Parameter Identification Method For Photovoltaic Cell Nonlinear System

Photovoltaic cells form photovoltaic arrays in series and parallel,and play an important role in photovoltaic power generation systems.Therefore,it is the basis for optimizing photovoltaic cell design,improving the working efficiency and real-time control of photovoltaic power generation systems to identify the parameters of photovoltaic cells in different states and analyze the influence of the basic battery parameters on the performance of photovoltaic system.Based on the gradient search method and the Newton search method,this paper discusses the parameter identification problem of the photovoltaic cell nonlinear system by using the hierarchical identification principle and the multi-innovation identification theory,and the main results are as follows:（1）For the photovoltaic cell nonlinear system,the single-diode photovoltaic cell model is taken as the research object,and by using the iterative identification combined with the gradient search method and the Newton search method,a gradient-based iterative algorithm and a Newton iterative algorithm of the single-diode photovoltaic cell model are obtained.（2）By using the decomposition technology,the parameter identification model of the single-diode photovoltaic cell model is decomposed into two sub-identification models with fewer parameter,and a two-stage parameter identification model is obtained.By using the interactive estimation theory to deal with the coupling problem,the computational load is reduced,and a two-stage gradient-based iterative algorithm and a two-stage Newton iterative algorithm are obtained.（3）According to the multi-innovation identification theory,the innovation vector is generalized to the innovation matrix,which increases the utilization rate of the known data.Combined with the two-stage parameter identification model of the single-diode photovoltaic cell model,a hierarchical multi-innovation gradient-based iterative algorithm for the single-diode photovoltaic cell model is derived by using the negative gradient search.The paper gives several parameter estimation algorithms for photovoltaic cell nonlinear systems and the algorithm flowcharts,and uses the numerical examples to verify the the effectiveness of the proposed algorithms.