High gain non-isolated switched inductor SEPIC converter for renewable energy applications

Abstract High step-up DC-DC converters are required in renewable energy systems to efficiently interface low-voltage sources with high-voltage loads and DC microgrids. The conventional high gain converter suffers from high voltage stress of semiconductor devices, low efficiency and complex circuit architecture. A high gain non-isolated switched inductor single-ended primary-inductor converter (SI-SEPIC) for renewable energy applications is presented in this research. The suggested topology adopts the switched-inductor network to realize a much higher voltage conversion ratio. The converter retains the intrinsic benefits of standard SEPIC converter, such as non-inverted output voltage and wide working range, which make it suited for solar systems, fuel cells, battery-powered systems and DC microgrids. The converter is analyzed in detail in terms of operating modes, steady state characteristics, derivation of voltage gain, design of components and performance evaluation. The proposed converter is experimentally validated with a laboratory prototype of 75 W. The experimental results support the validity of the proposed SI-SEPIC converter for renewable energy applications with steady operation; high voltage gain and high-power conversion efficiency.