One of the key areas for reducing the carbon footprint is transport, particularly the development of electric mobility, which is currently growing rapidly. In this context, the hybrid electric transport market is growing. Hybridization applications have seen their power increase and with it that of power electronics converters allowing to adapt the voltage levels of energy sources and the energy exchanges between them. This increase in power is accompanied by higher losses to be evacuated, resulting in a significant impact firstly on the size of the converters, and therefore of the overall system, and then on the energy efficiency of the entire chain. Efforts have already been made at CEA-LITEN to develop high-efficiency DC-DC converters (in particular by using interleaved DC-DC converters). The objective of the thesis will be to go further by studying the so-called partial power converters (PPC). The different architectures/topologies will be studied for hybrid applications associating a fuel cell and a battery on the one hand, and applications associating 2 batteries (one power type battery and the other, energy type battery) on the other hand. The work aims to determine the best architecture/topologies for each of the typical applications allowing a significant reduction in the size of the converters and the improvement of the efficiency of the whole system