A Novel Decentralized Unbalance Load Sharing Approach for Islanded Microgrids

The presence of unbalance in the load, particularly in islanded microgrids, has recently gained attention as it leads to unbalance in load voltage and current. Existing works in this area mainly focus on reducing the unbalance in load voltage or sharing the negative sequence current equally. Most of these methods rely on the knowledge of load voltages, which requires a low-bandwidth communication infrastructure to send the load information to the local DG controllers. However, low bandwidth communication increases the overall cost and reduces the reliability of the system. In this paper, a decentralized control approach for islanded microgrids is proposed to share the load current unbalance factors (CUFs) equally among the distributed generation (DG) units. It is shown that in an islanded microgrid, the presence of unbalance in the load current affects the output voltages of DG causing them to become unbalanced as well. A droop-based control approach is developed to compensate for the unbalance in DG output voltages to achieve equal sharing of the CUF. A detailed MATLAB/Simulink based as well as OPAL-RT based real-time hardware-in-the-loop experimental studies are presented to validate the performance of the proposed decentralized approach.