Design and Control of High Efficient DC/DC Converter for PV String /

Abstract

In renewable energy sources specifically in Photovoltaics systems DC/DC converter plays a vital role as the power generated by the PV system is non-linear and changes with solar irradiance and temperature. So, these systems require converters that have a wide input voltage range, high voltage gain, high power range, and improved efficiency. With the growth of renewable energy sources around the world, the demand for the most costeffective

and efficient converters which can operate at high frequency and have less switching and conduction loss has grown. High efficiency is one of the most difficult goals to attain in power electronic converters. In this thesis, an analysis of non-isolated reduced redundant power processing converter topology is presented to evaluate its efficiency and reliability for the photovoltaic system. The proposed converter has a very simple design and the least number of circuit elements. The converter is designed in such a way that it always operates in continuous conduction mode. The mathematical modeling of the 3 kW converter is presented to show the theoretical analysis of the step-up voltage ratio of the converter. For further evaluation of the performance and efficiency of the converter, a simulation study is conducted in PSIM software. The overall efficiency of the converter is improved for a wide input voltage range and voltage gain specifically for Photovoltaic systems. A comparison between SiC MOSFET and Si MOSFET switches was also made for a 3 kW I-IIB Buck-boost/Boost non-isolated Reduced redundant converter for the photovoltaic system with a wide input voltage range. Mathematical calculations were used to investigate the switching and conduction losses, and software simulations in PSIM were used to verify their authenticity. In high-frequency power applications, the results suggest that SiC MOSFET can work more efficiently than Si MOSFET. Si MOSFETs, on the other hand, are still preferred for small voltage and low power applications due to their lower cost.