직렬연결 보조 변압기를 활용한 전류 밸런싱 인터리브드 Partial Power Processing 컨버터

초록

LLC converters are widely used in high-efficiency, high-frequency applications. For high-current applications, interleaved LLC converters are commonly adopted because of their advantages in current sharing and input current ripple reduction. However, this topology suffers from resonant current imbalance caused by mismatches in the passive components of the resonant tanks. Various methods, such as coupled inductors, have been proposed to address this issue, but they typically require pulse frequency modulation control to regulate output voltage. Partial power processing converters (PPPCs) offer a simple output voltage regulation method by adopting pulse width modulation, but conventional PPPCs require an additional control method to balance the resonant currents. This study proposes a novel interleaved PPPC structure, where auxiliary transformers are connected in series at the secondary side. The proposed converter effectively mitigates current imbalance caused by component tolerances while simplifying the output voltage regulation method. Moreover, it can reduce the number of boost converters in the auxiliary circuit. A 2 kW hardware prototype is built and tested to verify the performance of the proposed converter.

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