本课题设计中主要研究后备式，它具有电路简单，经济实用的特点。

I studied the off-line one in my thesis. It has the features such as a simple circuit and a nice use with low cost.

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摘 要 分别介绍了UPS和EPS的功能、工作原理、分类，以及常见的后备式、在线式、在线交互式三种UPS的主要特点。

The functions, working principle, classification of UPS and EPS, as well as the main characteristics of the common type of back-up, on-line, on-line interactive UPS are expatiated.

youdao

摘 要 分别介绍了UPS和EPS的功能、工作原理、分类，以及常见的后备式、在线式、在线交互式三种UPS的主要特点。

The functions, working principle, classification of UPS and EPS, as well as the main characteristics of the common type of back-up, on-line, on-line interactive UPS are expatiated.

youdao