This letter proposes a simple and effective hold-up time extension method for server power systems, in which the fan is only turned off during the hold-up time with ac input loss. Due to the elimination of the fan power in the proposed method, the efficiency of the dc-dc converter increases during the hold-up time; thus, the energy stored in the link capacitor decreases less sharply, compared with the conventional method. That is, the hold-up time can be extended without additional devices, volume increase, and operational change of the dc-dc converter, maintaining high efficiency and high power density. The effectiveness of the proposed method is verified by a prototype with 90-264 Vac,rms input, 800 W/12 V output specifications of the server power supply.

中文翻译：

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在服务器电源系统中使用风扇控制的有效保持时间延长方法


这封信提出了一种简单有效的服务器电源系统保持时间延长方法，其中风扇仅在交流输入损耗的保持时间内关闭。由于所提出的方法消除了风扇功率，DC-DC转换器的效率在保持时间内提高；因此，与传统方法相比，存储在链路电容器中的能量减少得不太急剧。也就是说，无需额外的器件、体积的增加和DC-DC转换器的操作变化就可以延长保持时间，从而保持高效率和高功率密度。通过具有 90-264 Vac,rms 输入、800 W/12 V 输出规格的服务器电源原型验证了所提方法的有效性。