摘要
LCL滤波器由于具有滤波特性好、体积小的优势,被广泛应用于并网变换器中。但其电容支路极易产生谐振,为抑制谐振尖峰,本文采用反馈电容电流的方法,提高系统阻尼系数,并提出在反馈回路中增加比例调节器,不仅能够控制反馈深度,而且使得调节器的设计相对独立。同时在αβ坐标系下,采用比例谐振调节器对不平衡电网下LCL并网系统进行控制。然后根据根轨迹原理,对比例谐振调节器参数、比例调节器参数以及LCL滤波器参数之间的关系进行了分析,并通过选定合适的闭环极点确定调节器参数。最后搭建容量为3.5 k V·A并网变换器实验平台,验证了文中所提理论及设计方法的合理性和可行性。
LCL filter has been widely used in grid-connected converter for its good filtering performance and small size. However,capacitor branch may cause resonance,thus the active damping based on capacitor current feedback is an ef-fective way to damp resonance peaks. Moreover,a proportional regulator is used in feedback loop,which can control the feedback strength and make the design of tuning process relatively independent. Under the unbalanced grid voltage , LCL filter based grid-connected converter is built,in which a proportional-resonant（PR）regulator is adopted in the sta-tionary αβ reference frame. According to the theory of root locus,the relationships among PR regulator,proportional regulator and LCL filter are analyzed,and appropriate parameters are selected to guarantee the stability of system. Fi-nally,the reasonability and feasibility of the control strategy and design method are verified by the simulation results of a 3.5 kV·A grid-connected converter.
出处
《电力系统及其自动化学报》
CSCD
北大核心
2017年第1期90-96,共7页
Proceedings of the CSU-EPSA
基金
国家质检总局公益性行业科研专项经费项目(201310153)
关键词
不平衡电网
LCL滤波器
比例谐振调节器
谐振尖峰
根轨迹
unbalanced grid voltage
LCL filter
proportional-resonant（PR）regulator
resonant peak
root-locus
