Evaluation of Dual-Active Bridge Converter for DC Energy Buildings

Two-stage isolated active front-end (i-AFE) converters, based on an ac-dc and isolated dc-dc power stages, have gained significant research attention in the last few years due to several applications that need isolated power factor correction, including electric vehicles, and dc energy buildings. DC energy buildings have specific standards related to voltage levels, protection zones, and isolation. These requirements define the specific objectives for the power converters design. The dcdc stage is typically a challenge to design because the standard solution, the dual-active bridge converter, has limitations regarding soft-switching range, circulating current, and losses. To address the design of the dc-dc stage for i-AFE converters, this paper presents a guideline considering DC energy buildings as an application. The methodology and design requirements for DAB converters are described. In addition, a 5-kW prototype was assembled, and tested in the laboratory to validate the presented analysis.