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초록

This paper proposes an asymmetric resonant frequency design for an 11 kW CLLC resonant converters and demonstrates its effectiveness. Conventional CLLC converters are designed with symmetric resonant frequencies. However, this can lead to lower efficiency when the required voltages differ between charging and discharging operations in bidirectional mode. To overcome this issue, the proposed design sets the secondary side resonant frequency differently from the primary side, reducing the required frequency range and enhancing bidirectional performance. Using the fundamental harmonic approximation (FHA), this study derives equivalent circuits and voltage gain equations for both modes and designs a converter accordingly. Finally, loss analysis is conducted for each design approach through simulation, and the results are experimentally validated.

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