Over 98% Efficiency SiC-MOSFET Based Four-Phase Interleaved Bidirectional DC-DC Converter Featuring Wide-Range Voltage Ratio

Abstract

A novel floating four-phase interleaved charge-pump bidirectional dc-dc converter (F4P-ICPBDC) with wide buck/boost voltage ratio is proposed in this article. The interleaved structure is employed to mitigate the current ripple across the low-voltage side capacitor and inductors, while the floating configuration facilitates the high buck/boost voltage conversion ratio. To ensure a balanced average inductor current throughout the entire range of duty cycle, a cost-effective asymmetric duty limit control strategy is implemented. In addition, bidirectional synchronous rectification operations are seamlessly carried out without the need for additional hardware, thereby enhancing the overall converter efficiency. Furthermore, the full operating principles, device stresses, current ripple characteristics, as well as parameters design guideline of the converter are illustrated. Finally, A 1 kW-50 kHz prototype, utilizing SiC-mosfets, is developed to validate the wide buck/boost voltage ratio of the proposed converter between the constant low-voltage side (72 V) and the adjustable high-voltage side (400-800 V). The maximum efficiencies of the converter are recorded as 98.3% in the Buck mode and 97.6% in the Boost mode, respectively. Experimental results validate the feasibility and the efficacy of the proposed converter.