摘要
无隔离光伏并网系统中存在直流分量,可能导致系统故障和安全问题。IEEE 1547-2003规定注入网侧的直流分量应小于额定电流的0.5%。输出电流中的直流分量会造成输出功率基波频率波动、直流电压纹波、输出电流出现二次谐波。提出采用滑动平均滤波器提取三相交流输出电流的直流分量,电流环采用比例积分谐振控制器调节直流分量和基波分量的方案,实现精确控制直流分量的目的。搭建了50 kVA的原理样机,通过实验证明,该方案使得直流分量降低到额定电流的0.5%以内,同时有效控制输出电流总谐波畸变率、二阶谐波和直流电压纹波。
The DC component is a special issue in transformerless grid-connected photovoltaic(PV)inverter systems and may cause problems regarding system operation and safety.The IEEE standard 1547-2003 stipulates that the DC component in the grid-side should be less than 0.5%of the rated current.The DC component can cause DC-link voltage ripple,line-frequency power ripple,and a further second-order harmonic in the AC current.This paper proposed an effective solution to minimize the DC component in three-phase AC currents and developed a method for accurate extraction of the DC component based on moving average filter.A proportional integral-resonant controller is further designed to regulate the DC and line-frequency component in the current loop to provide precise control of the DC current.The proposed method was validated on a 50 kVA experimental prototype,where the DC current is effectively attenuated to be within 0.5%of the rated current.The total harmonic distortion and the second-order harmonic are also reduced as well as the DC-link voltage ripple.
作者
徐荣
阮俊
黄学
任向阳
XU Rong;RUAN Jun;HUANG Xue;REN Xiangyang(DAQO Group Co.,Ltd.,Nanjing 211153,China;Shanghai Electrical Apparatus Research Institute(Group)Co.,Ltd.,Shanghai 200063,China)
出处
《电器与能效管理技术》
2019年第22期53-59,共7页
Electrical & Energy Management Technology
关键词
直流分量
比例积分谐振控制
并网逆变器
无隔离变压器
滑动平均滤波
DC component
proportional-integral resonant(PIR)control
grid-connected inverter
transformerless
moving average filter
