锁相环在微机保护中的应用

摘要

To the traditional sampling method of microcomputer protection , because of sampling frequency is hard to automatic tracking the measured frequency and as the changing of the measured frequency and change, will inevitably lead to the error of FFT computation .Synchronous sampling phase-locked loop technology which is adopted by this paper is to lock the frequency of alternating voltage, current signal of the microcomputer protection device, in order to improve the measurement accuracy and real-time properties. Combining with the experiments of phase-locked loop to control AD7656 modulus conversion chip , proving the feasibility of the integral period sampling synchronization in microcomputer protection device, and solving the problem of poor real-time properties, software compling complex and so on.%针对微机保护中采用传统的采样方法，采样频率难以自动跟踪被测量的频率变化而发生变化，必然会导致FFT运算产生误差。本文采用锁相环同步采样技术实现对微机保护装置中交流电压、电流信号的频率和相位进行锁定，以提高测量精度和实时性。结合锁相环控制AD7656模数转换芯片的实验，证明整周期同步采样在微机保护装置中的可行性，解决了软件同步采样的实时性差、软件编写复杂等问题。