考虑多点局部阴影的光伏阵列建模及复合型最大功率跟踪算法研究

Modeling of Photovoltaic Array with Multi-Partial Shadows and Study of the Hybrid Maximum Power Point Tracking Algorithm

构成光伏组件的每个光伏电池在运行中由于制造、遮挡等因素的影响,其输出会有差异。当若干个光伏电池受到不同程度阴影遮挡导致其输出与正常电池有较大差异的时候,组件输出的P-U曲线会出现多峰情况,针对单峰的传统最大功率点跟踪(Maximum Power Point Tracking,MPPT)策略很可能失效,从而陷入局部最优值。为解决该问题,推导了多点局部阴影下的光伏阵列数学模型,该模型能够理想描述任意阴影情况下的阵列输出特性曲线。基于此模型,提出了结合全局扫描法、电导增量法,以及快速逼近公式的复合型MPPT算法,并进行了仿真验证。仿真结果表明:相比于传统算法,算法在光伏组件受到遮挡时不会陷入局部最优;同时,相比于全局搜索法,该算法寻优效率更高。

The PV module is composed of the solar cells,and the output of each solar cell is different because of its production,shading,etc.When several solar cells are under different shadows and their outputs are greatly different from the normal ones,the output of the P-U curve of the PV module can have multiple peaks,therefore the traditional Maximum Power Point Tracking strategy suitable for single peak may fail to manage this phenomena,and thus fall into the local maximum power point.To address this drawback,the general mathematical model in conditions of multi-partial shadows is derived.It can ideally describe the output characteristic curve of PV array in any shadow case.Furthermore,the Hybrid Maximum Power Point Tacking(MPPT) algorithm combining the global algorithm,incremental conductance,as well as a fast approxima-tion formula,is proposed based on this model in the paper.The simulation results show that compared with the traditional algorithm,the algorithm proposed in this paper is will not fall into local maximum power point under conditions of multi-partial shadows;and compared with the global search method,this algorithm is more efficient in optimization.