Current balance performance evaluations for transformer-linked three phase DC-DC LLC resonant converter

The dc-dc LLC resonant converter can achieve complete soft switching operation in all power semiconductor devices. However, the single phase and interleaved LLC resonant converter required large size smoothing capacitor in the output terminal because the output current ripple of the LLC converter is higher than other isolated dc-dc converter. To solve the problem, the three phase dc-dc LLC resonant converter is proposed in this paper. The output current ripple through the output capacitor is reduced because of superposed each phase output current. In addition to this, the transformer-linked method is applied for the proposed three phase dc-dc LLC resonant converter to obtain the miniaturized performance in the high frequency transformer in the proposed converter. The proposed transformer-linked converter has additional advantage for the each phase current balance. In this paper, the current balance performance of the proposed transformer-linked three phase dc-dc LLC resonant converter is discussed and evaluated from the experimental point of view.