Modeling And Parameter Identification Of I-V Characteristics Of Photovoltaic Panel Under Uniform And Non-uniform Irradiance

Due to the increasing global extreme climatic phenomena and the insufficient supply of fossil fuels,such as coal and petroleum,renewable power generation is receiving more and more attention from various countries.Photovoltaic power generation has some advantages compared with fossil fuels,such as clean,pollution-free and renewable.Photovoltaic power generation has broad application prospects.Photovoltaic panel,as the main body of photovoltaic power stations,study its I-V characteristics.which is helpful to solve the output power of photovoltaic panel under different operating conditions,and is beneficial to the arrangement of PV panel and tracking of maximum power of photovoltaic panel.Therefore,this thesis selects the modeling of photovoltaic panel I-V characteristics and parameter identification as the main content.This thesis introduces the principles of photovoltaic power generation,as well as the single-diode model and shape model commonly used to model the I-V characteristics of photovoltaic panel,and summarizes and categorizes the parameters identification of different models.This thesis proposes a voltage and current based error criterion,which is used to obtain the physical parameters of the single-diode model of the photovoltaic panel during the curve fitting process.The error criterion takes into account the characteristics of I-V curve of the photovoltaic panel under uniform irradiation,uses the maximum power point as the demarcation point,and the voltage and current square error are used in it.Four optimization algorithms and different verification data are used to verify the error criterion.,which includes experimental data and setting data.The results show that,compared with the traditional current based error criterion,the voltage and current based error criterion has higher accuracy in parameter identification and maximum power calculation,which verifies the accuracy of proposed error criterion.In this thesis,the shape model is used to model the I-V characteristics of photovoltaic panel under non-uniform irradiation.First.the shape model is used to obtain an explicit and analytical expression of voltage of photovoltaic cell in terms of current,which considers the negative voltage characteristics of the single-diode model.The model is expanded to photovoltaic cell strings,photovoltaic modules,and even larger series structures.Comparing with Newton’s method and Lambert function method,it is found that the results obtained with proposed model are similar to above two methods,however,the computational complexity and average computing time are reduced significantly by the proposed model.Using different shading scenarios to verify the model,the I-V curves calculated with proposed model have a high correspondence with experimental data,proposed model accurately estimates the maximum power point.