A Proposed Bidirectional Three-Level dc-dc Power Converter for Applications in Smart Grids: An Experimental Validation

The integration of renewable energy sources (RES), energy storage systems (ESS), and electric mobility into smart grids requires the use of dc-dc back-end power converters for adjusting voltage levels. Although a dc-dc converter applied for RES only operates in unidirectional mode, when applied to ESS or EM, the bidirectional mode is a fundamental requisite for exchanging power with the electrical power grid. In this context, this paper presents an experimental validation of a proposed bidirectional three-level dc-dc converter considering its application for smart grids. Traditionally, the dc-dc power converters of such applications are two-level converters. However, by employing a three-level topology, it is possible to improve the quality of the variables controlled by the power converter. Moreover, since the proposed dc-dc converter is controlled to produce a controlled current, the proposed current control and modulation strategies are introduced and described. A complete analysis of the operation principle of the proposed bidirectional three-level dc-dc power converter is presented, supported by experimental validation, employing a laboratory prototype.