Negative-sequence admittance control scheme for distributed compensation of grid voltage unbalance

This paper proposes to ease the responsibility of the grid for voltage unbalance correction with distributed generation systems. Specifically, the functionality to decrease the negative-sequence voltage at the grid connection point is added to the control of distributed generation inverters. By controlling the negative-sequence admittance of DG inverters, co-operative compensation for unbalanced grids is achieved. Detailed control scheme and small-signal modeling are presented, together with simulation results for the verification.