域的划分，提出最大功率点跟踪控制的新思路。.本项目的开展，将为光伏系统高效、可靠运行提供坚实的技术保障，推动光伏产业持久发展。

本项目的研究内容和目标是建立光伏阵列在故障下的数学模型，根据故障阵列的输出提出建立电压、电流分区域故障诊断方法，为基于电特性故障诊断及故障电池板定位提供理论基础；利用组合功率单元和最优传感器配置相结合的方法降低传感器数量，解决光伏阵列规模与传感器数量之间的矛盾；将故障诊断信息与故障态下多极值最大功率点跟踪相结合，利用故障诊断信息将阵列划分为无故障区和故障区，从无故障区向故障区搜索最大功率点，或者直接分析故障区电池板的损坏率来定位最大功率点工作区间，为多极值点最大功率点跟踪提供新的研究思路。.本项目提出了最优传感器布置方法以及故障诊断与最大功率点跟踪相结合实现故障下阵列优化运行，难点是故障阵列输出特性及传感器在电池板不同工作点下信息解读，采用了基于图论的数学手段以及电池板能量守恒原理，取得的成果有：.(1)提出了最优传感器放置方法；在最优传感器放置方法的基础上，通过改变阵列工作点实现传感器输出信息二次利用进而实现无支路电流传感器故障诊断。.(2)根据故障诊断信息，本项目提出了虚拟最大功率点跟踪，进而提高故障下最优运行效率。.(3)分析了故障阵列的成因，对故障特性进行了分类，总结了不同类型故障下电池板、组串以及阵列的电气输出特性。.(4)针对大规模阵列故障诊断，目前广泛热成像的手段，提出了基于参数模型的故障诊断方法。此外，针对热成像图中色度渐变的想象，提出了修正算法。