不对称电网下基于改进的DSOGI-FLL同步方案  

Improved DSOGI-FLL Synchronization Scheme Under Unbalanced Power Grid

作　　者：杜田雨 付子义[1] 白云涛 DU Tianyu;FU Ziyi;BAI Yuntao(School of Electrical Engineering and Automation,Henan Polytechnic University,Jiaozuo 454150,China;State Grid Henan Nanyang Power Supply Company,Nanyang 473000,China;Sanmenxia Yixiang Aluminium Co.,Ltd.,Sanmenxia 472435,China)

机构地区：[1]河南理工大学电气工程与自动化学院,河南焦作454150 [2]国网河南省电力公司南阳供电公司,河南南阳473000 [3]三门峡义翔铝业有限公司,河南三门峡472435

出　　处：《电力科学与工程》2020年第9期30-39,共10页Electric Power Science and Engineering

基　　金：国家重点研发计划专项资助项目(2016YFC0600906)。

摘　　要：三相并网变流器稳定运行需要电网电压同步信号的准确检测。基于双二阶广义积分器锁频环(DSOGI-FLL)可实现在电压不对称工况下同步信号的提取,但在频率跟踪的暂态过程中锁频环输出波动较大。针对这一问题,根据DSOGI-FLL频率响应状态空间模型分析了锁频环在电网电压不对称时的锁频响应特性。研究发现在电网电压不对称工况下,负序分量会给锁频环的动态性能带来不利影响。为了改善不对称工况下锁频环(FLL)的响应性能,提出一种改进的锁频环结构。该方案增加了由降阶谐振器组成的陷波器,能有效抑制二倍频波动,减小动态过程中的振荡;然后将负序分量考虑在内重新设计了增益归一化模型,使频率检测的响应时间不受电压正、负序分量的影响。仿真结果验证了本文所提方法的有效性和可行性。The stable operation of the three-phase grid-connected converter requires accurate detection of the grid voltage synchronization signal.Based on the double second-order generalized integrator frequency-locked loop(DSOGI-FLL),the synchronization signal can be extracted under asymmetric voltage conditions,but the output of the frequency-locked loop fluctuates greatly during the transient process of frequency tracking.To solve this problem,this paper analyzes the frequency-locked response characteristics of the frequency-locked loop when the grid voltage is asymmetric according to the DSOGI-FLL frequency response state space model.It is found that the negative sequence component would adversely affect the dynamic performance of the FLL under the condition of asymmetrical grid voltage.Thus,this scheme adds a notch filter composed of a reduced-order resonator,which can effectively suppress the double frequency fluctuations and reduce the oscillation in the dynamic process.Then,the gain normalization model considering the negative-sequence components is redesigned,so that the response time of frequency detection is not affected by the positive and negative sequence components of the voltage.The simulation results verify the effectiveness and feasibility of the proposed method.

关 键 词：二阶广义积分器 锁频环 三相不平衡 归一化增益 陷波器 

分 类 号：TM46[电气工程—电器]