Negative-Sequence Control to Avoid Voltage Imbalance Propagation across an Inverter-Based Islanded Multi-Microgrid

The problem of voltage imbalance propagation in an inverter-based islanded multi-microgrid consists of avoiding the propagation of the voltage imbalance generated within one microgrid to the remaining microgrids in the multi-microgrid system. Without the participation of the main grid, no previous studies have yet addressed this issue in the challenging scenario of islanding mode. The contribution of this paper is a negative-sequence control that solves the voltage imbalance propagation problem using the relative gain array method. The novelty and significance lie in the extension of the aforementioned method to dynamic systems described with models with complex-valued variables. The performance achieved with the developed method includes the elimination of the negative-sequence voltages at all the point-of-common-coupling nodes with an adequate distribution of inverter negative-sequence currents. Experimental results are obtained from a laboratory setup to validate the performance of the proposed control.