Series/Parallel Connection Method of DC-DC Transformer for Scalable Power Converter Systems using USPM

This paper proposes a series or parallel connection method of a DC-DC transformer (DCX) to achieve power scalability. Universal Smart Power Module (USPM) modularizes all power converter components. The power converter is realized by combining several USPMs to simplify the power electronics design. A USPM with galvanic isolation (isolated USPM) operates as a DCX. Isolated USPM must have high efficiency over a wide power range. In addition, the voltage or current must be balanced when connected in series or parallel. A dual-active-bridge converter is chosen as the main circuit for the isolated USPM for these requirements. The proposed method is demonstrated by an experimental setup. As a result, the current balance is improved by 75.0pt. in parallel connection, and the voltage balance is improved by 37.0pt. in series connection.