The Improved Control Method of Parallel Microgrid Inverters

Abstract

The parallel of inverters is inevitable in the operation of distributed generation with a Microgrid. However, due to the difference in line impedance between each parallel inverter and the public AC bus in the microgrid, the m available control method is insufficient to overcome the disadvantages such as unbalancing distribution of power, large circulating current, and poor dynamic characteristics, etc., especially when the line impedance difference is large. To conquer the above problems, the paper proposed an improved droop control strategy, in which a differential module is adapted to the droop control to improve the dynamic response. Further, a modified adaptive virtual resistance is proposed, so that the system can maintain high response speed, high stability, and robustness. These can effectively benefit power sharing and circulation suppression of parallel inverters while ensuring excellent dynamic characteristics of the system. Finally, the effectiveness of the improved control method is verified by the simulation results.