Hard- and Soft-Switched
Technical Lecture Session
DC-DC Converter Applications
AC link, microinverter, dual active bridge
In this paper, a new three port converter is proposed that interfaces two DC voltage sources of different magnitude and an output AC port. The proposed converter is primarily based on dual active bridge topology where, the secondary bridge is composed of four quadrant bidirectional switches, realized by placing regular MOSFETs in back to back fashion. In this configuration, the secondary side can be directly connected to an AC port. The primary bridge can also be used as an interleaved bidirectional boost converter by connecting two inductors across the transformer primary, which forms an additional input DC port. The power flow between the DC ports to the AC port is based on dual phase shift modulation where a phase shift is introduced between the two legs of the primary bridge switches and another phase shift between the primary and secondary bridge. This enables the standard sine pulse width modulation to be used for synthesizing AC output. A 200W prototype was built to experimentally verify the theoretical analysis of the proposed converter.