An Interleaved Boost and Dual Active Bridge-Based Single-Stage Three-Port DC–DC–AC Converter With Sine PWM Modulation

In this article, a new three-port converter is proposed that interfaces two dc voltage sources of different magnitudes and an output ac port in a single stage. The proposed converter is primarily based on the dual active bridge topology where the secondary bridge is composed of four quadrant bidirectional switches, which allows it to 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 bridges. This enables the standard sine pulsewidth modulation to be used for synthesizing ac output. For the power flow mode between the two dc ports alone, a parallel boost modulation is proposed that improves the system efficiency by removing any circulating current introduced by traditional interleaving. The proposed converter achieves fully soft switched three-port power conversion with a reduced number of active devices compared to the existing topologies. The modulation scheme is also much simpler and requires no optimization or complex control. A PowerSim-based simulation program is used for validating the proposed converter. A 200-W prototype is built to experimentally verify the theoretical analysis of the proposed converter.