Abstract

Bidirectional CLLLC resonant dc-dc converters with an asymmetric tank can narrow the switching frequency bandwidth required to meet the asymmetric voltage gains in the two directions of power flow. Consequently, higher power density and efficiency may be feasible. in this paper, a CLLLC resonant converter with asymmetric primary and secondary capacitances is investigated for charging and discharging the next-generation 900 V traction battery of an electric vehicle. First, a new voltage gain equation is formulated using the First Harmonic Approximation. Then, the proposed gain equation is used to design the asymmetric resonant tank. the effects of asymmetric capacitances on the switching frequency bandwidth and capacitor sizing are investigated to predict the optimal ratio. Results are verified through simulations and experiments performed on the hardware prototype of the converter that uses a fully magnetically integrated transformer to meet the high-power density requirement in onboard electric vehicle chargers.

Department(s)

Electrical and Computer Engineering

Comments

Vehicle Technologies Office, Grant DE-EE0008449

Keywords and Phrases

Asymmetric resonant tank; CLLLC resonant converter; electric vehicle; onboard charger; voltage gain equation

Document Type

Article - Conference proceedings

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2025 Institute of Electrical and Electronics Engineers, All rights reserved.

Publication Date

01 Jan 2023

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