An Improved Boost-Based dc/dc Converter With High-Voltage Step-Up Ratio for DC Microgrids

Abstract

In this article, an improved ripple-free input current boost-based high step-up (HSU) dc/dc converter compared to the coupled inductor (CI) ones is proposed, where the large CI is replaced by an inductor and a built-in transformer. By doing so, the energy is transferred to the output by two smaller magnetic components. Hence, a more compact and more efficient coupled magnetic component with greater flexibility in increasing its turns ratio is succeeded, allowing us to achieve higher dc voltage gains (higher than 20). Additionally, an active clamp is employed to recycle the leakage energy of the transformer, eliminating at the same time the switching losses. Therefore, by increasing the switching frequency it is feasible to build a highly efficient, reduced-size HSU converter that can be integrated along with a low maximum power point voltage photovoltaic module for dc microgrid applications. Finally, a 250-W-rated prototype has been implemented to verify the functionality of the presented converter in continuous conduction mode operation with an input voltage range of 16–20 V and an output voltage of 400 V.