Dynamic disturbance control for microgrid with energy storage system based on composite active damping

Due to large-scale distributed renewable energy access, it brings challenges to the power quality and reliability of the grid. Microgrid has great potential to integrate distributed energy to meet grid requirements. However, there is a risk of oscillation when multiple distributed energy sources are connected to microgrid through LCL filter in the form of voltage sources. In order to improve the impedance characteristics of distributed energy systems, the traditional passive damping strategy has a limited effect on improving the phase margin of impedance and will bring large power consumption. Traditional active damping control also fails to improve the stability margin and impedance characteristics. This paper presents a composite active damping control strategy based on lithium battery energy storage system. Firstly, the mechanism of the control strategy is analyzed based on the transfer function, and the improvement of the stability and impedance characteristics of the system is proved. Finally, the effectiveness of the strategy to improve the dynamic disturbance stability of microgrid is verified by simulation examples and experimental tests.