Martyniuk V. Dynamic commutation system of the topology of solar panels taking into account the characteristics of the cloud cover

The dissertation work is devoted to creating optimal conditions for the operation of an array of solar power modules and simultaneously maximizing energy production under existing weather conditions by creating a system of dynamic commutation of the topology of solar panels, which determines the optimal structure of an array of solar panels taking into account the parameters of cloud cover. In the first chapter, an analysis of the available methods for assessing the potential of solar energy and its main parameters is carried out. A study of the current state of development of semiconductor solar energy converters, features of their operation in conditions of partial shading, as well as ways of reducing its negative impact is carried out. The state of development of equivalent circuits, mathematical models and topologies is analyzed. Mathematical models of cloud cover are analyzed in details. The classification and comparative analysis of cloud cover image generation methods based on the use of noise is carried out. In the second chapter, mathematical relations are given that describe the improved model of the solar panel, which was obtained on the basis of the analysis of equivalent substitution schemes. Two methods of determining the parameters of the model are proposed, namely, the method of selecting ideality coefficients and resistances. The features of the algorithms of the proposed methods are considered and recommendations are given for the use of weight functions, which allows to obtain a more accurate estimate of the values of the model parameters. The use of the simple iteration method and the relaxation method for solving transcendental equations and ensuring the convergence of numerical methods is proposed. It is shown that the smallest approximation error values are provided by the Gaussian window function. Calculated values of model parameters for KC200GT and ST40 solar panels are given. A comparative analysis of the proposed methods of determining model parameters with modern methods presented in the literature is carried out. The comparison is made for KC200GT and ST40 solar panels and it is established that the proposed methods of determining the parameters provide a better approximation of the I-V curves. The dependence of the parameters of the improved model of the solar panel on the level of irradiance and temperature is determined, with the corresponding error values. The third chapter is devoted to the creation of a mathematical model of cloud cover. The features of the proposed cloud cover model, based on the analysis of the spectral characteristics of the image of various types of clouds, are described. It is shown that proposed model based on the original image of the cloud cover generates the cloud image, which reproduces the main features of the original image. The use of a weight function is proposed to simplify the analysis of the original images and reduce the influence of the phenomenon of spectrum leakage. The method of determining the parameters of the created model is considered, and the peculiarities of the phase-frequency characteristic and the method of its generation are investigated. The methods of regression analysis and principal component analysis are used to approximate the amplitude-frequency characteristic. An example of use is given to determine the values of the model parameters for the cloud cover image under study. A comparative analysis of the proposed model with the spectral synthesis algorithm is carried out. The approximation error that provides the presented models is determined. The values of the model parameters are compared with the values obtained by the brute force method, which indicates the effectiveness of the developed model. The fourth chapter is devoted to the computer modeling of the I-V and output power characteristics of the solar panel array for the KC200GT panel in the Matlab Simulink software environment. Schematic models of non-switched and switched arrays of solar panels are developed and described, and the features of their use are given with the necessary parameter calculations. The operation of the dynamic switching system and switching of the topology of the array of solar panels during operation to ensure the maximum output power in conditions of partial shading are simulated. The initial characteristics for the studied arrays were obtained based on the parameter values of the solar panel and cloud cover models, which were obtained in the previous sections. A comparative analysis of this system with a non-switched array is carried out in order to evaluate the efficiency of the proposed switching algorithm, which confirmed the theoretical calculations and feasibility of the developed dynamic switching system and the proposed mathematical models of solar panels and cloud cover.