UPS高可靠性技术的分析与实现

深入地介绍和分析了相控整流或非相控整流为主的传统UPS,指出了当前一般UPS系统所存在的工作频率低、输入功率因数低等诸多问题.在此基础上提出了一种新的控制技术———IGBT/IPM PWM DSP全数字高精度整流技术.通过对电路设计的改进、功率器件的优化选择,从而提高UPS的可靠性,彻底解决电网污染及其所保护的电子系统受干扰等问题,使输入功率因数≌1.最后验证了该设计方案的正确性.     

An improved method to get fuzzy threshold

It is offered a new method to get Fuzzy threshold in this article. First, the fundamental principals of Image Segmentation is showed, as well as some characteristics of threshold. And then, the custom Fuzzy Binary method are stated. In order to solve the problem that the parameters of custom Fuzzy threshold are difficult to set, combined with other custom and easy-to-accomplish binary methods, bypassing the problem smartly, we can get the both merits of these two. What's more, the method is very easy and clear. It is proved effective by practice, and can get good performance in similar situations.     

求函数导数的常用方法的教学体会

该文讨论了高等数学中求函数导数的一些常用的方法。