Lukianov M. Distributed power supply system for electric transport based on solar panels

Lukianov M.O. Distributed Power Supply System for Electric Transport Based on Solar Panels. – Qualifying scientific work, the manuscript. Thesis for the degree of Philosophy Doctor, in specialty 171 - Electronics. –National Technical University of Ukraine "Igor Sikorsky Kyiv Polytechnic Institute", Ministry of Education and Science of Ukraine, Kyiv, 2024. The dissertation focuses on advancing the control theory for modular solar panel converters through feedback signal correction. The achieved outcomes significantly contribute to the progress of renewable energy sources and power supply systems for electric transport. In the first chapter, the analysis of contemporary challenges in connecting solar panels to power lines of electric transport with various levels of AC and DC voltage is conducted. It is demonstrated that connecting renewable energy sources to traction lines allows reducing the load on centralized substations and improving the quality of electrical energy. Various methods of connecting solar panels are compared, including the use of low-frequency transformers, integration into DC power conditioner units, additional equipment for traction lines, and energy storage systems. Based on a review of current trends in photovoltaic systems and conversion technology, the relevant scientific problem of developing a modular converter system is identified. This system involves selecting converter topologies and connection methods for efficient power scaling of the solar station and aligning the voltage of photovoltaic panel arrays with the traction network. In the second chapter, a methodology for comparing popular converter topologies used in photovoltaics is developed based on relative assessment of cost and losses in semiconductor elements. The chosen topology for the modular converter cell is determined as a result. An economic analysis is provided for the installation of systems consisting of multiple connected converters, converters with galvanic isolation, and hybrid multi-port converters integrating energy storage. Relative cost and loss evaluations are obtained for classical photovoltaic solutions and the proposed modular converter system. The third chapter presents the structure of the proposed modular converter and the development of a universal control system for such a converter. Stability analysis of the embedded control system for the tested converter is conducted, along with the impact of the developed control system on the overall stability of the system. Regulator parameters are determined to ensure the converter's operation with necessary stability margins. In the fourth chapter, modeling and experimental verification of the developed modular converter are carried out. A Simulink model is constructed to test different types of connection for modular converters - parallel/series at the input/output. Imbalances in currents and voltages of each module are measured. Simulation results validate theoretical calculations and demonstrate the ability of the developed control system to eliminate imbalances in currents/voltages for both sequentially and parallel-connected converters, ensuring imbalances below 5%. The scientific and technical task of reducing imbalances in currents and voltages of cells in the modular power supply system for electric transport based on solar panels is successfully addressed in this work through the implementation of the developed control theory, relying on feedback signal correction of converters. Keywords: power converters, modular PV converters, power supply network for electric transport.