A Bidirectional Resonant DC-DC Converter Suitable for Wide Voltage Gain Range

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Abstract

This paper proposes a new bidirectional LLC resonant dc-dc converter suitable for wide voltage gain range applications (e.g., energy storage systems). The proposed converter overcomes the narrow voltage gain range of conventional resonant dc-dc converters, and meanwhile achieves high efficiency throughout the wide range of operation voltage. It is achieved by configuring a full-bridge mode and a half-bridge mode operation during each switching cycle. A fixed-frequency phase-shift control scheme is proposed and the normalized voltage gain can be always from 0.5 to 1, regardless of the load. The transformer root-mean-square (rms) currents in both the forward and reverse power flow directions have a small variation with respect to the voltage gain, which is beneficial to the conduction losses reduction throughout a wide voltage range. Moreover, the power devices are soft-switched for minimum switching losses. The operation principles and characteristics of the proposed converter are firstly analyzed in this paper. Then the analytical solutions for the voltage gain, soft-switching, and rms currents are derived, which facilitates the parameters design and optimization. Finally, the proposed topology and analysis are verified with experimental results obtained from a 1-kW converter prototype.
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This paper proposes a new bidirectional LLC resonant dc-dc converter suitable for wide voltage gain range applications (e.g., energy storage systems). The proposed converter overcomes the narrow voltage gain range of conventional resonant dc-dc converters, and meanwhile achieves high efficiency throughout the wide range of operation voltage. It is achieved by configuring a full-bridge mode and a half-bridge mode operation during each switching cycle. A fixed-frequency phase-shift control scheme is proposed and the normalized voltage gain can be always from 0.5 to 1, regardless of the load. The transformer root-mean-square (rms) currents in both the forward and reverse power flow directions have a small variation with respect to the voltage gain, which is beneficial to the conduction losses reduction throughout a wide voltage range. Moreover, the power devices are soft-switched for minimum switching losses. The operation principles and characteristics of the proposed converter are firstly analyzed in this paper. Then the analytical solutions for the voltage gain, soft-switching, and rms currents are derived, which facilitates the parameters design and optimization. Finally, the proposed topology and analysis are verified with experimental results obtained from a 1-kW converter prototype.
Original languageEnglish
JournalI E E E Transactions on Power Electronics
Volume33
Issue number4
Pages (from-to)2957-2975
ISSN0885-8993
DOI
StatePublished - Apr 2018
Publication categoryResearch
Peer-reviewedYes

    Research areas

  • Isolated bidirectional dc-dc converter, LLC resonant converter, wide voltage gain

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