中文摘要：

光伏系统普遍存在局部阴影或光照不均匀现象，局部阴影将导致光伏系统输出功率降低，甚至形成热斑现象，可能破坏组件的表面封装材料，严重时会烧坏单体光伏电池的物理结构而造成光伏组件永久损坏或发生火灾。该文对光伏组件在不同遮挡情况下的输出特性进行研究，总结热斑现象产生的原因及热斑情况下光伏组件输出特性及功率损耗的变化规律，提出一种利用光伏组件输出曲线斜率对遮挡个数进行诊断并通过短路电流对阴影强度进行预估的方法。在此基础上，进一步提出一种基于模糊控制的热斑故障诊断及优化控制策略，通过对光伏组件输出特性进行扫描并进行模糊诊断，实现热斑检测及优化控制，延长光伏组件使用寿命。仿真与实验结果验证了所提出的故障诊断方法的正确性和可行性。

英文摘要：

Partial shading instances are very common in photovoltaic （PV）systems. Partial shading will lead to the decrease of the PV system output power, even cause a hot spot phenomenon which may destroy the structure of the PV cell and in severe cases it may cause fire. In this paper, the output characteristics of PV module under partial shading condition was deeply studied, and the changing regularity of the output characteristics of PV module with hot spot was summarized. Then a method to detect whether there is a hot spot using the slope and the short-circuit current was proposed. Based on the method, this paper also proposed a fault diagnosis and optimal control strategy based on fuzzy control. Through the scan of output characteristic of PV module and the fuzzy diagnosis, the hot spot detection and the optimal control has been realized, and the service life of PV module has been extended. Finally, simulation and experimental results were presented to validate the proposed method.