不对称电网同步相位的快速开环捕获方法研究  

Research on Fast Phase Synchronization Scheme for Three-phase Unbalanced Power System

作　　者：熊连松[1] 卓放[1] 刘小康[1] 祝明华[1] 陈颖[1] 

机构地区：[1]西安交通大学电气工程学院,陕西省西安市710049

出　　处：《中国电机工程学报》2015年第22期5682-5691,共10页Proceedings of the CSEE

基　　金：国家重点基础研究发展计划项目(973项目)(2015CB251004)~~

摘　　要：快速准确地获取电网同步相位是并网逆变器控制的基本要求。然而,当电网发生严重不对称故障时,传统软锁相环(software phase-locked loop,SPLL)方法的动态响应时间较长(大于一个工频周期),因此无法满足高性能逆变器控制对锁相快速性的要求。据此,提出电网同步相位的快速开环捕获方法,可显著提高电网电压不对称条件下的相位同步速度。该方法首先通过构造电网电压的虚拟正交信号并使用对称分量法,实现了电网电压基波正序分量的快速准确提取,接下来通过对该正序分量进行开环锁相,即可快速获得电网电压基波正序分量的实时相位。最后,论文提出一种改进的虚拟正交信号构造方法,有效地提高了构造信号的准确度。各种工况下的实验结果同时表明:提出的开环锁相方法可在电网不对称且畸变的恶劣环境下实现快速准确地捕获电网的实时同步相位,具有较强的鲁棒性。Prompt and accurate phase detection is an essential qualification for the control of grid-connected inverters. However, the commonly used phase-locked loop methods consume too much time, longer than one grid period, to lock the new phase under severe grid unbalance condition, resulting in failing to satisfy the need for high speed and accuracy of phase synchronization. In order to solve this problem, an open-loop phase locking scheme was proposed in this paper. By constructing virtual orthogonal signals and adopting the method of symmetrical components, this scheme first realizes the fast fundamental-frequency positive sequence（FFPS） components extracting from the unsymmetrical grid voltages within 3 ms, and these FFPS components are further employed to perform open-loop phase calculation that is free from self-tuning closed-loop control and thus improves the dynamic performance remarkably. Finally, an improved orthogonal signal generation algorithm was presented, remarkably improving the immediacy and precision of signal configuration. The proposed method is characterized by easy implementation, strong robustness and remarkable rapidness, which are verified by experimental results.

关 键 词：开环锁相 虚拟正交信号 对称分量法 谐波消除算法 

分 类 号：TM935[电气工程—电力电子与电力传动]