基于自适应虚拟阻抗的分布式电源并联控制策略

Distributed Generation Parallel Control Strategy Based on Adaptive Virtual Impedance

当传统下垂控制策略应用于低电压微电网分布式电源并联系统时,其等效输出阻抗易受线路阻抗的影响而呈阻性,致使无功功率不能完成精准分配,破坏微电网系统的稳定性。因此,分析了低电压微电网系统的等效输出阻抗,并提出将自适应虚拟阻抗添加到电压电流双闭环控制方法,结合下垂特性可实现无功和有功功率的解耦,还能对产生的环流进行有效抑制;又利用CAN通讯技术通过引入电压补偿信号在线监测无功功率分配,以提高各分布式电源无功功率的分配精准度。最后通过在仿真平台建立两台逆变器并联运行模型,验证了该方法的可行性和稳定性。

When the traditional droop control strategy is applied to a low-voltage microgrid distributed power supply parallel system,its equivalent output impedance is susceptible to difference due to the line impedance and becomes resistive.This will cause the reactive power to be unable to complete accurate distribution and destroy the stability of the microgrid system.In view of the above problems,the equivalent output impedance of the low-voltage microgrid system is analyzed,and a method of adding adaptive virtual impedance to the double closed-loop control of voltage and current is proposed.The decoupling of reactive power and active power can be achieved by combining the droop characteristics.The generated circulating current can be effectively suppressed.The CAN communication technology is used to monitor the reactive power distribution online by introducing a voltage compensation signal to improve the accuracy of the distributed reactive power distribution.Finally,by establishing a model of two inverters running in parallel on the simulation platform,the feasibility and stability of the method are verified.