A Novel Decentralized Unbalance Load Sharing Approach For Islanded Microgrids

Abstract

The presence of unbalance in the load, particularly, in Islanded Microgrids is gaining increased attention recently as it introduces unbalance in both load voltage and current. The existing work in this area is mainly focused on reducing the unbalance in the load voltage or sharing the negative sequence current equally. Furthermore, most of these methods are based on the knowledge of load voltages which requires a low bandwidth communication infrastructure to send the load information to the local DG controllers. However, the low bandwidth communication increases the overall cost and reduces the reliability of system. In this paper, a decentralized control approach for Islanded Micro-grid to share the load current unbalance factors equally among distributed generation (DG) units is proposed. It is shown in the paper that in an Islanded Microgrid, the presence of unbalance in the load current effects the DG output voltages causing them to become unbalanced as well. A droop-based control approach is developed that compensates the unbalance in DG output voltages and thus, achieving equal unbalance current factor sharing. A detailed Matlab/Simulink based study is presented to validate the performance of the proposed decentralized approach.