Power sharing between parallel inverters in microgrid by improved droop control

Microgrid is a main part of the future intelligent and sustainable power system. In order to improve the flexibility of a microgrid and realize the plug and play feature of distributed generation and load, this paper proposed an improved droop control to control the parallel inverters in microgrid to solve the problem that the traditional droop control cannot efficiently allot power between multiple inverters. In the proposed improved droop controller, new components are added to the reference voltage and frequency of each parallel inverter based on a feedback loop of the main bus voltage and frequency, respectively. The proposed control strategy is tested with Matlab/Simulink simulation model of a microgrid in the islanding mode which is more difficult to achieve power sharing in. Different supply and load variations are investigated in order to show the robustness of the proposed control. Results are compared with the traditional droop control showing superior performance of the proposed control.