Three-Phase Single-Stage Three-Port High-Frequency Isolated DC–AC Converter

In order to further improve the integration of the ac-grid-connected hybrid energy storage system, a novel three-phase single-stage three-port high-frequency isolated dc–ac converter is proposed in this article. This converter connects two dc ports and one ac port via a three-winding transformer, saving one ac-side port. The ac-side port uses the matrix converter and the dc-side ports use the interleaved parallel boost converter, which has the advantages of low dc-side current ripple and wide voltage range. The proposed converter achieves galvanic isolation and bidirectional power conversion with the single-stage structure to improve the integration of the converter. A hybrid pulse width modulation plus space vector phase-shift modulation is proposed to achieve the direct control of the ac side current synthesizing vector and, thus, ensures the sinusoidal three-phase currents. On this basis, the relationship between the control freedoms is constrained with the optimization objective of minimizing the root-mean-square value of the transformer resonant current; thus, the efficiency of the converter is improved. The correctness and the effectiveness of the proposed converter and the corresponding modulation are verified by the detailed experimental results.