Voltage and reactive power control of microgrids based on distributed consensus algorithm

摘要

In a low-voltage microgrid system, due to the influence of property of line impedance and other factors, the reactive power supplied by distributed generations could not be shared accurately based on conventional droop control. To improve the power sharing accuracy, a voltage and reactive power control approach of microgrids (MGs) based on distributed consensus algorithm (DCA) is proposed in this paper. Based on the communication technology and hierarchical control theory, an architecture of distributed hierarchical control is introduced which consists of local control level and distributed secondary control level. The local control level involves droop control, virtual impedance control and proportional-resonance (PR) voltage and current control to achieve reactive power sharing. In secondary control level, an observer is designed based on DCA to get global average value, which restores the voltage deviation and improves the accuracy of reactive power sharing. Besides, the method not only can reduce the high bandwidth requirements, but also improve the reliability and extended flexibility of MGs. Finally, the simulation experiment platform is built based on Matlab/Simulink software and dSPACE1103. Real-time simulation results are shown to demonstrate the effectiveness and robustness endowed by the proposed method. The results indicate that the DCA is very robust with respect to communication impairments, such as packet delays and random packet losses.