Efficient Control Scheme for Compensating Voltage Unbalance and Harmonics in Islanded Microgrid Inverters

The paper proposes a novel droop-control approach to fully cancel out unbalanced and harmonic voltages in AC-islanded microgrids, focusing on perfecting power distribution in distributed generators (DG). It designs a control system for DG units to immediately correct voltage imbalances and harmonics, ensuring even compensatory load distribution for real and reactive power issues and harmonic disturbances. The scheme includes droop controllers, voltage and current control units, an imbalance, and a harmonics correction loop. In addition, the secondary controller is used to maintain voltage and frequency, thus ensuring high-quality voltage at the point of common coupling (PCC). The MATLAB simulation results demonstrate that the scheme effectively manages voltage imbalances and harmonics and fully cancels these issues.