Analysis of a DC-DC step-up transformerless high conversion ratio converter for storage and renewable energy systems

Power converters have rapidly evolved to meet industry requirements. Nowadays, renewable energy and energy storage applications require the availability of DC voltages. In some cases the differences between these levels must be large, hence an efficient and high conversion ratio converter is needed. Hence, this work proposes a transformerless high conversion ratio DC-DC step-up converter. The proposal is able to increase the output voltage up to ten times the input voltage with a duty cycle close to 0.5. The proposed topology merges the switching inductors strategy, and the switching capacitors strategy, with a conventional boost converter. Besides, a steady-state analysis of the converter is performed to obtain voltage and current ripples to size the energy storage elements. Also, an efficiency analysis is performed including the effect of the parasitic elements of the semiconductors. Finally, the proposed topology is assessed through numerical simulation on the 1 kW system.