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延长服务器电源系统保持时间的方法，其中风扇仅在交流输入损失的保持时间内关闭。由于在所提出的方法中消除了风扇功率，dc-dc 转换器的效率在保持时间内增加；因此，与传统方法相比，存储在链路电容器中的能量下降幅度较小。也就是说，保持时间可以延长而无需额外设备、体积增加和 dc-dc 转换器的操作变化，保持高效率和高功率密度。所提出方法的有效性通过具有 90–264 Vac,rms 输入、800 W/12 V 输出规格的服务器电源的原型进行验证。