Design and Analysis of a Novel Two-Switch Transformerless High Step-Up DC-DC Converter for Grid-Connected Renewable Energy Sources

Abstract

Renewable Energy Sources (RESs), particularly Photovoltaic (PV) systems, inherently produce variable DC voltages that often cannot meet load or grid requirements directly. Consequently, a reliable and efficient DC-DC converter is required to interface RESs with downstream converters and loads. This paper proposes a non-isolated, high-gain, transformerless step-up DC-DC converter that provides continuous input current and a non-inverting output voltage. The proposed topology is designed to minimize switching losses and to maintain a low component count, thereby improving conversion efficiency while containing cost and implementation complexity. A comprehensive analytical model that includes parasitic elements is developed to derive the converter voltage gain. Comparative analyses of device voltage and current stresses against recently reported topologies are presented. The results demonstrate that the proposed converter achieves high voltage gain with reduced voltage and current stresses on switching devices, while preserving acceptable component current levels. Conduction intervals of switches and diodes, as well as switching loss contributions, are analyzed and quantified. Experimental validation is provided by a 100 W prototype, and measured results corroborate the theoretical predictions and simulation outcomes. The proposed converter thus represents an effective and practical solution for high-gain DC–DC conversion in renewable energy applications, offering an advantageous trade-off between efficiency, component simplicity, and cost.