The objective of this thesis is to show the work done during the internship period at the company IKOS CONSULTIG. IKOS is the reference company in the railway industry with expertise recognized by major stakeholders in the industry. The project under review concerns the 200kW charging converter with IGBT technology, which powers the Opportunity Charger, with inverted pantograph, for charging Electric Buses. DC/DC converter, that is forced-ventilated, consists of multiple power stages, such as Buck-Boost module, R-Bridge module, which ensure the ability both to work with wide ranges of input and output voltages and to provide galvanic isolation from the power grid.