Contributions to the Development of Multilevel Inverters for Grid-Connected Photovoltaic Systems

• Grant number: 24/11105-2
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: July 01, 2025
• End date: June 30, 2027
• Field of knowledge: Engineering - Electrical Engineering - Industrial Electronics, Electronic Systems and Controls
• Principal Investigator: Jose Antenor Pomilio
• Grantee: Caique Creomenes Almeida de Carvallho
• Host Institution: Faculdade de Engenharia Elétrica e de Computação (FEEC). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil

Abstract

Power converters are essential in converting solar energy into electricity, with particular emphasis on photovoltaic inverters, which convert the direct current (DC) from solar panels into alternating current (AC) used by the electrical grid. There are different types of inverters, including those with and without transformers. Although transformers can negatively impact performance, transformerless topologies are preferred in low-power applications for their cost-effectiveness and efficiency. However, these topologies can allow leakage currents, compromising power quality and triggering protections. This leakage current is primarily determined by the capacitance of the photovoltaic panel. One operational challenge is the variation of capacitance with environmental conditions, which impacts the leakage current value and the correct operation of the system. Studies aim to minimize these effects and ensure compliance with standards. The doctoral project proposes a new five-level single-phase inverter topology designed for grid connection and variable operation between three or five levels, adapting to leakage current levels in the system to improve efficiency and versatility. This allows for continuous operation on the electrical grid, selecting the mode of operation based on leakage current levels, andmaintaining the quality of the current produced by the inverter. (AU)