摘要
针对离网并联逆变器的功率分配问题,以及负载不平衡条件下三相电压不平衡度过大,设计了微电网应对负载不平衡的控制策略。设计了三相电网电压的龙贝格观测器,并证明其稳定性。该观测器同样可用于三相电流的观测。采用分序虚拟阻抗,独立配置正序虚拟阻抗和负序虚拟阻抗,使逆变器输出功率均分,并减小负序网络下线路阻抗引起的不平衡电压。改进有功下垂方程,使母线电压保持在传统有功下垂方程给定电压值附近。在Matlab/Simulink仿真平台和搭建的逆变器并联系统中,验证该控制策略的有效性,仿真结果和实验分析表明:设计的观测器能够准确地获取电压和电流的正、负序分量;此处控制策略在功率均分的前提下,大幅降低了三相电压不平衡度,提高了电能质量。
Aiming at the power distribution problem of off-grid parallel inverters and the excessively large three-phase voltage unbalance under load unbalance conditions,a control strategy for the microgrid to deal with load unbalance is designed.The Luenberger observer for the three-phase grid voltage is designed and its stability is proved.The observer can also be used to observe the three-phase current.The positive sequence virtual impedance and the negative sequence virtual impedance are independently configured to make the inverter output power sharing and reduce the unbalanced voltage caused by the line impedance under the negative sequence network.The active power droop equation is proved to keep the bus voltage near the voltage value given by the traditional active droop equation.In the Matlab/Simulink simulation platform and built the inverter parallel system,the effectiveness of the control strategy is verified.The simulation results and experimental analysis show that the designed observer can accurately obtain the positive and negative sequence components of voltage and current.The control strategy greatly reduces the three-phase voltage unbalance and improves the power quality under the premise of power sharing.
作者
程勇
李聪
王耀辉
贺虎成
CHENG Yong;LI Cong;WANG Yao-hui;HE Hu-cheng(Xi’an University of Science and Technology,Xi'an 710054,China)
出处
《电力电子技术》
CSCD
北大核心
2022年第3期64-68,共5页
Power Electronics
基金
陕西省自然科学基础研究计划-陕煤联合基金(2019JLM-51)。
关键词
微电网
下垂方程
功率均分
虚拟阻抗
microgrid
droop equation
power sharing
virtual impedance
