High Step-Up DC-DC Converter Using Built-In Transformer Voltage Multiplier Cell and Dual Boost Concepts

This article proposes a new high step-up dc-dc converter for fuel cell applications. Built-in transformers and voltage multiplier cells are integrated into the structure to step-up the voltage gain. This article proposes a new topology with common ground. Two of them are connected using the dual boost concept. Thus, the final structure provides input current interleaved that reduces the current ripple, output-series connection that increases the voltage gain, and floating ground on the output voltage, which can be a limitation for some applications. Additionally, on designing the built-in transformer with a leakage inductance value much less than the magnetizing inductance value (less than 0.5%), the proposed topology does not need a clamp circuit, which reduces the number of components and increases the efficiency. Operational steps, static gain analysis, and design guide of the new converter are described in detail herein. Furthermore, a 1-kW, 48–800-V prototype was built to verify the theoretical analysis. Tests in the laboratory reached 94.60% of maximum efficiency at 480 W and 93.00% of efficiency at 1.0 kW (rated power).