考虑随机阴影影响的光伏阵列失配运行特性

Operation Mismatches of Photovoltaic Array Considering Random Shadows

目前为了减少功率失配损失,一般太阳能模组串联时都配置旁路二极管以提供一个能量散逸的途径;而在并联运行前,还将配置阻断二极管以防止功率逆向传送。本文基于上述新配置条件重点考察了随机阴影导致的光伏阵列运行失配特性,并比较了不同串并联模式下的阵列抗失配能力。研究结果表明:由于多辐射强度导致功率曲线多峰走向的趋势,常规单调MPPT算法可能因只检测到伪极大值点而失效;其次,局部辐射强度导致的"门槛效应",即局部阴影的变化并不一定对全局功率输出有影响;最后,为了相对提高输出功率,提出全阵列设计时应优先考虑并联的建议。

Photovoltaic cells would operation as load when local solar irradiation declines in series connection, which would result in the damages easily. Nowadays modules are often configured with bypass diodes to provide energy releasing route. Furthermore, blocking diode is series connected before parallel connection in order to prevent inverse power injection. Based on such configurations, this paper is mainly devoted to investigate the operation mismatches of the photovoltaic array caused by random shadows, and compared different abilities under diverse series/parallel patterns. Researches indicate that： firstly, traditional monotone algorithms of MPPT could be invalid for detecting false maximum only. Secondly, the ＂doorsill effect＂ of local irradiation intensities, namely that global power output might not be influenced by changes of local shadows. Finally, suggestions are put forward that parallel connection should be ranked prior consideration with whole array design, to boost power output relatively.