Hot Spot Detection And Optimal Control Of PV Module Under Partial Shadow

In this thesis PV module under partial shadow is the research object. The maincontent includes: Mathematical Modeling of PV module under partial shadow,output characteristics of the bypass diode structure PV modules under partial shadow,PV module hot spot detection method, fault diagnosis and optimal control of PVmodule based on fuzzy control.In this thesis, the mathematical model and output characteristics of Photovoltaiccells is analyzed and created for occlusion complexity. This thesis proposed amethod which can simulate the output characteristics of PV modules in most of theocclusion. Comparing with traditional model, this model can regulate the parameterssuch as light intensity, temperature, shelter area. So this model can accurately reflectthe output characteristics of PV module under flexible illumination, temperature andshadow.Partial shadow and uneven illumination is commonly found in a variety ofphotovoltaic power generation system. In order to avoid hot spot phenomenon,general method is to parallel bypass diodes for the photovoltaic cells in the modules.This thesis analyzes PV module with different bypass diode structure underocclusion from the perspective of power. Through simulation and experiment, themost appropriate PV module structure is found. By using the structure, underocclusion PV module can export more power than other structures and reduce thepower loss caused due to the mismatchHot spot might occur when PV module is blocked. By analyzing the cause of hotspot and output characteristics of PV module under hot spot, this thesis proposed amethod to detect whether there is a hot spot using the slope and the short-circuitcurrent. Based on the method, this thesis also proposes a fault diagnosis methodbased on fuzzy control. In this method, Buck-Boost converter is used to optimallycontrol PV models. The method was verified from the angle of the simulation and experiment. The result of simulation can experiment indicate that the methodproposed by the thesis can detect whether there is a hot spot, can optimally controlPV modules, avoid hot spots, at the same time the PV models can export power asmuch as possible.