ZVZCS Full-Bridge Three-Level DC/DC Converter With Reduced Device Count

Abstract

This letter proposes a new zero-voltage and zero-current switching (ZVZCS) full-bridge (FB) three-level dc/dc converter (TLDC) with the reduced device count. The merits of the proposed converter with the corresponding modulation strategy are concluded as follows. In comparison with the zero-voltage-switching FB TLDC: 1) only one blocking capacitor is added to realize the ZVZCS strategy, 2) the primary circulating current and duty cycle loss can be effectively reduced. Also, the wide input voltage range can be satisfied because of having two working patterns. More significantly, the proposed converter with the corresponding modulation strategy can reduce the device count by removing the primary blocking diodes in comparison with other ZVZCS FB TLDCs, which would reduce the conduction losses of primary power devices and thus increase the converter's efficiency. Finally, experimental results are presented to verify the proposed converter with the corresponding modulation strategy.