Study on a Non-Isolated High Step-Up SEPIC-Based DC-DC Converter with Continuous Input Current for Photovoltaic Applications

The objective of this paper is to propose, study and analyze a non-isolated high step-up SEPIC-based DC-DC converter for photovoltaic applications. The proposed structure is based on the SEPIC converter and utilizes a two-winding coupled inductor along with an improved voltage multiplier cell in order to enhance the output voltage level. Moreover, a passive voltage clamp is used to reduce the voltage stress on the main switch and recover the energy stored in the leakage inductance of the coupled inductor. Hence, an active switch with low RDS-ON could be employed. Meanwhile, due to soft switching condition at turn-off instant of diodes, their reverse-recovery problems are solved. Furthermore, the presented converter has the merits such as continuous input current, high efficiency and low cost and size which make it a promising solution for photovoltaic applications. At the end, the converter is compared to different types of DC-DC converters to show its advantages over the converters designed before. In order to verify the performance of the converter, a 200-W laboratory prototype is implemented and experimental results are taken and depicted. Results prove the feasibility and functionality of the presented converter for photovoltaic systems.