Novel ZCS Transformerless High Gain DC-DC Converters for Renewable Energy Conversion Systems

This paper proposes new zero current switching (ZCS) transformerless high gain DC-DC converters for renewable energy conversion systems. A conventional high gain transformerless DC-DC converters derived with a simple auxiliary resonant network to obtain zero current switching (ZCS) turn-off condition of the main switches. The proposed converter is operated to achieve high step-up and soft-switching operations in order to have minimized current stresses and reduced switching losses, since the high duty ratios to the main switches does not affect the overall performance of this converter. The advantages of this converter are minimized turn-off losses and duty ratio is not limited. The proposed converter improves the overall efficiency over hard-switching converter for high voltage energy conversion system applications. In this paper a new ZCS high gain DC-DC converter is presented, analyzed in detail to demonstrate the operation principles and verified by the simulation results.