一种基于最小均衡差的光伏阵列重构方案

Reconfiguration scheme of photovoltaic array based on minimum equalization difference

对于光伏阵列而言,局部阴影是其最常见的导致输出功率损失的原因,由局部阴影导致的功率损失不仅与阴影面积相关,更多地取决于阴影的分布位置以及光伏阵列中各光伏板之间的连接方式。为了提升阴影条件下光伏阵列的输出功率,提出了一种基于网式连接(TCT)结构的光伏阵列重构方法,重点研究了如何根据不同的阴影条件,合理重构光伏板之间的连接关系。所提方法将光伏阵列分为固定结构和自由结构两部分,局部阴影条件下遵循均衡差原则,根据不同的阴影模式调整自由结构部分光伏板的连接方式,确定最佳的连接关系。仿真结果表明,在多种阴影条件下,相较于重构前,重构后光伏阵列的输出功率明显提高,且P-U特性曲线更趋向于呈现单峰值特性,更有利于最大功率点跟踪控制的实现。

For photovoltaic arrays,partial shadow is the most common cause of output power loss.The power loss caused by partial shadow is not only related to shadow area,but also depends more on the distribution of shadow and the connection mode among photovoltaic panels in photovoltaic array.In order to improve the output power of photovoltaic arrays under shading condition,a reconfiguration method of photovoltaic arrays based on TCT(Total Cross Tied)structure is proposed,which focuses on how to reasonably reconstruct the connection relationship among photovoltaic panels according to different shading conditions.The proposed method divides photovoltaic arrays into fixed structure and free structure.According to the equalization difference principle under partial shading condition,the connection mode of partial photovoltaic panel in free structure is adjusted according to different shading modes,and the optimal connection mode is determined.Simulative results show that,under various shading conditions,the output power of the photovoltaic array after reconstruction is significantly improved compared with that before reconstruction,and the P-U characteristic curve tends to show a single peak value characteristic,which is more conducive to the realization of maximum power point tracking control.