A DC-DC hybrid switched-capacitor LLC resonant converter integrating a ladder cell at the input of the LLC resonant converter using frequency modulation is proposed in this paper. This converter has six switches that are subjected to half the voltage of the input source. All switches commutate at zero voltage over the entire load range, and the diodes of the output rectifier bridge commutate at zero current. The proposed converter has the following characteristics: (a) symmetrical operation, (b) simple frequency modulation, (c) commutation of all switches at zero voltage, (d) all switches subjected to half the input voltage, and (e) static gain practically immune to load variations. Theoretical analysis, design, and experimental results in the laboratory for a prototype of 2 kW, 1000 VDC input, 48 VDC output, and 90 kHz switching frequency are included in this study. The maximum efficiency measured was 97.3%. INDEX TERMS DC-DC converter, LLC, resonant converter, switched-capacitor, zero voltage switching.

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This paper presents a new power converter topology<br>generated by the integration of the asymmetrical ZVS-PWM dcdc converter with a switched-capacitor ladder-type commutation<br>cell. Circuit operation and theoretical analysis with emphasis on<br>the soft-commutation process are included in the paper. The<br>main advantage of the proposed converter with respect to the<br>conventional asymmetrical half-bridge dc-dc converter is the<br>reduction of the voltage stress across the power switches to the<br>half of the input dc bus voltage, enabling the utilization of lower<br>voltage rating components. Experiments conducted on a<br>laboratory prototype with 1.4 kW power-rating, 800 V input<br>voltage, 48 V output voltage and 100 kHz switching frequency<br>are included, to verify the theoretical analysis and the design<br>methodology. The maximum efficiency of the experimental nonoptimized prototype was 93.6%.<br>Index Terms - Asymmetrical dc-dc converter, pulse-widthmodulation, switched-capacitor, zero voltage switching.<div><br><br></div>

This paper presents a new power converter topology<br>generated by the integration of the asymmetrical ZVS-PWM dcdc converter with a switched-capacitor ladder-type commutation<br>cell. Circuit operation and theoretical analysis with emphasis on<br>the soft-commutation process are included in the paper. The<br>main advantage of the proposed converter with respect to the<br>conventional asymmetrical half-bridge dc-dc converter is the<br>reduction of the voltage stress across the power switches to the<br>half of the input dc bus voltage, enabling the utilization of lower<br>voltage rating components. Experiments conducted on a<br>laboratory prototype with 1.4 kW power-rating, 800 V input<br>voltage, 48 V output voltage and 100 kHz switching frequency<br>are included, to verify the theoretical analysis and the design<br>methodology. The maximum efficiency of the experimental nonoptimized prototype was 93.6%.<br>Index Terms - Asymmetrical dc-dc converter, pulse-widthmodulation, switched-capacitor, zero voltage switching.<div><br><br></div>