The significant advancements in energy transition, particularly in the integration of renewable energy sources, have compelled energy engineers to devise sustainable storage solutions for the long term. Green hydrogen has emerged as the leading contender in this competition. Nevertheless, electrolyzers require substantial quantities of DC currents. The incorporation of a high-performance power-electronic embedded power system for the electrolyzers is an essential and unavoidable aspect of the design process. The design of a rectifier-transformer necessitates numerous unique considerations in contrast to a conventional grid transformer. The primary objective of this thesis is to validate and optimize the methodology employed by Siemens Energy for the design of rectifier-transformers, with an exclusive emphasis on the electrical aspects.