A High Efficiency and Power Density, High Step-Up, Non-isolated DC-DC Converter Based on Multicell Approach

This paper presents a non-isolated high step-up DC-DC converter, based on the implementation of several Dual Active Bridge (DAB) converter cells associated in input-parallel output-series (IPOS). The resulting modular converter produces a high voltage gain, (up to 9 times, up to 200 V voltage output in this prototype configuration) with high efficiency (higher than 95 %) and high power density (higher than 9 kW/L). A prototype was built and characterized to validate the concept. A comparison with conventional topologies are presented together with the theoretical analysis of the structure. Practical results confirm the high efficiency and the voltage balance among the cells of the prototype. The converter design and implementation can be easily scalable from lower to higher transformation ratio at reduced efforts due to its modularity. The topology being fully current bidirectional, the modular converter can also be designed for high stepdown applications.