基于光学电流互感器的低频高精度锁相环  

Low-frequency high-precision PLL based on optical current transducer

作　　者：袁嫣红[1] 廖小松[1] 袁海骏 陈益新[3] 刘明昊[1] 

机构地区：[1]浙江理工大学机械与自动控制学院,浙江杭州310018 [2]上海舜宇海逸光电技术有限公司,上海201210 [3]上海交通大学应用物理系,上海200030

出　　处：《电力自动化设备》2009年第12期101-105,共5页Electric Power Automation Equipment

基　　金：上海市重点科技创新基金项目(0904H168100)~~

摘　　要：针对低频区信号锁相所面临的精度低、稳定性差等缺点,提出了一种提高锁相精度的方法。以光学电流互感器测试系统为研究对象,设计了以CD4046为核心的锁相环电路,并对影响锁相精度的原因进行了研究。于被测信号进入锁相环之前,采用运放形成2次过零比较,克服了专用快速比较器产生自激振荡的同时,缩短了入锁信号的上升沿时间;设计了用于滤除工频噪声的二阶有源带通滤波器;将锁相环路中压控振荡器的固有中心频率进行了参数优化,使得2个输入的固有频差在理论上最小。结果表明,引入该锁相方法后的锁相精度由0.3%周期提高到0.03%周期(1°变为6′),并且锁相的稳定性和抗干扰性等其他性能指标都有了显著提高。Aiming at the low-precision and instability of phase-lock in low-frequency area,a way is put forward to improve its precision. A PLL（Phase-Locked Loop） circuit with CD4046 as its core is designed for an optical current transducer test system and the factors affecting phase-lock precision are analyzed. Before the tested signal enters into PLL,two zero-crossing comparisons are carried out with operational amplifier to avoid the self-oscillation of the high- speed comparators and shorten the rising edge of signal entering into PLL. The second- order active band pass filter is designed to remove power frequency noise. The central frequency of voltage control oscillator is optimized to theoretically minimize the intrinsic frequency difference of two imports. Results show that,the precision is increased from 0.3 % to 0.03 % of period （from 1°to 6′）, as welt as the stability and anti-interference ability.

关 键 词：锁相环 光学电流互感器 中心频率 过零比较器 有源带通滤波器 

分 类 号：TM733[电气工程—电力系统及自动化]