Resonant Capacitor On/Off Control of Half-Bridge LLC Converter for High Efficiency Server Power Supply

고효율 서버용 전원 장치를 위한 하프-브리지 LLC 컨버터의 공진 커패시터 온-오프 제어

In this letter, a simple control method of the HB LLC converter with one additional switch and capacitor in the primary side is proposed for wide-input-voltage applications with the hold-up time conditions. At nominal input, since the proposed method enables the HB LLC converter to operate with large transformer magnetizing inductance, it can reduce the conduction and switch turn-off losses in the primary side, which makes a high efficiency. On the other hand, during the hold-up time, since the proposed method increases the resonant capacitance by turning on one additional switch, the HB LLC converter can obtain high voltage gain.