摘要
在独立微电网逆变器并联运行系统中,由于线路阻抗的影响,采用传统下垂控制时,各微源无法按容量比例精确分配功率.为了解决这一问题,深入分析了该系统运行时的负载功率分配原理,得出功率分配不精确的根本原因是两台逆变器的容量与其总输出阻抗不相匹配,因此提出了一种微电网分层控制策略.在第一层控制中,通过添加虚拟阻抗使得逆变器的输出总阻抗为感性,以削弱线路阻抗的影响;在第二层控制中,增加了无功功率的补偿控制,以提高各微源的无功功率分配精度,同时,还添加了频率和电压的恢复控制来消除各微源逆变器输出的频率和电压偏差.最后,基于Matlab/Simulink的仿真结果表明了所提控制策略的正确性和有效性.
Due to the influence of line impedance, the traditional droop control cannot be utilized to achieve accurate power in proportion for islanded microgrid. Aiming at this problem, the paper takes a deep analysis of power sharing algorithm, then draws a conclusion that the root cause of imprecise distri bution is its capacity fails to match with total output impedance, hence presents a hierarchical control strategy. To reduce the influence of line impedance, a method of virtual impedance is proposed to make total output impedance of inverter inductive in the first layer of control. In the second control, a com- pensation control algorithm o{ reactive power is introduced in order to improve the property of load dis- tribution. At the same time, a restoration control strategy is also added to eliminate the deviation of out- put frequency and voltage of each micro source. Finally, a microgrid model is designed using Matlab/ Simulink simulation platform, and the simulation results verify the accuracy and effectiveness of the con trol strategy.
出处
《中北大学学报（自然科学版）》
CAS
2018年第1期54-60,共7页
Journal of North University of China(Natural Science Edition)
关键词
微电网
逆变器
下垂控制
虚拟阻抗
microgird
inverter
droop control
virtual impedance
