software pll meaning in English

可将其称为软件锁相环

The software includes procedures to control and monitor the ups such as software pll ( phase - locked loops ) , the value modulation of the output voltage , the producing of pwm signals and kinds of protections the control system and operation principal are analyzed and verified by detailed simulation and experiment results
系统软件部分则包括ups各种系统功能的实现，其中主要研究了软件锁相环(市电跟踪) 、有效值调节、各类保护、 pwm波的生成、闭环控制等的实现。