Single-Stage AC-DC Cascaded Converter for Applications in Solid State Transformers

Abstract

– This paper proposes the study and development of a single-stage multilevel AC-DC converter for application in Solid-State Transformers (SST). The proposed topology is based on the dual active bridge (DAB) converter associated with the three-state switching cell (3SSC). The converter’s structure is able to be scalled-up, by basic modules, and then be applied at high voltages, as well as operate as rectifier or inverter. In order to validate the entire study, a prototype was assembled with two 1 kW modules, with 110 V AC input voltage, 400 V primary and secondary bus voltage, and 20 kHz switching frequency. The experimental results clearly and consistently show the correct operation of the converter. The bi-directionality was demonstrated by the experimentals tests. The topology is capable of operating with high power factor and low THD, as well.