Abstract:
With the rapid development of the new energy industry, the application demand of a wide range of conditions is more and more extensive. As the classical topology of bidirectional DC-DC converter, dual active bridge DC-DC converter has the problems of decreasing soft switching range, increasing current peak value and current RMS value in wide range applications. Therefore, this paper focuses on analyzing the influence of wide input conditions on the characteristics of dual active bridge DC-DC converter under triple phase shift control, and deduces the theoretical expressions of the variation of soft switching range, current peak value and current RMS with switching frequency under wide input voltage. On this basis, a phase-shifting variable frequency hybrid control strategy is proposed.By adjusting the switching frequency, the soft switching range of the dual active bridge DC-DC converter is extended, and the current peak value and current effective value are reduced, and the overall efficiency of the converter is improved. Finally, a prototype of a 1kW dual-active bridge DC-DC converter based on SiC device is built to verify the effectiveness of the proposed control strategy.